ML20071G342
| ML20071G342 | |
| Person / Time | |
|---|---|
| Site: | Shoreham File:Long Island Lighting Company icon.png |
| Issue date: | 12/22/1978 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20071F735 | List: |
| References | |
| FOIA-93-375 NUDOCS 7901090014 | |
| Download: ML20071G342 (14) | |
Text
"
. :.., = : x
- m m ;
_ u: a 24 ~~
g
..g pe:.....y.
..., ~...z u. :ry~m.m -. d. w...,w :,y.,,+ v. 4. -
py
.:v.:M. i.;-@g a..>':,qq%..%'y
- w. r...s,- %e n y
. *.w.m(. $$ (u!J *
..,r. ';.
.. e
- f..
f
.g.p..
d.A9.v.g w W.
.ta.
[.g:p 1.+,-t
\\
rq r
.: n. ;..
Q--?J[x,j/ys ar, THIS DOCUMENT CONTAINS.'.
.7.I.['O e 7
Lc
' 'P00R,QUAllTY PAGES; j l:e El,:;
~
. ~ DEC 2 2.878
... s.
,l.'. '.'i '] ':l W ?.Q....y.
- ~.,p_; ;y
, Docket.No. 50-322 g.:
s.
c.+;-
y.
... g.; s
.. MEMORANDUM FOR:? D.'8/Yassa110 Assistant Ofrector for LWRs, DPM-
~
> i. '. r. :::,:..
,.'?.....
,. R. L. Tedesco,p :istant Director for Reactor Safety. 055
< '. FRGt:,4. f Ass j
- ,4 v.* /;,
. c..i.. l '. i i... * *,
1
SUBJECT:
. <( ' SAFEIT EVALUATION REPORT. INPUT - $HORDIAN NUCLEAR POWER STATION
-:....' c.
..::,.pg.7.w.7):' Nuclear Power Station
+;: -
I.l,:
I;;cg.Shoreham Plant Name:...
f Milestone Muder: *,[..:'(...;
',r!,. 50-322 -
Dockat Nu d er:
v.
. ' '..R f l'24-21)
Responsible Branchl' :l
. dj:. ;. 0t;'.:;. *Q +.
L1cens1ng Stage:..
- 14. List!4 e
and Pro,fect Manager ' l...:
J.'. Wilson;J..,.
Systars safety Branch.Involvedf-Reactor Systans Branch - -
- 4sER. Input Applement.
. ' Descriptfoo of Revteur..rt.4.dydhN/AW:fsw t for;;ope
'Requestad Compteties Deto.e
- RevfewStatoss.yr lete.excep
'9 Ni#$.T$I N?$# f.l:
.-Comp $TM.M.u,.4'W.D.M..I,'
~
' N.
, Enciesed is an spd6te'-
out.
out input' from the Anactor. systems
- . Branch,(RS8)..for,.the.$horeham. Safety. Evaloation. Report." Note that the
$' enclosed changes' refisrence page,anders of the August.1978 dreft SEA provided to R$8,,t 'the Shorehen project manager., W r;,j:f.L. e..e y
= M #Wlthat.dt%4.Wt nWYAn W:.ir;& ^ M"n'ece.
F.Q un expect stentffasnt additional work will"be ssary to resolve the
, open issues remataing.in R$8 SER.fnputa Scheduline of this additional work
' from the app 1feant and considere.addf tional faformation whfch will be neededt will be dependent on. receipt of Branch.' For yeve fnfoeustion.-there are approxfsetely afas of the original twenty-ffve areas (plus three generic artes) for which open f tans are still remstiing.
...a m,
~
.; c.. - y.. :
. / Ortgenl assed W cJ. /
Rotwrt L. Tedeces 4 ' Robert L.' Tede'see, Assistant Direttor
'. J' for Reactor safety y*
..y.) "y... '. ',..v.Divistoa.of systans safety
.;.r...
, "cc:.S. Han' aver T. Novak
Enclosure:
".' R. Mattson G. Meretts SER Update
- N F. Schroeder R. Frahs
[790109001'[
j,*E',,',
" * "1 " '
Contact:
Bill Mills, NRR 49-28172 SEE PREVIOU$ CONCURRENCE:
.n..
_. 5.LRS8 3.1ML._ MSS 1RSS @}.th O..
E1.1 i
.JiMas Thak kindeseo
-I ~,.
