ENS 51117
ENS Event | |
|---|---|
17:20 Apr 12, 2015 | |
| Title | 60-Day Optional Telephonic Notification for an Invalid Containment Isolation Activation. |
| Event Description | This 60-day telephone notification is being submitted in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to report an invalid actuation of the Train B Phase A Containment Isolation at Sequoyah Nuclear Plant.
At 1320 EDT on April 12, 2015, during planned performance of the Containment Isolation Train-A, Phase A Isolation Testing and Emergency Gas Treatment System (EGTS) Cleanup System Test, the main control room received several Train-B annunciators. Upon investigation, it was determined that an invalid signal to the Train-B Solid State Protective System (SSPS) actuated the Train B, Phase A Containment Isolation. The invalid isolation signal was the result of a human performance error during the performance of the Phase A Isolation Test surveillance procedure. Operations personnel responded to the SSPS initiation, testing was aborted, ensured that all equipment operated as designed and restored affected systems in accordance with plant procedures. Approval to restart testing was obtained. All prerequisites were met and testing of the SSPS Train-A, Phase A Isolation was completed satisfactorily. As part of the prerequisite test alignment of the Train-A, Phase A, Unit 2 had entered a planned 7 day action for EGTS being inoperable. During the test when the Train-B of Phase A actuated, the suction dampers for Unit 1 supply to EGTS were closed per plant procedures. This prevented Train-B EGTS from aligning to Unit 1 and allowed Train-B of EGTS to remain operable for Unit 2. An SSPS Phase A signal can be generated automatically by a Safety Injection Signal (SIS) or manually. At the time of the event, plant conditions for an SIS did not exist; therefore, the Phase A actuation was invalid. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Sequoyah  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1265.97 h52.749 days <br />7.536 weeks <br />1.734 months <br />) | |
| Opened: | Frank Conlow 11:18 Jun 4, 2015 |
| NRC Officer: | Vince Klco |
| Last Updated: | Jun 4, 2015 |
| 51117 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 551302021-01-11T16:52:00011 January 2021 16:52:00
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