ENS 52443
ENS Event | |
|---|---|
07:20 Dec 19, 2016 | |
| Title | Unisolable Leak on High Pressure Core Spray |
| Event Description | On December 18, 2016 at 2320 [PST], a leak was discovered on the High Pressure Core Spray (HPCS) system minimum flow line. The leak is located at a bolted flange downstream of the manual isolation valve HPCS-V-53. The location of the leak is not isolable from the suppression pool. This provides a direct path from inside the Primary Containment to the Reactor Building.
High Pressure Core Spray system is a single train Emergency Core Cooling System (ECCS) system, therefore inoperability is reportable per 10 CFR 50.72(b)(3)(v)(D). Based on the location of the leak, Primary Containment integrity is compromised. Primary Containment was declared inoperable and is reportable per 10 CFR 50.72(b)(3)(ii)(A). The cause of the leak is under investigation. Actions are underway to cool down and enter MODE 4. The licensee has notified the NRC Resident Inspector.
Engineering evaluations indicate that there was neither a High Pressure Core Spray (HPCS) system inoperability nor a condition that resulted in a significantly degraded principal safety barrier (Primary Containment). Therefore, this event does not meet the reporting criteria in 10 CFR 50.72(b)(3)(v)(D) and 10 CFR 50.72(b)(3)(ii)(A), and Event Notification# 52443 is being retracted. Bases for the retraction are: (1) Extent or accumulation of water flooding the HPCS room would not have prevented the system from fulfilling any of its designated safety functions, if the system had received a starting signal due to an emergency; and (2) the consequences of the HPCS Minimum Flow Line leak into the Reactor Building were within the dose limits and did not have a significant effect on Primary Containment integrity; therefore, the Primary Containment was degraded but operable. The licensee has notified the NRC Resident Inspector. Notified R4DO (Groom). |
| Where | |
|---|---|
Columbia Generating Station  Washington (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| LER: | 05000397/LER-2016-005 |
| Time - Person (Reporting Time:+0.32 h0.0133 days <br />0.0019 weeks <br />4.38336e-4 months <br />) | |
| Opened: | David Porter 07:39 Dec 19, 2016 |
| NRC Officer: | Bethany Cecere |
| Last Updated: | May 24, 2017 |
| 52443 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Shutdown (0 %) |
| After | Hot Shutdown (0 %) |