ML20085L998
| ML20085L998 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/19/1974 |
| From: | Eric Thomas TENNESSEE VALLEY AUTHORITY |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085M003 | List: |
| References | |
| AO-BFAO-7310W, AO-BFAO-7313W, AO-BFAO-7315W, AO-BFAO-7322W, AO-BFAO-7326W, AO-BFAO-7327W, AO-BFAO-7333W, AO-BFAO-7340W, AO-BFAO-7341W, AO-BFAO-7346W, AO-BFAO-7352W, AO-BFAO-735W, AO-BFAO-741OW, AO-BFAO-741W, NUDOCS 8311070065 | |
| Download: ML20085L998 (3) | |
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TENNESSEE VAL Y AUTHO AITY F-T3 '7 q Ci-IATTANOCGA, TENNESSEE, d, -.1.- \\
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Mr. John F. O' Leary, Director g
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U.S. Atomic Energy Co= mission Washington, D.C.
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Dear Mr. O' Leary:
TENUESSEE VALLEY AUTHORITY - BROWNS FERRY UUCLEAR PLA'.'T UNIT 1 -
DOCi:ET NO. 50-259 - FACILITY OPERATIUG LICE'ISE DPR A:2ND:CNT 1 TO AEiOPPAL OCCURRENCE REPORTS - BFAO-735W, BFAO-7310W, BFAO-7313W, BFAO-7315W, BFAO-7322W, BFAO-7326W, BFAO-7327W, BFAO-7333U, BFAO-73 BOW, BFAO-73klV, BFAO-7346W, BFAO-7352W, BFAO-7hlW, AND BFAO-7h10W The enclosed report n=endment provides the. additional details regarding the cause and corrective actions taken concerning the setpoint drift associated with Barton (!'odels 278, 288, and 288A) differential-pressure indicating switches on Browns Ferry unit 1.
The setpoints on the sub, Ject switches were found outside the technical specification limit.
Very truly yours, TENNESSIE VALLEY ALTIORITY 2: V--
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E. F. Thonas Director of Power Production Enclosure CC (Enclosure):
l'r. Nor~an C.. Foseley, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, IFJ., Suite 816 Atlanta, Georgia 30303 THERE IS ONLY ONE COPY OF THIS AMENDMENT IN FILE AND THIS COPY IS IT.
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Amendment 1 to abnormal occurrence reports BFAO-735W, BFAO-7310W, BFAO-7313W. BFAO-7315U, BFAO-7322W, BFAO-T326W, BFAO-7327W, BFAO-7333W, BFAO-7340W, BFAO-7341W, BFAO-7346W, BFAO-7352W, BFAO-Th1W, and BFAO-Th10W.
Occurrence LLtes:
August 13, 1973; Septer,ber 8, 1973; Septenber 14, 1973; l
September 20, 1973; October 9, 1973; October 15, 1973; l
October 16, 1973; Hovember 8,1973; november 15, 1973; november 16, 1973; December 6,1973; January h,197h; January 6, 1974; February 3, 1974.
j Facility:
Browns Ferry Nuclear Plant unit 1 i
Desirnation of Anr>arent Cause of Occurrence:
6 As a result of a detailed investigation concerning the occurrence of drifting setpoints on several Barton differential-pressure indicating
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switches (l',odels 278, 288, and 288A), vc have identified the interpretation W application of the associated surveillance instruction as the single The interpretation and application of apparent cause of the occurrences.
the instruction were not adequate to identify and correct deviations in.
the instrument performance and did not provide sufficient consideration to the status of the mechanical devices which interface the process measuring component and the electrical switch components.
4 Two contributing causes have also been identified as a result of the One of these is the exposure of certain Barton Model 278 investigation.
and 288 instruments to a severe vibration environment. The other contribu-ting cause is relar,ed i,o a apveific part, c,f the cicetrical.c'? itch Mhn-tion technique involving the rate at which the simulated process variable vas driven in its approach to the switch actuation point. This rate was not sufficiently controlled and, as a result, introduced errors in the switch actuation point verification and in the electrical switch calibration.
I Corrective Actions:
To prevent the possibility of a similar recurrence, the. surveillance instruc-tions, calibration check procedures, calibration procedure, c3ectrical switch calibration, and the specific techniques for performing these procedures have been reiterated to the instrument maintenance staff.
In addition to the above aci, ions, ve have made arrangements with the instru-ment manufacturer to provide specialized training for key. personnel on our -
instrument maintenance staff. This training is scheduled fron April 30,.197h, to May 2, 197h. Upon the return of these key personnel to our Browns Ferry site, ve vill conduct a formal training session to further qualify the other members of our in. trument staff in the calibration and maintenance of these a
This training pro 6 ram.is scheduled to be. completed.on May 24,197h.
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When the additional training has beed completed, an evaluation of each of the Barton instruments in critical service vill be conducted by our As a result -of that evaluation, any additional plant instrument staff.
corrective action deemed necessary vill be incorporated into the next scheduled surveillance activity for cach of the instruments.
We have completed a modification to the Barton (Models 278 and 288)
This modification instruments as reco== ended by General Electric Company.
was designed to provide the necessary protection for setpoint drift resulting from exposure to hi h vibration and involved the addition of a switch-S locking device which we believe vill prevent the possibility of further setpoint drift as a result of vibration.
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