ENS 42407
ENS Event | |
|---|---|
07:17 Mar 12, 2006 | |
| Title | Llrt Test Identified Piping Penetration with Excessive Leakage |
| Event Description | While performing local leak rate testing [LLRT] during a planned refueling outage, Susquehanna discovered a Type C penetration on Unit 1 with a leak rate of 12,700 sccm. The limit for this penetration, which can bypass secondary containment, is 4,247 sccm or 9 scfh. Even with this leak rate, the combined leak rate for all penetrations and valves subject to Type B and C tests meets the acceptance criteria of 10CFR50 Appendix J, which is 190,744.7 sccm. This condition seriously degrades the condition of the nuclear power plant, including its principal safety barriers, and is reportable in accordance with 10CFR50.72(b)(3)(ii).
The licensee informed the NRC Resident Inspector.
THE FOLLOWING IS A RETRACTION OF ENS NOTIFICATION #42407 On March 12, 2006, Susquehanna Steam Electric Station reported that a Type C penetration valve on Unit 1 experienced a leak rate of 12,700 sccm during testing. This leakage rate exceeded the TS allowed limit of 4,247 sccm (9 scfh) for Secondary Containment Bypass Leakage (SCBL) valves. Although a non-intrusive investigation determined that a significant amount of the leakage was past a non-Technical Specification test boundary valve, workers were unable to immediately quantify the exact amount of leakage attributable to this valve. Susquehanna conservatively assigned all leakage experienced during the test to the primary containment isolation valve being tested and reported the situation as a condition that seriously degraded the nuclear power plant per 10CFR50.72(b)(3)(ii). Subsequently, Susquehanna successfully re-worked the test boundary valve that was adversely affecting the leak rate test results. With no other changes in test conditions beyond this improvement in the test boundary, the test was re-performed with 464 sccm leakage observed. Total calculated leakage for SCBL amounted to 1306 sccm, well within Tech Spec limits. These results indicate that the excessive leakage was leakage past the test boundary valve and not the tested PCIV. As such, the SCBL limit was never exceeded and the ENS notification (#42407) is, therefore, being retracted. The licensee informed the NRC Resident Inspector. Notified R1DO (Dan Holody). |
| Where | |
|---|---|
Susquehanna  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+1.92 h0.08 days <br />0.0114 weeks <br />0.00263 months <br />) | |
| Opened: | Jim Hufford 09:12 Mar 12, 2006 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Apr 18, 2006 |
| 42407 - NRC Website
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WEEKMONTHYEARENS 564342023-03-26T20:03:00026 March 2023 20:03:00
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