Accepting the Science of Biological Effects of Low Level Radiation

By Rod Adams

A group of past presidents and fellows of the American Nuclear Society has composed an important open letter to ANS on a topic that has been the subject of controversy since before I first joined the society in 1994. The subject line of that letter is “Resolving the issue of the science of biological effects of low level radiation.” The letter is currently the only item on a new web site that has been created in memory of Ted Rockwell, one of the pioneers of ANS and the namesake of its award for lifetime achievement.

LNT and “no safe dose”

Ted was a strong science supporter who argued for many years that we needed to stop accepting an assumption created in the 1950s without data as the basis for our radiation protection regulations. That assumption, which most insiders call the “LNT”—linear no-threshold dose response—says that risk from radiation is linearly proportional to dose all the way to the origin of zero risk, zero dose.

Many people who support the continued use of this assumption as the basis for regulation plug their ears and cover their eyes to the fact that those who oppose the use of nuclear energy, food irradiation, or medical treatments that take advantage of radiation’s useful properties translate our mathematically neutral term into something far more fear-inspiring: They loudly and frequently proclaim that the scientific consensus is that there is “no safe dose” of radiation.

Some people who support the use of nuclear energy and who are nuclear professionals help turn up the volume of this repeated cry:

Delvan Neville, lead author of the study and a graduate research assistant in the Department of Nuclear Engineering and Radiation Health Physics at Oregon State University, told the Statesman Journal Apr. 28, “You can’t say there is absolutely zero risk because any radiation is assumed to carry at least some small risk.”

While most scientists and engineers understand that the LNT assumption means that tiny doses have tiny risks that disappear into the noise of daily living, the people who scream “no safe dose” want their listeners to believe it means that all radiation is dangerous. They see no need to complicate the conversation with trivial matters like measurements and units (I am being ironic here).

Scientists and engineers almost immediately ask “how much” before starting to get worried; but others can be spurred into action simply by hearing that there is “radiation” or “contamination” and it is coming to get them and their children. When it comes to radiation and radiation dose rates, we nuclear professionals have not made it easy for ourselves or for the public, using a complicated set of units, and in the United States remaining stubbornly “American” by refusing to convert to the international standards.

Aside: There is no good reason for our failure to accept international radiation-related measurement units of Sieverts, Bequerel, and Grays. Laziness and “it’s always been that way” are lousy reasons. I’m going to make a new pledge right now—I will use International System of Units (SI) units exclusively and no longer use Rem, Curies, or Rad. After experiencing the communications confusion complicated by incompatible units during and after the Fukushima event, the Health Physics Society adopted a position statement specifying exclusive use of SI units for talking or writing about radiation, and perhaps ANS should adopt it as well. End Aside.

Physics or biology?

Leaving aside the propaganda value associated with the cry of “no safe dose,” an important factor that supports a high priority to the effort to resolve the biological effects of low-level radiation is the fact that the LNT uses the wrong science altogether.

The LNT assumption was created by persons who viewed the world through the lens of physics. When dealing with inanimate physical objects all the way down to the tiniest particles like neutrons, protons, mesons, and baryons, statistics and uncertainty principles work well to predict the outcome of each event. An atom that fissions or decays into a new isotope has no mechanism that works to reverse that change. A radiation response assumption that applies in physics, however, is an inadequate assumption when the target is a living organism that has inherent repair mechanisms. Biology is the right science to use here.

At the time that the LNT was accepted, decision-makers had an excuse. Molecular biology was a brand new science and there were few tools available for measuring the effects that various doses of radiation have on living organisms.

The assumption itself, however, has since inhibited a major tool used by biologists and those who study the efficacy of medical treatments: Since all radiation was assumed to be damaging and could only be used in medicine in cases where there was an existing condition that might be improved, it was considered unethical to set up well-designed randomized controlled trials to expose healthy people to carefully measured doses of radiation while having a controlled, unexposed group.

Instead, health effects studies involving humans have normally been of the less precise observational methods of case-control or cohort variety, with occupationally or accidentally exposed persons. The nature of the exposures in those studies often introduces a large measurement uncertainty, and there are complicating factors that are often difficult to address in an observational study.

Science marches on, but will LNT?

Molecular biology and its available tools have progressed dramatically since the LNT was adopted by BEIR I (Committee on the Biological Effects of Ionizing Radiation) in 1956. It is now possible to measure effects, both short-term and long-term, and to watch the response and repair mechanisms actually at work. One of the key findings that biologists have uncovered in recent years is the fact that the number of radiation-induced DNA events at modest radiation dose rates are dwarfed, by several orders of magnitude, by essentially identical events caused by “ordinary” oxidative stress.

This area of research (and others) could lead to a far better understanding of the biological effects of low-level radiation. Unfortunately, the pace of the research effort has slowed down in the United States because the Department of Energy’s low dose research program was defunded in 2011 for unexplained reasons.

It is past time to replace the LNT assumption with a model that uses the correct scientific discipline—biology, rather than physics—to predict biological effects of low-level radiation. I’ll conclude by quoting the final paragraph of the ANS past presidents’ open letter, which I encourage all ANS members, both past and present, to read, understand, and sign:

The LNT model has been long-embedded into our thinking about radiation risk and nuclear energy to the point of near unquestioned acceptance. Because of strict adherence to this hypothesis, untold physiological damage has resulted from the Fukushima accident—a situation in which no person has received a sufficient radiation dose to cause a significant health issue—yet thousands have had their lives unnecessarily and intolerably uprooted. The proposed actions will spark controversy because it could very well dislodge long-held beliefs. But as a community of science-minded professionals, it is our responsibility to provide leadership. We ask that our Society serve in this capacity.

Additional reading

Yes Vermont Yankee (June 23, 2014)  “No Safe Dose” is Bad Science. Updated. Guest Post by Howard Shaffer

Atomic Insights (June 21, 2014) Resolving the issue of the science of biological effects of low level radiation

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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.

Nuclear Energy Blogger Carnival 214

ferriswheel 201x268The 214th Carnival of Nuclear Energy Bloggers has been posted at Atomic Power Review.  You can click here to access this latest edition of a long-standing tradition.

Each week, a new edition of the Carnival is hosted at one of the top English-language nuclear blogs. This rotating feature of nuclear “posts of the week” represents the dedication of those who are working toward a future of energy abundance, improved health, and broadened security through nuclear science and technology.

Past editions of the carnival have been hosted at Yes Vermont Yankee, Atomic Power Review, ANS Nuclear Cafe, NEI Nuclear Notes, Next Big Future, Atomic Insights, Hiroshima Syndrome, Things Worse Than Nuclear Power, EntrepreNuke, Thorium MSR and Deregulate the Atom.

This is a great collaborative effort that deserves your support.  If you have a pro-nuclear energy blog and would like to host an edition of the carnival, please contact Brain Wang at Next Big Future to get on the rotation.

What will it take to move nuclear energy forward?

By Paul Bowersox

Such was the provocative title of the Focus on Communications Workshop held at the 2014 American Nuclear Society Annual Meeting on the afternoon of Wednesday, June 19.

Nuclear energy is not in a great place right now in the United States (although globally it is a different story). A few nuclear plants have closed recently in the United States, while a few are under construction—but there are no “new orders” coming in. A short list of other nuclear plants are at risk. Some anticipate great things from small modular reactors someday—some remain skeptical. Public support wavers around 50/50 nationally in Gallup polls. What to do? My report from the workshop follows.


