Category Archives: Nuclear pioneers

First Criticality at Shippingport


Shippingport Atomic Power Station, America's first full scale nuclear power plant, is in the foreground of this photo; the oblong red building is the above-ground portion of this mostly below-ground plant.  The newer Beaver Valley nuclear plants are behind.

Shippingport Atomic Power Station, America’s first full scale nuclear power plant, is in the foreground of this photo; the oblong red building is the above-ground portion of this mostly below-ground plant. The newer Beaver Valley nuclear plants are behind.

by Herb Feinroth

The formation of the American Nuclear Society in December 1954 occurred shortly after the initial groundbreaking for the Shippingport Atomic Power Station in September 1954. The project was authorized by President Eisenhower in July 1953 to demonstrate to the world the benefits of the peaceful atom, and the project was executed in such a way as to assure that the new evolving technology would be available to all potential users in the United States and overseas.

The reactor portion of the Shippingport plant was designed and developed by the Bettis Atomic Power Laboratory under the direction, and in technical cooperation with, the Naval Reactors (NR) Group of the Atomic Energy Commission (AEC). Westinghouse Electric Company operated the Bettis Laboratory for the AEC. Duquesne Light Company financed the design and construction of the turbine generator portion of the plant, provided $5 million of the cost of the reactor plant, and was responsible for operation and maintenance of the entire plant. Duquesne reimbursed the AEC for the steam produced by the reactor. The Shippingport project thus represented a joint endeavor of the government, a private electric utility, and an industrial concern.

The Shippingport plant operated successfully for almost 30 years using three different reactor core and fuel technologies, producing a wealth of technology and data of great value to the emerging nuclear power industry. This brief article provides some details on the early history. with specific reference to some of the individuals who later played an important part in the nuclear industry and in ANS. It will be followed by other articles in the future covering such matters as (1) the new fuel and core designs developed for the higher power pressurized water reactor core 2, (2) the major structural deficiency that was discovered by accident during start up testing on PWR core 2 that almost led to a large loss of coolant accident, and led to the codification of new quality assurance requirements for all U.S. nuclear power plant systems and components, and (3) the development and operation of a 60-MWe thorium breeder reactor design for the third and final core at Shippingport.

Feinroth Shippingport Criticality

Shippingport Atomic Power Station Control Room at first criticality; photo courtesy Herb Feinroth

The above photograph was taken in the control room during the first criticality of Shippingport on December 2, 1957, where many of the individuals who had contributed to the design, development, and construction of the plant were present. Many of these people later became active leaders in ANS and in various aspects of nuclear power development in later decades. From left to right they are:

  • Milton Shaw, Naval Reactors, (seated) head of the plant systems group at NR and later director of Civilian Reactor Development Division at the AEC, where he focused on the sodium cooled breeder reactor development and commercialization, leading to successful operation of the Fast Flux Test Facility at the Hanford site, and initial steps toward a prototype fast breeder reactor at Clinch River Tennessee.
  • Harry Mandil, NR, head of reactor core and fuel design at NR, and later a founder of MPR Associates, a still active engineering firm supporting commercial nuclear powers and its continuing march forward in the 21st century.
  • Vince Lascara, NR, head of financial management at NR. He and people like Seymour Beckler and Mel Greer provided critical administrative and contract support at NR, with some (Greer for example) later transferring to provide staff support to key congressional committees lending critical behind-the-scenes support to such initiatives as the emerging Three Mile Island-2 recovery effort during the early years of the Reagan administration.
  • Jack Grigg, head of electrical and controls engineering at NR
  • Captain Barker, PWR project officer at NR
  • Parrish, vice president of Duquesne Light
  • Admiral Hyman Rickover, NR director
  • Lawton Geiger, manager, Pittsburgh Naval Reactors Office
  • Walter Lyman, vice president of Duquesne Light
  • Charlie Jones, chief engineer for Duquesne Light, later becoming one of the founders of the Nuclear Utility Services (NUS) company, one of the first nuclear plant consulting companies to help individual utilities choose and then construct and operate nuclear power plants.
  • John Simpson, manager, Bettis Laboratory, who later oversaw the development and operation of the Yankee Atomic Power plant, partly based on the experience at Shippingport. He also served as ANS president.
  • Commander “Salt Water” Willie Shor, NR field representative at Shippingport (currently living in a retirement home in Chevy Chase, DC)
  • Foreground, Dixie Duvall, Duquesne operator at the PWR control rod panel during initial approach to criticality. Dixie later joined Charlie Jones at NUS.

Not present during this initial criticality assembly, but having an outsized influence in the design and development of the seed and blanket cores used at Shippingport, was Alvin Radkowsky, chief physicist at NR. Alvin was the inventor of the seed and blanket concept used in all three Shippingport core concepts. This concept had the major advantage of minimizing the quantity of uranium (or thorium) needed to generate a defined quantity of nuclear electricity. The specific seed and blanket concepts demonstrated at Shippingport were not adopted by the nuclear industry, primarily for economic reasons (they depend on an active reprocessing industry that never developed, primarily for policy reasons). Instead, slightly enriched uranium fuel was chosen as the reference fuel. However, the nuclear and fuel concepts used at Shippingport did in fact find their way into subsequent light water reactor core designs, where U235 enrichment variations within the core and within individual fuel assemblies have significantly improved fuel efficiency and economics in today’s commercial LWRs. It should also be mentioned that the natural uranium blanket at Shippingport core 1 and 2 produced over half the lifetime energy, and for the first time used cylindrical zircaloy clad tubes to encase and protect the enclosed urainum fuel. After 60 years, this same zirconium based tubing pioneered at Shippingport is still used in todays’ LWR commercial reactors.

Control Room, Shippingport Atomic Power Station.  Westinghouse photo PRX-19630 from press release package on Shippingport in Will Davis collection.

Control Room, Shippingport Atomic Power Station. Westinghouse photo from press package on Shippingport in Will Davis collection.

Information on the Shippingport project was broadly disseminated to the nuclear industry as quickly as possible, by means of unclassified periodic and topical reports, and special interim technical reports. For example, details of the design and construction of the plant were presented at the International Atomic Energy Agency’s Geneva Conferences of 1955 and 1958 and in the book titled “Shippingport Pressurized Water Reactor” USAEC, Addison Wesley Publishing Co. Reading, Mass, 1958. For those interested, this book presents many of the key decisions and explanations of the design choices made for the reactor, primary system, containment, and balance of plant for the Shippingport project.

I personally arrived at the Naval Reactors Headquarters Office in DC in June 1957, six months before initial criticality. Upon being commissioned as a Navy ensign after graduating the University of Pennsylvania with an engineering degree, I was immediately assigned to review and comment/approve System Design Descriptions prepared by Bettis Laboratory engineers, including one for the on-site radioactive waste processing systems. I reported to Mark Forssell, in Milton Shaw’s plant systems group. Every letter of comment I wrote in draft was reviewed and commented on by Forssell and Shaw and, through the “pink” system, by Rickover. During my second year at NR, Don Couchman resigned as PWR project officer to leave the government to join Charlie Jones and others at NUS. I was appointed as PWR project officer reporting directly to Rickover. Initially, it was too much for me, and I was soon reassigned to work under Harry Mandil on PWR core 2 design. I was sent to the Shippingport site to observe and report on the first refueling of Seed 1, containing 32 highly enriched seed assemblies that were all replaced through refueling nozzles in the reactor vessel head. This began on November 2, 1959, and was completed, with return to full power on May 7, 1960, after a six month refueling operation (it was originally planned for 3 months). The refueling was performed by Duquesne Light maintenance personnel, with the assistance and collaboration from Bettis engineering personnel. There were many lessons learned during this first refueling operation, which were then reported to the public via a 250-page published report, WAPD-233 dated July, 1960, “The First Refueling of the Shippingport Atomic Power Station,” authored by T.D. Sutter Jr. of Bettis Laboratory and myself, with a forward by Admiral Rickover and Phillip Fleger, chairman of the board, Duquesne Light. Based on the lessons learned, the second refueling, in 1962, was completed about half the time as needed for the first refueling.

Shippingport Atomic Power Station under construction.  Westinghouse photo PR-18392 from Shippingport press package in Will Davis collection.

Shippingport Atomic Power Station under construction. Westinghouse photo PR-18392 from Shippingport press package in Will Davis collection.

In a must-read book titled “The Rickover Effect,” Ted Rockwell, one of Rickover’s senior engineers during the early days, summarized the many principles of engineering and management practiced by Rickover, in both the military and civilian projects, and how this had a lasting influence on the development of nuclear power. I can attest to the truth of this, having applied these principles throughout my career, first during my 14 years at NR, then during my days with AEC’s Reactor Development (FFTF) program, then with my contributions to the creation and initial implementation of the Department of Energy’s research program on Three Mile Island, and later in my career in the private sector developing an accident resistant fuel cladding with the capability to avoid completely the extensive fuel melting that occurred during the TMI-2 and Fukushima accidents. I will report on these developments in future blogs. For those who have questions and comments, which I welcome, you may contact me at


Herb FeinrothHerb Feinroth has had a distinguished career in nuclear energy. Herb worked for the AEC and Naval Reactors in the PWR Project office, from 1957-1974. He then became chief of the LMFBR facilities and director of the Reactor Technology Branch of the AEC from 1974-1984. Moving to private employment Herb became founder and president of Gamma Technologies consulting on a large and varied number of reactor technologies and projects. Herb also is founder of and a part owner in Ceramic Tubular Products LLC developing ceramic LWR fuel cladding. Now retired, Herb is writing down for posterity some of his many experiences in his decades in nuclear energy.

