ML20085M652
| ML20085M652 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/23/1973 |
| From: | Eric Thomas TENNESSEE VALLEY AUTHORITY |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085M654 | List: |
| References | |
| AO-BFAO-7340W, NUDOCS 8311090147 | |
| Download: ML20085M652 (3) | |
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TENNESSEE VALLEY AUTHOFilTY T-~~3M 77 rT -
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CHATTANOOGA, TENNESSEE ij ' ' / / c. {
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November 23, 1973 j@yfi[6]
OIb{7 Mr. John F. O' Leary, Director V
Directorate of Licensing Office of Regulation U.S. Atcmic Energy Ccmmission Washington, DC 20545
Dear Mr. O' Leary:
TEHITESSEE VALLEY AUTHORITY - BEGMS FERRY IiUCLEAR PIAllT UUlT 1 -
DOCK 3T H0. 50-259 - FACILITY OPERATING LICEUSE DPR ABNORMAL OCCURRENCE REPORT DFAO-734Gi The enclosed report is to provide details concerning HPCI steamflow excessive pressure switches' malfunctions which occurred on Browns Ferry Nuclear Plant unit 1 on Hovember 15, 1973, and is submitted in accordance with Appendix A to Regulatory Guide 1.16, Revision 1, October 1973 Very truly yours,
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ITENUESSEE VALIEY AUTHORITY 0-
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E. F. Thomas I (
Director of Power Production Enclosure CC(Enclosure):
Mr. Norman C. Moseley, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, IM.
Atlanta, Georgia 30303
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ABNOR!'AL OCCURRENCE REPORT Report No.--BFAO-73!40W Report Date--November 23, 1973 Occurrence Date--November 15, 1973 Facility--Browns Ferry nuclear Plant unit 1 Identificatien of Occurrence Unit 1 HPCI steamflow excessive pressure switches malfunctioned.
Conditions Prior to Occurrence Reactor'at 25-percent ther=al power during startup testing.
Description of Occurrence During accelerated surveillance testing on November 15, 1973, HPCI steamfica excessive pressure switches PDIS-73-1A and 1B were found to operate outside technical specification setpoint of less than or equal to 90 psid as specified in Table 3.2.B.
The as-found settings were 92 5 and 96.o psid, respectively.
Analysis of Occurrence These switches have two contacts in parallel that form a trip logic in the trip system. The trip logic acts to trip the HPCI turbine and isolate the system upon hiSh steamline flow. Since only one set of contacts -in each switch was found out of technical specification setting and the other two contacts tested satisfactorily, the logic would have performed its intended function if required.
Corrective Action
. Locking plate assemblies have been received and are being installed in all Barton Model 288 switches, and an accelerated testing frequency of once a week has been initiated and will continue 1.ntil three consecutive tests prove satisfactory.
The testing frequency will then continue on a biweekly schedule until three consecutive biweekly tests are satisfactory, whereupon'the original schedule will be resumed.
-Failure Data Barton Model 288
, Serial Nos.: PDIS-73-3A, 288-5843; PDIs-73-1B, 288-5842 0
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Switch Date Failure Corrective Action PDIS-73-1A 9/20/73 Operated outside tech spec limit Reset switch, adjusted for free operaticn PDIS-73-1A 11/15/73 Operated outside tech spec limit Installing new locking plate assembly PDIS-73-1B 11/15/73 Operated outside tech spec limit Installing new locking-plate assembly M
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