After a rather interesting and timely short interchange on how cyclotron gamma irradiation could solve certain problems of secondary fermentation in wine… the workshop got down to business. An important discussion on effective communication methods and strategies for nuclear energy was led by Mimi Limbach of Potomac Communications Group, using detailed polling data. The meeting then turned to the politics and economics of nuclear energy, led by ANS Washington representative Craig Piercy.


In the United States, natural gas prices are low due to the “fracking boom,” and will remain low in the near future, making gas an attractive option for new power plants. Meanwhile, while our economy is growing very slowly, so is electricity demand. In past decades electricity demand in the United States grew multiple percent each year, occasionally even in double digits—now, it’s about 1 percent growth per year. Electricity capacity certainly needs to be replaced in coming years, but not so much added. This is in marked contrast to developing countries around the globe, where nearly all new electrical generation that is added to global supply, will be added. And it will be a lot.

The biggest opportunities for U.S. nuclear will be overseas, as all trends indicate. But at the same time, Piercy pointed out that the U.S. nuclear industry has to be strong domestically to be strong internationally.

EPA carbon rule

The U.S. Environmental Protection Agency about a month ago released a proposed rule for state-by-state requirements on lowering carbon output from power plants, and there are big differences in the levels of required carbon cuts among individual states. The one major outlier is Vermont, where the EPA proposes no carbon reduction from current levels at all. No doubt this is due to the scheduled closing of the Vermont Yankee nuclear plant. The EPA must recognize that making up for all of Vermont Yankee’s essentially carbon-free electricity, with other sources of essentially carbon-free electricity, will be a tough and expensive job all by itself. What a waste, some might say.

The workshop discussion brought forward a rather remarkable point: To comply with the EPA, many U.S. states do have the option to build one big nuclear plant, retire a couple of coal plants, and “call it a day and job well done.” Will they? Regardless, more of the focus for ANS will now apparently shift to the states, and especially on convincing the states to include nuclear in their energy portfolios.

In effect this will be changing Renewable Energy Portfolios, which 29 states have, into Clean Energy Portfolios. A change of one word will mean a lot for U.S. nuclear energy. That is, it would be a change in state policies so that nuclear gets some credit for being low carbon.

An interesting discussion on industrial electricity prices in Germany ensued. Piercy noted that electricity prices have roughly doubled in Germany since 2008, when the country began its great experiment in nuclear energy phaseout, and then a more rapid phaseout after Fukushima. Will the United States travel down this de-industrializing road? Germany’s experience may serve as a very informative example—and warning.

A realistic US nuclear policy agenda

Workshop discussion concluded with what a realistic U.S. nuclear policy agenda would look like.

First, some movement on nuclear waste policy is needed, now. The current Energy Bill in Congress may actually include some funding for a pilot interim storage facility—and that would be movement.

Second, a “good for nuclear” EPA carbon rule is needed, now. Public comments are open on the EPA rule, and ANS as a national organization will definitely be weighing in on this.

Third, low dose radiation health effects—or more accurately, the lack thereof—is an overriding issue. From discussion: Is it really the case that one can add up all radiation exposure throughout a lifetime and extrapolate some health effect from that number? It’s certainly one way to regulate radiation exposure, but is the situation with radiation dose more akin to a more familiar example: Occasionally drinking a glass of wine may even be good for you—but drink bottles every day and you’ll see plenty of adverse health effects? There seems to be some shifting among the scientific community regarding biological effects of low dose radation, and research continues. Note: My impression is that until such a shift in scientific consensus is reflected in the National Academy of Sciences’ Biological Effects of Ionizing Radiation reports, this debate will continue without major change in policy, and without change in very expensive regulatory requirements. At any rate, all attending the workshop agreed that fear of radiation is demonstrably completely out of proportion to actual risk, or fear of risks from, say, chemical toxins that are all around us in everyday life, and this fear is costing the world dearly. Nonetheless, without a change in the “public level of dread” of radiation, one wonders how well nuclear energy will succeed long term. (That is, until one needs a CT scan.)

A shift toward seeing nuclear energy technology trade with other countries as a requirement of effective nonproliferation policy, rather than its antithesis, is another change that needs to happen soon, and some shifting in attitudes is going on here in Congress, Piercy reported. Countries that want to use nuclear energy (and this number will continue to grow) have a wide range of potential suppliers around the globe—and not just the United States. Flexibility in agreements with other countries concerning their rights to uranium enrichment and reprocessing, even though they really have no intention of actually acting on them, is increasingly seen as a necessity if the United States is to remain relevant in nuclear. Otherwise, customers can just go somewhere else for nuclear energy technology, where such restrictions are not imposed. So, as goes U.S. engagement in nuclear trade, and for that matter strength in the U.S. domestic nuclear energy industry, so goes U.S. influence in global safety and nonproliferation.

Continued education, and research and development (and a Nuclear Regulatory Commission licensing structure) on advanced reactors and fuels, remains a continuing priority today, along with the extension of the current nuclear fleet, of courseand perhaps finding new ways to facilitate private company investments in new nuclear technologies. The rest of the world is moving fast on thison fast reactors, anyway. While we are not yet at the point that a 3-D printer in the garage can build a lot of nuclear components, it is getting easier and cheaper for nuclear startups than in years past and there is great potential for innovation.


They say all politics is local. Perhaps the main thing I take away from the workshop discussion is that now more than ever, nuclear energy politics and policy, with impetus from the new EPA carbon rule, will be forged at the grassroots level of the states as well. Stay tuned.

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Paul Bowersox is on ANS staff in the Communications and Outreach Department and he manages ANS social media.

Nuclear Honors and Awards—From the 2014 ANS Annual Meeting

Thank you for your remarkable contributions to continuing progress and advancement in nuclear sciences and technologies—and congratulations to American Nuclear Society honors and awards recipients at the 2014 ANS Annual Meeting.

Photos and citations below.

ANS Fellow

Rizwan Uddin

For his seminal contributions to advancing our understanding of density wave oscillations, nuclear-coupled density wave oscillations, and boiling water reactor stability. For his significant contributions to advance coarse mesh nodal methods and relaxing the limitations on coarse mesh methods to make them applicable to a much larger class of engineering problems. Presented by ANS President Donald Hoffman (right).

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Henry DeWolf Smyth Nuclear Statesman Award

Luis E. Echavarri

For outstanding lifetime statesmanship and leadership in the global nuclear arena, including directing OECD/NEA activities, and promoting the global development of safe and economic commercial nuclear power. Presented by Marvin S. Fertel (left), ANS Presidential Citation recipient, President and CEO of the Nuclear Energy Institute.

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Arthur Holly Compton Award in Education

Michael Podowski

For his exceptional dedication to the education of nuclear engineers, and for his pioneering initiative to establish a degree program for Navy personnel that has been critical to the future of nuclear engineering education at Rensselaer Polytechnic Institute and beyond. Presented by ANS Honors and Awards Committee Chair Steven J. Zinkle (right).

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Special Award

Mitchell T. Farmer

For major internationally recognized contributions to the understanding and modeling of severe accident phenomena in LWR plants, and for technical assistance to Japan following the Fukushima accident.

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Landis Young Member Engineering Achievement Award

Elia Merzari

In recognition of Dr. Merzari’s pacesetting contributions to simulation of complex turbulent flows and multi-scale/multi-physics simulations of nuclear reactor designs.

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Don Miller Award

Hidekazu Yoshikawa and Douglas M. Chapin

In recognition of outstanding accomplishments in the fields of Instrumentation, Control, and Human-Machine Interface Technologies. Received by Joseph Naser on behalf of Dr. Yoshikawa and Dr. Chapin.