They Harnessed the ATOM – the first Navy prototype nuclear plant

By Will Davis

This past week, a remarkable article was printed in The Atlantic, which gave a full first-person account of the initial trial run of the STR Mark I nuclear prototype plant—the plant that paved the way for the success of the first nuclear powered vessel ever built, the submarine USS NAUTILUS.

At the time this prototype plant was built in the Idaho desert, at what was at that time called the National Reactor Testing Station (NRTS), there was actually a rather remarkable amount of information provided to the public about the plant—mostly in terms of photographs of the plant, if not anything in any real technical detail. Let’s take a look at some of the unclassified views released to the public and published in widely available resources, along with a few details of the plant’s history.


The photograph above was released January 20, 1954, and was both distributed by wire photo channels (you are seeing a scan of an original photo) and was published in a remarkable PR brochure entitled “They Harnessed the ATOM,” which you’ll see more of shortly. This is the STR Mark I prototype at NRTS Idaho Falls; “STR” stood for “Submarine Thermal Reactor,” the original designation for this plant that was later redesignated “S1W” for “Submarine, First design, Westinghouse.” At the time this plant was constructed, its designer, the Bettis Atomic Power Laboratory, was operated by Westinghouse for the U.S. government—hence the “W” designation. This of course is the plant whose operation was detailed in the article linked above.

STR Mark I door

Above, the front cover of the brochure “They Harnessed the ATOM” that shows a view into the open door of the STR Mark I prototype. The simulated submarine hull is clearly visible, as is the large tank of water at the opposite end that surrounded the reactor compartment and that was used for shielding.

STR Mark I inside

Inside “They Harnessed the ATOM” is this view (above) looking down onto the STR Mark I prototype power plant. The power plant of course developed a fair amount of waste heat, which had to be dissipated; in these early days, cooling towers were not used but rather spray ponds. The spray pond for STR Mark I is seen below, also from this brochure. The pond, it was said, held 2 million gallons of water and could cool 22 500 gallons of water per minute.

STR Mark I spray pond

Another publication of that time that featured photos and some scant details on the construction of this prototype was “Selected Articles on Nuclear Power,” which took several articles that had appeared in the Westinghouse employee magazine “The Westinghouse Engineer” and republished them essentially as an advertising brochure—although this one was much more pointed at industry than the previous one shown, which was pointed at the general public. Inside the front cover of “Selected Articles,” we find the illustration seen below.

STR Mark I Selected Articles

The upper part of the illustration is a view similar to, but not identical with, that seen earlier while the lower appears to show a student examining a model of the power plant. Naturally, the model is an exterior model only (not a cutaway) and shows no real details of the nature of the construction of the nuclear steam supply system, propulsion or control equipment, or actual plant arrangement.

Inside this publication is an interesting and concise timeline of use to historians:

Timetable of Submarine Thermal Reactor Project

• April 1948 – Formal project established at Argonne National Laboratory

• June 1948 – Original Navy-Westinghouse contract

• December 1948 – Original AEC–Westinghouse contract

• March 1950 – Occupancy of new facilities at Bettis Site

• August 1950 – Commencement of STR Mark I construction, National Reactor Testing Station, Idaho

• August 1951 – Award of NAUTILUS construction contract to Electric Boat Division, General Dynamics Corporation

• June 1952 – Keel plate laying of USS NAUTILUS (SSN-571)

• March 1953 – First critical operation of STR Mark I prototype plant

• January 1954 – Launching of USS NAUTILUS

• September 1954 – Commissioning of USS NAUTILUS

As can be seen from the timetable above, time was of the essence for the prototype power plant, as the keel for the operational submarine (which would house the plant designated STR Mark II) had already been laid down less than a year before the first startup of the prototype reactor. As is so vividly described in the Atlantic account, the actual prototype’s design was already well up the learning curve and the performance so satisfactory that NAUTILUS went to sea confident in its ability to perform. Of course, Admiral Rickover’s choice to build the first prototype plant as a simulated, land-locked submarine section in order to prove out not just concept but physical construction was exactly correct. A similar design process—use of an actual power plant design that could be duplicated perfectly for a production submarine—was employed for the Submarine Intermediate Reactor Mark I, built thousands of miles away to test principles for what would become USS SEAWOLF at the same time.

From the brochure "The Seawolf Story," Knolls Atomic Power Laboratory.  "In the early morning of March 20, 1954, the prototype power plant of the Seawolf was 'launched' into its location in the 225 ft. diameter steel sphere located at the West Milton Site of the Knolls Atomic Power Laboratory."

From the brochure “The Seawolf Story,” Knolls Atomic Power Laboratory. “In the early morning of March 20, 1954, the prototype power plant of the Seawolf was ‘launched’ into its location in the 225 ft. diameter steel sphere located at the West Milton Site of the Knolls Atomic Power Laboratory.”

What happened to STR Mark I, later known as S1W? The plant operated for decades, as an integral part of Admiral Rickover’s system that insisted that Navy nuclear propulsion personnel obtain qualification on a land-based plant before being assigned to a nuclear powered ship or submarine. The plant finally shut down for the last time in October 1989.

It may be difficult to imagine today that photos such as we have seen were released, but several of these have actually circulated fairly widely. In fact, it would certainly appear that India took notice of the design of these early submarine prototype plants; look at the links below, and note the overall, external design of the prototype plant for the first Indian nuclear submarines.

“INS Arihant reactor to be made critical next week” (May 2013)

INS Arihant reactor goes critical (August 2013)

In a First for India, Nuclear Sub’s Reactor Activated (August 2013)

Were it not for the fact that the above-linked articles’ photos are color, one might assume the view was of the STR Mark I prototype in 1954 and not of an Indian nuclear sub prototype in 2013.

For more information:

“Nuclear Navy celebrates end of an era at Idaho Falls.” Article at INL.GOV website about the shutdown of the last operating Navy nuclear prototype at the former NRTS Naval Reactors Facility.

Photos and brochures used in this article are in Will Davis’s library.


SavannahWillinControlRoomWill Davis is the Communications Director for the N/S Savannah Association, Inc. where he also serves as historian, newsletter editor and member of the board of directors. Davis has recently been engaged by the Global America Business Institute as a consultant. He is also a consultant to, and writer for, the American Nuclear Society; an active ANS member, he is serving on the ANS Communications Committee 2013–2016. In addition, he is a contributing author for Fuel Cycle Week, and writes his own popular blog Atomic Power Review. Davis is a former US Navy reactor operator, qualified on S8G and S5W plants. Davis is temporarily managing all social media for the American Nuclear Society.

Caught in the Leadership Paradox: Insight from Admiral Rickover

By Paul E. Cantonwine

Recent scandals at the U.S. Department of Veterans Affairs (VA) and General Motors (GM) have struck a chord with the media and the American people because they represent the worst in bureaucracies—where the lives of individuals seem to get lost in the bureaucratic woods. In the case of the VA, lying about wait times blocked pathways for care and potentially resulted in the early deaths of some veterans. In the case of GM, the bureaucracy put horse blinders on its employees so that they couldn’t recognize the safety significance of ignition switch problems linked to at least 13 deaths.

While it is the nature of organizations to have leaders responsible for directing or dictating from the top down, it is also true that accomplishment only occurs through individual action. Thus, the Leadership Paradox is that while a leader is responsible for the actions of the organization, the actions occur from the individual decisions of those who follow. Organizational scandals, then, are usually a result of a leader’s failure in responding to the Leadership Paradox.

The Leadership Paradox and Admiral Rickover

Hyman_Rickover_1955 155x200To provide some insight into the current problems at GM and the VA, consider the thought of the greatest military engineer and government bureaucrat in U.S. history: Admiral Hyman George Rickover (1900–1986). Admiral Rickover served more than 60 years of active military duty in the U.S. Navy—longer than anyone in our history. He is known as the Father of the Nuclear Navy, and for 34 years he led the organization that developed the pressurized water reactor technology that propels our nuclear Navy and provides about 14 percent of U.S. electricity (boiling water reactors provide an additional 6 percent, approximately).

Admiral Rickover’s approach to the never-ending challenge of the Leadership Paradox was to create an organization made up of professionals. As a leader he then only had to “manage” the standards used in decision-making by the individuals rather than each individual decision. Rickover shaped the culture of his organization, the Naval Nuclear Propulsion Program, by fostering excellence and professionalism.

Professionalism and responsibility

Professionalism occurs when individuals act in the best interest of those being served according to objective values and ethical norms, even when an action is perceived to not be in the best interest of the individual or their organization. That is, there are times when professionals must sacrifice their own interest (or that of their organization) to meet the objective values and ethical norms of the profession. Professionals, in this sense, are serving something greater than the bureaucratic organization that employs them.

If Admiral Rickover had a mantra to shape a professional culture, it would have been, “I am personally responsible.” As a leader, Rickover felt personally responsible for every aspect of his organization, and he instilled this value in everyone working in the organization. In 1961 during Congressional testimony he put it this way: “Responsibility is a unique concept; it may only reside and inhere in a single individual. You may share it with others, but your portion is not diminished. You may delegate it, but it is still with you. You may disclaim it, but you cannot divest yourself of it. Even if you do not recognize it or admit its presence, you cannot escape it. If responsibility is rightfully yours, no evasion, ignorance, or passing the blame can shift the burden to someone else. Unless you can point your finger at the man who is responsible when something goes wrong, then you have never had anyone really responsible.”

rickover2 310x201For everyone in the organization to feel personally responsible, a leader has to act personally responsible. Actions really do speak louder than words.  For Rickover, this meant sometimes getting into the details, because he recognized the truism that the devil is always in the details. His mechanism for keeping an eye on the details was through communications from the bottom up that were called “the pinks.” The pinks referred to the pink carbon copy version of letters that he required people, throughout his organization, to write weekly about problems in their areas of responsibility. These pinks provided Rickover a pulse of his organization’s health and were a way to bypass bureaucratic structure to communicate problems. If he thought a problem was significant, he would hold those responsible accountable on Monday.

