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April 22, 1977 1
W{n MEMORAMDUM I'00 R. Tesdsco, Assistant Director
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Ior Plant Syaeens,
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w D. Ross,,ssistant Director for Reactor Safaty,
's S S TROM:
J.
P. F.n i gh t, Assistaat Director 0
for Engineerin:, DSS i
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'f, TCISMIC RE '2V ALU ATIO!': NORT2 ANNA. DAVIS-3ISSr.
4 M~
AllD DIA51.0 C A!IT O S 50 -338, JWS
SUBJECT:
I and 2 and Davi s-
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The ACRS letters tus ;;c r th.'.n na Un i t s !!o.
l discovery of the Lloscri fault Bessa Unic No. 1 and the sear Diablo Canyon Units No. 1 and 2 have lead to a acionic
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re-evaluation for each of encse facilities.
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speak to letters written on North Anna and Davis-3esseaccouplish
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lhe ACKS f
a detailed review of those systens necessary to renoval".
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" safe shutdown and continued shutdovn heat initial phase of plan to use a consistent approach for the l.*
the Diablo Canyon evaluation.
,11 that must
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'In order to proceed further we need the guidance evaluation that vill pi 3,7 4
be devnloped throu;;h a sys tens produen the fo11oving information:
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to bring assuning an SSC has taken place, 4
(a)
A scenario, standby and finally cold shutdovu.
the plant to hot for:n a scenario developed by l j
,e have attached in draftfor Diablo Canyou.,(Euclosura 1) the applicant (b)
Identification of the s y s t e..s t 'a n t nust operate to i
schicve hot standby under this scenario.
(c)
Idantificacian of the systens that nust operate to achieve cold shutdown undet this reviev.
f 0500220515 050722 Chen
((kggab63 Contact
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biablo Canyon l',.
pon I..
tesai
.soreh Anns Davis 9 3 se W \\'.
27535 Ex'
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.t-in._. +r,r-m lt April 22, 1977 2-
- 3. Tedesco D, 7.oss trace available to Peta 11ed drawings are*or vill be and positively end point
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cach systen from sourcesuch as block valves, branch to identify.conponents operato or have no required linen that either nust function.
tio'n of the i
Assumin; a loss of offsite power identif ca (hours) vs. long term the 11stind of (d) terr.
significance of shortloss of offolte power vich respect to (days) developed in (b) and (c).
equipment complation of the a enjor milestono in the I know that licensing cetion for each of these planco.
This effort is the linit but I already stretched to a priority this item as are your resourcesyour consideration of nust request
/
detailed listing of equipmentproposed 6.atter.
a draft was removal that
..lso attached is and heat
- 2) and a required for shutdownfor Diablo Canyon (Cnclosura for Horch the applicant starting f
by Wootinghouse prepared by can serve and the list as a general system
- 3),
perhaps these of the syste=s (Enclosure for cach plant in a list De vill need bo th, Anna in thoso systens
. point.
fuuctional components order to proceed.
effort I hope th a t we can a significant Since this will be of contact in the appropriate systons coam being review a point the me=bors of the throughout establish branches to which recourso established, in Engineering any have this task.
3.s s is t an t Direct J. P. Knir.ht, Lu db a ur e s :
for Engineering Safety
.As stated Division of Systens 5'
ccav/ encl.
iSS y
R. Heinecan,
.iS S P.
- Ross,
- 1. Sihweil, DSS 4
,osnak, DSS i
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m April 22, 1977
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}tElf0RA!: DUP. I'OR:
R. Tendsco, Assistant Director 2l'2J4 for Plant Systens, USS h
4 D.
- Ross,
,.s c is c an t Director e
M..!
'for Reactor Sainty,
's S S i
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TRO)!:.
J. P. Eu l t.h t, Assistant Director I
for Engineerin;;, DSS I
f SU15J ECT :
SEISMIC RE-2VALUATIOl* : NORT*d ANNA. DAVIS-BESSE A!!D DI AM.0 CA!n'ON 50-538, J % 4;"Y l
The ACRS icttern f or iiorth Anna t'n i t s !! o. I and 2 and Davi s-3 conc Unit No. 1 and the d i s c o,r c r y of the !!o c S r i fault I,
near Diablo Canyon Units No. 1 and 2 have lead to a aciscic re-evaluation for each of these facilitics.
I
- ,i b
- 1 h c ACKS inttern vritten on :lorth Anna and Davis-3 conc speak to 4
a detailed reviev of thouc systens neccesary to accomplish t
"safo chutdown and continued shutdovn heat renoval"
'fe S
inn to une a concistcut approach for the initial phanc of
),
the Diablo Canyon evaluation,
'In' order to proccad further vc need the guidance that nust
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n r.yntean evaluation that' vill be developed throu;;h a
produce tho following information:
.o p
J4 (a)
A scenario, aonuning an SGC han tahen place, to bring lej the pinnt to hot neandby and finally cold ethutdown.
t'c have r. t t a ch e d in draft form a scenario developed by
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the applicant for Diablo Canyon. (Encic nure 1) e l
y (b)
Identificition of the cyste.n that nunt operate to f
achicyc hot ntandby under this scenario.
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(c)
Identification of the n y c t e a r, that nurt operate to W,
achieve cold shutdown under this reviev.
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Contact:
8 l*. Chen blablo Cnnyon l
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Tedesco April 22, 1977 D. '.*. o r. c available to trace Petailed drawings. arc ~or vill be Note:
from source to end point and positively block valves, branch cach sy n t ert such as thne either nust operate or hava no requirec,.
identify components lines function.
identification of the of offsite power (d)
Ancuning a locoof short teri (hours) vs. long ter l
(days) loco of offaite po cr with respect to the listing of significance developed in (b) and (c)..
equipuent i
in the completion of the This effort in a major milestonc for each of th ese planto.
I know that to the linic but I licensing cetion already stretched thic iten an a priorit/
are your reneurecoyour cencideration of nunt request j
natter.
3 detailed listing of equipnent
..lso attached in a draft required for chutdown and heat renoval that v a r.
proposed for Diablo Canyon (Enclocurc 2) and a
,f' by Wcutinghounc prepared by the a p p i. ic an t for North a starting general systen list Annn (Enclosure 3).
Perhaps chece can serve as a lia of th e systens and the will need *ooth, functional componento in thone systens for each plant'in Mc 6
, point.
b'.
order to proceed, effort I hope that we can oignificar.t y
of contact in the appropriate nyatenc Since thin will be a
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branches to which the r:enborn of the revicu teon boing f'
cotablich a point 8
chroughout havc recourse Enginocring nity
. f[" f established.in this tank.
p J. P. Kn i gh t,
.'.a s i s t an t Dire
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'5 Lu do o ur e s :
.An neated for Engineering 9'
Safety g
Division of Systens g.
cc:v/nnel.
pi
- n. Heincuan, ii S S l'"
F. Schroeder, DSS V. I.cn ar oy a, DSS T...ovah,.SS T. Ippolito,
- t. S S 9
P.
- Ronn,
.s S S
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- 1. Sihucil, USS R.
onnah, DSS
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