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Mishima Award

Tatsuo Shikama

For his sustained and impactful contributions to the field of irradiation materials science and his leadership and guidance of the next generation of researchers.

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W. Bennett Lewis Award

Marcel Boiteux

In recognition of a lifetime of pioneering contributions to sustainable energy, in particular his leadership role in building a large fleet of nuclear power plants, enhancing energy independence and replacing the use of carbon intensive fuels, with reliable, economical, and clean nuclear energy.



Walter H. Zinn Award

Kyle H. Turner

In recognition of a lifetime of advancing the United States’ nuclear industry including establishing a predictable regulatory approval path for new reactor deployment and establishing a predictable regulatory approval path for site permits and combined licenses under Part 52.  To be presented at a future ANS Operations and Power Division event.


Lifetime Achievement in Fuel Cycle and Waste Management

James C. Bresee

In recognition of major lifetime contributions that significantly advanced the scientific, engineering, societal, and regulatory aspects of the nuclear fuel cycle and nuclear waste management mission.

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Samuel Glasstone Award

For outstanding achievement by an ANS Student Section.

Finalists: Missouri Institute of Science and Technology; Rensselaer Polytechnic Institute; University of Florida; and University of Wisconsin-Madison. Winner to be selected and announced during ANS Annual Meeting.



Nuclear Energy Blogger and Author Carnival 213

ferris wheel 202x201It’s time for the 213th Carnival of Nuclear Energy Bloggers and Authors, hosted this week right here at the ANS Nuclear Cafe.  It’s a big week for ANS, with the Annual Meeting going on in Reno… so without any further remarks we’ll dive right in!


NewsOK / Robert Bruce Hayes

Beware of Junk Science  -  Robert Hayes reminds us that it’s possible to become afraid of something we don’t really understand, based upon selected facts we’re told to cloud or steer an issue.


Atomic Insights – Rod Adams

Radiation Health Effects for Medical Doctors

Misinformation about radiation health effects does not just affect the nuclear industry and dramatically increase the costs associated with all nuclear energy technologies. It is also having a deleterious effect on the beneficial use of radiation and radioactive materials in medical diagnosis and treatment.

Throughout their training programs, medical doctors have been taught to do everything they can to minimize radiation exposure. This message has become so intense in recent decades that many medical professionals shy away from ordering tests that would help them do their jobs better and provide better patient outcomes.

Atomic Show #216 – Just The Fracks, Ma’am

Greg Kozera is President of the Virginia Oil and Gas Association and is the author of a recently released book entitled “Just the Fracks, Ma’am; The Truth About Hydrofracking and the Next Great American Boom.”  Kozera and Rod Adams discuss energy options, the value of natural gas as a feedstock for material production, and the actions of certain members of the natural gas industry to discourage competitors like coal and nuclear.


Nuke Power Talk / Gail Marcus

Nuclear Engineering Students Among “Most Impressive” at MIT

Gail Marcus was pleased and proud to discover that three nuclear engineering students were profiled in a group of only fourteen students identified as among the most outstanding at MIT last year.  She notes in Nuke Power Talk that this is an impressively high percentage in an already elite group, and she considers this a very positive sign for the future of the nuclear industry.


Forbes / Jim Conca

EPA Hits Nuclear Industry with Kryptonite

EPA’s latest proposed emissions rule for nuclear power plants focuses on a non-issue that has never been a problem; Kr-85.  Kr-85 is a noble gas that cannot react with anything, can’t form chemical compounds or even individual molecules, and can’t enter biological pathways.  Kr-85 can’t do anything but dissipate immediately upon leaving the reactor.

Why on Earth is China Nervous about Plutonium in Japan?

China is nervous about Japan making atomic weapons and has complained to the International Atomic Energy Agency that Japan has over 1,400 pounds of plutonium that it did not report.  This is actually amusing since this Pu cannot be made into weapons.  Also funny is China’s faked outrage.



Next Big Future / Brian Wang

China could complete 9 nuclear reactors in the next 7 months

By the end of 2014, the number of reactors in the country is expected
reach 30, bringing the total nuclear capacity to around 27 GWe. In
2015, capacity should reach 36 GWe, as a further eight reactors are
brought online. 18 units are expected to start up within the next two
years, taking nuclear capacity close to the projected 40 GWe figure.


ANS Nuclear Cafe – submitted by Paul Bowersox

Spent Fuel Pool Fire Risk Drops to Zero Months After Shutdown

Rod Adams addresses the real issues that concern operation and maintenance of spent fuel pools at nuclear power plants in this thorough article.  The constant effort on the part of some anti-nuclear activists to make spent fuel pools into a looming threat is dispatched in detail; the realities are presented so that actual risk may be perceived, and once understood, placed in perspective.

Pathfinder – A Path Not Taken

Will Davis presents a history of one of the most unusual commercial nuclear power plants ever built – a boiling water reactor capable of producing highly superheated steam.  The reasons for its failure are explored, as is some not-before-seen history.  For those interested in placing SMR’s at existing power plant sites, this post might be quite interesting – and important.


That’s it for this week’s posts.  Thanks to all of our contributors!

Communications Sessions start June 16 at 2014 ANS Annual Meeting

By Mimi Limbach

One of the many highlights at American Nuclear Society national meetings is the opportunity to hear terrific communicators sharing their insights and best practices, along with lively and informative panel discussions that follow. The June 2014 ANS Annual Meeting offers three of these popular sessions—if you will be in Reno, Nev., be sure to schedule them on your meeting calendar.

Communicating with Communities: Panel discussion with Chip Cameron, John Kotek, and Nicole Stricker. Monday, June 16, 1 p.m. in Carson 1

Both community and policy-maker support are critical for successfully siting and operating nuclear facilities. In back-to-back sessions, panelists will explore the strategies and tactics that work, along with those that don’t, in building support for nuclear facilities and operations. They also will discuss the specific challenges they face as well as the actions they are taking to reach out to and educate policy makers on the benefits of nuclear energy facilities.

The panelists: Chip Cameron, former US Nuclear Regulatory Commission assistant general counsel and an expert on outreach, conflict resolution and the National Environmental Policy Act (NEPA),  is going to kick off our discussion with a brief presentation that will set the table for both sessions. His background and his work as a public meeting facilitator provide him with a unique perspective on the interplay between legal constructs and “real” communication. He’s going to talk about how communication with communities and policy makers has been affected over the past 40 years by the public participation requirements in NEPA law. He will describe how legal requirements can offer formal and often underutilized tools for communication.

From there, he’ll be joined by Nicole Stricker and John Kotek, who will have some lively experiences from Idaho National Lab (INL) and the Blue Ribbon Commission on America’s Nuclear Future, respectively, to bring the discussion to life. Nicole is the senior science writer and nuclear communications lead at INL with substantial experience in communicating with communities, social media, media outreach, and science communications. Before joining INL, Nicole was a journalist covering science in Idaho. John is a partner in Gallatin Group. He served as staff director of the Blue Ribbon Commission on America’s Nuclear Future that recommended a path forward  for nuclear waste disposition. Previously he was deputy manager for the US Department of Energy’s Idaho Operations Office. He also served as a Congressional Fellow in Sen. Jeff Bingaman’s office (D., New Mexico).

