ML20235J454

Special Rept 87-01,Rev 1:on 870321,three Seismic Triggers Would Not Provide Required Control Room Annunciation Upon Receipt of Horizontal 0.1 G Seismic Acceleration.All Instruments Removed from Site Repaired.Instructions Revised

ML20235J454
Person / Time
Site:	Browns Ferry
Issue date:	07/02/1987
From:	Robert Lewis TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
87-01, 87-1, NUDOCS 8707150569
Download: ML20235J454 (3)

Text

. - - - . .

I 4

• y J TENNESSEE VALLEY AUTHORITYL I Browns Ferry Nuclear Plant

'P.O.~ Box 2000 Decatur, AlabtJea 35602-1 July 2, 1987 t l

l U.S. Nuclear Regulatory' Commission Document Control Desk 4' Washington, D.C. 20555

Dear Sir:

1 TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT'(BFN)' UNITS 1,-2. AND 3. .

DOCKET NOS. 50-259, 260, AND 296 - FACILITY OPERATING LICENSES DPR-33, -52 AND -68 SPECIAL REPORT 87-01 R1 The enclosed special report provides additional details concerning the loss of seismic monitoring instrumentation. This report'is being furnished-pursuant tc-plant technical specification requirement 3.2.J.3.

Very truly yours, TENNESSEE VALLEY AUTHORITY Robert L. Lewis  !

Plant Manager Browns Ferry Nuclear Plant Enclosures cc (Enclosures):

Regional Administration INPO Records Center U.S. Nuclear Regulatory Commission Suite 1500 Office of Inspection and Enforcement 1100 Circle 75 Parkway Region II Atlanta, Georgia 30339 101 Marietta Street -Suite 2900 Atlanta, Georgia 30303 NRC Resident Inspector, Browns Ferry Nuclear Plant

B707150569 870702 j PDR ADOCK 05000259  !

g PDR  !

I An Equal Opportunity Employer a

f.#

i Special Report 87-01 Revision 1 Loss of Seismic Monitoring Instrumentation The seismic monitoring system is physica11y' located in unit 1 at Browns l Ferry Nuclear Plant (BFN) and provides seismicity data for all three BFN units which are presently defueled. l The seismic monitoring system utilized is provided by two vendors.

Kinemetrics Systems is the supplier of three blaxial seismic switches l (triggers), which provide control room annunciation, and of three triaxial time history strong motion accelographu (SMA-2), located on various reactor building floor elevations. Teledyne supplies three triaxial peak l

accelographs which are installed on piping systems within the unit i reactor  !

building. j l

In the course of TVA's procedures upgrade program it was recognized that l l

t vendor manuals and documentation for the seismic monitoring instrumentation, required by technical specifications, needed improvement or, in some cases, the information was nonexistent. Consequently, a representative from Kinemetrics Systems company was brought onsite to provide' hands-on training for instrument mechanics and engineers relative to proper testing, calibration, and servicing of the instruments. On March 21, 1987, culminating the four-day training course,'the seismic triggers located in the reactor building on the base slab were carefully examined. In the opinion of the vendor specialist, none of the three triggers would have provided the required control room annunciation upon receipt of a horizontal 0.1 g seismic acceleration. It is not known how long the seismic triggers were not fully functional. Located adjacent to the triggers is a SMA-2, l Immediate attention was focused on the SMA-2 located on the reactor building l l base slab, as it is the most critical for seismic monitoring. After fleid I work it was restored to operable status the next~ day. Another SKA-2, located on the reactor building third floor, was not considered serviceable j onsite, so it was taken back to Kinemetrics, along with the three seismic- i triggers. The remaining SMA-2 of the three was found to be in satisfactory condition.

The vendor manuals and other instructions furnished with the instruments were not written for power plant maintenance personnel, but for I seismologists. The seismic triggers installed at BFN are approximately 15 years old and are regarded as one-of-a-kind. Kinemetrics Systems has only recently made training available to utilities, as utilities represent a very small portion of their business. Surveillance instructions, previously regarded as adequate, did not provide detail necessary for the average technician. Maintenance personnel, for example, were not trained to recognize that a small crinkle in the foil-like flexor would hamper the overall performance of the seismic trigger. Such a crinkle was found in one trigger.

l I

l Page 1 of 2 l

l I

L_____-__-___-_______________-_________-__-__

p.,

=

All instruments comoved from the site were repaired and restored to operation within 30 days. Surveillance instructions have been revised to include more detailed inspections of the instruments. The revised surveillance procedure for the three Teledyne peak accelographs was performed on May 28, 1987. These instruments utilize a piece of magnetic tape to record the maximum seismic activity at their mounted locations and were found to be out of calibration. How long the peak accelographs have been out of calibration cannot-be determined. These accelographs have been replaced with newer model recorders.

TVA geologists believe, based on regional records, that no seismic activity since initial startup has been of a magnitude (greater than 0.01'g) recordable on plant instrumentation. i d

i 4

)

i l

l I

l 1

I l l l Page 2 of 2 l

1 1