ML20128K184

Special Rept:On 850501,surveillance Test for Triaxial Response Spectrum Analyzer Revealed That Acceptable Limits for Specific Acceleration Input of Negative 0.05g Could Not Be Met.Cause Undetermined.Investigation Continuing

ML20128K184
Person / Time
Site:	Limerick
Issue date:	06/13/1985
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
CON-#385-530 NUDOCS 8507100509
Download: ML20128K184 (3)

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a PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 (2151841-4000 June 13, 1985 Docket No. 50-352 License No. NPF-27 Dr. Thomas E. Murley, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

SUBJECT:

Special Reporting Requirement for Inoperable Seismic Monitoring at Limerick Generating Station

REFERENCE:

Technical Specification 3.3.7.2 and 6.9.2

Dear Dr. Murley:

This special report is being submitted pursant to the requirements of Technical Specifications 3.3.7.2 and 6.9.2 which state:

3.3.7.2 The seismic monitoring instrumentation shown in Table 3.3.7.2-l* shall be OPERABLE.

APPLICABILITY: At all times.

ACTION:

a. With one or more of the above required seismic monitoring instruments inoperable for more than 30 days, prepare and submit a Special Report to the Commission pursuant to Specification 6.9.2 within the next 10 days outlining the cause of the malfunction and the plans for restoring the instrument (s) to OPERABLE status.

SPECIAL REPORTS 6.9.2 Special reports shall be submitted to the Regional Administrator of the Regional Office of the NRC within the time period specified for each report. j

\ I D' 8507100509 850613 7 PDR ADOCM 05000352 W 8 PDR W

Dr. Thomas E. Murley June 13, 1985 Page 2 DESCRIPTION OF EVENT:

On May 1, 1985, with the unit in cold shutdown, the surveillance test for the Triaxial Response Spectrum Analyzer (Model No. 505N1 MRAD Corp., TRSA) was performed. The TRSA analyzes data and provides acceleration values for a range of

. frequencies (0-33.5 HZ). The ST for the TRSA revealed that acceptable limits for the specific acceleration input of a negative 0.05g could not be met; however, all other acceleration inputs were within acceptable limits.

CAUSE OF EVENT:

.The specific cause of failure in the TRSA is undetermined.

The investigation is continuing.

CONSEQUENCES OF EVENT:

The operators are alerted to a seismic event by annunciators in the control room which receive signals from the operable components of the seismic monitoring system. The TRSA is not required to be operable for the operators to receive annunciation of a seismic event.

The TRSA is used to analyze magnetic tape data collected at various plant locations by independent triaxial accelerometers.

The TRSA is utilized to analyze data following a seismic event and provides evaluation of gravitational acceleration with -respect to vibrational. frequency. With the TRSA inoperable, the data could be sent off-site for analysis by another TRSA.

Since the operators would have received indication in the control room of a seismic event and the data of -such an event could have been analyzed in a timely manner off-site the safety consequences of this condition are considered minimal.

CORRECTIVE ACTION:

A field representative from the manufacturer of the TRSA is scheduled to arrive on site on June 12, 1985 to address this problem and effect repairs.

A follow up report detailing the exact cause and corrective action will be submitted by July 15, 1985.

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' Dr. Thomr.s E. Murley ~Juna 13, 1985 Page 3 Should you require additional information, please do not hesitate to' contact us. l

- Very truly yours, W. T. Ullrich Superintendent Nuclear Generation Division ec: LGS Resident Site Inspector See Attached Service List 4

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