Personalizing safety and facing the facts

Other ways Rickover fostered professionalism was to personalize safety and to promote facing the facts to avoid “hoping for the best” when evidence suggested the contrary was a possibility. To personalize safety, Rickover was well known for ending technical debates with anecdotes to support the more conservative decision. One famous story is from a meeting discussing the technical merits of sealing the reactor head to the pressure vessel with a gasket/bolt design, versus using a more conservative design that used both a gasket/bolt and a weld. When the team initially recommended the gasket/bolt design, Rickover made his point about conservatism in design by asking the technical team to consider the question: “What would you do if your son was a sailor on this ship?” Thinking about safety in these personal terms highlighted the interests of those being served (the sailors) over the interests of the organization (to minimize cost), and led the team to change their recommendation to the more conservative design.

To help his organization face the facts, Rickover encouraged open debates that were void of any sense of organizational status. He once put it this way: “Free discussion requires an atmosphere unembarrassed by any suggestion of authority or even respect. If a subordinate always agrees with his superior he is a useless part of the organization.”

In our highly civilized society, bureaucratic organizations are absolutely critical to the delivery of goods and services that make life possible. GM and the VA both provide an important service to the United States. But when the purpose of an organization becomes the self-interest of the organization, professionalism within the organization is compromised and decisions are no longer made in the best interest of those being served. Like Admiral Rickover before, the leaders of bureaucracies like GM and the VA must recognize that the best response to the Leadership Paradox is to promote true professionalism among the individuals working within their organizations. For good or for bad, it is individuals who make things happen.


cantonwine 110x154Paul E. Cantonwine is a practicing engineer and editor/compiler of The Never-Ending Challenge of Engineering: Admiral H.G. Rickover in His Own Words (ANS 2014). The book is highly recommended for everyone interested in engineering, effective leadership, and nuclear history and is available at the ANS Store.

Excitement about U-235 as coal competitor–circa 1939 & 1940

By Rod Adams

Conventional wisdom says that the general public was introduced to atomic energy by the explosions at Hiroshima and Nagasaki. According to that version of history, the introduction instilled a strong dose of fear that remains to be overcome.

Some observers who like to paint nuclear energy in a negative light have stated that the program to build nuclear power plants grew from a desire to find a civilian use for a technology developed solely from a desire to create weapons.

Accounts of the early days after the discovery of the fission chain reaction, however, show that physicists who were engaged in the study of the atomic nucleus and the use of neutrons to produce artificial radioactivity were keenly interested in producing useful power. They were motivated not only by a scientific desire to gain a better understanding of the fundamental structure of the atom, but also by a desire to provide the world with a new power source to compete with coal and oil. The stories also show, however, that writers who covered the scientific advances often asked questions indicating that they envisioned weapons or doomsday scenarios.

As a digital subscriber to the New York Times, widely referred to as “the paper of record,” I recently performed an archive search using the term “chain reaction” and a date range starting on 01/01/1938 and ending on 01/01/1944. The results of that search confirmed my suspicion that the atomic pioneers were primarily interested in fuel production—though, when pressed, they acknowledged the possibility of explosive energy release.

The search returned 10 articles published between February 1939 and March 1941, with no additional results after that date. Even before the Manhattan Project started, scientists apparently stopped discussing chain reactions in public. Some of the 10 pieces discovered were short inclusions in a regular column titled Science in the News. Here are sample quotes from those pieces showing atomic energy optimism:

Frederic Joliot, co-winner of the 1935 Nobel Prize for chemistry, is trying to find a way to make a $2 pound of uranium give up as much heat or power as is now obtained from burning $10,000 worth of coal.

Uranium atoms will do the firecracker trick under certain restrictions. If scientists can find practical means to set up uranium chain reactions, then it is estimated that it may be possible to obtain from one pound of uranium as much energy as is at present obtained from 1,250 tons of coal.

(Associated Press, Uranium as a Coal Substitute, New York Times, June 19, 1939)

Roberts and Kuper agree that “a chain reaction cannot be ruled out definitely for either slow or fast neutrons,” but decide that “there is no evidence of any kind that such a reaction will really occur.” They throw more cold water over dreamers by showing that uranium has not very great economic advantage over coal even if it could be used. “Uranium oxide (96 per cent pure) sells for approximately $2 a pound, which is roughly equal to the price of a ton of coal at the mine. In terms of energy dollar—uranium is cheaper by a factor of 8.5.”

Though this may look good to a financier, Roberts and Kuper point out that as the demand for uranium increases so does the price. In the end further refinement would be necessary and the limited supply of high-grade ore would soon be exhausted. “If uranium were to replace 500,000,000 tons of coal used annually in this country,” argue these skeptics, “the amount of uranium consumed would increase 15,000 per cent.”

(Kaempffert, Waldemar, Atomic Energy From Uranium, The New York Times, October 22, 1939)

There was also a lengthy front-page article titled Vast Power Source In Atomic Energy Opened by Science published on May 5, 1940. That article documented a high level of public interest in the new discoveries and described an optimistic attitude among both academic and industrial researchers. That article provided technical information that I had previously thought was a closely-guarded, Manhattan Project secret.

A natural substance found abundantly in many parts of the earth, now separated for the first time in pure form, has been found in pioneer experiments at the Physics Department of Columbia University to be capable of yielding such energy that one pound of it is equal in power output to 5,000,000 pounds of coal or 3,000,000 pounds of gasoline, it became known yesterday.

The discovery was announced in the current issue of The Physical Review, official publication of American physicists and one of the leading scientific journals of its kind in the world.

Professor John R. Dunning, Columbia physicist, who headed the scientific team whose research led to the experimental proof of the vast power in the newly isolated substance, told a colleague, it was learned, that improvement in the methods of extraction of the substance was the only step that remained to be solved for its introduction as a new source of power. Other leading physicists agreed with him.

A chunk of five to ten pounds of the new substance, a close relative of uranium and known as U-235, would drive an ocean liner or an ocean-going submarine for an indefinite period around the oceans of the world without refueling, it was said. For such a chunk would possess the power-output of 25,000,000 to 50,000,000 pounds of coal, or 15,000,000 to 30,000,000 pounds of gasoline.

Uranium ore, in which the U-235 also is present, is found in the Belgian Congo, Canada, Colorado, England and Germany, in relatively large amounts. It is 1,000,000 times more abundant than radium, with which it is associated in pitchblende ores.

(Laurence, William L., Vast Power Source in Atomic Energy Opened by Science, New York Times, May 7, 1940, P. 1)

The article continues on page 51 to provide a number of details that show a rather remarkable pace of advancement in understanding, considering the fact that only 18 months had passed since the initial recognition that neutrons could cause uranium to split into two pieces.

Not only is the energy-liberating process automatic and self-regenerating, it was explained, but it also is self-regulating. The energy liberated from the atoms heats up the water so that it turns into steam. When all the water supplied has been turned into steam, there is nothing left to slow down the fast-traveling neutrons, and fast neutrons just go through the uranium without breaking up its atoms and releasing its energy. This brings the whole process to a stop until more cool water is supplied.

As one leading physicist explained it, “the colder the water the better the reaction. The reaction is self-limiting because heat (generated by the split atoms) speeds up the neutrons and the faster the neutrons the less the reaction.”

“The faster you feed in the cold water,” the scientist added, “the faster the water will come out hot on the other side, because more neutrons will be slowed down and thus more atoms split and more energy is liberated. Thus the process is admirably suited for power generation.”

Because of the nature of the neutrons, even the slow-traveling ones, it was explained further, it is necessary to have a mass of at least five pounds, and possibly as high as twenty, to make the process work on a practical scale. In a smaller amount even low energy neutrons would escape into the open without splitting the initial “trigger-atom” that sets off the process. To start the process it is necessary for the neutron to remain inside the mass, so that it would enter the nucleus of an atom to start the splitting process.

One of the scientists explained the process of the energy-liberation from U-235 by comparing it to the burning of coal. Whereas coal uses oxygen to liberate its energy, he explained, the U-235 uses slow neutrons for the same purpose. The process of combustion in the case of the U-235, he added, is, atom for atom, 100,000,000 times as effective as is the case in the combustion of coal. However, as the atomic weight of the uranium is 235, compared with 16 for the oxygen and 12 for the carbon, there are fewer uranium atoms for a given weight than there are oxygen and carbon atoms. This reduces the energy relations of the U-235, compared with coal, to a ratio of 5,000,000 to 1.

There are several new methods being considered for increasing the yield of the new substance to large-scale amounts. But as to this, scientists greet the questioner with a profound silence.

(Laurence, William L., Vast Power Source in Atomic Energy Opened by Science, New York Times, May 7, 1940, P. 51)

On May 12, 1940, the New York Times Science in the News column written by Waldemar Kaempffert, its longtime science editor, included a section titled Atomic Power—Not Yet. That piece, published just one week later, had a completely different tone and expressed a sense of impossibility for the near term development of the technology:

Last week’s hullabaloo about atomic power naturally prompted this department to look into the possibility of dispensing with coal and oil. It is our sad duty to report that the prospect is not bright. If there is any thought of Germany’s making use of the work done at the universities of Columbia and Minnesota, and the General Electric Company’s laboratories, it must be dismissed. Yet physicists never were so near to doing away with coal and oil as sources of energy and turning to ordinary matter as they are now.

