ENS 48862
ENS Event | |
|---|---|
04:00 Jan 21, 2013 | |
| Title | Interim Part 21 Report Involving Review of Seismic Testing Methodology |
| Event Description | The following information was received via fax:
ATC Nuclear in Oak Ridge, TN is making an initial notification of a Potential Part 21 Defect in accordance with 10 CFR 21.21(a)(2). A recent review performed January 21, 2013 of seismic Test Response Spectra (TRS) for seismic qualification activities identified that Required Response Spectra (RRS) may not have been completely enveloped for portions of the required frequency range during test performance of the Operational Basis Events (OBE's) and the Safe Shutdown Earthquake(s) (SSEs) for some customers. Specifically, some TRS results may have been below the provided RRS in the 10-25 Hz range in certain circumstances and thus not fully meeting the RRS and required acceptance criteria of IEEE 344 1975/1987/2004. The condition is the result of the instrumentation methodology and inherent tri-axial table characteristics where vibrational energy is not fully transmitted to the unit under test in all test conditions. The safety significance is that the Basic Component may not perform its intended safety function during or following a seismic event exceeding the as-tested vibration frequencies. ATC has demonstrated through actual testing to date that this probability is very low. Many customers provide RRS that include conservatism; however, this also has not been credited in the ATC Nuclear evaluation methodology discussed below. The affected customers, purchase orders, and relevant information have been provided as Attachment 1 [not attached to this report - customers notified were XCEL Energy, Bechtel Power Corporation, TVA for Watts Bar 2 (Projected Operation 12/2015) and Preferred Metal Technologies, Inc.] to this interim notification. ATC Nuclear developed a systematic evaluation methodology which has been independently corroborated by industry experts to evaluate the seismic tri-axial test programs of concern conducted by ATC Nuclear. The systematic evaluation involves review of the TRS to determine if adequate test margin exists within the test data when compared to the RRS, evaluation of the table test acceleration versus fixture acceleration as necessary, and when required, retesting of the component. For all program reviews completed to date (~70% of all programs) for operating licensees, all re-evaluation and re-testing has resulted in no reduction in seismic withstand capabilities and no failures. The evaluation included prioritization of operating reactors early in the process to the extent possible to ensure minimal impact to those facilities. Based on the successful completion of evaluations to date, ATC Nuclear is confident this issue will be resolved through the methodology established and worst-case may result in the submittal of an addenda to existing qualification reports in situations where retesting has been required for a basic component. ATC Nuclear will need until May 15, 2013 to conclude the evaluation process. Should, during any re-testing, a condition arise warranting notification, that notification will be immediately made at the time of discovery to the affected customer. All orders since the point of discovery have been addressed through corrective actions to prevent recurrence and are unaffected. The below contact information should be utilized regarding any questions. R.A. Chalifoux Vice-President QA, ATC Nuclear Tel: (865) 384-0124 email: rchalifoux@argoturbo.com
The following information was obtained from ATC Nuclear via facsimile: ATC Nuclear in Oak Ridge, TN has concluded the evaluation of a potential Part 21 defect in accordance with 10 CFR 21.21(a) (2). The evaluation for reportability with respect to the remaining licensees in Attachment 1 of the original NRC Interim Report (ML1309/ML13091A388) determined, as anticipated, no safety degradation exists. Based on the results of the evaluation, reportability under 10 CFR Part 21 is not required for this issue. Affected customers will be receiving revised documentation as appropriate. The [above] contact information should be utilized regarding any questions. Notified R1DO (Burritt), R2DO (McCoy), R3DO (Lipa), R4DO (Spitzberg) and Part 21 Group (via email). |
| Where | |
|---|---|
| Atc Nuclear Oak Ridge, Tennessee (NRC Region 1) | |
| Organization: | Atc Nuclear |
| Reporting | |
| 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
| Time - Person (Reporting Time:+1596.48 h66.52 days <br />9.503 weeks <br />2.187 months <br />) | |
| Opened: | R. A. Chalifoux 15:29 Mar 28, 2013 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Jun 5, 2013 |
| 48862 - NRC Website | |
Atc Nuclear with 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
WEEKMONTHYEARENS 488622013-01-21T04:00:00021 January 2013 04:00:00
[Table view]10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Interim Part 21 Report Involving Review of Seismic Testing Methodology 2013-01-21T04:00:00 | |