ML20215H640

Provides Addl Info in Response to Rc Deyoung Re High Temps Experienced in Upper Level of Safeguards Bldg. Exhaust Duct Sys Will Be Installed in Safeguards Bldg to Limit Max Space Temp Rise

ML20215H640
Person / Time
Site:	Surry, 05000000
Issue date:	11/16/1972
From:	Ragone S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Deyoung R US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20215H426	List: ML20215H423 ML20215H509 ML20215H606 ML20215H640 ML20215H698 ML20215H885 ML20215H962
References
FOIA-87-20 6369, NUDOCS 8706240169
Download: ML20215H640 (2)

Text

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V1BOINIA Ex.zernic Axn Powra COMPANY . ,

Ricuxown,V mosmA 20261  % ; ( fj, g~~ NOVs01W2 3 November 16, 1972 e , '; ,

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Mr. R. C. DeYoung, Assistant Olrector Docket Nos 0-280 for Press'urized Water Reactors Olrectorate of Licensing United States Atomic Energy Commission e Washington, D. C. 20545 -

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Dear Mr.,

DeYoung:

We have reviewed your letter to Mr. Ragone dated.0ctober 11, 1972, i stating your conclusions concerning our report on the " Operating incident  !

of July 27,1972,".and reques ting additionai information relative to the high  !

temperatures experienced in the upper level of the safeguards building. The following'sur ary will substantiate that while temperatures up. to 172*F have been observed in the past,; modifications to the safeguards building ventilation system will assure that in the future 4~ temperature of 125'F will not be exceeded.

Modificailon to the safeguards building ventilation system consists of the InsRallation of an exhaust duct system designed to limit the maximum space temperature rise In the building to 25*F when the summer ambient 's j 100*F. .Since the building Is not normally occupied, the design temperature was established by equipment operational limits. The limiting component is a Fisher type 546'E/P converter which has a maximum ambient operating temperature of 150*F. These E/P converters are used on the decay heat removal valve (HCV-MS-104) and the atmospheric steam dump valves (RV-MS-101 A, B and C) .

j Safety equipment that may have been exposed to temperatures up to 172*F during power range operation are the main steam trip valves, atmospheric steam dump valves and decay heat release valve. All other safety related equipment is located on the ground floor where maximum temperatures were below .

Il0*F. The only instruments located Itthe areat,wf.th.:sia.ec.l_ fled temperatut.e_ ' - :.7 ;

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limits are the E/P converters mentione,d,abovi. ~$ubseq'uent physical Yifninat!~oL?'~y i and operational checks gave no e,vidence tb.at .these were adversely 4'f fected . 3 r*-

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by the 172*F envi ronmer.t. The main steam trip valves, atmo'pheric s steam dump valves and decay heat release valve have been successfully stroked since the incident to verify that their performance was not detrimentally affected by the elevated temperature.

As stated in the report, " Operating incident of July 27, 1972,"

the vent covers were removed from the safeguards building prior to the incident, on July 10, 1972, to improve ventilation in the area. This lowered the ambient temperature to approximately 142'F.

Since corrective action was taken as soor. as the high ambient temperatures were detected, the equipment was not subjected to elevated temperatures for -

a prolonged period of time. This coupled with subsequent Lt.spection and operation of the equipment assures that safety equipment in the safeguards

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building was not adversely af fected by exp.osure to a 172'F environment.

Very truly yours, l

Stanley,/Ra e Vice President

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