Building Policy-Maker Support for Nuclear Facilities: Panel discussion adds Harsh Desai and Craig Piercy. Monday, June 16, 2:30 p.m. in Carson 1

Our community-communications focus will set the context for more political examples after the break at 2:30 pm. The discussion will focus on what it takes to build policy-maker support for nuclear facilities, how communities play a critical role, and what formal and informal communication looks like from both points of view. AAAS/ANS Congressional Fellow Harsh Desai and ANS Washington Representative Craig Piercy will provide their perspectives on the politics of siting and what it takes to educate policy makers so it can be successful. Harsh Desai is working in Sen. Diane Feinstein’s office (D., Cal.) during his fellowship, where he focuses on science, nuclear, and energy policy. Craig Piercy develops and carries out ANS’s federal outreach on Capitol Hill and with the Executive Branch on behalf of the 11,000 men and women of ANS. Craig heads the Washington Office of Bose Public Affairs.

Focus on Communications Workshop: What Will It Take to Move Nuclear Energy Forward? Sponsored by the ANS Center for Nuclear Science and Technology Information, Wednesday, June 18, 4:00 – 5:30 p.m. in Rooms N-3 and N-4

Our nuclear community has plenty of issues to address. Some nuclear plants are closing or under threat either because of economics, equipment, implacable opposition from activists, or a combination of these factors. Nuclear science budgets are smaller and smaller due to federal budget cuts. Sanctions or pending sanctions on Russia are negatively affecting joint research projects between U.S. universities and Russian researchers, placing some of them in stasis. And export restrictions (and in some cases, bureaucracy) may compromise the ability of U.S. companies to compete and win in international tender offers, and compromises our seat at the table in international nonproliferation regimes. This workshop will address the role that ANS members can play in addressing these issues, including messaging and outreach approaches that will be compelling and effective. Join ANS Washington Representative Craig Piercy and ANS Distinguished Service Award recipient and Potomac Communications Group Managing Partner Mimi Limbach for a lively discussion and a focus on the actions that each of us can take. Beer, wine, and snacks will be served, courtesy of the ANS Center for Nuclear Science and Technology Information.

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Pathfinder: A Path Not Taken

Pathfinder Atomic Power Plant.  Press photo, Will Davis collection.

Pathfinder Atomic Power Plant. Press photo, Will Davis collection.

by Will Davis

The recent U.S. Environmental Protection Agency announcement of policy regarding carbon emissions from power plants has triggered a renewed interest in nuclear energy over the past few weeks; along with this of course comes a focus on small modular reactors (SMRs) and their availability for replacing existing fossil-fueled plants or facilities. We have discussed this topic here at ANS Nuclear Cafe before, in terms of the possibility of adding an SMR onto an existing facility—see “The Hook-Ons.”

A major potential stopper in the concept of adding a reactor to an existing generating plant is this: Water-cooled nuclear reactors cannot produce superheated steam—that is, steam that has been boiled from water and that is then heated up even further before being used to run an engine or turbine. Superheating the steam requires more energy (from whatever the fuel source is), but, importantly, drives the efficiency of the power plant up quite a bit overall. Water-cooled plants can’t do this because of the limits of boiling water using either the reactor directly or due to the limits of boiling some water using other water (the pressurized water concept). Yes, some water-cooled reactors do achieve a tiny bit of superheat—but not enough so that the steam plant they’re supplying can be designed for high temperature, dry, superheated steam (“dry steam” has no entrained water droplets). Why is this a problem? Because for many years fossil-fired generating plants have been designed for superheated steam in order to drive up efficiency.

So, one would need to add a superheater fired by fossil fuel (as was done at some early nuclear plants) or else replace the entire power plant (turbine and all) with an SMR nuclear plant, possibly reusing the electric and water infrastructure. It’s a major consideration.

In the early days of atomic energy, the idea of developing a water–cooled reactor that actually could superheat steam (thus avoiding this conundrum) was tossed around quite a lot—the potential advantages were great, but the technical barriers were also enormous. Fuel temperature was the major consideration, because the fuel had to exist in a steam environment that reactor designers normally avoided. However, one reactor was actually built and operated here in the United States that attempted to do just this. The power plant in question was Northern States Power Company’s (NSP) Pathfinder Atomic Power Plant (named after early explorer John C. Fremont, known by Indians as “the path finder”) near Sioux Falls, South Dakota—one of two commercial reactor plants designed by the Allis-Chalmers (A-C) Manufacturing Company.* It is also, unfortunately, possibly the least successful commercial power reactor built in the United States. Pathfinder represents the first, and last, time on U.S. soil that a water–cooled, superheated steam reactor was built for commercial power.

Pathfinder under construction.  Photo - The Atomic Energy Deskbook.

Pathfinder under construction. Photo – The Atomic Energy Deskbook.

Pathfinder was originally contracted in 1957, with A-C acting as the prime contractor; the architect-engineer (Pioneer Service & Engineering Co.) and constructor (Fegles Construction Co. and Power Service Corporation) were responsible to A-C under the arrangement, not to the plant’s owner, NSP. The financing arrangement was typical for early reactors of the day: NSP funded most of the cost (eventually over $30 million) with a consortium of utilities contributing another $3.65 million for R&D costs. The U.S. Atomic Energy Commission (AEC) contributed another $8 million for R&D and also waived fuel costs for the first five years (a value estimated initially at about $1.8 million)—both under the third round of the Power Demonstration Reactor Program.

As initially conceived, the plant that became Pathfinder was to be a controlled recirculation, direct cycle boiling water reactor—and was referred to frequently in early literature as the CRBR or Controlled Circulation Boiling water Reactor. In 1958 however, A-C began to redesign the plant to remove its original superheater (which would have been fired either on oil or coal—this had not yet been decided) and develop an integrated steam superheater in the actual reactor itself. This would employ a “two region” core—one section of the core would, first, heat up and boil the water; the steam from this section would then reverse course and head down through a central superheating core (of wholly different construction) and then exit the reactor. Below, we see a flow diagram showing the steam system as the plant was redesigned.

Pathfinder flow diagram.  Nuclear Reactor Plant Data, Volume 1 - Power Reactors.  ASME 1959

Pathfinder flow diagram. Nuclear Reactor Plant Data, Volume 1 – Power Reactors. ASME 1959

Construction and testing of Pathfinder proved exceedingly difficult and protracted—in part, no doubt, because of the groundbreaking design of the reactor itself, but also because of the complicated control and indication systems required for the plant. Without getting into deep technical detail, this plant’s control system was made highly complicated by the need to incorporate many automatic protections for the superheater itself, as well as protections against rapid changes in flow or power. It also seems clear in retrospect that A-C’s relatively small and new Atomic Energy Division was in well over its head.

Construction of the plant began in July 1959; at that time, the reactor was expected to attain criticality in May 1962 with full commercial operation expected sometime in the fall of 1962. In fact, construction of the plant was completed in summer of 1962 but the control rod drives and vessel internals were not shipped to the site until October. After this, a drawn-out period of contesting with the AEC over the plant protection and control systems ensued so that the AEC did not even issue a low power operating license to NSP until March 1964; the reactor was made critical on March 24, 1964.

 Pathfinder Core A

Above: A look directly downward at the Pathfinder reactor core. The boiling elements around the exterior of the core surround the superheater at center. This view is only inside the core shroud; outside of this, but of course inside the reactor vessel, were a large number of submerged steam separators—designed to remove entrained steam from water being carried down to the recirculating pumps. Source: Northern States Power Company—Pathfinder Atomic Power Plant Operations Manual, Allis-Chalmers Manufacturing Company/Atomic Energy Division, Preliminary, December 1961, Will Davis collection.

