ENS 48615
ENS Event | |
|---|---|
04:08 Oct 26, 2012 | |
| Title | 60-Day Optional Telephonic Notification for an Invalid Actuation of the Essential Spray Pond System |
| Event Description | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.
This telephone notification is being made pursuant to the reporting requirements of 10 CFR 50.73(a)(2)(iv)(A) and 50.73(a)(1) to describe an invalid actuation of the Palo Verde Nuclear Generating Station (PVNGS) Unit 2 essential spray pond system (SP) which serves as the ultimate heat sink as described in 10 CFR 50.73(a)(2)(iv)(B)(9). On October 25, 2012, at approximately 2108, Mountain Standard Time, during refueling outage 2R17, Unit 2 experienced an invalid actuation of the train B essential spray pond system. Testing of the train B engineered safeguards features actuation system (ESFAS) was in progress. During the test, following activities to reset the train B containment spray actuation signal (CSAS), the procedure required a check of contact status on a relay contact which provides input to the train B Load Sequencer. The guidance required the use of a digital multi-meter to perform the contact status check. When the digital multi-meter test leads were landed and removed from the circuit, the train B Load Sequencer changed output modes which resulted in automatic starting of the train B essential chilled water system, essential cooling water system, essential fuel building air filtration unit and essential spray pond system. This was a partial actuation of the train B ESF equipment and all the affected equipment responded as designed. No equipment failures resulted from the event. The event was entered into the PVNGS corrective action program. The invalid actuation was caused by an incorrect testing methodology in the procedure instructions which resulted in the unintended interaction of the digital multi-meter and the digital train B Load Sequencer. The inadequate procedures will be revised to modify the testing methodology for verification of relay contact status. The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1328.98 h55.374 days <br />7.911 weeks <br />1.82 months <br />) | |
| Opened: | Fara Oreshack 14:07 Dec 20, 2012 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Dec 20, 2012 |
| 48615 - NRC Website
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WEEKMONTHYEARENS 559262022-04-12T03:45:00012 April 2022 03:45:00
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