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 Seismic Study Summary: Before receiving a license to operate a clean, safe, temporary facility to store spent nuclear fuel at a proposed Skull Valley site, Private Fuel Storage, LLC (PFS) must show that the facility is designed to withstand an earthquake that could occur at or near the site. PFS has performed extensive studies and concluded that the facility is designed to withstand earthquakes that could occur on nearby faults, such as the Stansbury fault. PFS updated its analysis and submitted it to the NRC in spring 2001. The NRC issued a supplement to the Safety Evaluation Report in December 2001 that evaluated PFS's analysis and reached the same conclusion. Background: The application PFS submitted in 1997 contained extensive data and analysis on the site geology and seismic characteristics and concluded that the Skull Valley site is safe and suitable for a temporary storage facility. While there are many unknowns - such as exactly when the next earthquake will occur - we have designed our facility to withstand any credible earthquake scenario with very minimal risk to the facility itself, and no risk to the public. In February 1999, PFS announced it had completed an extensive nine-month study of subsurface conditions in the vicinity of its proposed facility in Skull Valley and had submitted this supplemental data and analysis to the Nuclear Regulatory Commission (NRC), the state of Utah, and other parties involved in the licensing of its facility. The data were thoroughly analyzed by the NRC in its Safety Evaluation Report issued in September 2000. The data confirmed the existence of faults under and near the site, as noted earlier by PFS in its license application to the NRC, and provided additional details on the location, age and activity of those and other nearby faults. This expansive study was conducted to gather more detailed information so that PFS could respond more comprehensively to questions raised by the NRC, the state, and other licensing participants. This information augments the previous geological information that was included in the PFS license application. The study found a previously unidentified fault (Eastern Fault) about a half-mile east of the proposed site. The data indicate that it is an "active" fault, that is, capable of slipping and causing an earthquake. The latest analysis takes into consideration the combined effects of both the Eastern Fault and the Stansbury Fault, and their relative degree of activity. The study concludes that the resulting ground motions are consistent with the facility seismic design basis. The study also identifies minor faults under the facility site, which by themselves are incapable of causing an earthquake, that pose little risk to the facility. NRC regulations require an applicant to perform studies and analysis to provide "reasonable assurance" that the facility is designed to protect "all facility components important to safety." PFS analysis shows that in the event of a major earthquake (Stansbury Fault - 7.0 on the Richter scale), the 18-foot high, 180-ton concrete casks that store the spent fuel rods might tilt as much as four inches. The casks will not tip over in an earthquake, nor in any other credible event scenario. However, PFS analyzed for this non-credible event and found that the fuel rods will remain intact and well protected by the 2 1/2-foot thick concrete casks and steel canisters that contain them. For more information on this topic, see FAQs: Earthquake Issues. Safety
Evaluation Report
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