ML20085G309

AO BFAO-7321W:on 731007,drywell Pressure Switches PS-64-56B & PS-64-56C Exceeded Tech Spec Setpoint.Switch Mechanisms Inspected,Switches Recalibr & Frequency of Testing Increased to Once Every 2 Wks

ML20085G309
Person / Time
Site:	Browns Ferry
Issue date:	10/17/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G310	List: ML20085G309 ML20085G324
References
BFAO-7321W, NUDOCS 8308240813
Download: ML20085G309 (2)

Text

_ . _ _ _ _ _ _ _ _ _ - _ - _ _ _

"'+ +

4 uw e4 weg%.semp e unipw -eM h l .

TENNESSEE VALLEY AUTHOAITY t-~~J M i

CHATTANOOGA, TENNESSEE i: Y 'l/e 37401 L Lf/A f.1tiie m.- n

~ A{.-- O

@ l Q/'%

October 17, 1973 h/ 6 SM'E85fe%

i O) \p ( panTru ASHip

/\}g \

im}

L s.Q7UAf"g%f .

u)b 8(L d gbG ocT20W3"gd DM(~*'OMM. ,

NY(

ys, n2rt W Mr. John F. O' Leary, Director ([ t;'7T g,p /7 j Directorate of Licensing '

g...w.m g Cf Office of Regulation N U.S. Atomic Energy Cc=sission 'G d, p f' Washington, DC 205k5 Daar Mr. O'Ioary:

TEICESSF2 VALLEY AUTEORITY - EROWNS FERRY HUCLEAR PIMT UNIT 1 -

DOCiO2 UO. 50-259 - FACILITY OPERATIHO LICENSE DPR ALUCEMAL OCCU3dENCE REPORT DFI.0-7321W The purpoce of this report is to provide details concerning the malfunction of two dryvell pressure switches in unit 1 at Browns Ferry nuclear Plant on Cetober 7, 1973 This occurrence was reported by telegran on October 8 to the Region II Directorate of Regulatory Operations, Atlanta, Georgia.

Description of the Incident

• Durira routine surveillance testing on October 7, dryvell pressure switches PS-64-56B and C vere found to. operate outside the technical specification setpoint of equal to or less than 2 psig. The as-found settings vere 2.05 and 2.02 psig, respectively. These switches are arranged in a one out of two taken twice logic in the reactor protection systen. The other two channels were tested and found to operate satisfactorily. If recuired, the RPS logic would have perfomed its intended function. The reactor was in startup mode at rated temperature

and pressure for turbine balance testing.

t Investigation and Corrective Action -

These are Static-0-Ring, model 12N-AA4 switches, with a range of 0.2 to 6 psig. .The switch techanicas were thoroughly inspected and operated to detemine the cause of the cetpoint drift. No irregularities were fcund in the mechanica. The switches were recalibrated and subsequently operated several times to ensure repeatability. Functional testing frequency of I

s V 8308240813 731017 PDR ADOCK 05000259 b1 h S PM _.

7,730 COPY SENT REGION N

.f.. '

,- -----m.u-,.- - _

O O

,2 Mr. John F. O' Leary October 17, 1973 TMIESSEE VAll2Y AUTHORITY - BRO' JUS FERRY NUCLEAR PLA*;T UNIT 1 -

DCCET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNOWE OCCUR?2NC3 P2 PORT EFAO-7321w once every two weeks has been initiated and will be continued antil three consecutive tests prove catisfactory perfomance. At that time, the original teet schedule of one a month will be resumed.

Ver/ truly yours, TENUESSEE VAIL 2Y AUTECRITY

/ 4 l1 r

/

W

,f

/ E. F. Thomas

[g Director of Power Production CC: Mr. Norman C. Moseley, Director Region II Regulatorj Cperaticac Office, USAEC 230 Peachtree Street, IN.

Atlanta, Gecrgia 30303 -

9

{

..w..-.. , - - .- . .