05000259/FIN-2012002-04
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Finding | |
|---|---|
| Title | Repeated Failure to Report ECCS Analyses Methodology Change or Errors |
| Description | During discussions between the NRC staff, the fuel vendor, and the licensee starting in April 2010, the NRC staff questioned the appropriateness of the application of credit for spray cooling in the Units 2 and 3 ECCS evaluation, and the effect non-single failure proof ADS would have on the ECCS evaluation model for the BFN units. In a letter dated April 30, 2010 the licensee acknowledged the single failure issue with ADS and indicated that the estimated effect of the change or error on peak clad temperature (PCT) was not significant (greater than 50 degrees Fahrenheit). TVA committed to modify the ADS to provide a single failure proof automatic initiation capability of 4 ADS valves. The licensee also outlined the compensatory measures intended to address the identified degraded/nonconforming condition. Subsequently, on June 30, 2011, TVA submitted the annual ECCS evaluation model report and indicated a minor change to the radiative heat transfer model which resulted in a minor change in PCT for Units 2 and 3. On October 7, 2011, TVA submitted a revised ECCS analysis in support of a Unit 1 fuel transition request. This analysis provided a methodology change to address the evaluation model error associated with spray cooling, which had been identified by the NRC staff, and for which the licensee implemented operating restrictions to ensure that the effects of the error would not cause the predicted PCTs at Units 2 and 3 to exceed 2200F.. This analysis was also applicable for current operating conditions for Units 2 and 3 and was not previously reported to the NRC. NRC review identified that the effect of the evaluation model error would have resulted in greater than a 50 degree increase in predicted PCT for Units 2 and 3. On February 29, 2012, TVA initiated Service Request 514121 which recognized that a 30-day report for a significant change in peak clad temperature consistent with 10 CFR 50.46 had not been submitted. As of March 30, 2012, TVA had not submitted the required 30-day report for a significant change in peak clad temperature consistent with 10 CFR 50.46 which was identified on February 29, 2012. Following the end of the reporting period, TVA submitted the required report per 10 CFR 50.46 on April 18, 2012. Analysis: The inspectors determined that the licensees repeated failure to report changes or errors in the ECCS analyses was a performance deficiency. The inspectors reviewed this issue in accordance with IMC 0612, Appendix B, and determined the performance deficiency did not constitute a Finding, but the failure to report impacted the regulatory process and was subject to traditional enforcement consistent with the discussion for Block 7, Figure 2, Paragraph 2.a.v. The violation was determined to be more than minor per the NRC Enforcement Manual, Section 2.10.F, since the NRC has evidence that this failure to report has occurred repeatedly. This violation was determined to be a Severity Level IV violation based on section 6.9 of the NRC Enforcement Policy. Enforcement: 10 CFR 50.46 (a)(3)(ii), requires for each change to or error discovered in an acceptable evaluation model or in the application of such a model that affects the temperature calculation, the licensee shall report the nature of the change or error and its estimated effect on the limiting ECCS analysis to the Commission at least annually. If the change or error is significant, the applicant or licensee shall provide this report within 30 days and include with the report a proposed schedule for providing a reanalysis or taking other action as may be needed to show compliance with 10 CFR 50.46 requirements. Contrary to the above, the licensee failed to report each change or error discovered in an acceptable evaluation model or in the application of such a model that affects the temperature calculation for Units 2 and 3. Specifically, from May 29, 2011 to April 18, 2012, the licensee failed to report a significant change in peak clad temperature associated with an error related to spray cooling to the NRC within 30 days, and include with the report a proposed schedule for providing reanalysis or taking other action as may be needed to show compliance. The licensee subsequently submitted the required report per 10 CFR 50.46. Because this violation was determined to be a Severity Level IV violation and was entered into the licensees CAP as PER 531752, this violation is being treated as an NCV consistent with the Enforcement Policy. This NCV is identified as NCV 05000260(296)/2012002-04, Repeated Failure to Report ECCS Analyses Methodology Change or Errors. |
| Site: | Browns Ferry  |
|---|---|
| Report | IR 05000259/2012002 Section 4OA5 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | TEV: Severity level IV |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | C Fletcher C Stancil E Guthrie K Korth L Pressley P Niebaum R Carrion |
| INPO aspect | |
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Finding - Browns Ferry - IR 05000259/2012002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Browns Ferry) @ 2012Q1
Self-Identified List (Browns Ferry)
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