Monthly Archives: April 2011

Nuclear News publishes Special Report on Fukushima

Nuclear News, the monthly publication of the American Nuclear Society, today published a Special Report on Fukushima Daiichi after the earthquake and tsunami.  The 8-page Special Report will be included in the April 2011 edition of Nuclear News, which has been mailed to subscribers.

The April 2011 Nuclear News also contains a special section on outage management, which includes the following features:

  • an interview with Tim Borgen about Monticello’s outage training center
  • Point Lepreau Refurbishment Project—A second go at retubing
  • A low-key refueling results in outage success at Fermi-2

For more information—including how to subscribe—visit the ANS website.

Decommissioning Fukushima

It has all the challenges of Three Mile Island plus there are four damaged reactors not just one

By Dan Yurman

The effort to contain the nuclear reactor crisis at Fukushima brings to mind the 1933 horror movie King Kong, in which a giant ape, escaped from captivity, and perched at the top of the Empire State Building, is fatally wounded by a swarm of war planes of the era.

King Kong - image source Wikipedia

While fictional film character Carl Denham intones his famous last line “It was beauty killed the beast,” a less prosaic New York sanitation department might have been wondering how to remove a giant dead gorilla carcass from the corner of 5th Ave. and 34th St.

Kong’s fall would have created a cleanup problem of  immense scale. It would have been “beyond the design basis” of even the entire fleet of city garbage trucks.

Six gorillas at Fukushima

This dramatic movie metaphor is relevant as a visual image of the scope of the problem faced by Tokyo Electric Power Corp. (TEPCO) with the eventual decommissioning of six reactors at Fukushima. The utility doesn’t have just one dead giant gorilla, there are six. The first three nuclear reactors are likely to be found to be fatally compromised with heat damaged fuel assemblies from loss of cooling water.  Partial melting of fuel may be part of the problem.

Massive hydrogen explosions blew the roofs off of secondary containment structures at reactors 1, 3, and 4. The fourth reactor is also likely severely damaged beyond repair. Its spent fuel pool is exposed to the open air as a result of one of the huge hydrogen explosions.

The fifth and sixth reactors, relatively undamaged, may never restart because of wrecked balance of plant infrastructure and ferocious public opposition which is leveraged by Japanese law that gives veto power over nuclear facilities to the provincial government.

BWR reactor schematic. Image from World Nuclear Association

The 15-meter high tsunami swept away the normal infrastructure of a nuclear power station which, along with rubble from the hydrogen explosions, put debris across access roads and rail sidings blocking delivery of emergency equipment. Efforts to control leaks from buildings and trenches may go on for months or years. In short, it will be a very dangerous place to conduct cleanup work.

Precedent from Three Mile Island

The precedent TEPCO will have to rely on is the cleanup of the Three Mile Island (TMI) accident in the U.S. The cleanup of the badly damaged reactor at Three Mile Island, which began in 1979, took more than a decade ending in 1993. TEPCO’s timeline may be much longer.

The New York Times reported that the first major phase of the TMI cleanup was completed in April 1990, when workers finished shipping 150 tons of radioactive wreckage from the damaged reactor vessel to Idaho for storage. According to a history of the Idaho lab’s involvement in the project, 49 casks containing reactor fuel debris were transported by rail through 10 states in 22 shipments. Cleanup at that point had cost over $1 billion.

TMI cask on US Hwy 20 near INL. Image courtesy Idaho National Laboratory

There are significant differences between the situation at TMI and Fukushima. The biggest and most dangerous differences are the extent of uncontrolled radioactive contamination outside the reactors at the plant site.

A second cleanup challenge, unlike the TMI experience, is that the surrounding countryside in Japan is like a war zone with lack of access by road and rail, power lines are down, and potable water, food, and housing are all in very short supply.

There some immediate steps TEPCO needs to take to start the cleanup process at Fukushima. It must get most of the radioactive water off the site and control what remains. It needs to control radioactive debris from the hydrogen explosions. Most importantly, it must find a path to remove the fuel from the damaged reactors or execute a plan to store it in place indefinitely.

Drying out the Fukushima reactor site

The removal of huge volumes of radioactive water from the site is the first priority. The Japanese have been pouring uncounted tons/day of water on four reactors since mid-March.  Headlines in the news media on April 5 report TEPCO needs to remove 11,500 metric tonnes of water from the plant.

The Wall Street Journal reported April 5 that TEPCO was discharging 4,800 (short) tons/day of radioactive water directly into the ocean. That would be 96,000pounds or about 11,500 gallons of water. TEPCO characterized the radioactivity level of the discharge as “low.”

Fukushima reactor complex prior to March 11, 2011

According to the WSJ, authorities said about 20,000 tons of radioactive seawater still remain in the turbine building and the cable trench of each of reactors Nos. 1-3, for a total of 60,000 tons. That’s 120 million pounds of water or 14,370,000 gallons of water. (1 gallon of water weighs 8.35 pounds)

Readers should be aware that the western press has had numerous difficulties with translations of Japanese language reports of reactor status information. Mistakes and errors by TEPCO, as well as wholesale retractions, have created problems for almost all numerical references from the utility subjecting them to continuous second guessing and review.

Anyway you count it, there is a lot of water and no way to store or dispose of it on the site. The option exists for TEPCO is to run a pipeline several miles out to sea from the reactor site and pump the water out there.

According to a BBC report for April 4, 2011, the Kuroshio Current is the North Pacific equivalent of the Gulf Stream in the Atlantic. It hugs the Asian continental slope until about 35 degrees North, where it is deflected due east into the deep ocean as the Kuroshio Extension.

Experts interviewed by the BBC say this means pollutants in its grasp, such as radioactive water from Fukushima, will tend over time to be driven out into the middle of the Pacific where they will become well mixed and diluted over time.

There will likely be heated political objections to this scenario, but TEPCO is more or less out of land-based options. It needs to get the radioactive water out of the plant if it has any chance to make progress with gaining control of even more dangerous radioactive contamination throughout the entire reactor complex including spent fuel in Unit 4 and damaged fuel in Units 1-3.

Update July 2011 – TEPCO  installed a water treatment system supplied by Areva to treat 115,000 tonnes of radioactive water.  The system has faced challenges in terms of reliability and output volumes. TEPCO and Areva continue to make progress with the system to achieve its full production capabilities.

