ENS 41103
ENS Event | |
|---|---|
05:50 Oct 8, 2004 | |
| Title | High Pressure Coolant Injection (Hpci) System Declared Inoperable |
| Event Description | On 10/08/04 on Unit Two, the HPCI Valve Operability was being performed. During the course of this evolution the suction path was transferred from the Condensate Storage Tank (CST) to the Suppression Pool. When the HPCI System was aligned to the Suppression Pool the Suction Pressure decreased from 25.5 psig to 1.5 psig. With HPCI aligned to the suppression pool and with suction pressure less than 14 psig the HPCI System was declared INOPERABLE.
Investigation continues as to the cause of the low suction pressure. Preliminarily it is suspected that the Suppression Pool suction path was not adequately filled and vented following a recent tag out of that suction path for maintenance inspection activities. Investigation continues. The Licensee notified the NRC Resident Inspector.
The following information was obtained from the licensee via facsimile: The Unit 2 HPCI system was considered inoperable, since the technical information that would conclusively support its continued operability given the condition encountered could not be assembled within the time constraints of the reporting requirements. Subsequent to the event the system was confirmed be properly filled and vented with a negligible amount of air vented in the process. It was determined that this small amount of air was introduced to the suction piping as a result of an inspection activity performed for the HPCI suction check valve prior to the event. A limited amount of air remained in the torus suction piping causing the decrease in suction experienced during the event. Engineering reviewed the implications of the low suction pressure on the ability of the HPCI system to perform its safety function given the design of the system and the suction sources available. In each case Engineering was able to conclusively determine that the HPCI system would not have tripped due to low suction pressure had it received an automatic initiation signal and was actually operable during the time frame that Operations had conservatively treated the system as inoperable. Additionally, the effect of the trapped air being entrained in the pump suction was also analyzed, and the conclusion reached was that the air would not have prevented the pump's proper performance. Based on this information, the event reported on 10/08/2004 is not reportable. The licensee has notified the NRC Resident Inspector. The Headquarters Operations Officer notified R2DO (Bonser). |
| Where | |
|---|---|
Hatch  Georgia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | |
| Time - Person (Reporting Time:+3.38 h0.141 days <br />0.0201 weeks <br />0.00463 months <br />) | |
| Opened: | Greg Johnson 09:13 Oct 8, 2004 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Oct 28, 2004 |
| 41103 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (99 %) |
| After | Power Operation (99 %) |
WEEKMONTHYEARENS 435032007-07-18T16:20:00018 July 2007 16:20:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unanalyzed Condition - Vent Space Less than Design Basis ENS 411032004-10-08T05:50:0008 October 2004 05:50:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor High Pressure Coolant Injection (Hpci) System Declared Inoperable ENS 397122003-03-29T07:55:00029 March 2003 07:55:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 2007-07-18T16:20:00 | |