ENS 46253
ENS Event | |
|---|---|
08:13 Sep 15, 2010 | |
| Title | Hpci Declared Inoperable During Surveillance Testing |
| Event Description | In preparation for quarterly valve testing, the High Pressure Coolant Injection system was declared inoperable and the technical specification required actions were implemented. The system was available for on-line risk. During the testing, the inboard steam isolation valve was stroked closed and reopened and operated properly. The valve was reclosed to continue with valve testing. When an attempt was made to reopen the inboard isolation valve, the valve failed to indicate full open.
The system remained inoperable due to the valve malfunction. Therefore, the condition is being reported in accordance with 10 CFR 50.72 (b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Maintenance activities are currently in progress to restore the system to the operable status. The licensee entered a 14-day Limiting Condition of Operation per Technical Specification 3.5.1. The licensee notified the NRC Resident Inspector.
On September 15, 2010, the NRC Operation Center was notified of Event Number 46253 that described a failure of the High Pressure Coolant Injection (HPCI) system inboard steam isolation valve to fully reopen using the Main Control Room (MCR) control switch. At the time, it was not readily apparent that the system was capable of performing its intended safety function. Therefore, the condition was reported in accordance with 10 CFR 50.72 (b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Troubleshooting identified that a contact in the control switch circuit had malfunctioned. This contact is bypassed during an initiation signal. Therefore the valve would have opened fully in the event the HPCI system received an initiation signal. In light of these findings, the HPCI function was not impaired as a result of the contact malfunction and would have been capable of performing its safety function. Therefore, the notification associated with Event Number 46253 is being retracted. The NRC Resident Inspector has been notified. R3DO (Dave Passehl) has been notified. |
| Where | |
|---|---|
Dresden  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+3.83 h0.16 days <br />0.0228 weeks <br />0.00525 months <br />) | |
| Opened: | Beth Jenkins 12:03 Sep 15, 2010 |
| NRC Officer: | Karl Diederich |
| Last Updated: | Oct 8, 2010 |
| 46253 - NRC Website
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Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |