05000456/FIN-2011004-03
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Finding | |
|---|---|
| Title | Failure to Control High Energy Line Break Barrier Doors |
| Description | The inspectors identified a finding of very low safety significance and an associated NCV of 10 CFR Part 50, Appendix B, Criterion III, Design Control, when licensee personnel failed to ensure that Unit 1 and Unit 2 boundary doors credited as shut in design basis High Energy Line Break (HELB) room heat-up calculations were effectively controlled in station procedures. Specifically, doors separating divisions for the Unit 1 and Unit 2 Engineered Safety Feature (ESF) Switchgear Rooms and Miscellaneous Electrical Equipment Rooms (MEERs) were not considered HELB boundaries in the stations Plant Barrier Impairment (PBI) procedure as required. Therefore, these doors could have been impaired for various reasons (e.g., maintenance) without the licensee ensuring that regulatory requirements were maintained, including those contained in the Technical Specifications (TSs) and 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants. The licensee entered this issue into their corrective action program as IR 1242942. Corrective actions included a revision to the stations PBI procedure to ensure that these barrier doors were considered HELB boundaries. The performance deficiency was determined to be more than minor because it was associated with the Protection Against External Events attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, if these doors had been impaired during a design basis turbine building HELB event with an active single failure of a HELB isolation damper, both electrical divisions in the ESF Switchgear Rooms or MEERs could have been adversely affected by the harsh steam environment. The inspectors determined the finding could be evaluated using the SDP in accordance with IMC 0609, Significance Determination Process, Attachment 0609.04, Phase - 1 Initial Screening and Characterization of Findings, Table 4a, for the Mitigating Systems Cornerstone. Specifically, the inspectors answered No to all of the Mitigating Systems Cornerstone questions in Table 4a of IMC 0609.04 and, as a result, the finding screened as having very low safety significance (Green). Due to the age of this issue, it was not reflective of current licensee performance and therefore the inspectors did not assign a cross-cutting aspect to this finding. |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2011004 Section 1R15 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | A Garmoe B Palagi D Reeser E Duncan G O'Dwyer J Benjamin M Perry R Ng |
| INPO aspect | |
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Finding - Braidwood - IR 05000456/2011004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2011Q3
Self-Identified List (Braidwood)
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