ML20136C355

Discusses Depressurization Event on 770924.Believes Fuel Integrity Not Violated & Plant May Be Operated as Designed. Sequence of Events & Related Correspondence Encl

ML20136C355
Person / Time
Site:	Davis Besse, Three Mile Island
Issue date:	10/05/1977
From:	Lauer J BABCOCK & WILCOX CO.
To:	Domeck C TOLEDO EDISON CO.
References
TASK-TF, TASK-TMR NUDOCS 7909190476
Download: ML20136C355 (117)

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TELEC0PY Power cenernum crean l

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biTD Wem:= A E5m October 5, 1977 Bili-1578 File: T1.2/12B

'llr, C. C. Domech cc: J. D. Len@on nacicar Project Encineer J. C. Leg g D.J.Demro ix ToledoEdisonComsnv ,

Po.eer Engineering r.n'd Construction E. C. Ilovah/2 330 Madison Avenue Toledo, Ohio 43552 .

Subject:

Toledo Edison Company 24, 1977 DEPRE55UR12ATION EVE li 0F SEPTEMBER -

Davis-Besse Unit 1 B&W Reference USS-14 i

Dear Mr. Domeck:

i f DMI is reviewing the available data regarding the 2300 psigon transient the even September 24 in which the reactor coolant pressuredropped from to about 950 psig in 7.5 ninutes.

period im.ediately thereaf ter c there was apparentlydsome the reactor

- steam 3-if . / - form :

reactor coolant system, one steam g ,, ,, . <. 7 generator o n . .. ( second h ure This transient does not appear to have caused any excessive diose stress boundary of the reactor coolant or secondary system l We becaus to the design transients. upon the conditions to confirm that stress levels are within ASME are also evaluating to determine whether this transient has any effe:: diate con:crn.

, ... ,q-calculated fatigue life of the components, but this would be of no ime

, u.w . ~n w ~ d cavitation None The reactor coolant pu .ps were exposed 'to condi be operated

' of these things appear to have happened andWe wesuggest feel that theofpu-ps a series h isk of may with only minor risk of additional damage to the pumps.

pryr;isjve start-unel;s under This is not close observation considered to be a safety in concern.

order ?to minimiz furthering cny latent damages. _ , S.r. s , w .o . w : ..~ ~has L~ teu m:

s Based upon our evaluation of the transient conditionsT we do not fe However, been any viciation of fuel integrity which would preclude safe startup.

we have made no evaluation regarding effect upon fuel life. l t In sumary, BM! considers As that there has an economic beenurge con:crn,we noprogressive degradation of s and it may be operated as designed.

startup of the RC pumps under close observation.

Please advise if you need further advice. Very truly yours A. H. Lazar,denior Project Manager

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