ENS 48772
ENS Event | |
|---|---|
10:28 Feb 20, 2013 | |
| Title | Degraded Condition - Containment Penetration Fails Local Leak-Rate Testing |
| Event Description | On February 20, 2013, at 0538 EST, local leak-rate testing (LLRT) of the 'A' feedwater check valves 2B21-F010A and 2B21-F077A revealed that neither valve would pressurize. Based on this information this line would not remain water filled post-LOCA and would result in the 'as found' minimum pathway leakage exceeding the limiting condition of operation (LCO) for Technical Specification 3.6.1.1. The cause for the LLRT failures will be determined and required corrective maintenance will be performed and valves successfully tested during the current refueling outage.
The licensee notified the NRC Resident Inspector.
Subsequent investigation into the reported LLRT failure revealed that the initial LLRT performed on feedwater check valve 2B21-F010A was not considered an acceptable test, since that LLRT was not representative of the 'as found' condition of this check valve. The test volume for this valve had been slowly filled such that the check valve did not have the normal expected differential pressure across the valve disc to achieve normal check valve seating. After draining the test volume and refilling it by allowing the test volume to gravity fill from the reactor pressure vessel, the expected differential pressure across the valve disc occurred and seated the disc in such a way that it was more representative of the 'as found' condition for the check valve. An LLRT was then performed with a leakage of 50 accm [actual cubic centimeters per minute] against an acceptance criterion of 194 accm. No maintenance or operation of the check valve had occurred between the initial invalid test and the subsequent test performed with the disc in its 'as found' condition. An engineering evaluation was performed that documented the acceptability of using this means for establishing the test volume for feedwater check valves 2B21-F010A and 2B21-F010B for the 'A' and 'B' loops of feedwater, respectively. This engineering evaluation concluded that establishment of the required test volume in the manner described for primary containment penetration 9A satisfies the Hatch LLRT program requirements and that the leakage acceptance criterion for feedwater check valve 2B21-F010A in its 'as found' state was satisfied. The 2B21-F077A valve will be retested at a later date. Based on this information, the LLRT of this check valve in its 'as found' state was successful which actually resulted in successful minimum pathway leak rate test results for primary containment penetration 9A. These conclusive test results clearly indicated that the initial test results were incorrect and the 'as found' condition of this penetration isolation capability did not represent a significant degradation of a principal safety barrier as described in 10CFR50.72(b)(3)(ii)(A). For these reasons Notification # 48772 is being retracted. The licensee notified the NRC Resident Inspector. Notified the R2DO (McCoy). |
| Where | |
|---|---|
Hatch  Georgia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-0.12 h-0.005 days <br />-7.142857e-4 weeks <br />-1.64376e-4 months <br />) | |
| Opened: | Jim Anderson 10:21 Feb 20, 2013 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Feb 22, 2013 |
| 48772 - NRC Website
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WEEKMONTHYEARENS 569592024-02-11T15:11:00011 February 2024 15:11:00
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