Pools May be “Adequate,” But Dry Casks are Safer

 

The Nuclear Regulatory Commission (NRC) today released its staff paper evaluating Tier 3 recommendations based on lessons learned from the March 2011 nuclear accident at Fukushima.

The paper reiterates the NRC’s position that storing spent nuclear fuel in wet pools at commercial nuclear power plants provides “adequate protection” for public health and safety and the environment. The NRC also stated that it will continue to study spent fuel storage issues for up to five more years.

But “adequate” is not good enough, especially when there is a safer alternative.

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UCS Comments on Expedited Transfer of Spent Fuel from Pools to Dry Casks

On June 15, UCS submitted comments to the NRC on the recommendations of the post-Fukushima Task Force for expedited transfer of spent fuel to dry casks.

UCS supports the accelerated transfer of spent fuel from pools to dry casks. A chief advantage of such transfer is to increase the safety margin for events (either severe accidents or terrorist attacks) that cause a loss of water from the pool and result in heating of the spent fuel to the ignition temperature of the fuel’s zirconium alloy cladding, a self-sustaining zirconium fire, fuel damage, and massive radiological release.

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Reflections on the Seoul Nuclear Security Summit

                                                                                            Photo credit

I just returned from a week in South Korea to attend a large nuclear industry conference and a few events related to the Nuclear Security Summit. I had low expectations for the outcome of the Summit, and the communiqué released following the Summit certainly did not contain any pleasant surprises.

There is absolutely no indication that the international community is willing to grapple with the fundamental problem that has led to the situation we are in today: namely, the fact that too many countries continue to invoke “national sovereignty” to thwart the creation of effective international instruments to help control the nuclear terrorism dangers of plutonium, highly enriched uranium and other weapon-usable materials. This attitude is blocking the development of policies to effectively protect bomb-usable materials that have already been produced and to stop compounding the problem by producing more of them.

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NRC’s Post-Fukushima Response: Going in Circles?

                                  

One of the most important tasks before the Nuclear Regulatory Commission (NRC) today is moving forward quickly on implementing the safety improvements recommended by its Fukushima Near-Term Task Force, and considering additional safety enhancements that have been identified by the NRC staff.

For a while it appeared that this was actually taking place.

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UCS Comments on Threat Assumptions for Dry Cask Security

The termination of the Yucca Mountain repository project has left the US with no near-term prospects for a final disposal site for spent nuclear fuel. Until the repository program gets back on track, dry cask storage of spent fuel can be an acceptable interim option for many decades, but it is not risk-free. Long-term dry cask storage raises safety and security concerns that the Nuclear Regulatory Commission (NRC) and the nuclear industry will have to resolve.

With regard to security, spent fuel dry casks will have to be robustly protected against sabotage attacks that could cause a significant amount of the radioactive material they contain to be released into the environment. Even though a typical dry cask only contains a fraction of the amount of fuel in a reactor core, it contains a greater quantity of the long-lived isotope cesium-137 than the quantity currently estimated to have been released to the atmosphere during the Fukushima disaster.

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NRC Document Details the Secret History of Nuclear Industry Stonewalling After 9/11

A document recently made public by the Nuclear Regulatory Commission (NRC) sheds some light on the response of the U.S. nuclear industry to the vulnerabilities in nuclear power plant security and preparedness that became evident following the September 11, 2001 terrorist attacks.

The vast majority of information on this subject is not available to the public. Although there is a legitimate interest in protecting information that could be useful to terrorists planning attacks, in our view the NRC cast an overly broad net over information related to nuclear power plant security after 9/11. This has inhibited the ability of the public to independently evaluate the claims made by the NRC and the nuclear industry that the security upgrades undertaken after 9/11 were implemented rapidly and were adequate in scope to deal with threat of radiological sabotage. 

The recently released document clearly illustrates how the nuclear industry uses secrecy to its advantage to engage in private conduct that was completely at odds with the image it presented to the public.