Plans to build a pipeline to pump radioactive water out to sea have been set aside, but a giant barge has been pressed into service to carry some low level contaminated water away from the plant via ocean dumping.

Securing the site

Next, the site needs to be washed down to remove surface radioactive contamination. Yes, this will produce more radioactive water, but it’s better to send it out to sea than to leave it in place to harm site workers.

Also, according to an April 6 New York Times report, radioactive particles from the spent fuel pool for unit 4 may have been blown miles away by the hydrogen explosion. These materials need to be found and removed to a safe interim disposal area.

Update July 2011: The government has mapped radioactive hot spots of Cesium-137 outside the 20 km evacuation zone.  Of 57 such hot spots mapped as of 07 July 2011, eight are above 20 mSv which is the Japanese standard for concern.  There have been media reports the C-137 has gotten into the food supply with contamination of feed for cattle and also found in harvested tea leaves.

Fukushima reactor complex after hydrogen explosions at reactors 1, 2 & 4

Fukushima reactor units 1-4 could to be covered by an semi-rigid, inflatable tent the size of a football stadium. This structure, supported by a light steel framework and constant air pressure blown into it, would protect the damaged reactors and cleanup workers from the elements. While a typhoon or other extreme weather could damage the air supported structure, it is easier, quicker, and less costly, to rebuild one than to try to encase all four reactors in a giant concrete shell.

None of this site preparation work can take place until the reactors themselves are in a state of cold shutdown. This may be accomplished through restoration of electrical power and control of the reactor cooling systems. If the cooling systems are damaged, and don’t work, TEPCO will have to come up with a system that does the job which will likely continue producing hundreds of tons a day of radioactive wastewater.

It could be some time, perhaps as long as several years, before remote controlled, radiation hardened robots can be sent into the reactor cores at Units 1-3 to take a look at damage there. The reason is the wreckage of the damaged secondary containment structures at reactor units 1 & 2 will have to be removed so a work crew and their gear can be staged to access the primary containment structure.  Unit 3, which has a relatively intact secondary containment structure, could be the first reactor to give up its secrets.

According to a Wall Street Journal interview April 2 with veterans of the cleanup at TMI, heat damaged fuel elements will be difficult to extract from the reactor pressure vessels especially if temperatures were high enough to melt the zirconium cladding that hold the fuel elements in place. Once that happens, fuel pellets fall to the floor of the reactor pressure vessel.

If the any of the fuel itself is melted, TEPCO might opt to wait for years with a buttoned up reactor pressure vessel and secure primary containment structure for everything to cool down through natural attenuation of residual heat and the cycle of radioactive half lives. Eventually, like TMI, the fuel from the reactors and spent fuel pools could be transferred to permanent dry cask storage.

TMI fuel metl down - Image courtesy Idaho National Laboratory

If TEPCO can’t find safe technical path forward to this solution, then an alternative is to eventually entomb the reactor pressure vessels in place by pouring concrete into the primary containment structures for units 1-3, and the spent fuel pool in unit 4. This solution may be forced on TEPCO if it finds that any of the primary containment structures are damaged from the original earthquake or by aftershocks.

According to a Bloomberg news report for March 30, the government hasn’t ruled out sealing the plants 1-4 in concrete says Chief Cabinet Secretary Yukio Edano. Though he didn’t mention it, one of the issues the government will need to evaluate is whether the primary containment structures could safely hold all that concrete.  That weight could put new stressed on the structures.

Cost of cleanup

TEPCO’s long-term cleanup costs could be in the tens of billions and take decades to complete. This activity alone could turn the utility into a semi-permanent ward of the state unless cleanup, and liabilities, are taken over entirely by the government through some form of receivership for the reactor site.

Fukushima could remain a no man’s land for decades given the huge, almost unimaginable costs of cleanup. The government will likely look to find reasons to stretch out cleanup for financial reasons regardless of domestic and international pressure.  Japan’s government is carrying a huge debt load as it is.

The complexity of performing the decommissioning of six reactors four of which are severely damaged and in an unknown condition will drive up costs at every turn. The last time Japan decommissioned a reactor, which was a clean site, it took the government more than two decades to complete the job.

By comparison, the decommission of the Zion nuclear power plant in Illinois, which is well controlled under regulatory scrutiny from the NRC, is expected to cost $900 million and take a decade to complete. A New York Times report for November 22, 2010, noted it cost Exelon $10 million a year just to “baby sit” the plant in cold shutdown status.

Zion nuclear power station in Illinois awaiting decommissioning

The plant will be chopped up into pieces and shipped to a special landfill in Utah that can receive solid radioactive waste. There will be no separation of radioactive and non-radioactive materials. Everything will be assumed to be radioactive and will go to one disposal site.

Where to put radioactive waste?

This raises a key question for Japan. Where will it dispose of radioactive debris from Fukushima? It can’t leave the material at the seashore to perpetually contaminate the cities and farms in the surrounding countryside and pollute highly productive fishing waters.

The Kyodo News wire service reported April 5 that the Japanese government is studying the possibility of borrowing a Japan-funded radioactive waste disposal facility from Russia to help contain radioactive water.

“We are checking whether it is technically possible to use the facility for this current event, and whether the facility’s machines are working smoothly,” Hidehiko Nishiyama, a spokesman for the government’s Nuclear and Industrial Safety Agency, told a press conference.

Suzuran - At this time, it is moored opposite Vladivostok's shores at the Zvezda Shipyard in Bolshoy Kamen Bay.

He also said Japan has been communicating with Russia about using a floating facility, called Suzuran, (right) which Japan gave to Russia in 2001 to help dispose of low-level radioactive liquid waste from decommissioned nuclear-powered submarines.

Japan gave the facility to Russia as environmental concerns were raised after Russia dumped radioactive waste into the Sea of Japan in 1993 in the process of dismantling its nuclear subs.

There is even less certainty for high level waste and other solid radioactive debris (RH-TRU) which cannot be contact handled in the near term. Ten years ago, Japan created the Nuclear Waste Management Organization of Japan (NUMO) which was established under the jurisdiction of the Ministry of Economy, Trade and Industry.

NUMO is responsible for selecting a permanent deep geologic repository site, construction, operation and closure of the facility for waste emplacement by 2040. Site selection was begun in 2002.

Final selection of a repository location is expected by 2027. Japan may have to speed up the site selection process once it gets serious about the decommissioning of the six reactors at Fukushima. A 2008 briefing shows a lot of process work but not much progress in selecting much less building a geologic repository for high level waste.  There’s a long way to go.


Dan Yurman publishes Idaho Samizdat, a blog about nuclear energy. He is a frequent contributor to the ANS Nuclear Café.

ANS’s Corradini testifies to Congress on Fukushima

On Wednesday, April 6, Dr. Michael Corradini is appearing on behalf of the American Nuclear Society before the U.S. House Energy and Commerce Subcommittee on Oversight and Investigations.

The hearing—which begins at 9:00 am ET—is entitled “The U.S. Government Response to the Nuclear Power Plant Incident in Japan.” A  webcast and additional information, including all prepared testimony,  will be available via the Committee website.   Dr. Corradini’s prepared testimony is below.

In his prepared testimony, Dr. Corradini announces that he has been asked by ANS leadership to serve as co-chair of an ANS Special Commission on Fukushima Daiichi.  Dr. Dale Klein will also serve as co-chair.  This ANS Commission will examine the major technical aspects of the event to help policymakers and the public better understand its consequences and its lessons for the US nuclear industry.

Dr. Dale Klein is associate vice chancellor for research at the University of Texas System and Associate Director of the Energy Institute at the University of Texas at Austin. He was a member of the Nuclear Regulatory Commission from 2006-2010 and served as its chairman from 2006-2009.

Michael Corradini
American Nuclear Society
April 6, 2011

Chairman Stearns, Ranking Member DeGette, members of the
Subcommittee, thank you for the opportunity to testify.


I am currently chair of the Nuclear Engineering and Engineering Physics program at the University of Wisconsin, Madison. I am also involved in a
number of nuclear energy activities for the National Academies, the Department of Energy, and the Nuclear Regulatory Commission. Specifically, I am a member of the DOE Nuclear Energy Advisory Committee and chair of its Reactor Technology Subcommittee. In addition, I am a member of the French Atomic Energy Scientific Committee and the NRC’s Advisory Committee for Reactor Safeguards.

I appear today on behalf of the American Nuclear Society, a professional organization comprised of 11,000 men and women who work in the nuclear industry, the medical community, our national laboratories, universities, and government agencies.

On behalf of all ANS members, I would like to express my deepest sympathies to the people of Japan for their loss and hardship. My sons and I were in Osaka in 1995 at the time of the Kobe earthquake and we witnessed the tragic effects of that natural disaster. From what I have seen from news reports and photos on the web, this is a tragedy that is orders of magnitude more devastating and, thus, even more sobering. While we are here to discuss the Fukushima power plants, I wanted to be sure we put this in context to this tragic natural disaster, with over 12,000 dead and over 15,000 missing.

The American Nuclear Society has organized the Japan Relief Fund, targeted specifically to help our friends, colleagues, and their families in Japan who have been affected by the earthquake and tsunami. More information can be found at the American Nuclear Society website.

The leadership of ANS has asked me to serve as co-chair of a Special Commission on Fukushima Daiichi. This Commission will examine the major technical aspects of the event to help policymakers and the public better understand its consequences and its lessons for the U.S. nuclear industry.

It is probably useful to begin by providing some current information and
perspectives about the events and how they relate to the U.S. plants and safety practices. That is my role here today. I want to briefly focus on three general topics:

  • The effects of the natural disaster on the Fukushima-Daiichi plants.
  • The effects of the accident progression on the surrounding region.
  • How we can learn from these events for our U.S. nuclear industry?

To review these topics, I have made use of the information provided on the
websites of the Tokyo Electric Power Company (TEPCO), the Nuclear and
Industrial Safety Agency (NISA), the Ministry of Education, Culture, Science
and Technology (MEXT), Japan Atomic Industrial Forum (JAIF), and the
International Atomic Energy Agency (IAEA), as well as discussions with colleagues and specific press reports. Although there is so much that we do not know about what has happened in Fukushima and surrounding areas, I have found the information from these sources to be consistent and helpful to answer many questions. This timely availability of information is a tribute to Japan and its institutions since these nuclear troubles occurred in the midst of the response to the many injuries and property destruction caused by the earthquake on the general population.


Fukushima Daiichi, pre earthquake and tsunami

As we now know, the Tohoku earthquake, which occurred at 2:46pm on Friday, March 11th, on the east coast of northern Japan, was measured at 9.0 on the Richter scale and is believed to be the 4th largest earthquake in recorded history. As a point of reference, the next most serious quake was in 2004 off the coast of Sumatra with a tsunami resulting in 227,000 deaths. Following the earthquake on Friday afternoon, the nuclear plants at Fukushima-Daiichi, Fukushima-Daini, and Osonawa plant sites shut down as designed, and emergency power systems were activated as expected; even though the earthquake was beyond the design basis. At the Daiichi plants, the design basis safe-shutdown earthquake was 8.2 as measured on the Richter scale, which is a design base above historical values. The Tohoku earthquake caused a tsunami, which hit the east coast of Japan within the first hour of the quake. The size of the water waves that hit the Daiichi plant were significantly above the design base on which the seawall was constructed (17 ft) to mitigate its effects. The tsunami appears to have been the primary cause of the initial on-site damage, making the backup power systems and associated pumping, electrical and venting systems inoperable for Units 1, 2, 3, 4.

On-site battery power was able to run the emergency control and pumping systems at the plant site until about midnight on Friday and then the plants experienced a loss of all electrical power for an extended period of time. By the afternoon of Saturday, March 12th, portable generators and portable fire pumps were moved onto the Fukushima-Daiichi site and seawater was pumped in to cool the reactor cores for Units 1, 2, and 3. Decay heat was removed by venting the steam from above the containment suppression pools. The initial lack of water-cooling caused the reactor cores to be severely degraded, causing metal-water chemical reactions and hydrogen gas generation. Hydrogen was released during steam venting causing the destructive combustion events in reactor buildings outside of containment.

In addition to cooling the reactors, it has been necessary for plant personnel to replenish the water in each unit’s spent fuel pools that was lost due to water evaporation caused by decay heat. This is especially true for Unit 4, since it was undergoing maintenance at the time of the earthquake and its relatively “hotter” reactor core fuel assemblies were also placed in the spent fuel pool. For reasons that are not completely clear at this time, the water supply at spent fuel pools at these units reached very low levels over the first few days, causing the spent fuel to become severely damaged, resulting in hydrogen generation and combustion, fuel rod cladding failures, and radioactivity releases to the environment. Seawater was then sprayed in to refill these water pools and they now remain cooled.

This mode of cooling continued until fresh water was brought to the site about two weeks after the earthquake. The reactor plants and the spent fuel are now being cooled by injection of fresh water.

Immediately following the earthquake and tsunami and the subsequent loss of on-site electrical power, the Nuclear and Industrial Safety Agency declared a site emergency, and by the evening of March 11th, residents within 10km of the Fukushima-Daiichi plant were instructed to evacuate. By Saturday afternoon, NISA advised residents within 20km to evacuate and those between 20km to 30km away to remain in their homes as shelter or voluntarily leave the area. In the first few days after the earthquake, the airborne radiation levels were much higher than natural background (normally around 0.3 to 0.4 microSieverts per hour). By a week after the event, they had already fallen to levels a couple of times above natural background. In fact, the air-borne doses outside of a 60km radius from the plant now have readings close to normal. At this time this event has not become a national health disaster for Japan.

I would also note that we have the technical capability to measure radiation and its elemental sources in extremely small amounts far below any levels that are harmful to the human body.

The source of the radioactive release is not precisely known, but some indications are that it came primarily from the heating, degradation, and subsequent failure of the spent fuel. The levels of radiation on the plant site were much higher, and following the hydrogen combustion events, only a select crew of workers in rotating shifts was allowed on-site to deal with the emergency. Nevertheless, based on reports from NISA, 21 workers received doses exceeding 100 mSv. No worker has received a dose above 250 mSv, which is the allowable dose limit for emergency workers, and this is similar to standards in the United States.

The safety approach used in designing and testing the plants in Japan are similar to those used in the United States. The U.S. has adopted a philosophy of defense-in-depth, which recognizes that nuclear reactors require the highest standards of design, construction, oversight, and operation. Designs for every individual reactor in the United States take into account site-specific factors and include a detailed evaluation for natural events, as they relate to that site. There are multiple physical barriers to radiation in every nuclear plant design. In addition, there are both diverse and redundant safety systems that are required to be maintained in operable condition and frequently tested to ensure that the plant is in a high condition of readiness to respond to any accident situation.

Satellite photo of damage to reactors 4 (left) and 3 (right) of Fukushima Daiichi on March 16, five days after the earthquake struck.

Nevertheless, this natural disaster exceeded the design basis envelope for those nuclear plants at the Daiichi site and we need to learn from this and continually improve our safety posture so that beyond design basis events can be managed. In the coming months, the NRC will do a review of the accident and the safety posture of our plants. Over the longer term, lessons-learned from this event will be used to review the key areas of plant design, operation, and readiness. I know I speak for all the ANS members, that we stand ready to help the industry and the government in this effort.

To promote some further discussion on these points let me suggest some items to consider. First, the events in Japan accentuated the need for the United States to evaluate our entire civilian infrastructure (not just nuclear plants) and  emergency preparedness for extreme natural disasters. Second, for our nuclear plants, we continually need to ask ourselves “what-if” questions and what we may have missed. This was done for the Three Mile Island accident and this resulted in the Severe Accident Management Guidelines being used in U.S. plants today. I expect that these guidelines will be reviewed in light of lessons-learned from these events. The NRC has also pioneered the use of Probabilistic Risk Assessment in WASH-1400 and has been used extensively. This technique can be used for such beyond-design basis events. Finally, we need to reexamine how we manage spent fuel both in its storage on-site as well as its final disposition.

The ANS has recently issued a study on technical options for spent-fuel disposition that may be useful to this end. Also, I assume the Blue Ribbon
Commission will consider these recent events as they formulate their policy
recommendations for spent nuclear fuel as directed by the President.

So in closing, let me offer some final thoughts:

  • First, while there is still much more information to gather, I think we now have an overall understanding of what happened at Fukushima Daiichi.
  • Second, while radioactive materials have been released into the environment, it does not appear, based on current data, that there will be widespread public health consequences.
  • Third, because of differences in U.S. seismology and installed safety equipment, it is highly unlikely that Fukushima-like event could occur at a U.S. nuclear plant. Nonetheless, the U.S. nuclear industry—and every other industrial sector for that matter—should use this opportunity to ensure that it can respond quickly and effectively to extreme natural events.

Thank you.


Is Fukushima a teachable moment for nuclear educators?

By Rod Adams

There are many facets of my chosen avocation as a pro-nuclear blogger and podcaster, but one aspect that has been prominent during the 25 days since the Japanese earthquake, tsunami, and nuclear nightmare at Fukushima has been that of atomic educator. Following the role model of my favorite teachers, I have worked hard to maintain a two-way flow of information—successful educators have to be open-minded learners. There is no doubt that I know a lot more about the design and operation of boiling water reactors with MK I containment vessels now than I knew four weeks ago.

Arial view of units 1-4 Fukushima Dai-ichi March 30, 2011Some nuclear energy advocates might cringe at my use of of the alliterative phrase of “nuclear nightmare at Fukushima,” but I hope they will think hard about all of the implications of that choice of words.

It is hard to imagine a more nightmarish scenario than having a multi-unit nuclear power plant installation hit with a massive earthquake, a subsiding coast line, and a massive tidal wave that wiped out a significant portion of the local grid, the emergency diesel generators, and the electrical components required to enable even moderately difficult power restoration. Even the most ardent antinuclear activists with whom I have butted heads would have had to work hard to imagine that kind of initiating event.

Fukushima was truly a nightmare for those of us who favor the increasing use of nuclear energy as a way to reduce our rapid depletion of the earth’s valuable store of hydrocarbons. It was pretty easy to recognize very early in the accident that it had the potential to be the story that the opposition to nuclear energy has been eagerly anticipating for many years.

Even the timing added to the bad dream quality of the event—there was already a steadily increasing drumbeat of reminders from organized antinuclear groups that an explosion and fire at a nuclear power plant had once killed people—25 years ago this month.

