Thursday, October 27, 2011

Lessons learned and questions to be asked pertaining to American boiling water reactor (and pressurized water reactor) accidents

The accidents at Fukushima Daiichi represent a new paradigm in nuclear power plant accidents, where in contrast to the meltdown at Three Mile Island, emissions from melted fuel assemblies were not contained within a pressurized vessel. Given the large numbers of boiling water reactors still operating in the United States as well as in other nations, and the high risk of operating these reactors without a tertiary power backup system, failure of the primary electrical system (as happened during the recent earthquake in the Maryland area) followed by failure of the backup diesel generators is now a much more likely possible scenario than was previously recognized before the accident in Japan. Considering the key role that first responders utilizing traditional fire equipment played in mitigating the impact of the accident in Japan, all community first responders in the area of any nuclear power plant should now be training in the methodologies necessary to provide large quantities of water to cool melted fuel assemblies in an emergency situation where primary and secondary containment structures and electrical cooling capacities have been damaged or destroyed.

Question 1: are the Plymouth, Kingston, and Duxbury fire departments aware that in the event of a similar accident at the Plymouth, MA, boiling water reactor they may be called to provide services similar to those executed by the fire companies in Japan, who may have saved the day in the several weeks following the Fukushima Daiichi disaster? Are there any fire departments anywhere in the US that are preparing for this kind of emergency situation?

Question 2: With respect to the large quantities of water pumped onto the melted fuel assemblies in Japan, wouldn’t it be practical to surround each American water reactor with a series of dikes that would prevent runoff of highly contaminated accident-derived cooling water? What are the contingency plans of the US NRC, which was very proactive in proposing emergency responses to the Japan accident, for US reactors to recover highly radioactive water used to cool melted fuel assemblies during an accident?

Question 3: A lingering question pertaining to liability for damages resulting from the accident in Japan remains unresolved. General Electric’s blatantly incompetent boiling water design, discussed in the first chapter of the Fukushima Daiichi: Nuclear Information Handbook, provides an obvious legal basis for significant compensation by GE to the many communities impacted by the accident in Japan (+/- 20 billion US dollars)? Why has GE been exempt from any damage claims with respect to the vulnerability of their boiling water reactors to meltdown accidents? Given the large number of GE designed boiling water reactors in the US and the likely possibility of future fuel meltdown accidents, why should GE not set aside +/- 100 billion dollars in an escrow account to compensate future victims of a design flaw-related nuclear accident in the US?

Reduced airborne emissions

In the Wall Street Journal of October 18, 2011, Mitsuru Obe reported that TEPCO estimates airborne radiation releases are now down to 100 million Bq/hr and that steam leakage has essentially ended because all damaged reactor temperatures have recently fallen below 100 degrees Celsius. TEPCO, the Japanese government, and local first responders can be congratulated on the successful mitigation of what could have been a much larger release of accident-derived emissions considering that three reactor cores and four spent fuel pools containing 4,368 fuel assemblies suffered simultaneous meltdowns. Given the approximately 43 million curies of radiocesium in these assemblies at risk of being released in this series of accidents, the successful cooling of the fuel assemblies that melted during this series of accidents is a major step in preventing further airborne releases. Three important issues remain to be documented and resolved.
• What is the ongoing rate of emissions of water-borne discharges from the continuing efforts to cool the melted fuel assemblies and maintain temperature below the boiling point of water?
• What proportion of these water-borne discharges have been recovered, and what is the amount of radiocesium and other isotopes that the radioactive waste water filters have successfully captured?
• What is the current estimate of the total source term of the Fukushima Daiichi MIME (multiple interlocking meltdown event), including both airborne and water-borne emissions?
Since there are seven accident point sources at Fukushima Daiichi, will TEPCO and NISA be more forthcoming and issue more detailed reports on airborne emissions from all seven accident sites as well as further information about the water-borne contaminants generated at each of the four reactor sites, which will need continual cooling indefinitely?

Thursday, October 6, 2011

NRC letter from Edward Markey

I urge you to read this interesting letter sent to the NRC by Edward Markey about the challenges of hurricanes and other extreme weather to nuclear power plants.