ENS 49217
ENS Event | |
|---|---|
04:00 Jul 26, 2013 | |
| Title | Potential Existence of Defects in Shield Passive Thermal Shutdown Seal System |
| Event Description | The defect being reported concerns an identified inconsistency between the intended design functionality of the SHIELD passive thermal shutdown seal (SDS) and that observed during post-service testing.
The purpose of the SDS is to reduce current reactor coolant system inventory losses to very small leakage rates for a plant that results in the loss of all reactor coolant pump (RCP) seal cooling. The SDS is a thermally actuated, passive device integral to the RCP Number 1 seal insert and is positioned between the Number 1 seal and the Number 1 seal leak-off line to provide a near leak-tight seal once activated. There are two delivered components associated with this report: 1. the SDS hardware, and 2. the Probability Risk Assessment (PRA) SDS model and the assigned SDS reliability. The hardware component is the SHIELD passive thermal shutdown seal. The associated PRA SDS model and assigned reliability basic component is WCAP-17100-P-A, Supplement 1, Rev. 0, 'PRA Model for the Westinghouse Shut Down Seal Supplemental Information for All Domestic Reactor Coolant Pump Models' (dated December 2012). The SDS has only been delivered and installed in the following plants: Beaver Valley Unit 2, Callaway, D.C. Cook Unit 1, Farley Units 1 and 2, and Wolf Creek. Westinghouse has concluded that the hardware itself will not adversely impact safe plant operation. Westinghouse has completed a root cause analysis (RCA) and an independent third party review of this RCA is expected to be completed by August 2013. In parallel, SDS design improvements are being considered and may be completed during the third quarter of 2013. Additionally, and if necessary, Westinghouse will revise WCAP-17100 and its Supplements, as needed, to reflect any new information that is developed. Affected customers have been informed via their respective Customer Project Managers of the post-service test failure. |
| Where | |
|---|---|
| Westinghouse Electric Company Cranberry Twp., Pennsylvania (NRC Region 1) | |
| Organization: | Westinghouse Electric Company |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+9.25 h0.385 days <br />0.0551 weeks <br />0.0127 months <br />) | |
| Opened: | James Gresham 13:15 Jul 26, 2013 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Jul 26, 2013 |
| 49217 - NRC Website | |
Westinghouse Electric Company with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 558362022-04-06T04:00:0006 April 2022 04:00:00
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