It is hard to imagine a worse situation than the one we faced on March 11, 2011. Not only were there vast areas of devastation and thousands of human casualties caused by the natural disasters, but there was also a highly visible nuclear power plant event. That nuclear event was occurring at the same time that hundreds of eager antinuclear Lilliputians had their updated media contact lists in hand. They were primed and ready to add as many more threads as possible to hold down the atomic Gulliver that they want us all to fear. The confluence of an event with an anniversary brought flashbacks of the incredible coincidence of a nuclear plant event occurring in Pennsylvania within weeks of the theater release of a movie about a core meltdown that actually included a line about causing damage to an area “the size of Pennsylvania.”

The one thing that the professional opposition to nuclear energy had not counted on was the fact that information sharing today is on a completely different plane than it was the last time there was significant damage at a nuclear power plant. In April 1986, as in 1979, there was no Internet and no world wide web. Cable television was only available in very limited markets; CNN had finally broken into the public consciousness, but only a few months before Chernobyl when it was the only television news organization with live coverage of the Challenger disaster.

Within just a few hours of the earthquake and tsunami, informal networks of nuclear energy experts began exchanging information using the wide range of tools that modern communications technology has delivered. Though the initial headlines were breathlessly scary, there were alternative paths through which the real story could be gathered and shared. There was plenty of reason for concern among professionals, but it soon became clear that the many layers of protection and procedural backups were having a positive effect on the net outcome.

There will be lessons learned and additional protective measures implemented, but the fact remains that the loss of life at Fukushima Dai-ichi has been limited to two workers who were killed by the tsunami while performing rounds. One other worker was killed when a crane fell at the separate Fukushima Daini nuclear power station. In contrast to that very limited human toll, the natural disaster has killed in excess of 20,000 people.

As one of my favorite nuclear experts likes to point out, nuclear energy systems are designed to provide many opportunities to respond. Bad things can and do happen, but the basic engineering choices made from the earliest days of the technology were aimed at making sure that they happen as slowly as possible. Slow motion disasters might not be optimal from a public relations point of view, but they are often very beneficial from a public health point of view. It saves lives and property when there is time to take preventive action.

Though there have been many bad moments and plenty of negative press coverage, the accurate information that nuclear energy experts have shared using modern communications paths that include the web and social networks have begun to sink in. Despite all of the gloom and doom scenarios, each day brings us one step closer to stability and each report of injuries brings a growing recognition among the public that their carefully stoked fears regarding a nuclear catastrophe have been misplaced. Professional journalists have begun to recognize that the scary stories they told at the beginning were fictional instead of factual.

On Sunday, April 2, 2011, there was a front page story in the Washington Post titled Nuclear power is the safest way to make electricity, according to study. Similar stories are beginning to pop up in other unexpected locations, including The Guardian, The Australian, the New York Times, and even

I chose to enter the nuclear energy profession just two years after the Three Mile Island accident. It has not been the easiest choice I could have made. Young nuclear professionals who harbor a little concern about their future employment prospects can rest assured that Fukushima will not result in another three decade slumber. That is largely due to the efforts of people with real nuclear knowledge and the means, motive, and opportunity to share it widely.


Rod Adams is a pro-nuclear advocate with extensive small nuclear plant operating experience. Adams is a former engineer officer, USS Von Steuben. He is founder of Adams Atomic Engines, Inc., and 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.

ANS Q&A on Radiation & Fukushima

Fear of the unknown is a powerful force.

Ionizing radiation by type - graphic courtesy of the Canadian Nuclear Safety Commission

Explaining radiation issue related to Fukushima in plain English is the objective of this briefing.

Note to Readers: The online version of this briefing in PDF format at the ANS website contains multiple links to additional sources of information.

Q: What is the health risk of radiation from the Fukushima incident to people in the United States?

A: There is no health risk of radiation from the Fukushima incident to people in the United States or its territories, as the United States (US) Centers for Disease Control and Prevention, the US Environmental Protection Agency (EPA), the US Food and Drug Administration (FDA), and the US Nuclear Regulatory Commission (NRC) have affirmed.

Q: But radiation from Fukushima has been detected within the United States?

A: Yes. That’s because we are able to detect very small amounts of radiation. Through the use of extremely sensitive equipment, some US laboratories have been able to detect very minute quantities of one type of radioactive material, Iodine-131 (I-131). The EPA has detected levels of I-131 of 0.8 picocuries per liter at locations in the US. This level is 5,000 times lower than the safe limit set by the FDA and poses no risk to health.

Q: Would taking potassium iodide tablets be a prudent precaution?

A: No. Potassium iodide provides some protection against the absorption of I-131 if it gets into the food and water we consume. However, food contaminated with I-131 is not being exported from Japan, and normal everyday background radiation is 100,000 times more than the highest radiation level detected in the United States from the Fukushima incident. In addition, iodine tablets can be risky for pregnant women, and/or people who are allergic or have certain skin disorders. Too much iodine can cause a thyroid disorder in infants. Iodine tablets also can cause side effects like nausea and rashes. Note that iodized salt is of no value as an anti-radiation medicine, as it is not possible to ingest amounts approaching an effective dose.

Q: What about the radiation risk to people living in Japan?

A: People living within 12 miles have been evacuated as a precaution, and people within 19 miles have been advised to leave the area or to stay indoors and try to make their homes airtight. U.S. citizens located within 50 miles of the plant site were initially advised by the United States Nuclear Regulatory Commission to leave the area for the time being. In an appearance before a U.S. Senate Subcommittee on March 30, NRC Chair Gregory Jazco stated that he believes a 20- mile evacuation zone around the Fukushima Daiichi nuclear plant in Japan represents a “safe distance,” given radiation readings around the damaged plant. The Japanese government advised against using tap water for infant formula when levels of I-131 temporarily exceeded recommended safe levels, although those restrictions have been lifted in all areas except four locations around Fukushima. Also, tests for plutonium in the Fukushima area found levels indistinguishable from normal background, and thus pose no health risk. The samples are being tested to determine if any particles are from the power plants rather than old nuclear weapon tests. Although these were all sensible precautions, increases in radiation in the area have been so small as to not pose a measurable health risk.

Q: What about the radiation risk to people working at the site?