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NRC’s Path After Fukushima: Still Lined with Pitfalls

On Friday, August 19, the Nuclear Regulatory Commission (NRC) released its initial response to the recommendations of the Fukushima Near-Term Task Force. The NRC did not address the substance of the Task Force recommendations, but only the process for further evaluating them. The NRC’s response, in the form of a “Staff Requirements Memorandum” (SRM), represents an attempt at reconciling the often differing views of NRC Commissioners.

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NRC Study Shows the Serious Consequences of a Fukushima- Type Accident in the US

UCS has obtained a preliminary analysis by the Nuclear Regulatory Commission (NRC) of a hypothetical severe accident at a nuclear power plant in Pennsylvania very similar to the one at Fukushima Daiichi. The NRC analysis finds that—even assuming early evacuation of the area—the accident could cause nearly 1,000 cancer deaths among the population within 50 miles of the plant, on average. Under unfavorable weather conditions, that number could be much higher.

The October 2010 draft report, which UCS obtained under the Freedom of Information Act (FOIA), contains some of the results of a long-delayed NRC study known as the State of the Art Reactor Consequence Analyses (SOARCA) project. The NRC initiated SOARCA in 2005 to provide “updated and more realistic analyses of severe reactor accidents.”

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Panic on the 18th Floor?

Several years ago the Nuclear Regulatory Commission started a research program known as the “State of the Art Reactor Consequence Analyses,” or SOARCA, which I discussed in a post on April 6. SOARCA’s mission is to assess the consequences of “severe accident scenarios” at nuclear power plants that might release radioactivity into the environment.

UCS has long been concerned that the NRC imposed constraints on the SOARCA program that would significantly skew its results to ensure an outcome suggesting the public has little to fear from severe nuclear plant accidents. In 2006, to bolster confidence in the process, UCS requested that the NRC publicly release its guidelines for the program, the constraints it imposed on it, and the assumptions underlying the program’s assessment of accident scenarios as well as its justifications for them.

The NRC refused to release that information, despite the fact that the NRC plans to make SOARCA’s results public and, earlier in 2006, NRC Commissioner Gregory Jaczko—now the agency’s chairman—called for the agency to release the material UCS requested.

UCS just discovered from a new set of FOIA documents that in March 2010 Chairman Jaczko again asked the NRC to release the SOARCA materials. The agency still has not done so.

One reason UCS questioned the SOARCA process was that around the time the program was created, NRC staff and at least one commissioner repeatedly asserted that a previous study of this type—the 1982 Calculation of Reactor Consequences (CRAC2) study conducted by Sandia National Laboratory—overstated the potential severity of nuclear accidents. UCS was concerned that the NRC may have shaped the SOARCA study to produce results that cast the nuclear power industry in a more positive light.

For instance, in 2007, an NRC staff member provided preliminary SOARCA results to the Advisory Committee on Reactor Safeguards (ACRS) that concluded a long-term station blackout at the Peach Bottom nuclear power plant in Pennsylvania would result in zero early fatalities from acute radiation exposure and zero latent cancer fatalities if new “B.5.b” safety measures were taken into account (see April 6’s post). If these measures were not included, the preliminary results found, there would still be zero early fatalities, and 25 latent cancer fatalities.

The staff member pointed out that these were far fewer fatalities than were projected by the 1982 CRAC2 study, which found 92 early fatalities and 2,700 latent cancer fatalities. These results differ by so much one would expect the NRC to fully explain what changes in the analysis or assumptions in the SOARCA assessment led to such a different estimate. But it did not release the underlying details of the analysis.

Notes from this same 2007 meeting show that ACRS participants questioned the restrictions the NRC placed on SOARCA’s analysis of accident scenarios. The notes state that although the NRC staff agreed that a more comprehensive analysis of the kind the ACRS participants recommended “would certainly be desirable, performing such a study would go well beyond the scope described in the Commission’s Staff Requirements Memo” that set the terms of SOARCA analysis. This implies that the ACRS participants at that meeting, like UCS, were concerned about the limits the NRC placed on SOARCA.