It takes about 100 hours to make one microgram of uranium-235 or 1,000,000 hours or over a century to make one gram. About 100 grams (a little more than three ounces) would be required to make serious experiments in generating energy on a small scale. At least five pounds would be required to drive an ocean liner. It may be that a more rapid means of producing U-235 than that now available may be evolved. But the prospect of using U-235 in the present war is zero.

As matters stand we are not likely to spend centuries in accumulating the necessary uranium-235. By the time we had it so much would be known about the structure of matter that easier means of developing power from the atom would have been discovered. Accordingly, this department has decided to place the usual order for coal to be shot into the cellar, and preparing itself for the usual task of shoveling expensive black lumps into a hungry furnace.

(Kaempffert, Waldemar, Science in the News: Atomic Power—Not Yet, The New York Times, May 12, 1940)

I was immensely curious about the abrupt turnaround in such a short period of time from the same publication. The mystery was solved when I found out that Germany’s push west into the Low Countries and France started on May 10, 1940. Based on the expressed concerns that Germany might be actively pursuing the technology, it’s possible that the discouragement was motivated by something other than telling the complete truth.

It seems quite apparent that if the fission chain reaction had been discovered just a few years earlier or later, nuclear energy history would not have been defined by explosives—but by steady, controllable, non-coal power produced in simple piles, designed to turn heat into useful power in ways similar to those used to turn coal combustion heat into useful power.

U-235 200x200




Rod Adams is a nuclear advocate with extensive small nuclear plant operating experience. Adams is a former engineer officer, USS Von Steuben. He is the host and producer of The Atomic Show Podcast. Adams has been an ANS member since 2005. He writes about nuclear technology at his own blog, Atomic Insights.

Anniversary – 80 years ago, Leo Szilard envisioned neutron chain reaction

By Rod Adams

nuclearpioneers_final-200-x-75On September 12, 1933, slightly more than 80 years ago, Leo Szilard was the first person to imagine a reasonable mechanism for releasing the vast quantities of energy known to be stored in atomic nuclei. As it turned out, his concept worked the first time it was tried on December 2, 1942.



Szilard’s inspired thought occurred on a dreary fall afternoon in London at the intersection of Russell Square and Southampton Row. Earlier that day, Szilard had read an article in The Times that described a talk given by Ernest Rutherford about breaking down atomic nuclei using accelerated protons. There was a brief mention in the article about the possibility of using recently discovered neutrons to transmute nuclei, but the article gave the impression that Rutherford thought that fast-moving protons were a better option because they could be accelerated with reasonably achievable voltages due to their positive charges. (Note: James Chadwick announced his discovery of neutrons on February 27, 1932, in a letter to the British science journal Nature.)

According to the newspaper account, Rutherford dismissed any possibility that the process of bombarding atomic nuclei would result in a net energy output, even if each individual reaction produced densely concentrated energy. The total amount of energy required to get the protons up to the required velocity would be substantially more than the amount of energy released when the nucleus broke apart. According to Rutherford, anyone who believed that nuclear reactions would be a potent source of useful energy was talking “moonshine”.

Not only did Szilard have a natural tendency to regard such assertions as a challenge, but Szilard had many motivations for thinking about ways to liberate atomic energy. He had been engaged for some time in thoughts about releasing the energy stored in atomic nuclei as a means of producing the power required to travel into space. Those thoughts had been inspired by conversations with Otto Mandl about ways to save mankind from itself by heroically succeeding in developing the means to leave our home planet.

He had read a novel by H. G. Wells titled The World Set Free that described a world in which atomic energy had been liberated in the service of mankind, but Szilard claimed that he considered that story as mere fiction and did not credit it as any part of his inspiration. Coincidentally, there is a line in Wells’s book, which was published in 1914, that predicted that someone would solve the puzzle of releasing atomic energy as early as 1933 with a combination of “induction, intuition and luck”.

The problem which was already being mooted by such scientific men as Ramsay, Rutherford, and Soddy, in the very beginning of the twentieth century, the problem of inducing radio-activity in the heavier elements and so tapping the internal energy of atoms, was solved by a wonderful combination of induction, intuition, and luck by Holsten so soon as the year 1933.

Finally, Szilard was a recently emigrated refugee from Nazi Germany. He was a native Hungarian, but had been living and working in Germany since the end of the first World War. He had been thinking deeply about the implications of the Nazis developing weaponry based on some of the nuclear physics concepts that he and his colleagues had just begun to recognize experimentally.

As Szilard later recounted the story, when he reached the intersection of Southampton Row and Russell Square a red light caused him to pause, giving time for his fertile imagination to engage. Then the idea struck him: If a neutron entered an atomic nuclei, and the subsequent reaction released two neutrons, it would be possible to produce a chain reaction. Since neutrons have no charge, each of those newly released neutrons would be able to travel freely through matter until they struck another nucleus.

If there was a sufficiently large mass, with a sufficient purity of the material whose nuclei released two neutrons every time it was hit with one neutron, Szilard realized that there was a distinct potential for industrial-scale power sources. He recognized immediately that there was also a possibility that the reactions could be produced in a manner that was rapid enough to cause an explosion of great force before the material was scattered and the reaction stopped.

At the time of his creative thought, Szilard had no idea what kind of experiments would be needed to find the right material or who would be willing to fund the experiments. He did not have a job, did not have a laboratory, and did not have much experience in developing experiments. All he had was enough money saved up from previous work to support himself for about a year while living in a London hotel, taking long baths, keeping up with published papers and eating out at restaurants. He spent the next few months after September 1933 thinking, reading, and occasionally writing down his thoughts. This process was similar to that which Szilard had followed when he earned his PhD less than a year after starting his focused study of physics.

On March 12, 1934, Szilard applied for a patent that was eventually merged with several other patents into Improvements in or relating to the Transmutation of Chemical Elements. The key improvement that Szilard proposed over the work done by people like Rutherford and the Joliot-Curies was using neutrons and chain reactions instead of protons or alpha particles.

It is unfortunate that Szilard’s contribution to the improvement of the human condition has been too often overlooked.

Note: Much of the above is adapted and summarized from Richard Rhodes, “The Making of the Atomic Bomb

neutron chain reaction c 267x200




Rod Adams is a nuclear advocate with extensive small nuclear plant operating experience. Adams is a former engineer officer, USS Von Steuben. He is the host and producer of The Atomic Show Podcast. Adams has been an ANS member since 2005. He writes about nuclear technology at his own blog, Atomic Insights.

The Hook-Ons

by Will Davis

This week’s announcement by Babcock & Wilcox that it had signed the long-awaited funding agreement with the Department of Energy has been taken by advocates of small modular reactors (SMRs) as just the latest good news on the inevitable path to construction of at least one prototype nuclear plant using SMR reactor technology in the United States. It is widely hoped that this is the harbinger of the rapid spread of the market for SMR plants.

The chief advantage of SMRs other than cost reduction over large 1000–1600 MWe nuclear plants is that they can be located practically anywhere (assuming proper geologic characteristics and supply of cooling), since a primary design feature is that the major components of the reactor plant itself are to be easy to ship (i.e., by large truck over existing highways). This design asset potentially opens up locations previously considered unworkable (for large plants, with their enormous reactor vessels and other equipment that needs to be shipped intact to site) and may, in some cases, allow siting of SMR-driven power plants nearer to populated areas in order to take advantage of benefits to the grid (by siting source nearer to use) and even, if some have their way, to supply steam for process use to facilities already in existence or built new.

These concepts—siting closer to communities than with large commercial plants, and supply of steam for existing facilities—are, in fact, not new. In the early days of nuclear energy, a number of nuclear plants were built in order to supply steam to facilities already in use. In the cases of these early reactors, the facilities were all commercial electric power stations; the group of reactors came very loosely to be known as “hook-on” reactors. The concept of expanding the use of nuclear energy in such a way was actively pushed by the Atomic Energy Commission; three of the four plants we’re about to explore were (at least partly) funded under the AEC Power Demonstration Reactor Program.


Elk River  (Minnesota)

The Elk River Reactor, widely heralded as “Rural America’s First Atomic Power Plant,” was originally contracted to ACF Industries in 1959 for construction behind the Rural Co-Operative Power Association’s Elk River coal-fired plant (seen at far left in the above post card photo.) The reactor plant was a novel natural circulation, indirect cycle boiling water reactor that, while not fitting the modern definition of “small, modular” of today’s SMRs, did have a reactor vessel small enough to be shipped to the site on the smallest standard railroad flat car of the time (said cars measured 40 feet in length overall.) The 58-MWt reactor produced saturated steam at 922 psig and 536 °F, but the existing turbines in the plant required superheated steam. Construction of a coal-fired superheater interposed between the reactor plant and the power plant adjusted the steam conditions to 612 psig but 825 °F; of the total 22 MWe of generating capacity credited this installation, 7 MW was provided by the superheater.

The plant suffered teething pains that, today, seem not too surprising given the facts that the original reactor vendor was small, and that it was actually bought out by Allis-Chalmers while construction of the Elk River Reactor was in progress. Fuel element defects and reactor pressure vessel cladding cracks contributed (among other things) to delays in the start up of the plant, which did not achieve commercial operation until mid-1965, but after which operated with a very fair degree of reliability.

Eventually, further leakage from welds in the primary coolant system caused investigation into the overall condition of all welds in that system in 1968, and the determination was made that major rework would be required to fix the problems—a problem that looked all the worse given that Allis-Chalmers had decided to exit the nuclear power business in 1966. After considerable debate about what to do with the reactor plant (which was still technically AEC owned), the decision was made in March 1971 to decommission the reactor plant and completely remove it from the site. Below, a March 1971 UPI telephoto showing the plant as it looked at the time that the decommissioning decision was made.


Piqua  (Ohio)

The Piqua Nuclear Power Facility (PNPF) was built in the early 1960s in the town of Piqua, Ohio, as a part of the second round of the AEC Power Demonstration Reactor Program. The reactor was unique among the world’s commercial power reactors in being an organic-cooled and -moderated design. A commercial terphenyl preparation (marketed widely as Santowax-OMP by Monsanto) was used for this plant that, because of the low pressure of the primary, originally was designed without any containment whatsoever. The Advisory Committee on Reactor Safeguards, however, ordered that a containment be built. The reactor plant was built just across and down the river from the original Piqua municipal generating station, and supplied steam to it at 450 psia and 550 ºF through underground piping and a new bridge structure over the river. The reactor was rated 46 MWt, and the electric generating capacity credited to it was 11.4 MWe.


The Piqua Nuclear Power Facility is seen on the right, which is the east side of the Miami River; the municipal power plant is on the West side, just upstream.

PNPF began operation in 1963 and operated with occasional problems largely due to coolant breakdown until 1968 when a serious blockage occurred. The decision was made by the city of Piqua not to take over ownership of the plant, and it entered procedures to shut down and decommission immediately. The disposal method (after defueling) was selected by the AEC was SAFSTOR, in which the plant is left in place to allow decay of radioactivity at the same time guaranteeing no impact to the surroundings. The containment and support buildings are still clearly visible in Piqua to this day.

CVTR (South Carolina)

The Carolinas-Virginia Tube Reactor was built adjacent to an existing coal-fired plant (and hydroelectric dam facility) at Parr, South Carolina, under the third round of the AEC Power Demonstration Reactor Program in order to test out the pressure tube reactor concept. This plant was widely reported and heralded in the early 1960s as “The Southeast’s First Atomic Power Plant.” Westinghouse provided the 65-MWt pressurized (tube type) heavy water cooled and moderated reactor; Stone and Webster acted as architect-engineer. The plant (like Elk River, but unlike Piqua) required external superheating; of the rated electrical 17 MWe, 1.7 MWe was contributed by the superheater. The reactor and superheater provided steam at 415 psia and 725 ºF to the old powerhouse near by.

Carolinas-Virginia Nuclear Power Associates owned this plant; this organization was comprised of Duke Power Company, Carolina Power & Light Company, South Carolina Electric & Gas Company, and Virginia Electric and Power Company (the latter often referred to as VEPCO).

Below, a spectacular original pencil rendering of the CVTR plant facility, including the powerhouse and environs, from my collection. The drawing’s labeling is clear when blown up; it is signed “E.E. Grant 1960.” (Click to enlarge.)


The CVTR started up in 1962, and like the other plants we’ve shown so far, had a very short operating life (five years,) shutting down for good in 1967. The reactor was in SAFSTOR condition for many years, but in much more recent times has completely been decommissioned and removed, and today there is very little sign that the plant was ever there. Of course, the site of the former Parr generating station and the adjacent CVTR installation is quite near the Virgil C. Summer Nuclear Generating Station, which today is seeing construction of two Westinghouse AP1000 plants—so that the area of “The Southeast’s First Atomic Power Plant” is again at the cutting edge of nuclear energy’s advance.

Saxton (Pennsylvania)

A fourth early reactor actually is one that contributed the least to commercial power generation of those we’re visiting here, and is also that which is most commonly found in the literature to have the appellation “hook on”.

The Saxton Generating Station was selected to host construction of a nuclear reactor whose primary purpose was developmental testing of fuels, and which was to be officially known as the Saxton Experimental Nuclear Reactor. Owner of the reactor was Saxton Nuclear Experimental Corporation, a non-profit entity formed by Pennsylvania Electric Company, Metropolitan Edison Company, New Jersey Power and Light Company, and Jersey Central Power and Light Company—all of which were subsidiary companies of GPU or the General Public Utilities System. The diminutive pressurized water reactor, rated originally 20 MWt, had only a single loop (and thus one coolant pump and one steam generator) and provided steam to the center of Saxton Generating Station’s three turbine generators. While the containment was clearly visible beside the coal-fired plant, for safety reasons (considering the surrounding community) the reactor vessel was actually located some 15 feet below grade.

According to the February 1959 Atomic Industrial Forum “Forum Memo” magazine, in which the contract for the reactor was revealed, GPU had actually announced that it was considering a “hook on” at Saxton back in 1957 after terminating an investigation into building a pressurized water reactor in the Philippines (another GPU subsidiary was Manila Electric Company.) At that time, the rating of the Saxton plant was given as a very modest 5000 ekw (which we would now write as 5 MWe), although in point of fact later testing was planned at far above the original rated figures; the turbine to which the reactor piped steam was actually rated nominally at 13 MWe, allowing considerable room for uprating for temporary testing.

In the March 1959 issue of the Forum Memo, Elmer L. Lindseth, president of Cleveland Electric Illuminating Company and chairman of the Edison Electric Institute’s Committee on Atomic Power, was quoted as saying that Westinghouse would build the Saxton reactor plant at a fixed price of $6.25 million. GPU would under the same agreement provide the site, use of the No. 2 turbine, and bear operating and maintenance costs—all of which figured to roughly $2 million. Westinghouse also had exclusive fuel production rights for five years.

With Gilbert Associates serving as architect-engineer, construction of this unique “hook on” began in February 1960 (with AEC Construction Permit CPPR-6.) A provisional operating license was issued in November 1961, and the reactor fueled in early April 1962, with criticality achieved at 1:40 AM on April 13, 1962.  (Below, a view of the Saxton Experimental Nuclear Reactor next to the Saxton Generating Station.)


As has been mentioned, this plant was not entirely intended as a commercial power reactor; rather, its focus was the development of technology for further, future reactors. Quoting GPU in a Saxton advertising brochure of the day, “Investor owned utilities, dedicated to serving consumers in all walks of life, have invested $8,500,000 of private funds in the nation’s newest operational nuclear reactor so that ‘unknowns’ can be converted into ‘knowns’ and personnel can acquire valuable operating experience for use in designing and manning larger reactors in the future.”

Among other concepts, Saxton experimented with chemical control of reactivity (“chemical shim,” or use of boron in the primary coolant to control reactivity instead of just control rods) and also conducted extended operations with plutonium fuel (MOX or “Mixed OXide” fuel, containing both natural uranium dioxide and plutonium dioxide) beginning in the mid-late 1960s.

As a result of the nature of the program, it appears in retrospect that the plant spent as much of its life operating as not. From the 1964 AEC Report to Congress: “The Saxton Nuclear Experimental Corp.’s pressurized light water reactor near Altoona, Pa., was returned to power operation on January 30, after having been shut down since the previous November for modifications. The reactor, while producing small amounts of electric power, is primarily used for experiments to determine ways in which more heat energy can be obtained from specified amounts of fuel.” It would thus in hindsight be appropriate to consider that the waste heat from the Saxton reactor was not entirely wasted, if we simply view it as a byproduct of advanced fuels testing, by way of connecting the plant to the Saxton Generating Station.

Saxton was finally shut down in May 1972, and after a prolonged period of decommissioning, there is nothing visible at the site to hint that a power station of any sort once existed there. The entire power plant and reactor facility has been removed down to several feet below grade, and the area has been backfilled.

In closing, it’s interesting to consider the notion that today’s concept of placing lower output, transportable nuclear reactors at a now-expanded range of possible locations actually had a roughly correlative precedent early in the construction of nuclear power stations in this country. In the siting of plants nearer to populated areas, and in the use of small plants on grids that could not handle extremely large single generating sources, the early experience was perhaps a herald of things to come, even if it did take another roughly half century and the development of truly integrated, truck transportable, and inherently safe SMRs in order to realize the dream held up for these early small plants. The wide design disparity and newness of the technology associated with these early plants seemed to hint at troubles, which surely were encountered, but today nuclear technology is a half century further down the road so that the question of operability is quite far removed from consideration. As it turns out, everything old is new again—but today, with far better promise of success.

(All illustrations – Will Davis collection. Please do not reproduce without permission.)

(“Atomic Industrial Forum” was a trade group formed in 1953; it is a lineal predecessor of today’s Nuclear Energy Institute.)


WillDavisNewBioPicWill Davis is a consultant to, and writer for, the American Nuclear Society. In addition to this, he is a contributing author for Fuel Cycle Week, and also writes his own blog Atomic Power Review. Davis is a former US Navy Reactor Operator, qualified on S8G and S5W plants.

Ted Rockwell, Atomic Pioneer and Tireless Campaigner for Facts

By Rod Adams

letters from lynchburg 190x160On Sunday, March 31, 2013, just a few months before his 91st birthday, Ted Rockwell passed away quietly in his sleep. His passing has stimulated a profound sense of loss among nuclear energy professionals.

For many of us, Ted was a visible and active reminder that our technology, as established as it might seem to some people, is younger than the duration of a single human life. Ted may not have been around when people first realized that uranium nuclei had the potential to provide a reliable, energy dense source of heat, but he was actively involved in the process of taming the “new fire” known as atomic fission and bringing it indoors to begin to serve some of mankind’s growing energy needs.



When Ted started his professional career, Enrico Fermi and his team had not yet assembled Critical Pile #1, the simple construction of graphite bricks and uranium metal that conclusively demonstrated that a fission chain reaction could be established and controlled. Ted became a nuclear energy professional within a few months of that experimental demonstration, serving during the Manhattan Project as a member of an elite Process Improvement Task Force at the Clinton Engineer Works, the facility that is now known as the Oak Ridge National Laboratory.

