ENS 45526
ENS Event | |
|---|---|
05:44 Nov 29, 2009 | |
| Title | Containment Minimum Pathway Leak Rate Was Exceeded |
| Event Description | 10CFR50 Appendix J Local Leak Rate Testing determined the total 'as-found' containment minimum pathway leak rate exceeded the maximum allowable containment leak rate per the Containment Leakage Rate Testing Program. This was primarily due to three penetrations that could not be pressurized to full test pressure. The maximum allowable leakage was assigned to both valves in each penetration since the valves can not be tested individually.
This condition is reportable as a condition of the nuclear power plant, including its principal safety barriers, being seriously degraded per 10CFR50.72(b)(3)(ii)(A). The condition was discovered with the plant in Mode 5. Corrective actions have already been completed and all penetrations, as well as total containment leakage, is well within limits established by the Containment Leakage Rate Testing Program. The licensee has notified the NRC Resident Inspector.
On November 29, 2009, Waterford 3 reported that the total as-found containment minimum pathway leak rate exceeded the maximum allowable containment leak rate per the Containment Leakage Rate Testing Program. This was primarily due to three penetrations that could not be pressurized to full test pressure. The maximum allowable leakage was assigned to both valves in each penetration since the valves could not be tested individually. This condition was determined to be reportable as a condition of the nuclear power plant, including its principle safety barriers, being seriously degraded per 10CFR72(b)(3)(ii). Subsequently, Waterford 3 has evaluated the leak rates for all three penetrations and determined that as-found leakage rates assigned to the penetrations should not have been recorded at 630,000 sccm each, but should have been recorded at lower values. After one valve was re-worked in Penetration number 48, a Local Leak Rate Test (LLRT) was completed. With the new information from the second LLRT, a revised as-found leak rate of 97 sccm was assigned to the un-worked valve. For Penetration number 10, an Engineering evaluation of the test results was completed. The evaluation determined that the as-found leakage from this penetration was 191,000 sccm. This was based on calculating the maximum air flow capacity that could be obtained from the Leak Rate Monitor test equipment and using the first LLRT's penetration only reaching a test pressure of 43 psig instead of the 44 psig full test pressure. For Penetration number 11, troubleshooting activities determined that one of the valves had no detectable leakage; however, a leak rate of 9,100 sccm was assigned based on its previous as-left leakage value. With the lower leakage rates, the total as-found containment minimum pathway leak rate is calculated to be 230,682 sccm, which is within the limit of 630,000 SCCM. Since Waterford 3 had not exceeded the maximum allowable containment leak rate, EN #45526 is being retracted. The licensee notified the NRC Resident Inspector. Notified R4DO (Deese). |
| Where | |
|---|---|
Waterford  Louisiana (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-0.6 h-0.025 days <br />-0.00357 weeks <br />-8.2188e-4 months <br />) | |
| Opened: | John Jarrell 05:08 Nov 29, 2009 |
| NRC Officer: | John Knoke |
| Last Updated: | Dec 2, 2009 |
| 45526 - NRC Website
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Unit 3 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 568342023-11-05T16:33:0005 November 2023 16:33:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition - Two Steam Generator Tube Failures Identified ENS 538372019-01-18T19:33:00018 January 2019 19:33:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Reactor Coolant System Weld Does Not Meet Acceptance Criteria ENS 538342019-01-17T06:00:00017 January 2019 06:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Relevant Indication of Degraded Condition ENS 478972012-05-03T21:13:0003 May 2012 21:13:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Trains of the Controlled Ventilation Area System Inoperable ENS 455262009-11-29T05:44:00029 November 2009 05:44:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Containment Minimum Pathway Leak Rate Was Exceeded ENS 416592005-05-02T12:55:0002 May 2005 12:55:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded During Steam Generator Tube Inspection - Greater than 1% (106 Tubes) of the Tubes Were Found Defective ENS 416172005-04-19T22:51:00019 April 2005 22:51:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Found at Waterford Unit 3 ENS 402952003-11-04T06:00:0004 November 2003 06:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Number of Steam Generator Tubes Requiring Repair Exceeds 1 Percent ENS 402782003-10-27T01:00:00027 October 2003 01:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Indication of Leakage ENS 402772003-10-25T04:00:00025 October 2003 04:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degradation of the Reactor Coolant System (Rcs) Pressure Boundary 2023-11-05T16:33:00 | |