A: The Fukushima nuclear power plant workers are at risk for radiation exposure. However, they have extensive knowledge of how to minimize their exposure, training in the principles and practice of radiation protection, and portable radiation measurement instruments and protective gear. They are monitored closely to keep exposure well below internationally accepted standards.

Q: Is any level of exposure to radiation safe?

A: Yes. Safe levels of radiation are well understood and have been evaluated and agreed upon by many independent panels of experts. Daily exposure to very low levels of radiation is a normal part of life on planet Earth. Everyday we are exposed to radiation that is produced by the sun, radioactive materials in the earth and the air, and even trace amounts of naturally radioactive potassium and carbon contained in our own bodies.

Q: What is the risk of radioactivity getting into the US food supply?

A: Normally very little food from the Fukushima region is imported into the USA. Affected foods from the region around the Fukushima plant have been banned from export by the Government of Japan. Any food from that area not already restricted by the Government of Japan will be detained for testing by the U.S. Food and Drug Administration (FDA) and not allowed into the USA unless shown to be absolutely free of contamination. Food from areas further from the plant will also be diverted for testing by the FDA. The immense quantity of water in the Pacific Ocean rapidly and effectively dilutes radioactive material, so fish and seafood are likely to be unaffected. Nonetheless, all seafood from Japan will also be diverted for monitoring. Even if affected foods from the Fukushima region were not banned or monitored, one would need to eat enormous amounts exclusively to approach the normal exposure from everyday background radiation.

Q: So what preparations should I make to protect my health from Fukushima?

A: None are needed. You would be better served to consider other lifestyle factors which have proven, direct impacts upon human health, such as tobacco use, exercise and weight control.

Q: Where can I find more information?

A: Two good places to learn about radiation are the American Nuclear Society interactive radiation chart and the Health Physics Society radiation answers. Good sources of information on radiation effects from the Fukushima incident include the Food and Drug Administration reports on Fukushima food safety, the US Environmental Protection Agency, the International Atomic Energy Agency, the US Nuclear Regulatory Commission, the Centers for Disease Control and Prevention, and the Health Physics Society. Also see the joint statement by the American Association of Clinical Endocrinologists, the American Thyroid Association, the Endocrine Society, and the Society of Nuclear Medicine.

Updated April 5, 2011

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ANS and Fukushima

By Joe Colvin

In the days since Japan’s earthquake and tsunami combined to create the situation at Fukushima, nuclear professionals across the country have been united in our deep concern over the events in Japan and have contributed countless hours working to ensure that information provided to the public and media was based on fact and reason rather than hysteria and misinformation. I want to take this opportunity to express my appreciation to the many ANS members who stepped forward to support the efforts of the Society in this time of great need.

The Society has played—and is continuing to play—a major role in addressing the scientific and technical aspects of the accident at Fukushima with the public, policy makers, and the media. ANS headquarters, the ANS corporate officers, and our media, social media, and federal consultants have worked diligently, with the support of many members, to improve the public understanding of the situation in Japan. Within several hours of the events at Fukushima, ANS initiated the Crisis Communications Team, which has met daily by conference call since the accident to coordinate the Society’s activities, including media outreach. Though ANS members could not be everywhere, we have had a significant and positive effect.

ANS members have participated in more than 150 interviews in venues such as The Today ShowCBS Evening NewsNBC Nightly NewsCBS Morning News and local affiliates, CNNNPRGood Morning America, the New York Times, the Washington Post, and the Wall Street Journal—to name a few. Over one hundred members volunteered their services after Candace Davison, ANS Public Information Committee chair, explained the urgent need for media resources.

Thanks to your efforts, ANS members reached more than 81 million people through proactive media outreach. That’s over one in four U.S. households—a truly remarkable effort!

While some ANS members could not serve as media spokespersons due to company restrictions, they provided essential analysis of the ongoing technical events in Japan. That analysis helped to formulate documents such as the Japan Backgrounder and the ANS Talking Points. ANS Social Media Group members actively engaged in positive, proactive media outreach—something they have done so successfully in the past. They identified and shared media opportunities and formed the backbone of the early media efforts.

Those who could not speak helped those who could by lending information, analysis, and advice.

The ANS Nuclear Cafe blog site was repurposed as an information clearinghouse during the early morning hours of March 11. As ANS members shared links to factual, non-alarmist information provided on the blog, traffic to the site increased by a factor of 100.

The strength of the Society is rooted in our membership and catalyzed by effective and talented expertise. ANS Student Sections, Nuclear Engineering Departments, and Local Sections have engaged in efforts across the country to reach out via public forums, webinars, presentations, conversations with friends and colleagues, and social networks. ANS Professional Divisions have put together technical briefs and fact sheets, and our commercial publications, such as Nuclear News magazine, are focusing articles on the Fukushima events. You can also visit the ANS website to be inspired by the wealth of activities catalogued under ‘Featured Content.’

ANS members have engaged in the vital grassroots efforts that drive greater understanding—and thus greater acceptance—of nuclear science and technology.

In response to your overwhelming feedback, ANS established the ANS Japan Relief Fund to help our friends, colleagues, and their families in Japan who have been affected by the earthquake and tsunami. This fund symbolizes how the international nuclear community stands together to help one another.

ANS will continue to play a key role in placing the Fukushima incident into perspective, as well examining the factors that have contributed to the incident. We are in the process of outlining the important role that the Society can play in developing a greater understanding into the scientific and technical issues surrounding the accident at Fukushima. Nuclear professionals will continue to set the bar high for nuclear energy, which remains the safest source of electricity generation.

I look forward to working with you, the dedicated and passionate members of this Society, as we continue to promote the awareness and understanding of nuclear science and technology.


Joe Colvin is the 56th president of the American Nuclear Society. He has been an ANS member since 2001 and has worked to obtain senior nuclear utility expertise on ANS committees and the Board of Directors. Colvin is President Emeritus of the Nuclear Energy Institute, and he serves on the boards of Cameco Corporation, the world’s largest uranium company, and US Ecology, a hazardous and radioactive waste disposal company. He also is on the boards of non-profit organizations such as the Foundation for Nuclear Studies, which was set up by NEI to help provide the U.S. House and Senate with information on nuclear technology.

