05000424/LER-2012-001
| Vogtle Electric Generating Plant- Unit 1 | |
| Event date: | 02-15-2012 |
|---|---|
| Report date: | 04-11-2012 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(I)(B) 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4242012001R00 - NRC Website | |
Westinghouse -- Pressurized Water Reactor Energy Industry Identification Codes are identified in the text as [XX]
A. REQUIREMENT FOR REPORT
This report is required per 10 CFR 50.73(a)(2)(i)(B) due to the RWST [BQ] being inoperable for a duration of greater than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> due to the opening of a boundary valve with the unit in Mode 1. This resulted in operation of the unit in a condition prohibited by Technical Specification LCO 3.5.4 Condition D.
B. UNIT STATUS AT TIME OF EVENT
At the time of the event the unit was in Mode 1. Other than that described herein, there was no other inoperable equipment that contributed to this event.
C. DESCRIPTION OF EVENT
On February 15, 2012, during review of the new interpretation provided in NRC Information Notice 2012-01, it was determined that one of the items described in the information notice was applicable to Vogtle Electric Generating Plant (VEGP). Specifically, the information notice identified a utility that had received a non cited violation (NCV) for crediting administrative controls to close a boundary valve to isolate the non-seismic piping system from the seismically qualified RWST.
During the review, it was recognized that, considering the information provided in NRC Information Notice 2012-01, the RWST would be judged to be inoperable regardless of the administrative controls established when the RWST was aligned to non-seismic piping in Modes 1 — 4.
At VEGP, the RWST is seismically qualified, safety related and within the scope of the plant Technical Specifications (TS). The plant design includes the capability to align the Spent Fuel Pool Purification (SFPP) system [DA] for cleanup of the RWST. The SFPP is a non-safety, non-seismic system that is normally isolated from the RWST by a normally closed, safety related manually operated valve.
A review of system operating procedures identified that VEGP allowed the SFPP system boundary valve to be opened under administrative controls while the unit was operating in Modes 1-4 without declaring the RWST inoperable per TS LCO 3.5.4 Condition D. TS LCO 3.5.4 Condition D requires that the RWST be returned to Operable status with a completion time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. If the RWST is not returned to operable status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, TS LCO 3.5.4 Condition E requires that the unit be placed in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. A review of the Unit 2 Control Room logs for the past three years did not identify an instance where the Unit 2 boundary valve was opened in Modes 1-4 for greater than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. However, a review of the Unit 1 control room logs, for the past three years, identified that in the fall of 2009 with the unit in Mode 1, the boundary valve 0 SEOUEN11AL Vogtle Electric Generating Plant —Unit 1 05000424 had been opened under administrative controls for longer than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> on several occasions. Since the RWST was not declared inoperable, TS LCO actions were not entered. This resulted in operation of the unit which, under the interpretation provided by NRC Information Notice 2012-01, is considered to be a condition prohibited by TS and is reportable pursuant to 10 CFR 50.73(a)(2)(i)(B)
D. CAUSE OF EVENT
The direct cause of this event was an incorrect application of the use of compensatory measures (i.e., manual operator actions), when placing the non-seismic SFPP system in service on seismically qualified systems/components (RWST) during modes of operation when they are needed to perform their safety function. Prior to the issuance of NRC Information Notice 2012-01, manual operator actions had been evaluated and deemed acceptable in accordance with processes and procedures in place at that time. However, recently it has been determined that licensees cannot use compensatory measures when compromising the seismic qualification of a system/component.
E. SAFETY ASSESSMENT
This event had no significant safety consequence since a seismic event had not occurred while the SFPP system was in service on the RWST. Additionally this event did not involve a safety system functional failure since a dedicated operator was stationed at the boundary valve and would have been able to close the valve within a short period of time. This ensured the minimum required inventory in the RWST would have been available for accident mitigation requirements. This event would be considered low risk based on the following mitigating factors: very low frequency for a seismic initiating event, operator action to isolate the non-seismic piping after a seismic initiating event, and a small exposure time. The operator had sufficient response time based on a documented engineering analysis, had multiple cues, and had simple, proceduralized actions.
Therefore, the health and safety of the public were not affected by this event.
F. CORRECTIVE ACTION
The procedures that allowed opening the boundary valve in operational Modes 1-4 were revised to remove this capability. Additionally, the boundary valve between the RWST and SFPP system was locked closed and included in the safety related locked valve program.
NRC FORM 3438A (10-2010) NRC FORM 3864 00.2010)
G. ADDITIONAL INFORMATION
1) Failed Components: None.
2) Previous Similar Events: No previous similar events were Identified.
3) Energy Industry Identification System Code:
[Ba].-High Pressure Safety Injection System (PWR) [DA]-Fuel Pool Cooling and Purification System