Saturday, June 18, 2011

Fort Calhoun Nuclear Power Station Not Prepared for Worst Case Missouri River Flood Scenario (OPPD Licensee Event Report 2011-003)

Omaha Public Power District Licensee Event Report 2011-003, Revision 1, for the Fort Calhoun Station

In sum, Fort Calhoun is prepared for a worst case flood scenario per this report. There is currently a worst case flood scenario occurring along the Missouri River and discussed in Missouri River Floods Fort Calhoun Nuclear Power Station in Nebraska. Click the following link for the official page where this OPPD document can be viewed.

The NRC inspection appears to have been conducted in 2010, so let's hope that Fort Calhoun addressed each of these deficiencies before the 2011 flood. If not, then it is likely that the facility is not prepared for the flooding that is happening right now.


As a result of a Nuclear Regulatory Commission (NRC) inspection conducted from January 1 to June 21, 2010, the NRC determined that Fort Calhoun Station (FCS) did not have adequate procedures to protect the intake structure and auxiliary building against external flooding events. Specifically, contrary to Technical Specification 5.8.1.a, the station failed to maintain procedures for combating a significant flood as recommended by Regulatory Guide 1.33, Appendix A, section 6.w, “Acts of Nature.” The NRC identified the following violation of NRC requirements associated with a yellow significance determination process finding in the mitigating systems cornerstone in inspection report 05000285/2010008 dated October 6, 2010:

Technical Specification 5.8.1.a, “Procedures,” states, “Written procedures and administrative policies shall be established, implemented, and maintained covering the following activities:(a) The applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A,1978.” NRC Regulatory Guide 1.33, “Quality Assurance Program Requirements (Operation),”Appendix A, “Typical Procedures for Pressurized Water Reactors and Boiling Water Reactors,”Section 6, recommends procedures for combating emergencies and other significant events. Section 6.w, “Acts of Nature,” includes, in part, procedures for combating floods.

Contrary to Technical Specification 5.8.1.a, since 1978, written procedures and administrative policies were not maintained covering the applicable procedures recommended by NRCRegulatory Guide 1.33, Revision 2, Appendix A. Specifically, the licensee failed to maintain written procedures for combating a significant external flood as recommended by NRC Regulatory Guide, Appendix A, Section 6.w, “Acts of Nature.” The licensee’s written procedures did not adequately prescribe steps to mitigate external flood conditions in the Auxiliary Building and Intake Structure up to 1014 feet mean sea level, as documented in the Updated Final Safety Analysis Report [USAR]. The NRC reported that the station’s flood protection strategy was not fully effective during worst-case Missouri River flooding scenarios. The strategy required workers to install floodgates in front of the doors to the plant’s auxiliary building and intake structure, and then stack and drape sandbags over the top of the floodgates up to a height of five feet. The procedural guidance was inadequate because the cross-section on top of the floodgates would not support a stacked sandbag configuration that would retain five feet of moving water.

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