Impact of MOX Fuel at Fukushima

A plain English explanation

Based on alarms raised by scientists in Japan and elsewhere about the use of mixed oxide fuel (MOX) in the Fukushima reactor #3, the American Nuclear Society (ANS) published a technical brief on the issue on March 25, 2011. It contains factual information on the impact of mixed oxide fuel use at Fukushima Daiichi.

There are two key points that emerge from the ANS Technical Brief which was prepared by ANS members contributing their expertise as individuals and not on behalf of their respective employers.  The paper is being published online by the ANS Special Committee on Nuclear Nonproliferation.

No significant impact on reactor cooling or releases of radioactivity

Mixed Oxide (MOX) fuel has been used safely in nuclear power reactors for decades. The presence of a limited number of MOX fuel assemblies at Fukushima Daiichi Unit 3 has not had a significant impact on the ability to cool the reactor or on any radioactive releases from the site due to damage from the earthquake and tsunami.

Less than 6% of fuel in core was MOX

At the time of the magnitude 9.0 earthquake, Fukushima Daiichi Unit 3 was operating with 32 mixed oxide (MOX) fuel assemblies and 516 low enriched uranium (LEU) fuel assemblies in its reactor core. In other words, less than 6 percent of the fuel in the Unit 3 core was MOX fuel. There were no other MOX fuel assemblies (new, in operation or used) at the Fukushima Daiichi plant at the time of the accident.

Questions and Answers about MOX

A typical MOX fuel assembly for a commercial nuclear reactor

What is mixed oxide (MOX) fuel?

· MOX fuel is a mixture of plutonium and uranium.

· MOX fuel is typically made using plutonium recycled from used nuclear fuel (i.e., reactor-grade (RG) MOX), but it can also be made using surplus plutonium from nuclear weapons (i.e., weapons-grade (WG) MOX).

· Low-enriched uranium (LEU) fuel commonly used in commercial nuclear reactors initially has no plutonium. During irradiation in a reactor it builds up plutonium as a result of the nuclear reactions.

· Toward the end of its useful life LEU fuel contains about 1% plutonium and actually produces about half of its power from this plutonium rather than uranium. RG MOX is fabricated from this recycled plutonium.

· WG MOX has a higher concentration of the Pu-239 isotope, which is more desirable for power generation than other plutonium isotopes.

· Low enriched uranium (LEU) fuel for commercial nuclear reactors has about 95-97 percent U238 and the remainder, the importance fissile isotope of U235, at 3-5%.

· In MOX fuel plutonium takes the place of the U235 isotope in low enriched fuel in a range of 4-9 percent depending whether the plutonium was derived from reprocessing commercial spent fuel or from weapons grade plutonium.

How does reactor operation with MOX fuel differ from operation with LEU fuel?

· Based on current practice and future plans, MOX and LEU fuels would be loaded into the core at the same time, with the fraction of the core using MOX typically in the range of 30-40 percent.

· The MOX core would be designed and licensed to the same operating and safety criteria as an all LEU core (e.g. same operating temperature, electrical output, etc.). The MOX core may require enhanced reactivity controls (increased soluble boron in the reactor coolant and/or additional control rods) to meet the licensed operating conditions.

· Operations with a MOX core would be nearly identical to operations with an all LEU core.

Are the consequences of an accident worse using MOX fuel?

· Both LEU fuel and MOX fuel meet conservative NRC safety criteria for design basis events.

· Independent safety authorities in five different countries have reviewed the use of MOX fuel in commercial nuclear plants, including severe accident analysis, and found that it meets all licensing and safety requirements.

· For beyond design basis events (i.e. significant fuel damage, loss of primary containment integrity and some atmospheric dispersal) the consequences from a 40% WG MOX fuel core would not be significantly worse than those with an all LEU fuel core.

What about storing irradiated MOX fuel? Is MOX fuel hotter?

· Right after reactor shutdown, irradiated fuel produces heat due to the decay of radioactive isotopes contained within the fuel equal to about 7% of pre-shutdown operating power.

· Irradiated MOX fuel initially produces about 4 percent less decay heat than equivalent LEU fuel. Decay heat production falls off very rapidly for both fuel types, to less than 1 percent of original operating power after 24 hours. However, decay heat production in MOX fuel declines at a slower rate than LEU fuel due to isotopic differences in the irradiated MOX fuel. Eventually irradiated MOX fuel produces slightly more decay heat than irradiated LEU fuel, about 16 percent more after 5 years.

· After about 5 years, the decay heat load from both fuel types is about the same as one or two medium-sized hair dryers for each used fuel assembly. Used fuel with this decay heat rate is sufficiently cooled to allow loading into dry cask storage.

For more information on MOX fuel at Fukushima, please read the ANS Technical Brief available online at the ANS web site.

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46th Carnival of Nuclear Energy Blogs

The discontinuous nature of current events suggests this graphic of a mobius strip as the design basis for a roller coaster.

The 46th Carnival of Nuclear Energy Blogs is up at Next Big Future.  The

carnival  features blog posts from the leading U.S. nuclear bloggers and is a roundup of featured content from them.

This week there is continuing news from Fukushima, but there are also a diverse set of posts on nuclear energy topics.

If you want to hear the voice of the nuclear renaissance, the Carnival of Nuclear Energy Blogs is where to find it.

Past editions have been hosted at Cool Hand Nuke, NEI Nuclear Notes, ANS Nuclear Cafe, Yes Vermont Yankee, Idaho Samizdat, and several other popular nuclear energy blogs.

If you have a pro-nuclear energy blog, and would like to host an edition of the carnival, please contact Brian Wang at Next Big Future to get on the rotation.

This is a great collaborative effort that deserves your support. Please post a Tweet, a Facebook entry, or a link on your Web site or blog to support the carnival.

Small/modular reactors and near-term expectations

This article was originally scheduled to appear on March 17. It has since been slightly revised by the author.

by E. Michael Blake

There is considerable activity right now in the United States aimed at the addition of new nuclear generating capacity. Tens of millions of dollars are being spent, and hundreds of skilled professionals have been put to work. For the purposes of this post, I’ll call this activity nuclear expansion, although it actually involves two separate activities with very little overlap: the licensing of new, large, light-water reactors (LWR), and the development of small/modular reactors (SMR). While the latter activity might help return the United States nuclear industry to a leadership position worldwide, I believe it would be unwise to expect SMRs to be deployed on a large scale in the near term.

