05000289/FIN-2016001-02
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | On February 6, 2016, while making preparations to perform procedure 1303-11.45, PORV Setpoint Check, a senior operator identified that the assigned risk for this planned maintenance activity was inaccurate. Specifically, the risk for the maintenance activity was Yellow, not Green, as originally determined. The reason for the inaccurate risk was due to not previously recognizing the pressurizers block valve (RC-RV-2) would be rendered inoperable during the maintenance activity. This condition could result in failure to operate the pressurizers power operated relief valve. The failure to accurately assess the risk of the power operated relief valve setpoint check was a performance deficiency that was within the licensees ability to identify and correct. The inspectors noted that this maintenance activity had an inaccurate risk assessment for at least the past three years. This performance deficiency was a violation 10 CFR Part 50.65(a)(4), which requires, in part, the licensee to assess and manage the increase in risk that may result from the proposed maintenance activity. Contrary to the above, Exelon failed to accurately assess the risk for the power operated relief valve setpoint check over the past three years. The issue was more than minor because it was associated with the configuration control attribute of the initiating systems cornerstone and it adversely affected the cornerstone objective of limiting the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The inspectors determined that the finding was of very low safety significance (Green), based on IMC 0609, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, screening criteria. The finding screened to Green because the incremental core damage probability of failing to operate RC-RV-2 is less than 1.00 10-6 per year during the short period which the valve is rendered inoperable during each performance of this maintenance activity. Exelon has entered this issue into its corrective action program (issue report 2622859) and revised the risk assigned to this maintenance activity. Because this finding is of very low safety significance and had been entered into Exelons corrective action program, this violation is being treated as a Green, licensee-identified NCV, consistent with section 2.3.2 of the NRCs Enforcement Policy. |
| Site: | Three Mile Island  |
|---|---|
| Report | IR 05000289/2016001 Section 4OA7 |
| Date counted | Mar 31, 2016 (2016Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Werkheiser J Cruz L Dumont P Ott R Rolph S Barr S Kennedy |
| Violation of: | 10 CFR 50.65(a)(4) 10 CFR 50.65 |
| INPO aspect | |
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Finding - Three Mile Island - IR 05000289/2016001 | ||||||||||||||||||||||||||
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Finding List (Three Mile Island) @ 2016Q1
Self-Identified List (Three Mile Island)
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