ML18101A779
| ML18101A779 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 06/09/1995 |
| From: | Jason White NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| References | |
| 28904, 28907, 28908, PNO-I-95-018, PNO-I-95-18, NUDOCS 9506200134 | |
| Download: ML18101A779 (3) | |
Text
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- e DCS No:
05000272950607 Date:
June 9, 1995 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNl-9518 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 the Region I staff on this date.
Facility:
Salem Generating Station, Units 1 and 2 Public Service Electric and Gas Co.
Hancocks Bridge, New Jersey 08038 Docket Nos.:
License Nos.:
Event Nos.:
Event Location 050-00272, 050-00311 DPR-70, DPR-75 28904, 28907, 28908 Code: POW
SUBJECT:
AUTOMATIC REACTOR TRIP FROM 10% POWER Licensee Emergency Classification:
Notification of Unusual Event
---Alert
___ Site Area Emergency
___ General Emergency X
Not Applicable At 6:27 p.m. on June 7, 1995, Salem Unit 2 operators commenced a Technical Specification (TS 3.0.3) required shutdown from 100% power due to the declaration of two inoperable residual heat removal (RHR) trains. At 11:01 p.m. Unit 2 experienced an automatic reactor trip from 10% as operators removed the main generator from the grid.
As operators opened the secon9 of two circuit breakers tying the generator to the 500 KV ring bus, the fault detection devices associated with the breaker actuated.
The protective relay actuation caused loss of one source of power to the vital 4KV buses and one source of power to the non-vital 4KV buses for each of the Salem units. The 4KV vital buses for both units successfully swapped over to the alternate source of offsite power, as designed.
The loss of non-vital power did not significantly affect Salem unit 1, since it was in mode 5 at the time.
The loss of non-vital power caused loss of power to the F and G non-vital 4KV buses, with the result that no. 23 and no.
24 reactor coolant pumps (RCP) tripped.
The resulting low RCS flow caused a reactor trip (reactor power at 10 percent with low flow in more than one loop). All safety-related equipment operated as designed following the reactor trip. Unit 2 operators are continuing to bring the unit to cold shutdown.
Normal off-site power sources have been restored.
The operating challenges presented by this event, included: (1) the need to manually start temporary diesel-powered compressors to compensate for the loss of two of three station air compressors that were affected by the loss of power (the remaining air compressor was out of service for maintenance); (2) the need to manually start auxiliary feedwater pumps since the trip occurred at low power; (3) the need to shut main steam isolation valves to preclude excessive cooldown; (4) and the need to initiate auxiliary spray to control pressure since normal pressurizer sprays were affected by the loss of the RCPs.
Salem Unit 1 continues to be maintained in cold shutdown and was generally unaffected by the Unit 2 event.
9506200134 9~0609 PDR I&E PNO-I-95-018 PDR
e DCS No:
05000272950607 Date:
June 9, 1995 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNl-9518 The President of the Nuclear Business Unit (NBU), in conversation with the Regional Administrator, agreed to maintain both Salem units in cold shutdown for an indefinite period pending the completion of the following: (1) Significant Event Response Team review of the circumstances leading to, and causing, the reactor trip; (2) Special licensee team review of long-standing equipment reliability and operability issues; (3)
Meeting with NRC to discuss restart issues and resolution plan; (4) Implementation of Restart Readiness review and resolution of restart issues; and (5) Meeting with NRC to discuss outcome and conclusions from the restart readiness review.
Region I intends to confirm the licensee's commitments in a Confirmatory Action Letter.
Additional inspection personnel have been directed to the site to assist the resident inspectors in performing independent oversight and review of the reactor trip and the circumstances leading to it.
The licensee has issued a press release. The states of New Jersey and Delaware have been informed of the event.
Contact:
John R. White (610) 337-5114
- DCS No:
Date:
olo212950607 June 9, 1995 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNl-9518 DISTRIBUTION:
OWFN Chairman Selin Rogers de Planque TWFN AEOD IRM ACRS NMSS OIG RES LST PDR Mail:
DCD DOT:Trans only**
NRC Ops Ctr INPO**
NSAC** ---
Comm.
Comm.
OCAA OIP OCA OGC OPA EDO OE OSP NRR** (Phone Verif: A. Byrdsong 504-1168 or 504-1166)
Regional Offices ___ _
Licensee:
- General list for sending PNs by FAX Region I Form 83 (Rev. October 1994)
(Reactor Licensees)
RI Resident Office ---