ML20086D755

Updated AO 73-10:on 730417,relief Valve Initiation Time Delay Relay Failed to Actuate.Similar Event Occurred on 721020.Relay Replaced & Replacement Verified.No Further Action Necessary

ML20086D755
Person / Time
Site:	Vermont Yankee
Issue date:	04/20/1973
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086D757	List: ML20086D755 ML20086D765
References
AO-73-10, VYV-2626, NUDOCS 8312050080
Download: ML20086D755 (1)

Text

1 O O VbRMONT YANKEE NUCLEAR POWER CORPORATION

~

• SEVENTY SCVEN OROVE STRECT RUTLAND, VERMONT 05701 VYV-2626 " " ' '

P.O. BOX 157 VERNON. VERMONr 05354 April 20, 1973 5 LV

@ .m, A

! a f .Q Director .

G~ dO r"

Directorate of Licensing I 8g lO/

U.S. Atomic Energy Cornission N' c4. e' .j%g , 10 Washington, D.C. 20545 V

d,[ 4.[ ' y

REFERENCE:

Operating License DPR-28 '

. g i Docket No. 50-271 Abnormal Occurrence No. A0-73-10

Dear Sir:

l' l,I As defined by Technical Specifications for the Verciont Yankee Nuclear

}': Power Station, Section 6.7.B.d, we are reporting the following Abnormal Occurrence as A0-73-10.

f

. At approximately 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on April 17, during the performance of the Automatic Depressurization Systen "B" Logic Test, the Relief Valve 7F (d [? Initiation Time Delay Relay (No. 2E-K5B) failed to actuate in <120 seconds

! r p 'T as required by Table 3.2.1 of Technical Specifications. The relay was

! replaced and the replacement was verified to operate in <120 seconds as required by Technical Specifications. The reactor was operating at Approximately 75% power at the time of this occurrence. -

The Plant Operations Review Committee, in review of this incident, noted that this same switch had failed previously during a surveillance test on October 20, 1972. At that time the surveillance frequency of this switch was doubled (3 months vice 6) and testing during January showed satisfactory perfornance. PORC concluded that replacement of the "B" switch in this .

. Instance was appropriate. Since similar time delay relays have performed without difficulty, notably the companion switch in the "A" logic, no further action was deemed necessary.

Very truly yours, 8312050000 730420 PDR ADOCK 05000271 VERM0MT YANKEE NUCLEAR POWER CORPORATION S PDR

, lO .

./f m , ."^'

y B.W. Riley s

' '"#21

' fs; #.q{' Plant Superintendent

, c:)-

e COPY SENT A REG