ENS 43113
ENS Event | |
|---|---|
00:00 Jan 23, 2007 | |
| Title | Hpci Declared Inoperable Due to Faulty Flow Indicator |
| Event Description | The licensee discovered that the High Pressure Coolant Injection (HPCI) system flow control loop was degraded in such a manner that HPCI would not perform its safety function. The HPCI loop flow indicator indicated 200 GPM with no flow in the loop. The specification for that parameter is <100GPM. With the flow indicator in this condition the HPCI flow controller would perform non-conservatively (less flow into the system than was demanded), and would not perform its intended safety function therefore rendering HPCI inoperable.
The licensee declared HPCI inoperable and in accordance with Technical Specification 3.5.E.2 entered a 14 day LCO. The licensee has commenced troubleshooting and will initiate repairs as necessary to return the system to operation. The licensee notified the NRC Resident Inspector.
BASIS FOR RETRACTION: NRC Event Notification 43113 was conservatively made to ensure that the Eight-Hour Non-Emergency reporting requirements of 10CFR50.73 were met pending the evaluation of an atypical condition observed with the High Pressure Coolant Injection (HPCI) Flow Indicator that was observed by Operators during routine monitoring of plant equipment. After comparing the observed flow indication to allowable values for meter uncertainties, it was determined that the initial NRC Notification was not required. The HPCI system was capable of fulfilling all design safety functions. Additional measures to ensure system reliability were completed that included removing and bench testing the recently refurbished 'square root converter' and calibration verification of involved components. No degraded conditions were discovered. ENS Event Number 43113, made on 01/22/07, is being retracted. R1DO (Neil Perry) notified. The NRC Resident Inspector was notified of this retraction by the licensee. |
| Where | |
|---|---|
Vermont Yankee  Vermont (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-1.3 h-0.0542 days <br />-0.00774 weeks <br />-0.00178 months <br />) | |
| Opened: | Mike Ramsey 22:42 Jan 22, 2007 |
| NRC Officer: | Jason Kozal |
| Last Updated: | Mar 9, 2007 |
| 43113 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |