PNO-II-96-076, on 961031,Unit 2 Placed in Cold Shutdown Mode. Licensee Removing Four of SRVs to Be Sent Off Site for Setpoint Testing.Restart Date Will Be Determined Based on Evaluation of Test Results
| ML18038B778 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/31/1996 |
| From: | Lesser M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| References | |
| PNO-II-96-076, PNO-II-96-76, NUDOCS 9610310288 | |
| Download: ML18038B778 (2) | |
October 31, 1996 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-II-96-076 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance.
The information is as initially received without verification or evaluation, and is basically all that is known by Region II staff in Atlanta, Georgia on this date.
~Facilit Tennessee Valley Browns Ferry 2
Decatur, Alabama Dockets:
50-260 Authority Licensee Emer enc Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable
Subject:
SHUTDOWN TO EXCEED 72 HOURS DUE TO REVIEW SAFETY RELIEF VALVE OPERATION On October 29, 1996, Unit 2 experienced an automatic reactor scram due to a problem with the alternator-exciter collector on the main generator.
Licensee review of the scram determined that none of the 13 safety relief valves (SRV) opened during the transient.
Further review of the peak reactor pressure raised a question as to whether or not the SRVs should have operated.
The reactor pressure, as measured at the steam
- dome, peaked at 1131 psig.
The first set of 4 SRVs has a setpoint of 1105 +/-
11 psig, the second set of 4 SRVs is 1115 +/- 11 psig, and the third set of 5 SRVs is 1125 +/- 11 psig.
The licensee's preliminary evaluation, which accounted for pressure drop between the steam dome and the
The SRVs are Target Rock Two-Stage valves.
On October 31, 1996, at 2:12 a.m., Unit 2 was placed in Cold Shutdown mode.
The licensee is removing four of the SRVs to be sent off site for setpoint testing.
The licensee is currently scheduled to complete testing and evaluation of the SRVs by November 1, 1996.
The restart date will be determined based on evaluation of test results.
The NRC Resident Inspectors are following activities at the site.
This information is current as of 11:00 a.m.,
on October 31, 1996.
The State of Alabama has been notified.
Contact:
Mark S. Lesser (404)331-0342 96f03i0288 96i03i PDR IGE
- PNO-I I-96-076 PDR
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