Ted’s professional accomplishments are legendary; when he met Captain Rickover, he was in charge of the Radiation Shield Engineering Group at Oak Ridge. He then served as Admiral Rickover’s technical director during the development and construction of the USS Nautilus, the world’s first nuclear powered submarine, and during the development and construction of the Shippingport Atomic Power Station, the first commercial nuclear power plant in the United States. He was involved with the process to produce commercial quantities of zirconium and he was the assigned editor of the Shield Design Manual, a document that remains a basic reference for engineers more than 50 years after its initial publication.

In 1964, he and two of his colleagues from Naval Reactors left that organization to found MPR Associates, an engineering company built on the principles of excellence that they refined while working with Admiral Rickover. They had learned that one man can make a difference and that three men working together could build a formidable team to produce exceptional quality work.

Ted was the author of several books including The Rickover Effect: How One Man Made a Difference, and Creating the New World: Stories & Images from the Dawn of the Atomic Age, that should be a part of any collection on nuclear energy technology and history.

Though Ted stopped working full time at MPR several decades ago, he never got around to retiring. He was still actively writing and mentoring other nuclear energy professionals until the very end. He focused on several important nuclear energy topics including the health effects of low level radiation, using realistic assumptions to compute accident effects, the importance of agreeing on facts in order to achieve useful decisions, learning lessons from history and natural experiments, using nuclear energy to propel commercial ships, and the importance of sharing knowledge widely with as many different people as possible.

I had the good fortune to meet Ted at an ANS meeting nearly twenty years ago. He was a featured speaker at a session on the health effects of low level radiation organized by Jim Muckerheide in either 1994 or 1995. He has appeared as a guest on several Atomic Show podcasts and has provided a dozen or more guest posts on Atomic Insights. He was always generous with his time, his knowledge, and his vast experience.

Based on email correspondence with other nuclear energy professionals, my experience of Ted’s generosity was in no way unique; he was a mentor and an inspiration to dozens of others.

One of Ted’s many recent projects was serving as the technical editor for a not-yet-completed documentary about Admiral Rickover being produced by Michael Pack. His tireless efforts to share accurate information about nuclear energy technology are a good example for many people in the nuclear energy profession who are normally shy and retiring.

I think it is safe to say that the best tribute we can provide in memory of Theodore Rockwell is to continue his efforts against the spread of false information about radiation and nuclear energy by those who have been doing so for almost as long as Ted worked to correct that misinformation.

Ted Rockwell – Used fuel can be stored almost anywhere for at least 100 years

Ted Rockwell – There is nothing in the same class as nuclear




Rod Adams is a nuclear advocate with extensive small nuclear plant operating experience. Adams is a former engineer officer, USS Von Steuben. He is the host and producer of The Atomic Show Podcast. Adams has been an ANS member since 2005. He writes about nuclear technology at his own blog, Atomic Insights.

A tour of EBR-I: Birthplace of nuclear energy

Don Miley, tour guide at Idaho National Laboratory, takes viewers of this video on a trip to the Experimental Breeder Reactor I (EBR-I). In 1951, the first electricity from nuclear power was generated at EBR-I—using a reactor that actually bred more fuel than it consumed, using an all-plutonium core.

EBR-I paved the path for nuclear energy worldwide.

Looking for a unique and educational summer travel destination? The EBR-I National Historic Landmark is open to the public in the summer and to scheduled groups year-round

EBR-I Atomic Museum brochure

Thanks to Idaho National Laboratory

Virginia ANS section discovers hidden asset – Clay Condit

By Rod Adams

On January 31, 2013, about 30 lucky members of the Virginia section of the American Nuclear Society heard a series of informative tales from one of the many innovative pioneers of the First Atomic Age. Clay Condit, a man overflowing with personal memories of important nuclear energy milestones—like the initial start-up of the Submarine Thermal Reactor and the post accident analysis of the SL-1 tragedy—entertained the assembled members for a little more than an hour.

Clay retired from Westinghouse in 1992 after a 40-year long career in nuclear reactor physics and reactor operations. He spent most of that time at the 900-square-mile piece of the Idaho desert currently known as the Idaho National Laboratory. That site has been the home of 52 nuclear reactors.

Some of those reactors were carefully designed and maintained facilities used to develop new fuel materials, test new operational concepts, and/or train sailors for the US Navy. The Materials Test Rector (MTR), the Submarine Thermal Reactor (STR), the A1W prototypes for the USS Enterprise, and the Advanced Test Reactor fell into that category. Those facilities have provided decades of useful service, provided important practical training for more than 40,000 sailors, and have enabled such technological improvements as submarine reactor fuel designs that now last for the 33-year-long life of the ship instead of the two-year life achieved by the first core of the USS Nautilus.

Some of the other reactors built at INL—like the Integral Fast Reactor that evolved from the Experimental Breeder Reactor II—were also well-designed and maintained facilities that point the way to a reliable source of inexhaustible clean energy.

However, some of reactors built at the National Reactor Testing Station (one of INL’s former names) were rapid prototypes that were built quickly to test innovative concepts, some of which did not work out as well as the designers had hoped. As Clay explained, in the early days of the facility, there were two primary rules. First of all, any new project needed to pick a location that was at least five miles from any existing facility; secondly, the operators of any test reactor were required to notify the local sheriff to divert traffic on the through roads whenever they were conducting testing that might result in the release of any radioactive material.

From Clay’s point of view, the ability to move quickly and develop conceptual designs into operating machinery with few restrictions within the facility played an important role in the rapid improvement in nuclear energy technology. He stated that we need to find a way to reinvigorate nuclear technology development by reusing some of our existing assets of open spaces and readily available human resources.

After his retirement, Clay started devoting a major portion of his time to capturing and sharing knowledge about Idaho’s importance in the development of nuclear energy. He was instrumental in convincing the US Navy to donate the sail of the USS Hawkbill (SSN 666) to the town of Arco (the first community in the world ever to be lit by electricity generated by nuclear power), Idaho,  so that it could serve as the cornerstone of the Idaho Science Center. Clay is the founder, president, and primary tour guide of that facility, and he has been working for about a decade with other Arco boosters and INL veterans to create a destination where artifacts and stories about nuclear energy development at INL can be preserved and shared.

Talks like the one that Clay gave might be common for chapters that are near the national labs, but it was a unique experience for many of the Virginia section attendees, especially those who have never had the chance to attend ANS national meetings. Fortunately for us, Clay winters in Richmond; I hope we can convince him to be a more regular attendee at our meetings.

For show and tell, Clay brought a collection of artifacts and handouts, including a copy of a book titled Proving the Principle – A History of the Idaho National Engineering and Environmental Laboratory 1949-1999. I highly recommend reading the online version of that book; it provides a fascinating look at the history of a dynamic facility peopled by thinkers whose achievements were often shrouded in secrecy.

I’ve read Proving the Principle, but Clay’s talk added depth and personalized some of the events. One of the real benefits of participating in local ANS sections is the opportunity to hear interesting stories from people with real world experiences that may never again be repeated.

Of course, speakers are not the only reason to attend ANS local section meetings; it is also good to swap stories with other people who share some of the joys and challenges of working in our profession.

There was a little bit of depressing news broken at the meeting. On January 31, the day that we met, local news sources reported that Virginia state Senator John Watkins withdrew his bill to end the existing moratorium on uranium mining. The diverse coalition that has formed to halt the development of one of the largest known deposits in the United States has—so far—successfully convinced political decision makers that uranium mining entails too much risk and too little reward. There has been a well-orchestrated campaign of misinformation that has not been effectively addressed by people who understand the minuscule level of public risk associated with properly regulated, modern uranium mines and the substantial rewards that can come from developing valuable fuel sources.

There is a glimmer of hope that Virginia’s governor will use his authority to allow state regulators to begin drafting rules so that legislators will be able to make more informed decisions about the protections those regulations will provide to local populations. I hope that the governor pays attention to the careful work that has already been done to address the scientific questions. He should recognize that a deposit of material that could provide 20 percent of the United States with emission-free electricity for more than 2 years is worth developing. Perhaps it will help if more people who understand the technology find their voices and begin more forcefully communicating accurate information.

Governor McDonnell believes that Virginia should become the “Energy Capital of the East Coast”. That is a worthy goal that will be easier to reach by expanding our already substantial nuclear energy competence to include mining the required fuel material.



Rod Adams is a nuclear advocate with extensive small nuclear plant operating experience. Adams is a former engineer officer, USS Von Steuben. He is the host and producer of The Atomic Show Podcast. Adams has been an ANS member since 2005. He writes about nuclear technology at his own blog, Atomic Insights.

Looking forward to next 70 years of atomic fission

By Rod Adams

This past weekend the world quietly marked the 70th anniversary of the initial criticality of CP-1 (Critical Pile 1), the 55th anniversary of the initial criticality of the Shippingport nuclear power plant, and the decommissioning of the USS Enterprise, a 51 year-old nuclear-powered aircraft carrier. Those events have put me into a reflective but incredibly optimistic mood.

Imagine how exciting it must have been to be in the nuclear field in the early years. Talented engineers and scientists moved the technological needle from a basic pile of graphite bricks with uranium lumps, to full-scale power production, in machines that lasted for many decades, over a brief span of less than two decades. They accomplished that progress during a period when calculations were made with slide rules and modest-capacity computing devices that filled entire rooms, and when drawings were created by rooms full of people using hand tools. They overcame the disadvantage of having lost almost an entire decade (1946–1954) during which only the selected few could think nuclear thoughts without risking incarceration.

By 1990, the annual electricity production in the United States from steam plants—whose furnaces were heated using the controlled fission chain reaction that Fermi and his team had proven—exceeded the entire amount of electricity produced each year by all of the power plants that were operating in the United States in 1960. That commercial milestone occurred less than 50 years after the basic physical process was proven.