. 10/18n 10/19/78,b/31Rh IN.thf9s
- '*.,........4
!I~
l y,:,[* s.j t, p.[.
- p;:pg;f
- ,.j,yQ
- . :
,gtp
'.y,:
. J ; g,;,f '"W. ;
- 4..
'.s.
- w.. n*
...,. o; -l 3 -
.? :s :
c;,.<
+
T.b.' J p.am efeg
/,.l['. i',,[ Q4je:
.i
.o #
f
.. f.UNTED87ATse _, '
[1 NUCl.sAR REoULATORY c0MMisslON
,3-WA8HINoToN. O. C. 2968e
',..T. 3 l;.'l ;,
7 *....
OEC 2 21978 Docket No. 50-322 MEMORdNDUMFOR: D. B. Vassallo,' Assistant Director.for LWRs, DPM FROM:
R. L. Tedesco,' Assistant Director for Reactor Safety, DSS
SUBJECT:
SAFETY EVALUATION REPORT INPllf iSHOREHAM NUCLEAR POWER STATION a
Plant Name:
Shoreham Nuclear Power Station Docket Number:
50-322 Milestone Number:
24-21 Licensing Stage:
OL Responsible Branch LWR 4 and Proje:t Manager:
J. Wilson Systems Safety Branch Involved: Reactor Systems Branch Description of Review:
SER Input Supplement Requested Completion Date N/A Review Status:
Complete except for open issues Enclosed is an update of our previous input from the Reactor Systems Branch (RSB) for the Shoreham Safety Evaluation Report. Note that the enclosed changas reference page numbers of the August 1978 d'ift SER provided to R$B by the Shoreham project manager.
W. F,
We expect that significant additional work will be necessary to resolve the open issues remaining in RSB SER input. Scheduling of this additional work will be dependent on receipt of additional infonnation which will be needed from the applicant and consideration of prioritias within the Reactor Systems Branch. For your infonnation, there are approxinately nine of the original twenty-five areas (plus three generic areas) for which open items are still remaining.
( s C. s.,. A.J.
Robert L. Tedesco, Assistant Director for Reactor Safety Division of Systems safety Enclosures cc:
S. Hanauer T. Novak SER Update R. Mattson G. Mazetis F. Schroeder P. Frahm S. Varga W. Mills J. Wilson
Contact:
Bill Mills, NRR 49-28172 1
i4
-l,.
.e a W, 4., "'h'
%v., '
.N.
. mum,.. =
a.# w o
r A
' ' * ", 'f$,
. ( ' ',I I :O ll.
lf; .*,
c,-
.;(.
..F
. 7... ?,' Oy
, Q ;'.
P..U.g..y;;q,f '.
- f ;p y'l; u.pg.... g. c c. '.,.;,.
,, g.
,,...), i.,.
q4
- ?. k ' *., v, ;,..,
.p-w e.
l.y j. >.
a, W{. r,1 2..
n.s,,
c
/:A..
,, N h. ;s.' Insert 1.-l Remov,al 'of CR'D System Return t.ine 's,:
' 'a tr
,. ~....
W;.7 e,
e.,,.a..
,,7.; 6,s
~
- This in.,.,....
i i
.b sert o
, the' generic: presents our pos t on ased on OS$'in.rolvement in W..
study related to deletion of the CR0 system
,. :..,. ~ ' /. '...
. return.line..e Replace,the.first paragraph on page;4-21 with "r
?... ;,y.A. ?l ' '
'the following:....
1 y.
' j, 39...:,, ;.z;.i.,.
~
,, c.,,,
.y
.. ;.. n. d.l...y.f,.y., y,
' 3.. :v
.. p :... c..
s..,
"The app 1tcant has o. sed to" eliminate the.' control' rod drive system return lin. : pr..po..e to..the...v., reactor:...
l
.m..
i programtomidtstre'tNepotentfil(forpihcracking. Thisitem is being reviewed'c'n"a} gene'rfc bisis.by i'd staff with' regard'to capability of the system to.provi.de.... 'perfo7idan.
the impact on contro'1... rod. drive'sd.t'en preliminary r..rk,e'up wate..eview. /we fis..r..to the a
.s d that removal of vessel. Based on a..
tre return 1tne~ t/the' reiictor 'pressdre vessei'.is acceptable.