The ACRS participants also called into question how the SOARCA program was including the potential for human errors in its analysis, and asked for additional justification for the number used in the analysis of the probability of core damage, which is central to the study because it is used to screen out the consideration of accidents that the NRC asserts are too improbable.

NRC staff members have consistently maintained that SOARCA has determined that there would be no fatalities from acute radiation syndrome under any circumstances from severe accidents. So it was notable that one of the emails the NRC released in response to UCS’s February FOIA request indicated that talk of SOARCA’s analysis finding a non-zero number for such fatalities caught some NRC staff members’ attention and set off some alarms. In a February 3, 2011, email, a member of the NRC staff expressed consternation about a recent development in SOARCA:

[T]hanks for the status update. I had heard unconfirmed information that [the NRC Office of Research] was now suggesting that there is some increase to the estimated hypothetical number of fatalities (early or late?) from some of the SOARCA assessed scenarios. If true, this would be a change from previous results that our office would like to know about well before the staff publishes the SOARCA report for public comment.

A few days later, the staff member had his answer, and notified the commissioner he works under:

FYI: I mentioned last week that the SOARCA project has some emergent issues. A number of “120” early fatalities has circulated up here on 18 [the 18th floor of One White Flint North, NRC’s headquarters]. I will find out more but my sense is any number above zero for acute radiation syndrome effects would be suspect.

These emails might be construed as a staff member simply wondering why the new results seemed out of line with the old results. But in light of the discussion above and our concerns about the SOARCA program, it sounds to us like the kind of meddling by the politically appointed NRC in the work of the agency’s Office of Research that we suspected was happening all along.

The email quoted above goes on to say that a number of early fatalities “above zero” would be suspect because Chernobyl led to fewer than 120 early fatalities. Such a comparison, however, is not relevant.

The modeling code used by SOARCA calculates doses received by people off-site, based on timing of the release, plume modeling, population characteristics, and evacuation modeling. The studies do not estimate risks to on-site personnel. Thus the number of fatalities among Chernobyl emergency worker is not directly comparable with the early public fatalities SOARCA computed.

And why might one expect off-site residents to die from acute radiation syndrome from an accident at a U.S. light-water reactor when none died at Chernobyl?

In the case of Chernobyl, the radioactive plume’s extreme height, due to the initial violent explosion and subsequent hot graphite fire, dispersed much of the radioactive material far from the site, sparing the areas immediately surrounding the site from high radiation concentrations. The NRC came to the same conclusion in its 1989 study of Chernobyl, finding that “the high initial plume height contributed to relatively low initial dose rates in the immediate vicinity.” Most accidents at light-water reactors, however, would not result in such a high plume, and could therefore result in higher doses to nearby residents if they are not evacuated in a timely fashion.

In any event, it’s news that SOARCA studies are apparently showing there would be early fatalities from acute radiation exposure in a nuclear plant accident. To our knowledge, that has never before been disclosed.

It will be interesting to see how many acute fatalities are estimated in the draft SOARCA study when the NRC releases it publicly.


FOIA Documents from NRC

As noted in our post on Wednesday, in February 2011 UCS filed a Freedom of Information Act (FOIA) request for all information associated with the NRC’s “State of the Art Reactor Consequence Analyses,” or SOARCA, program.

SOARCA, according to the NRC, is “a research effort to realistically estimate the outcomes of postulated severe accident scenarios that might cause a nuclear power plant to release radioactive material into the environment.”

We have had questions about the program and the analysis it is performing, which led us to file the FOIA request

UCS received the first batch of FOIA documents in early March; these were documents that were already publicly available. The second set of FOIA documents arrived on March 25. Both sets are available on the NRC website at the links provided.