Aside: Apart from the rather smirky title of “Renaissance Watch,” a recurring feature in Nuclear News, I generally don’t use the term “nuclear renaissance,” in part because it suggests that what went before must have been “nuclear dark ages.” While there had been more than two decades without new-reactor activity in the U.S. before 2003, the people operating the reactors that were in service made those reactors far more productive and reliable than they were ever expected to be. Why is this not seen as a “renaissance?” End Aside.

While the push for new reactor construction, based on LWRs, does not have as many participants now as it did three years ago, there has been enough progress in licensing reviews to suggest that as many as four reactors could be under full-scale construction by this time next year, and that at least six more will be pursued despite some delays. This would re-establish the United States as a growing market–but not as the industry leader, because all of the reactor vendors have foreign ownership ranging from 50 percent (GE Hitachi Nuclear Energy) to 100 percent (Areva, Mitsubishi).

Could the U.S. dominate the SMR market?

Given the globalization of so many different enterprises, it might be unrealistic to expect that a revived American nuclear industry could ever again dominate the world LWR market the way it did in the 1960s and 1970s. An opportunity may exist, however, on the other side of the U.S. nuclear expansion: SMR development. By my rough count, half or more of the companies developing SMR concepts are American-owned.

Why this matters has nothing to do with nationalistic pride, and not all that much to do with the pursuit of a competitive edge in the global economy. In my view, the sprouting of designs from so many different sources attests to the creativity and innovation possible in this country’s nuclear energy community. The atmosphere of ingenuity and opportunity could attract more top-level talent to nuclear fields. This should generate cycles of product improvement that can make U.S.-developed SMRs the most desired fission-based energy production devices for decades to come (based on my perception that U.S. designs already appear to be more developed than those in other countries). All of the usual economic benefits should follow from that–abundant high-paying jobs, improved trade balance, and so forth.

Long overdue in this post is an explanation of what counts as an SMR. In essence, an SMR is a relatively small reactor (300 MWe is usually defined as the upper limit), designed so that the entire energy-producing unit is a module that takes up relatively little space, and several modules can be built together in a single facility.

If one looks back far enough in time, one can observe that small power reactors existed long before large reactors were developed. Since then, there have arisen design aspects, construction techniques, and innovations in fuels, materials, and coolants that can (according to the designers) overcome the historic economies of scale that spurred the move to larger reactor designs, starting about 40 years ago. Ideally, modular construction would allow a reactor to be put into service quickly, with most of the work done at the factory and only a few tasks (final assembly, testing, etc.) at the plant site.

That word “ideally” must be applied to all SMR attributes, especially those that, in the designers’ view, should allow them to receive lighter treatment from regulators than large LWRs get. The Nuclear Regulatory Commission, as far as I can see, has been receptive to the notion of SMRs (going back several years to discussions of “technology-neutral” licensing), and has begun pre-application reviews of designs for what are classed as “integral pressurized water reactors,” the SMRs that most closely resemble power reactors that have operating experience. The NRC’s job, however, is (and should be) to uphold public health and safety. If the agency eventually modifies some regulations for the sake of SMRs, it would only be once the claims made for these designs (such as inherent safety, insignificant radiation dose at the site boundary under any circumstances, and so forth) have been backed up by verifiable testing.

The closest thing yet to a demonstration project for an SMR is the Tennessee Valley Authority’s proposal to seek licenses for two or more of The Babcock & Wilcox Company’s mPower reactors at the Clinch River site in Tennessee. The effort would also entail certification of the reactor design by the NRC. Even if TVA pursues this (the project has not yet been approved by the TVA Board of Directors) and the NRC’s estimated schedule can be maintained, certification would be complete in mid-2018 and the first modules would enter service perhaps at the end of 2019. So, for what may be the most advanced SMR project, power operation is more than eight years away.

Two of the less conventional designs–GE Hitachi’s PRISM, and Hyperion Power’s HPM–are in a feasibility study stage for possible use at the Department of Energy’s Savannah River Site in South Carolina, to consume “legacy” materials left over from the site’s mission in nuclear weapons development. These designs, based on fast-neutron spectra and liquid metal coolants, depart substantially from the NRC’s experience base in reactor licensing. The site operator, Savannah River Nuclear Solutions, has encouraged the developers of other SMRs with actinide-burning capability to propose similar studies. It has been suggested that prototype versions of these SMRs could be built with limited licensing requirements, allowing the reactors to establish experience and prove principles while assisting in site cleanup–but even if the NRC is receptive to this approach, working out and using such a system would take years.

Could SMRs be developed more rapidly overseas?

Could SMR developers get their reactors built sooner by selling them overseas? My own view is that operating something in another country before it has passed muster in its own country smacks of imperialism. Besides, for some SMR models operation isn’t the only licensable aspect. If the reactor is shipped with fuel sealed in the vessel, with the entire reactor to be returned to the manufacturer after a long duty cycle, the manufacturer’s home base would be producing and managing what are just short of critical assemblies before shipments leave and after they return. Some SMRs also depend on closed fuel cycles, and thus reprocessing, for which there is no licensing system (or legal authority) now in place. Moving every aspect of a sealed-reactor SMR business offshore, to avoid the NRC at every turn, would not only increase the imperialism, it would export the jobs that SMR work would provide.

As with the other side of nuclear expansion–licensing of new large LWRS–the SMR effort will probably require vast reserves of patience. An untried licensing system under 10 CFR Part 52, and a demanding qualification process for DOE loan guarantees, have drained the enthusiasm of some large-LWR license applicants. The aftermath of the Fukushima Daiichi accident could further darken the prospects. Other applicants, however—including those for Vogtle-3 and -4 in Georgia, and Summer-2 and -3 in South Carolina–have thus far stayed the course and may be in full-scale construction by this time next year. For SMRs, opportunities like those offered by TVA and Savannah River may start the process of bringing the designs to reality, but there is every indication that it will be a long process, with usable energy not available for many years.


E. Michael Blake is a senior editor of the American Nuclear Society’s Nuclear News magazine. The views expressed in this article are the author’s, and do not represent the editorial position of Nuclear News magazine or the policy of the American Nuclear Society.