Unfortunate slow down

Even by then, however, the growth in nuclear energy production around the world was slowing down as a result of many factors, including an increasingly well-organized and well-funded movement expressly aimed at halting the use of nuclear energy. Nuclear technologists bear some of the blame for the loss of support; they (we) failed to explain why we’re so darned excited about the possibilities offered by this fascinating new technology.

We also failed to notice that there were a large number of rich and powerful people who were not enthusiastic about creating a power source that could approach a goal of being so inexpensive that no one would bother measuring how much was consumed each month. As a group, we were so happy to be working with a material that stored 2 million times as much energy per unit mass as the most energy-dense hydrocarbon fuels that we overlooked the fact that many people enjoy enormous benefits from selling hydrocarbon fuels. It is a great business to be in; anyone who bought fuel yesterday is likely to buy fuel again tomorrow.

People whose livelihoods depend on moving mass quantities of material from deep underground, through capital-intensive processing plants, and into furnaces and engines around the world, were not so terribly excited about the reality that Fermi had shown us—how we could use a material that allows a man with a backpack to transport as much energy as a supertanker.

Listen to nuclear communicators

On December 2, 2012, I gathered a group of nuclear professionals who have taken on a shared avocation of communicating the wonders of atomic fission and the possibilities that its unique characteristics can provide. You can listen to that conversation at Atomic Show #191 – 70th Anniversary of CP-1, the First Controlled Fission Chain Reaction.

We spoke about the magical simplicity of Fermi’s design and about the fact that, unlike the enormously expensive and still elusive effort to harness controlled nuclear fusion, Fermi and his team could be supremely confident that their device would work on the first try. We spoke about how it would be possible for a group of high school students, given the proper materials, to build a working fission reactor that could be safely started and controlled.

We then discussed how incredible it might be if we could treat nuclear technology in a manner similar to the way that we have treated computer hardware and software technology. Kirk Sorensen, a forward–thinking nuclear technologist who is the co-founder of Flibe Energy, has given several talks to audiences in Silicon Valley, and always comes away energized by thinking about how far we could advance our energy production systems if we adopted some of the knowledge-sharing principles that pervade the Valley.

I’ve had that experience one time at a Google Tech Talk; it may be time to make that trip again, to help increase support for the truly exciting developments in small modular reactor development that are happening in a number of places in the United States.

Shippingport Atomic Power Station

Though we were all in agreement that we could be doing far more with nuclear energy than we are today, we were not the first people to recognize just how wonderful it was that people had learned how to access atomic energy. Here is a quote from President Eisenhower’s famous Atoms for Peace speech to the United Nations, given on December 8, 1953.

The United States knows that if the fearful trend of atomic military build-up can be reversed, this greatest of destructive forces can be developed into a great boon, for the benefit of all mankind. The United States knows that peaceful power from atomic energy is no dream of the future. The capability, already proved, is here today. Who can doubt that, if the entire body of the world’s scientists and engineers had adequate amounts of fissionable material with which to test and develop their ideas, this capability would rapidly be transformed into universal, efficient and economic usage?

To hasten the day when fear of the atom will begin to disappear from the minds of the people and the governments of the East and West, there are certain steps that can be taken now.

To the making of these fateful decisions, the United States pledges before you, and therefore before the world, its determination to help solve the fearful atomic dilemma—to devote its entire heart and mind to finding the way by which the miraculous inventiveness of man shall not be dedicated to his death, but consecrated to his life.

(Emphasis added.)

That is the vision that keeps me moving forward. I share it as often as I can on whatever pulpits I am offered.

Solving the trilemma

Along with the material endowment provided by nature (God, if you prefer), nuclear knowledgeable people have in their minds the capability that will help to solve what the World Energy Council describes in a recent series of reports as a “trilemma”.

.. simultaneously address energy security, universal access to affordable energy services, and environmentally-sensitive production and use of energy is one of the most formidable challenges facing governments—indeed some might argue that it is the most formidable, or even the most important. The World Energy Trilemma report, now in its fourth year, aims to help governments rise to the challenge of tackling this ‘trilemma’.



Rod Adams is a nuclear advocate with extensive small nuclear plant operating experience. Adams is a former engineer officer, USS Von Steuben. He is the host and producer of The Atomic Show Podcast. Adams has been an ANS member since 2005. He writes about nuclear technology at his own blog, Atomic Insights.

A Weekend of Nuclear History

By Will Davis

The weekend of December 1–2, 2012, sees three events of note relative to the history of nuclear energy.


Saturday, December 1, saw the Inactivation Ceremony for USS Enterprise, CVN-65, which was the first nuclear-powered aircraft carrier ever built and by far the oldest nuclear-powered ship in service. (USS Nautilus, a nuclear-powered attack submarine, and the Russian nuclear-powered icebreaker Lenin preceded Enterprise into service, as did the cruiser USS Long Beach.) The USS Enterprise was launched on September 24, 1960 (view of launching seen above, at Newport News Shipbuilding and Drydock), and commissioned into service November 25, 1961. The ship was deactivated just past her 51st birthday. Much more information about the ship, which will be defueled and eventually dismantled, can be found at the official USS Enterprise website.

During the ceremony, the Secretary of the Navy revealed that the name Enterprise will live on in Navy history; the third Gerald R. Ford class nuclear-powered carrier will be CVN-80, USS Enterprise. Instead of eight A2W reactors as installed in CVN-65, CVN-80 will have two A1B reactors with a total power higher than that of the two A4W reactors installed in the Nimitz (CVN-68) class nuclear-powered carriers that followed the first nuclear USS Enterprise.

Sunday, December 2, marks the 70th anniversary of the first criticality of the first nuclear reactor ever built: Enrico Fermi’s “Atomic Pile,” known as CP-1 or “Chicago Pile 1,” achieved criticality  at 3:53 PM, December 2, 1942. The pile, according to “The Atomic Energy Deskbook,” Hogerton, 1963, contained 385 tons of graphite to act as the moderator. Hogerton relates the fact that when the pile was constructed, “only 6 tons of uranium metal were available and it was necessary to complete the assembly with 34 tons of uranium oxide.” The pile was built in layers of blocks of graphite and fuel, eventually 57 layers deep. According to Hogerton, “Critical conditions were achieved somewhat sooner than anticipated, so that the reactor assembly, which had been expected to be spherical, took the shape of an obloid spheroid somewhat flattened at the top.”

Argonne National Laboratory, under whose auspices the original CP-1 was built, has excellent resources on this famous anniversary. The Argonne page on the 70th anniversary gives background and perspective, while “The Dawn of the Nuclear Age” includes a video featuring two early nuclear pioneers, Dr. Harold Agnew and Dr. Len Koch. Agnew was one of the 49 persons present when the CP-1 achieved criticality in 1942.

December also marks a third anniversary: the Shippingport Atomic Power Station achieved its first criticality, and also later achieved full rated power, in December 1957. Shippingport was the first commercial nuclear generating station ordered in the United States, and it was the nation’s first large-scale nuclear power plant to generate electricity for civilian purposes.


Will Davis is a former US Navy Reactor Operator, qualified on S8G and S5W reactor plants.  Davis performs Social Media services for ANS under contract, writes for ANS Nuclear Cafe as well as for Fuel Cycle Week, and also writes his own Atomic Power Review blog.

The MTR—Gone now, but not forgotten

by Will Davis

Recently, Dr. Nicole Stricker of the Idaho National Laboratory sent a link for the following video to members of the ANS Social Media list.

INL Waste Video

The entire video is quite interesting, but my interest was tweaked during the time frame 3:23 to 3:28 in the video by what looked like a reactor vessel being tipped over during decommissioning of a nuclear facility; the voice-over at the time is talking about just that. A request for information revealed that the reactor shown at that moment in the video was the Materials Testing Reactor, or MTR.

I had known that the MTR had been long shut down, but was really unaware of its present status. The MTR has a place in nuclear history in the United States as the first widely available test reactor; according to The Atomic Energy Deskbook, the MTR was designed jointly by Oak Ridge and Argonne National Laboratories.  Blaw-Knox acted as architect-engineer, and the plant was built by the Fluor Corporation.

Let’s let the words of Phillips Petroleum Company, which operated the MTR for the Atomic Energy Commission, describe the facility; they’re found in the booklet (in my collection) whose cover is reproduced below.

“The Materials Testing Reactor is a unique and versatile research tool. It was designed and constructed as a pioneering step in the development of high neutron intensity reactors with the primary purpose of providing facilities to test the effects of neutron bombardment on materials of interest in future reactor construction. It has neutron fluxes 10 to 100 times greater than those in other reactors. As a result, it can provide radiation at a very high dose rate and produce isotopes with higher specific activity than those now available from other sources.

The MTR is a thermal (slow) neutron reactor using uranium enriched in isotope U235 as fuel, ordinary water as both moderator and coolant, and beryllium as the reflector. It is designed to generate the heat equivalent of 30,000 kilowatts.  Because of its high specific power, average neutron fluxes of 2 X 10^14 thermal neutrons per square centimeter per second and 5 X 10^13 fast neutrons per square centimeter per second are available. Peak thermal neutron fluxes of 5 X 10^14 neutrons per square centimeter per second exist in certain positions in the reactor.

