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NEI, EPRI Support Results of NRC Spent Fuel Pool Study

Aug. 6, 2013—NEI and the Electric Power Research Institute agree with a recent NRC study that concludes a beyond-design-basis earthquake would have minimal safety consequences on used fuel in the storage pool of a reference boiling water reactor like the ones used at Japan’s Fukushima Daiichi plant.

The study found that the used fuel pools for this type of reactor could withstand a hypothetical earthquake more severe than the one that struck Fukushima in March 2011.

Commenting on the NRC’s draft “Consequence Study of a Beyond-Design-Basis Earthquake Affecting the Spent Fuel Pool for a U.S. Mark I Boiling Water Reactor,” NEI Senior Technical Adviser Steven Kraft complimented agency staff for a comprehensive evaluation that corroborates its conclusion that, “based on this study and previous studies,” used fuel pools protect public health and safety.

“Despite analytically subjecting the reference plant spent fuel pool to an earthquake much larger than that for which it was designed and larger than one of the largest earthquakes known worldwide, the worst the study could find was an extremely small chance that the spent fuel pool would leak,” Kraft said in NEI’s Aug. 1 comment letter.

Robust design, ongoing surveillance and inspection, and well-trained security personnel all are characteristics that limit the risk of damage to used fuel pools, NEI’s letter notes.

EPRI’s July 31 comments listed other factors mentioned in the NRC study, including the relatively small heat load in the pool during most of the reactor operating cycle and fuel storage patterns during normal reactor operations that alternate cool and hot fuel elements—both of which limit the potential for overheating of the fuel. EPRI also mentioned the availability of systems such as water sprays to ensure that cooling water will be available even during severe accidents.

NEI said the study acknowledges—but does not credit in its analysis—the industry’s post-Fukushima initiatives to ensure the availability of cooling water and power in beyond-design-basis conditions. These initiatives include the industry’s diverse and flexible (FLEX) coping strategy and the NRC’s requirement for reliable used fuel instrumentation, which would further diminish the chance of a release of radiation.

NEI’s letter also said the study confirmed that health risks from severe earthquakes would be minimal whether the pools were loaded with fuel in high-density configurations, as is the current general practice, or in a low-density arrangement.

NEI concurs with the NRC’s independent Advisory Committee on Reactor Safeguards July 18 conclusion that expediting the transfer of used fuel to dry storage containers “does not provide a substantial safety enhancement” for Fukushima-style plants (see Nuclear Energy Overview, July 24).

The study did not quantify the risks associated with expedited movement of used fuel to dry storage containers. Had the NRC taken account of these risks—which include higher occupational doses to workers from handling “hotter” fuel and increased numbers of casks as well as the increased potential for cask drop accidents—the study’s conclusions would have been supported more strongly, Kraft said.

The NRC plans to extend the results of the study to all operating U.S. nuclear reactors, regardless of the design. NEI said the industry is looking forward to participating with other stakeholders and the agency in that endeavor.

The NRC will hold a public meeting Aug. 22 to discuss the draft report, during which it will accept public comments.