PNO-I-92-075, upon Investigation of Alarm Printed Out on Auxiliary Typewriter on 921213,operators Determined That Cpu for Overhead Annunciator (Oha) Had Failed to Perform, Resulting in Loss of Oha Sys for 1 H & 41 Minutes

PNO-I-92-075:upon Investigation of Alarm Printed Out on Auxiliary Typewriter on 921213,operators Determined That Cpu for Overhead Annunciator (Oha) Had Failed to Perform, Resulting in Loss of Oha Sys for 1 H & 41 Minutes

ML20126B275
Person / Time
Site:	Salem
Issue date:	12/15/1992
From:	Jason White NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-92-075, PNO-I-92-75, NUDOCS 9212220035
Download: ML20126B275 (2)

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DCS No: 50311921213 Date: December 15,1992 ERELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PN19275 This preliminary notification constitutes EARLY notice of events of POSSfBLE safety or public interest significance. The infonnation is as initially received without verification or evaluation, and is basically all that is known by the Region I staff on this date.

Facility: Licensee Emergency Classification:

Public Service Electric & Gas Co. Notification of Unusual Event Salem 2 Alert IIancocks Bridge, New Jersey Site Area Emergency General Emergency s

_X_. Not Applicable Docket No.: 50-311 License No.: NONE Event No.: 24752 Event Location Code: POW

Subject:

AUGMENTED INSPECTION TEAM DISPATCIIED TO SALEM UNIT 2 TO REVIEW FAILURE OF TIIE ANNUNCIATOR SYSTEM TO FUNCTION AS DESIGNED At 9:26 p.m. on 12/13/92, a reactor control room operator at Salem Unit 2 noticed an alarm being printed out on the auxiliary alarm typewriter in the Unit 2 control room. This typewriter records alanus and interfaces with the control room alarm annunciation system, which activates the overhead annunciator (OHA) indicators to alent ;perators of off-nonnal operating and equipment parameters. The operator noted that the related OHA was not illuminated when the auxiliary alarm typewriter was printing. Upon investigation, the operators detennined that the central processing unit (CPU) for the Ollas had apparently failed to perfonn since 7:45 p.m., according to the time clock associated with the CPU. The operators perfonned a manual reset of the affected CPU, and the system retumed to nonnal operation. The OIIA had failed "as is", that is, no change in indicated alann conditions occurred from 7:45 to 9:26 p.m.

The loss of OHA system updating for one hour and 41 minutes satisfied the licensee's criteria for an Alert declaratien (loss of the OHAs for a sustained 15 minutes), but since the problem was corrected in les than three minutes from the time of discovery, the licensee elected not to declare an Alert. On 12/14/92, the licensee did make a 10CFR50.72 report to infonn NRC to report a major loss of

.sssessment capability that was associated with the failum of the annunciator system.

The involved CPU is part of a new OHA system installed at Salem Unit 2 during the unit's last refueling outage in early 1992. An identical system was installed at Salem Unit I during that unit's last refueling outage in mid-IN2. The system was supplied by the Beta Computer Company, Dallas, Texas. The licensee has perfonied functional tests to assure themselves of the system's current operability and is continuing their investigatior, into the event. The vendor is expected on-site on 12/15/92.

The resident inspector was informed of the event on the morning of 12/14/92. NRC management detennined that the condition warranted review and evaluation by an Augmented Inspection Team (AIT).

Accordingly, some members of the AIT were dispatched on 12/14/92; and the remaining members are 1 0 expected to be on-site by 12/15/92. The AIT will include representatives from Region I, NRR and AEOD. The team leader is William Ruland, a Section Chief in DRS, Region I.

9212220035 921215 PDR ILE 1" - 7( , .

PNO-I-92-075 PDR- / -

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DCS No: 50311921213 Date: December 15, 1992 ERELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PN19275 The State cf New Jersey was informed of the AIT. In accordance with the existing Memoranda of Understanding (MOU), the State of New Jersey is sending an observer.

CONTACT: John R. White (ITS) 345-5114 DISTRIBUTION:

OWFN MNBB IcSt. NL Mail: ADM:DMB '

Chaimian Selin AEOD *

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