All of 1965 and 1966 were taken up with low power testing of the reactor and adjustment and modification of varied instrumentation and systems. NSP declared the plant to be in commercial operation August 1, 1966, but in fact the plant was not ready for sustained operation. Finally, in early 1967, the plant briefly achieved 90-percent power; the stage was set for the full power test. Further control problems delayed the test, but it was finally conducted in September—the plant, according to NSP, ran at its full rated power for 30 minutes, and was then to be inspected. This led to the lore about the reactor only ever achieving rated power for a half hour—and this is true, but only to an extent. The truth is below.

The Pathfinder reactor as actually built was designed to develop 203 MWt; the boiler section contributing 164 MWt and the superheater 39 MWt. The turbine generator was rated 66 MWe gross, with a net output of 61.8 MWe. However, the official NSP history states that the full power run of the plant was done at 58 MWe—obviously not the full rating. Only after examining the actual reactor plant manuals do we discover that the initial testing of the plant was planned for a lower superheat temperature (725 °F instead of 825 °F—see the flow diagram) and for a boiler power of 157.4 MWt/superheater power of 31.5 MWt. This was slated to develop (according to the manual) 62.5 MWe gross and 58.5 MWe net. Thus, the storied “only ran at full power for 30 minutes” is actually “only ran at its reduced, initial operation parameters for 30 minutes.” The reactor never did achieve its designed operating full power of 203 MWt.

Pathfinder Core BLeft, side view of the Pathfinder core. The boiler elements were constructed with low enriched uranium, but the superheater elements (originally planned for about 20% enrichment) were actually constructed with 93% enriched uranium. The reactor had both boiler and superheater control rods—but the superheater rods did not move on a scram; instead, they moved in at normal speed on “runback.” The superheater had to have steam flow in order to maintain cooling—and this led to much further complication on loss of steam flow (turbine trip, etc.) to ensure steam still flowed through the superheater long enough to cool it safely.

After the full power run was completed, the reactor was disassembled partly for examination and removal of some poison shims. Alarmingly, it was seen that the bottom ends of the steam separators around the reactor core had suffered “gross failure,” and the superheater elements’ seven and a half thousandths of an inch thick cladding was suffering high erosion. Further, during the shutdown the main condenser tubes had leaked, and some contamination had spread to the secondary plant. NSP had seen enough; in November, just two months after the 30-minute full power test (which came about five years after originally planned) it decided to shut down the plant permanently and decommission the reactor.

Statements by NSP officials in the company’s official history place most of the blame for the failure of the plant on the incorporation of the superheater, saying that it was the expense of including this design that doomed the plant. One wonders if the tipping point, indeed, had been the decision almost a decade earlier to “grab the brass ring,” and go for superheating in the reactor itself. What’s clear is that this was the only time this was attempted on U.S. soil in a commercial power reactor (another quite different boiler-superheater reactor was operated briefly in Puerto Rico, under AEC auspices and designed by General Nuclear Engineering/Combustion Engineering, and also led to no further progress).

Pathfinder post card, Will Davis collection.

Pathfinder post card, Will Davis collection.

The Pathfinder plant was written off by NSP in 1968; it was converted to a fossil fired peaker plant known as Pathfinder Peaking Plant. The isolated nuclear steam supply system was placed in SAFSTOR until 1991–1992 when decommissioning was performed; the peaking plant operated until summer 2000 when the cooling tower collapsed during severe weather. At that time, the plant’s owner, which by this time was Xcel Energy, decided to completely decommission the entire former Pathfinder plant. The Angus Anson Generating Station is immediately adjacent to the former Pathfinder site.

The silver lining of this whole affair? Well, for superheating reactors there was none. But for NSP, there was—company officials directly credit their long experience with Pathfinder as having contributed materially to their nuclear staff, their nuclear safety culture, and their successful construction and operation of Monticello and Prairie Island nuclear stations with little problem. In that sense, Pathfinder actually did live up to its name.

We find ourselves, today, far removed from Pathfinder, and the other nuclear superheating experiments (principally the ESADA superheat reactor, BORAX-V and BONUS in Puerto Rico) and so it’s no surprise that they’re largely forgotten. What we glean from learning about them is that the seemingly perfect direct match of a superheated steam producing reactor and an already built steam plant can’t be achieved, at least not with water-cooled reactors as are employed at the vast majority of the world’s nuclear generating stations today and as are planned under the Department of Energy’s SMR program as presently envisioned—although other programs exist to develop, for example, high temperature gas cooled reactors. This will be important to explain to the general public, who may either wish to see a wide deployment of nuclear energy to replace GHG-emitting sources, or on the other hand may be afraid of nuclear energy and thus could be desirous of more, and better, information.

*  The other was Dairyland Power Co-Operative’s Genoa No. 2 unit, known better in nuclear circles as the LaCrosse Boiling Water Reactor. A third reactor, the Elk River Reactor, fell under A-C’s control when ACF Industries sold its nuclear business to A-C in 1959. As a matter of interest, A-C also bought most of ALCO Products’ nuclear business in 1962. A-C announced it was exiting the nuclear business (except for providing support to projects still underway) on March 25, 1966, citing serious doubt that it would become profitable in the foreseeable future.



• Northern States Power Company—Pathfinder Atomic Power Plant Operating Manual, Allis-Chalmers Manufacturing Company 1961 (multiple volumes)

• “The Energy to Make Things Better”—An Illustrated History of Northern States Power Company.  Northern States Power Company, 1999.

• Nuclear Reactor Plant Data, Volume 1—Power Reactors, 1959.  American Society of Mechanical Engineers. McGraw-Hill, New York, 1959.

• Pathfinder Decommissioning Plan, Xcel Energy, February 2004.

(All items above in Will Davis collection; many thanks to Ray Dennis.)


For more information:

Pathfinder was partially funded by the AEC under the Power Demonstration Reactor Program. Read about that program here.

The recent EPA announcement stirred a fury of attention for nuclear power. The path forward is not something that can be immediately established, and doesn’t include a whole lot of easy answers. Read about the path forward here.


SavannahWillinControlRoomWill Davis is the Communications Director for the N/S Savannah Association, Inc. where he also serves as historian and as a 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.

Spent fuel pool fire risk goes to zero a few months after reactor shutdown

By Rod Adams

It’s time to stop worrying about the risk of a spent fuel pool fire at decommissioned nuclear reactors. Even at operating reactors, there is good reason to put the risk quite low on any table that prioritizes items worth fretting over.

According to modern analysis using up-to-date data and physically representative models—with appropriately conservative assumptions—the staff at the U. S. Nuclear Regulatory Commission has reached a series of important conclusions:

1. Spent nuclear fuel storage pools are strong, robust structures that are highly likely to survive even the strongest of potentially damaging events. That is true for even the most limiting case of elevated pools used in Mk 1 boiling water reactors:

The staff first evaluated whether a severe, though unlikely, earthquake would damage the spent fuel pool to the point of leaking. In order to assess the consequences that might result from a spent fuel pool leak, the study assumed seismic forces greater than the maximum earthquake reasonably expected to occur at the reference plant location. The NRC expects that the ground motion used in this study is more challenging for the spent fuel pool structure than that experienced at the Fukushima Daiichi nuclear power plant from the earthquake that occurred off the coast of Japan on March 11, 2011. That earthquake did not result in any spent fuel pool leaks.

(Emphasis added.)

2. If an event even more powerful than the already extreme assumption occurs and a pool is damaged enough to cause a significant leak, it is almost certain that the used fuel inside the pool will remain intact. The only period in which there is any doubt about that statement is during the first few months after the most recently operating fuel has been put into the pool:

In the unlikely situation that a leak occurs, this study shows that for the scenarios and spent fuel pool studied, spent fuel is only susceptible to a radiological release within a few months after the fuel is moved from the reactor into the spent fuel pool. After that time, the spent fuel is coolable by air for at least 72 hours. This study shows the likelihood of a radiological release from the spent fuel after the analyzed severe earthquake at the reference plant to be about one time in 10 million years or lower.