The enriched uranium fuel is contained in an active core which is inside a lattice region 40 by 70 centimeters in area and 60 centimeters high (16 x 28 x 24 inches). It is surrounded by a 40 inch high reflector of beryllium pieces. Both lattice and reflector are enclosed in a 55 inch diameter aluminum tank which is extended by stainless steel sections above and below to form a 30 foot deep well which is closed top and bottom with heavy lead filled steel plugs.  ….The reactor lattice and beryllium reflector are cooled by water flowing at a rate of 20,000 gallons per minute. This water enters near the top of the well at 100F and leaves near the bottom at 111F. The water is fed by gravity from a 170 foot high tank through the reactor tank to a vacuum spray evaporator system for cooling and degassing, then is pumped back to the tank.”

According to contemporary documents from Sylvania-Corning Nuclear Corporation in my collection, fuel elements for the MTR were “93% enriched uranium alloyed with aluminum, clad in aluminum, and formed into curved plates approximately 24″ long, 3″ wide and 1/16″ thick. The fuel element consists of nineteen such plates brazed into aluminum side plates to form a boxlike assembly approximately 3″ x 3″ in cross-section. Aluminum adaptors are welded to the ends of the fuel element. Each element contains 200 grams of U235 and normally 25 such elements fuel the reactor.”

In addition to offering irradiation services directly using the reactor, the MTR also offered gamma irradiation using spent fuel as described below by Phillips Petroleum:

“The gamma field is provided by used MTR fuel elements, which are stored under water until they have cooled sufficiently to be transferred to the chemical processing plant for recovery of U235.” At left, the original MTR canal where gamma irradiation was performed, which offered, according to Phillips, gamma fields up to 10^7 roentgens per hour.

The MTR first began operating in 1952—although, according to the excellent “Proving the Principle” (Susan M. Stacy/Idaho Operations Office of the Department of Energy, 2000), the plans were started for what became the MTR as early as 1944. The MTR, when placed in operation, quickly found itself with a list of experiments to perform and samples to irradiate. According to documentation provided by Erik Simpson, CWI media spokesman, the MTR performed over 15,000 irradiation experiments during its operational lifetime.

The MTR operated successfully as one of the most highly in – demand test reactors for many years. Time caught up to the MTR in 1970; according to “Proving the Principle,” the final experimental plutonium core (nicknamed “Phoenix”) was operated in the reactor through April 23, 1970, when the reactor was shut down. One final experiment in August 1970 saw the MTR go critical again for 48 hours when Aerojet, by then the MTR contractor, started it up for paid research into mercury contamination of wildlife. But that was it. The reactor never operated again.

The reactor was defueled, and parts of the facility were used for other purposes (some functions even going on next to the shutdown reactor itself without involving it) for some years until the DOE made the decision in 2005 to dispose of the facility. Erik Simpson has provided us with a copy of the 2007 Engineering Evaluation/Cost Analysis for the Materials Test Reactor End-State and Vessel Disposal; of the various site solutions described in this document, the one chosen and carried out is the one that called for removal of the above grade structure, the reactor vessel, and below-grade structure with the vessel being stabilized and stored onsite at a dedicated facility.

Erik provides us with two fascinating links that show much more than we saw in the opening video of the decommissioning of the MTR facility. In the first video link, we see a number of activities of the Idaho Cleanup Project; the MTR facility is seen in this video at the time frame 1:15 – 2:30. The second video link gives us a mostly time-lapse view of the demolition of the MTR reactor building (with the large internal shielding and beam tube/sample tube complex, as well as reactor vessel and tank extensions already gone), but slows to real-time to display the explosive demolition of the roof structure.

It goes without saying that in terms of the overall site, many reactor facilities have been remediated, or placed in some level of storage, or will be remediated. Dr. Stricker points out that the former NRTS site, now called the Idaho National Laboratory site, has housed 52 different reactors.

As related in “Proving the Principle,” there were serious last-minute attempts to revitalize the MTR with new projects and new money, but this wasn’t enough to prevent its  shutdown; designation of the MTR as a “historical Signature Property as designated by DOE Headquarters Advisory Council on Historic Preservation” (as related in the disposal analysis) wasn’t enough even to keep the building. We’ve at least put a marker for the MTR and all those who worked on, or at, the facility on the ANS Nuclear Cafe blog with this post, and noted its passing.

(Photo at top courtesy Idaho National Laboratory, via Dr. Nicole Stricker. Video links courtesy Erik Simpson.  MTR brochure photos, Will Davis collection.)

Additional resources

For more information, please visit Argonne National Laboratory’s Basic and Applied Science Research Reactors website—click HERE to open the the page dedicated to the MTR.


ANS Friday Nuclear Matinee: The First Nuclear Chain Reaction

Very highly recommended. On December 2, 1942, 49 scientists, led by Enrico Fermi, made history when Chicago Pile 1 (CP-1) went “critical” and produced the world’s first self-sustaining, controlled nuclear chain reaction.

Seventy years later, two of the last surviving CP-1 pioneers, Harold Agnew and Warren Nyer, recall and explain the events of that historic day.

Of course, nuclear chain reactions power the Sun and stars, and Earth had its own nuclear chain reactions long before humans achieved the controlled version — so some license is taken with the title of this post.

ANS Friday Nuclear Matinee triple feature

A triple feature for your viewing pleasure! Here we go:

1. Those atomic clocks can really come in handy! “GPS, Relativity, and Nuclear Detection” from Minute Physics:


2. This video regards Einstein’s mathematically proving the existence of atoms (and their size) in 1905. For more detail, see this Nuclear Pioneers post from the ANS Nuclear Cafe. Here’s the video “Albert Einstein: The Size and Existence of Atoms” from Minute Physics:


3. The ANS Student Conference in Las Vegas is now well underway. Here is one of the many beautiful videos shown during ANS President Eric Loewen’s keynote address at the conference, courtesy of Suzanne Hobbs Baker of PopAtomic Studios. Full-screen mode recommended:

Albert Einstein and the most elemental atomic theory

By Paul Bowersox

Albert Einstein’s birthdate was less than a week ago, on March 14,
in the year 1879.  Happy belated birthday, Albert!

Albert Einstein, age 4

As a slightly overdue commemoration of Albert Einstein’s 133nd birthday, I would like to make a quick note of his most “elemental” contribution to atomic theory—he was the first person to show a way to prove the existence of atoms—using an ordinary microscope!

Atomic theory

When you really get down to it, “atomic theory” begins with a claim that matter is made of atoms. This sounds obvious enough to us today, but not very long ago, relatively speaking, chemists and physicists were known to debate this idea fiercely. The idea of atoms as a shortcut for thinking about how matter worked seemed quite useful even more than a century ago—but then again, so did ideas like a stationary earth at the center of the universe. When Einstein was a young man, atoms had never been observed. Was the idea of atoms actually “real?” Or was something else, perhaps something unexpected, going on?

1905 was a good year

The year 1905 was a good year for 26-year-old Albert Einstein. While working at the patent office in Bern, Switzerland, he completed his PhD dissertation. He published his Special Theory of Relativity, which later led to the General Theory of Relativity, which led to his designation as “the father of modern physics.” Einstein also in 1905 proposed that light energy can be absorbed or emitted only in discrete packets called quanta, a provocative contradiction of the then-prevalent wave theory of light—and this led to Einstein’s winning of the Nobel Prize. Einstein in 1905 also explained the equivalency of mass and energy, expressed by the famous equation e=mc2.

Yet these were not sufficient world-changing, revolutionary advances in physics for a single year. Einstein also in 1905 mathematically proved the existence of atoms, and thus helped revolutionize all the sciences through the use of statistics and probability.

Albert Einstein, age 25

An atomic view of a liquid

Atomic theory says that any liquid is made up of molecules (invisible in 1905). Furthermore, these molecules are always in random, ceaseless motion. The average behavior of these molecules produces the overall properties of any liquid that we observe. But Einstein realized that this random chaos of jostling, invisible molecules would produce statistical fluctuations—for example, once in a while a small group of invisible molecules could, just for a moment, move in mostly the same direction. Then, another nearby group of molecules could for a moment move mostly in a different direction. A visible object, immersed among these invisible, randomly jostling molecules, wouldn’t move much most of the time, since it would normally be buffeted from all sides evenly—but then occasionally it could be “pushed” in one direction and then moments later pushed in a different direction, showing a “zigzag” motion.

Brownian motion

The jittery motion of tiny observable particles had been described by botanist Robert Brown as early as 1827, and was not surprisingly known as Brownian motion. Measuring this motion, however, and explaining it mathematically had proven extremely difficult. What was required, in short, was Einstein’s realization that even though observable particles are much larger, they still generate pressure the same way as the invisible molecules in which they are immersed. So, if the concentration of large particles varies, they too flow to even out their concentration just like the atoms and molecules in which they are immersed.

Brownian motion demonstration

Using this insight, and some associated mathematics, Einstein was able to accurately calculate the average distance an immersed visible particle would travel in a given time. His mathematical laws governing the movements of invisible particles could be tested and measured by observing the motion of the visible— simply using a microscope and a stopwatch, and a fluid containing many uniformly sized tiny, yet visible, particles. Although this was quite tricky to test a hundred years ago, eventually Einstein’s calculations were fully confirmed by Jean Perrin in 1909, winning Perrin the Nobel Prize.

Some implications

The existence of atoms and molecules was confirmed. With Einstein’s calculations, one could determine the size of these invisible atoms and
molecules. Also, the idea that heat is the result of the motion of atoms and molecules was confirmed. And finally, the vital importance of statistics and probability in physics had been established. This was a pivotal achievement, considering the truly revolutionary discoveries in quantum mechanics that were about to ensue. More broadly, Einstein’s use of statistical fluctuations, and probability theory, eventually revolutionized the study of all complex systems—weather, climate, stock markets, and evolution, to name a few—and forever improved our understanding of how the world works.


Paul Bowersox is a regular contributor to the ANS Nuclear Cafe and admirer of the achievements of the nuclear pioneers.