ML20085G145
| ML20085G145 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/26/1973 |
| From: | Eric Thomas TENNESSEE VALLEY AUTHORITY |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085G136 | List: |
| References | |
| AO-BFAO-7328W, NUDOCS 8308240314 | |
| Download: ML20085G145 (2) | |
Text
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- AUTHO AITY O CHATTANOOGA, TENNESSEE
/<~ 4 i 374O'I .J J f <! October 26, 1973 <h 05STWNEH$ ^ ^ /M' Nr ?f b[.th^;.-{/h !T I tj $ 007soj"b". 1:J. .c y17 e.u,,y/pr h i Mr. John F. O'Icary, Director \\2 czr l Directorate of Licensing \\ dJg p g' / l Office of Regulation N W g, A s U.S. Atomic Energy Ccamission Washington, DC 205!+5 Dear Mr. O'Ieary TENIESSEE VALIEY AUT-:0RITY - BRC',GS FERRY !;UCEAR PLAI;T UNIT 1 - l DOCIGT NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNOW.AL OCCURRENCE REPORT BFAO-7326W The purpose of this report is to provide details concerning the malfunction of level switches at Browns Ferry Nuclear Plant unit 1 on October 17, 1973 This occurrence was reported by telegram on October 18 to the Regica II Directorate of Regulatory Operations, i Atlanta, Georgia. Description cf the Incident During routine surveillance testing on October 17, HPCI condensate header low level. switches E-73-56A and B vere found to operate outside the tecnnical specification trip level setting specified in table 3 2.B of equal to or greater than elevation 551 feet. Investigation and Corrective Action The level switches are arranged in a one out of two logic. Either switch will initiate transfer of the EPCI suction from the condensate storage tank to the suppression chamber. Both switches were found inoperative and the transfer logic would not have operated. A simple adjustment of spring tensica made switch IS-73-56A operable. The switches are Robertshav model 83481 Levelac level switches. Both level switches were inspected and the switch-spring mechanisms found to be sluggish. The switch-spring mechanis=s were adjusted to obtain a positive snap action. In addition, residual magnetism was R evident in the mounting plate of switch IS-73-56B, which would contribute toward erratic switch operation. A vider airgap was established to 8308240314 731126 PDR ADOCK 05000259 S pyg f Q
i...... O 9 yi i I 2 l 9 Mr. John F. O'Icary October 26, 1973 TENNESSEE VALIl:Y AUT'{CRITY - BRO',CS FERRY :;UCLEAR PIJJ;T UNIT 1 - DOCKET I'O. 50-259 - FACILITY OPERATING LICE::SE DPR AENOR'4AL OCCURRENCE REPORT EFAO-7328W help eliminate this problem. The level switches were reset and operated several tines to ensure repeatability. These switches will be functionally tested once every 2 ueeks until three ccnsecutive tects prove satisfactory perfonnance. Very truly yours, TEUUESSEE VALLEY A'JTEORITY / E. F. Thomas Director of Power Production CC: Mr. Ho: nan C. Moseley, Director Re6 on II Regulatory Operations Office', USAEC 1 230 Penchtree Street, IN. Atlanta, Georgia 30303 c. I}}