(Emphasis added.)

3. Even if all else fails, and—somehow—there is an event that both empties the pool and causes the protective cladding on the fuel to catastrophically fail, the chance of anyone being exposed to enough radioactive material to cause a dose that would have any health impact is vanishingly tiny:

If a leak and radiological release were to occur, this study shows that the individual cancer fatality risk for a member of the public is several orders of magnitude lower than the Commission’s Quantitative Health Objective of two in one million (2×10-6/year). For such a radiological release, this study shows public and environmental effects are generally the same or smaller than earlier studies.

(Note: The quoted statements come from pages iii and iv of Consequence Study of a Beyond-Design-Basis Earthquake Affecting the Spent Fuel Pool for a U.S. Mark I Boiling Water Reactor dated October 2013. The numbered statements are my interpretation of what the analysis results mean to the rest of us.)

The staff at the NRC did not reach these conclusions lightly. Even though the NRC and its predecessor agency have been encouraged to study this area in excruciating detail for more than 40 years, the publicity surrounding the events at Fukushima and the mistaken belief that there were leaks from the spent fuel pools at that plant caused the agency to initiate yet another study, the results of which are quoted above.

That study was not a minor effort. After reviewing the document, which includes a total of 416 pages of material, including detailed responses to comments, I contacted the NRC public affairs office and asked the following question: “How much NRC time and money was invested into the production of the document titled “Consequence Study of a Beyond-Design-Basis Earthquake Affecting the Spent Fuel Pool for a U. S. Mark 1 Boiling Water Reactor” dated October 2013?”

Here is the answer I received from Scott Burnell, NRC Office of Public Affairs:

The staff was able to provide the following information. In FY2011, 11 staff worked a total of 275.75 hours on the Spent Fuel Pool Study. In FY2012, 24 staff worked a total of 4,623.25 hours on the project. In FY2013, 22 staff worked a total of 6,253.75 hours on the project. And for the portion of FY2014 until the report was submitted, eight staff worked a total of 378.5 hours on the project.

That makes a total of 11,530.25 hours. That is more than 5 person-years, but it involved at least 24 separate individuals. The current professional staff hour rate for the US NRC is $272, so the NRC staff time associated with the study cost licensees $3,136,228. There are many other costs associated with a study like this that are not included in that total.

It is no wonder to me that four of the five NRC commissioners—who have been appointed and confirmed as independent, knowledgeable professionals charged with ensuring that all activities associated with using radioactive material in the United States are adequately safe—voted to move on and stop studying the non-issue of storing used fuel in licensed spent fuel pools.

That decision was recorded on May 23, 2014, and documented in COMSECY-13-00030:

The Commission has approved the Staff’s recommendation that this Tier 3 Japan lessons-learned activity be closed and that no further generic assessments be pursued related to possible regulatory actions to require the expedited transfer of spent fuel to dry cask storage.

The only vote against closing the issue and continuing with more study and analysis was NRC Chairman Macfarlane. She is not only an academic with the  common academic belief that it’s worthwhile to keep studying interesting issues, even if they seemingly have little importance, but is also someone with a long publication history questioning virtually all spent fuel storage options.

It is also no surprise to me that Senators Boxer and Markey and their staffs have failed to get the message, and continue to insist that yet more expenditures be devoted to this issue, even though it has no impact on safety.

Finally, it is not surprising that professional nuclear energy skeptics such as the Natural Resources Defense Council and the Union of Concerned Scientists insist that the NRC analysis was incomplete, that there were scenarios that were not studied, and that there were hidden consequences that were not included. After all, interfering in all possible ways with any activity designed to provide temporary or permanent answers to the question: “What do you do with the waste?” has been a plank of the antinuclear platform for at least 40 years.

The effort to constipate nuclear energy by focusing on “the waste issue”, including pushing an expensive effort to move used fuel to dry casks as soon as possible, has been ongoing ever since Ralph Nader gathered a disparate collection of local activist groups in the summer of 1974 under the Critical Mass Energy Project banner.

There is no reason to keep expending money on this particular aspect of the waste issue. Dry cask storage is acceptably safe for an indefinite period of time. However, wet storage in licensed spent fuel pools is also acceptably safe for an indefinite period of time, even in spent fuel pools whose storage capacity has been computed, based on experience and careful study, to be substantially larger than was initially assumed when the pools were first designed in the 1960s and early 1970s.

spent fuel pool 303x201




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.

Nuclear Energy Bloggers’ Carnival, edition 212

carnivalThere is a lot going on in nuclear energy lately—and a correspondingly sizable haul of contributions by the internet’s nuclear bloggers this week, posted at Next Big Future.  A new US EPA rule on power plant carbon emissions figures prominently.

Each week, a new edition of the Carnival is hosted at one of the top English-language nuclear blogs. This rotating feature of nuclear “posts of the week” represents the dedication of those who are working toward a future of energy abundance, improved health, and broadened security through nuclear science and technology.

Past editions of the carnival have been hosted at Yes Vermont Yankee, Atomic Power Review, ANS Nuclear Cafe, NEI Nuclear Notes, Next Big Future, Atomic Insights, Hiroshima Syndrome, Things Worse Than Nuclear Power, EntrepreNuke, Thorium MSR and Deregulate the Atom.

This is a great collaborative effort that deserves your support.  If you have a pro-nuclear energy blog and would like to host an edition of the carnival, please contact Brain Wang at Next Big Future to get on the rotation.

Nuclear Matinee: CNBC’s Where The Jobs Are—The New Nuclear Generation at V.C. Summer

CNBC’s Mary Thompson visits the construction site of two new nuclear energy reactors at V.C. Summer Nuclear Generating Station in South Carolina, and talks with South Carolina Electric & Gas Company Chief Nuclear Officer Jeffrey Archie about new construction and operation jobs—in South Carolina and industry-wide.

Thanks to CNBC for sharing this video

cnbc vc summer snip 367x201

A CAN-CAN Dance around Vermont Yankee Decommissioning

By Howard Shaffer

View1Our Sierra Club local chapter recently sponsored a joint presentation—by two local anti-nuclear groups. A small audience of attendees heard of the horrors that citizens might expect during Vermont Yankee’s upcoming decommissioning. The presenters claimed that their participation in decommissioning will be needed to insure that all goes well because Entergy, and the US Nuclear Regulatory Commission, can’t be trusted. Included as usual was a litany of things about to go wrong—all caused by nuclear power!

The dancers

The partners were Citizens Awareness Network (CAN) leader Deb Katz of Massachusetts, and Citizens Action Network (also known as CAN) leader Chris Williams of Vermont and the Beyond Nuclear group. Using a new PowerPoint presentation, which anti-nuclear groups will undoubtedly use a lot more in the future, they detailed their fears and plans. They worked in a “tag team” switching back and forth a few times.

(Are the identical group name acronyms coincidental? The local press uses CAN for both, making it seem there is one larger organization.)

Katz has been active for many years in local opposition to the Yankee plant at Rowe, Massachusetts, and Vermont Yankee

Williams is a life-long anti-nuclear activist, by his own proud admission and his resume, beginning right out of college. He claims as a signal achievement the torpedoing of the proposed Marble Hill nuclear plant in Indiana. While retired in Vermont, he has been organizing and leading opposition to Vermont Yankee too

Their message—and what really happened

“We won” was Deb Katz’s opening line, referring to Entergy’s decision to shut down and decommission the Vermont Yankee plant by the end of the fuel cycle this year.

However, the “we” really didn’t do much winning. The Vermont Yankee plant has a 20-year license extension from the NRC, but projected an unprofitable future competing in the New England energy market against (currently) low natural gas prices. Entergy decided to plan to shutter the plant on its own… although it is possible that there was some political pressure on Vermont’s two energy utilities to not sign long-term contracts with the plant.

The presentation then went on to include the following messages (followed by my own analysis):

“We gave up on the NRC and targeted companies’ finances to make it hard for them to do business.”

True. Nuclear energy opponents have used every available means to run up costs. One of the latest was getting the Red Cross to claim that they needed to shelter an absurdly large number of people for an extended period, if there ever were an evacuation. The funding is to come from Vermont Yankeesee Vermont Yankee asked to pay $200,000 in 2014.

Connecticut Yankee and Yankee Rowe (Massachusetts) decommissionings had problems and cost overruns. Rate payers are still paying because decommissioning trust funds were exhausted. The Yankee Rowe site has PCB contamination and is a chemical pigsty.

Once again the tactic is to compare nuclear power to perfection. To compare Yankee Rowe’s initial cost to the decommissioning cost, without adjusting for 45 years of inflation, is absurd economicsbut also a tactic.

Vermont Yankee is the first Merchant Plant to be decommissioned, and if its decommissioning trust fund is exhausted, Vermont taxpayers will be stuck with the bill.

The NRC has stated that it will go back to the original owners, if necessary, to get the necessary funds for decommissioning. Congress intended for those who benefited from operating the plants to pay for decommissioning, not any government.  Meanwhile, a loss of funding for various purposes in the region from the Vermont Yankee plant will be keenly feltsee Millions for education, but not one cent for tribute.

The plant could have a fuel pool fire which would be devastating.

This of course has never happened and remains hypothetical.  At any rate, left out is time available for responders to intervene if such an event were to somehow come to pass.

Many nuclear power plants were bought at “fire sale” prices. The Decommissioning Trust Fund can be claimed as an asset. Executives are selling their stock. All Entergy nuclear plants are in trouble financially (i.e., it’s all about making money).

Actually, rather typical business practices are all that has been going on. Taking standard accounting rules and claiming some unique fault of nuclear power is a common tactic.

There needs to be a Citizens Advisory Panel to oversee the decommissioning process. The panel needs training. The Vermont State Nuclear Advisory Panel (VSNAP) should transition to a citizens’ panel. This should be in the Vermont budget bill this year.

Vermont (H.885) established the “Vermont Nuclear Decommissioning Citizens Advisory Panel,” replacing the Vermont State Nuclear Advisory Panel (which was a forum for anti-nuclear activism). The new panel includes two members appointed by the plant, one Union member from the IBEW who worked at the plant, representatives from towns in the 10-mile emergency planning zone, and state agencies.

This is a dangerous time. We are seeing the death spiral of Utilities. The Koch brothers are trying to stop it.

Why the demise of utilities would be such a good thing is not stated. Utilities, after all, are buying power from renewable sources under state mandates. Claiming dangers from a crisis of desperation sounds like a scare tactic.

We have three years to make good energy choicesto the next ISO auction (New England Independent System Operator, the regional grid manager).

What was not said was what terrible thing might happen if what they define as “good” is not done. 

Baseload for renewables is not needed. Hydro Quebec is the backup.

Hydro Quebec’s vast capacity is then the baseload. Another scare tactic.

Baseload will destroy renewables.

Baseload and renewables are coexisting right now. This statement shows a complete lack of knowledge of alternating current power supply realities. A great deal of research and development is ongoing to attempt to develop economical large-scale electric energy storage. If this comes into existence, then renewables plus storage will be part of baseload.

Positive notes

There was no media coverage.

Williams was supportive of a recent agreement between Vermont and Entergy, approved by the Public Service Board and in the Certificate of Public Good, under which the plant is continuing to operate. He said that it gets the job done. Katz was not so happy about the agreement, saying that it didn’t go far enough (surprise, surprise).

The future

We can expect more of the same by nuclear energy opponents locally and nationally—including a citizens’ panel underway for the San Onofre plant decommissioning.

Williams has been to the Palisades plant area in Michigan and expects to continue to help the opposition there. That plant has a license extension and a long-term contract.

can can dancers 320x260




Howard Shaffer has been an ANS member for 35 years.  He has contributed to ASME and ANS Standards committees, ANS committees, national meeting staffs, his local section, and was the 2001 ANS Congressional Fellow. He is a former member of the ANS Public Information Committee, consults in nuclear public outreach, and is coordinator of the Vermont Grassroots Project.  Shaffer holds a BSEE from Duke University and an MSNE from MIT. He is a regular contributor to the ANS Nuclear Cafe.

Recap from the 6th Thorium Energy Alliance Conference

By Lenka Kollar

The 6th annual Thorium Energy Alliance Conference was held in Chicago, Ill., last week and brought together professionals from the nuclear fields and others interested in energy issues.

Thorium as an energy source is not always a frequent point of discussion within the American Nuclear Society because the existing nuclear fuel cycle in the United States, and that of all other countries that use nuclear energy, is based on uranium. However, the potential for using thorium as an energy source is great and we should keep our minds open to researching alternative nuclear energy technologies (see “The Use of Thorium as Nuclear Fuel” – ANS Position Statement 78).



The conference started with opening remarks from Thorium Energy Alliance Executive Director John Kutsch, in which he explained that we have a “perceptual blindness” to the second- and third-order technologies that today’s research can create. He emphasized that we need to be thinking of the vast possibilities for new nuclear energy technology and the role that thorium can play in advanced reactor designs.

So, why use thorium if we already have a uranium fuel cycle? According to the TEA website, a thorium power plant will produce less than 1 percent of the waste of that from a traditional uranium power plant of the same magnitude. The waste from a thorium plant is also benign in less than 200 years, while uranium power plant waste remains radioactive for over 10,000 years. Also, thorium is much more abundant in the earth’s crust than uranium.

msr 400x293

In a liquid fluorite thorium reactor (LFTR) design, thorium and uranium-233 are dissolved in fluoride-based salts to form a liquid fuel. This fuel is pumped between the core and a heat exchanger to transfer heat to a secondary salt loop, which then transfers the heat to a steam turbine, as illustrated in the image above. This technology was first investigated at the Oak Ridge National Laboratory Molten-Salt Reactor Experiment in the 1960s.

If you want to learn more about thorium, check out the “Th” Thorium Documentary video playlist on YouTube, created by one of the TEAC6 conference attendees, Gordon McDowell. You can also see tweets from the event by clicking on #TEAC6 and support the cause through the Energy From Thorium Foundation. In addition, look forward to a new documentary coming out soon about the benefits of nuclear energy and using thorium as fuel, called The Good Reactor.


lenka kollar 127x150Lenka Kollar is the Owner & Editor of Nuclear Undone, a blog and consulting company focusing on educating the public about nuclear energy and nonproliferation issues. She is an active ANS member, serving on the Nuclear Nonproliferation Technical Group Executive Committee, Student Sections Committee, and Professional Women in ANS Committee. Connect with Lenka on LinkedIN and Twitter.

Nuclear Energy Blogger Carnival 211

ferris wheel 202x201The 211th Carnival of Nuclear Energy Bloggers and Authors has been posted at The Hiroshima Syndrome.  You can click here to access this latest entry in a long running tradition among the top English language pro-nuclear bloggers and authors.

Each week, a new edition of the Carnival is hosted at one of the top English-language nuclear blogs. This rotating feature of nuclear “posts of the week” represents the dedication of those who are working toward a future of energy abundance, improved health, and broadened security through nuclear science and technology.

Past editions of the carnival have been hosted at Yes Vermont Yankee, Atomic Power Review, ANS Nuclear Cafe, NEI Nuclear Notes, Next Big Future, Atomic Insights, Hiroshima Syndrome, Things Worse Than Nuclear Power, EntrepreNuke, Thorium MSR and Deregulate the Atom.

This is a great collaborative effort that deserves your support.  If you have a pro-nuclear energy blog and would like to host an edition of the carnival, please contact Brain Wang at Next Big Future to get on the rotation.

Plutonium Disposition by “Downblending and Disposal”

By Adam Hoffman

Plutonium_ring 211x201The subject of plutonium disposition has a long history that dates back to the end of the Cold War, combining complex technical, policy, and diplomatic issues. A discussion of this history is timely because the Department of Energy recently released a report1 evaluating technological alternatives to the current approach of disposing of plutonium using mixed oxide (MOX) fuel. One option—referred to as “downblending and disposal”—was assessed favorably in terms of cost, timeliness, and technical risk, but it introduces new technical and political challenges. This blog post provides a brief summary of the storied history of plutonium disposition.

In the wake of the Cold War, the United States and Russia were left with stockpiles of excess weapons-grade uranium and plutonium. In order to fulfill treaty commitments while supporting the global nuclear nonproliferation regime, the U.S. and Russia signed the Plutonium Management and Disposition Agreement2 (PMDA) in 2000. In this agreement, both parties committed to dispose of at least 34 metric tons of excess weapons-grade plutonium, primarily as MOX fuel for light water nuclear reactors. In 2010 this agreement was amended to permit Russia to consume plutonium in fast reactors with limitations on the production of additional weapons-grade plutonium.

The MOX approach was selected based on several evaluations of plutonium disposition options, including a 1994 report by the National Academy of Sciences (NAS) titled “Management and Disposition of Excess Weapons Plutonium.” This report advocated a “spent fuel standard” whereby the plutonium would be converted “to a form from which the plutonium would be as difficult to recover for weapons use as the larger and growing quantity of plutonium in commercial spent fuel.” The report recommended two options that fulfilled this objective: the consumption of plutonium in MOX fuel and the immobilization of plutonium with high-level radioactive waste (HLW). Although the report did not explicitly consider “downblending and disposal,” it recommended against vitrification without HLW, noting that “[f]or states such as Russia or the United States, a chemical barrier alone would be insignificant.”

To convert the weapons-grade plutonium to MOX fuel, the U.S. would build a MOX Fuel Fabrication Facility (MFFF) at the DOE’s Savannah River Site. In 2002, the DOE estimated that the MFFF would cost about $1 billion, but by 2007 the cost had escalated to $4.8 billion. In 2013 the construction cost further increased to $7.8 billion, and as of 2014 the total life-cycle costs of the MOX program are estimated to be about $30 billion. In light of the current budget environment, this cost escalation prompted the DOE to evaluate alternatives for plutonium disposition.

In April 2014, the DOE released a report comparing five options for plutonium disposition including the current MOX program. Of those options, “downblending and disposal” was assessed most favorably in terms of technical risk and expense, with a life-cycle cost estimate of only $9 billion. In this option, plutonium oxide would be mixed with inhibitor materials and disposed at a geologic repository. The Waste Isolation Pilot Plant (WIPP)—a repository for defense-related transuranic waste near Carlsbad, New Mexico—served as the reference case. WIPP received its first shipment of nuclear waste in 1999, and it has already disposed of several tons of plutonium from the Rocky Flats Plant. While the waste form for this option may not meet the “spent fuel standard” endorsed by the NAS report because it lacks a radiation barrier, this could potentially be offset by achieving a geologic barrier much sooner than would be possible for spent MOX fuel or vitrified HLW.

However, the downblending option faces several significant challenges. First, it would require a supplemental agreement with Russia pursuant to Article III of the PMDA. In the past, Russia has been reluctant to accept disposition options that do not degrade the isotopic distribution of the plutonium from weapons-grade to reactor-grade, including vitrification with HLW. In addition to not altering the isotopic distribution, downblending also lacks a radiation barrier. Thus downblending would represent a significant deviation from the existing bilateral agreement, complicating negotiations with Moscow.

In addition, there are technical and policy challenges associated with using WIPP as the geologic repository. First, WIPP does not have sufficient remaining statutory capacity to accept the 34 metric tons of plutonium associated with the PMDA. As a result, using WIPP for disposition could require the amendment of existing legislation or enactment of new legislation. Further complicating this option, there was an accidental release of radioactive material from WIPP in February. This event is under investigation, and it is possible that WIPP may not reopen for years. While an alternate repository can be used in place of WIPP, the licensing process adds significant uncertainty and could substantially erode the estimated cost savings for this option.

Downblending and disposal of excess plutonium is under consideration given the motivation to demonstrate progress in meeting nonproliferation objectives, delays in the U.S. MOX program, and the current federal fiscal environment. To foster a discussion of this topic, the American Association for the Advancement of Science will host a breakfast panel event on the morning of Wednesday, June 4, in Washington, DC on “downblending and disposal” as an option for weapons-grade plutonium disposition under the PMDA (link to RSVP). In light of the benefits and challenges associated with the downblending and disposition option, we expect a lively and informative discussion and invite American Nuclear Society members to attend. In addition, ANS will host a conference on plutonium science September 7–12, 2014, in Las Vegas, NV.


1Report of the Plutonium Disposition Working Group: Analysis of Surplus Weapon-Grade Plutonium Disposition Options,” Department of Energy, April 2014.

2Formally titled the Agreement between the Government of the United States of America and the Government of the Russian Federation Concerning the Management and Disposition of Plutonium Designated as No Longer Required for Defense Purposes and Related Cooperation


adam hoffman 100x137Dr. Adam Hoffman is an intern with the Center for Science, Technology, and Security Policy at the American Association for the Advancement of Science, where he is supporting various Center initiatives and programs. In September of 2013, Adam completed a Ph.D. in Nuclear Engineering and Radiological Sciences at the University of Michigan.  After completing the internship, Adam will begin the National Nuclear Security Administration Graduate Program at the U.S. Department of Energy, working in nuclear nonproliferation.

Nuclear Energy Blogger Carnival 210

ferris wheel 202x201The 210th Carnival of Nuclear Bloggers and Authors has been posted at Atomic Power Review.  You can click here to access this latest entry in a long running tradition among the top English language pro-nuclear bloggers and authors.

Each week, a new edition of the Carnival is hosted at one of the top English-language nuclear blogs. This rotating feature of nuclear “posts of the week” represents the dedication of those who are working toward a future of energy abundance, improved health, and broadened security through nuclear science and technology.

Past editions of the carnival have been hosted at Yes Vermont Yankee, Atomic Power Review, ANS Nuclear Cafe, NEI Nuclear Notes, Next Big Future, Atomic Insights, Hiroshima Syndrome, Things Worse Than Nuclear Power, EntrepreNuke, Thorium MSR and Deregulate the Atom.

This is a great collaborative effort that deserves your support.  If you have a pro-nuclear energy blog and would like to host an edition of the carnival, please contact Brain Wang at Next Big Future to get on the rotation.