However. we will requirel.,'the s'pplicant to,s.ubmit system performance j
data directly appifcable to Sho'rsham and we will require the
.g.
appitcant to conform to the~concidstons of. he s'eneric studies as t
applicable to $hcrohadduclear Power Station."
1
^
i i
I 4
..: v. ; ct, w.
m w-
.i.m.>
m L'$[4 % y ? O >lk'fi.?tt;$5y H f.t.g!!'f %y. Q'VR..;..r.. ; '.W:...
&wywt M
.e 9M
.. ;,' < :. v.:X f f,a '. n 4.g _,.
G
- ,r.Q ~
i. y. v, &. -
. '..,. n'
.p 4..,ps.; ; v.. t.. y' ;,g;.. u.. --
-. : \\.c.
. c. b e. ;;.-
a,.,
.c.
.a
. n>,
s x i,.. * %.:.: y n: >:
7
ip:y. ;ifG,1..[j c4,. e,.i,,[ '..x ;-
l N !Q.....p$,,.u...,.. f. m,..
.a..
t
, w'.. p,,.., ;;p : i,. '.;
3..;
t-u,..
y,.. ; e. u.,.-y...."
.. +
y%O: '.
- t. In_ sert.2.. - CR0 Pump Trip,at' Low',Reactd;Pressurs',.' :
1
..r:
x r..; y. t.
- g. o..
>a 2
,s. y
- This discussion presents' cur findings c'n this N em and notes 3-7 that we require the applicant to perform periodic testf.19.
f i...
'x Accordingly..this item remains open until the test procedure and frequency have been approved by the staff.
Insert the fo11cwing after the firs.t paragraph on page 4-21:
.c..
,. -..h >
c
., w
~
'.M 'Q.
'N D..
"The applicant has responded.that,the. operator would either bring the second 'pumi onIline or wouidl.in'itiat'e'a' manudl scram. Also,
~
the app 1'icant has statid that'the ' operator.'would have'at least 20 minute's after' contr'ol rod. drive pump failure before scram capability would be i,mpaired. We find 20 minutes to be an acceptable period of f,ime for operator' action and we will require the applicant to periodically demonstrate this capability for Shoreham."
i i
l i
1 1
'y, (
- a
'. V.l,0..',,. ?. 's'
'. ' ) ' * :,
'h
\\
'.. !; 4. ; c:.'..
.n
.s
., s -
.s
.Y 'l )4 I Y
'e l', (.f,~ o. r.i p.'.'
s, y
U
.g.r a-
,fJ.(. f ewt.
. =, -.
4
. ; :e s.v %;.khy,.
'. i-w hj,.
,, i - -.',
- r.'. u...,
W
- <>;.+
- . ;.
' p'
' t 4.
?.;,ry
'. f...,'
' > ' :.' -);'.;. "' -
s '. -
.- S
,.hc
.. s..... -
'r C; !..<.,..s
'i v
r.. w.*
y -
' r.'.
f
- . '. ls
- . y.'
.,s Insert 3.-
Loss'sf Offs"ite ' Pod, fConcube'nt with LOCA -
. 'p -
....u,
'f,
1:i t:',.
- p'. ~..a.,,;..
f,.
- ~ y. ';
o s
i l
~
,,, Recent staff d{scussion and evalu tion have c osed an open 5.
. item related to the treatment of loss of offsite power for
/. -
rst e g ete paragraph on 8...,,. E.
,. w..
'.. p e
.....s.y...
< ; ;q.. ;, f.
5s
<'r,.,$..
. t.
i
+.6-4 '.
5 s
i e
1 l
1 1
e 4
t 8t ' 4 kl.
' * * 's \\..
1 ' ?, >
l' " p
.,j 8.=
e
- y l
1
.w.
- w. m 4 %a
% a_.4..m..
.m_.m u A/
eq%g: s :
3 n..:
l,5,s l}:;a,::
.;f
.l cr."..
g ;
. n.
- ., 4'.7
- .c 7s Insert 4..
Worst Sinole Failure' for Small LOCA's
/
, <. A..;p,
$k. i ?.;r
.. W This discussion closes our review of information submitted by f #k... i
-,A.
.the applicant regarding the worst single failure for small LOCA's.
W.
'.s..
1 Replace the second and third paragraphs of Section 6.3.2 (page 6-40) with the followings.
g,,'..,,.
93
~
.-l r ~
7
, i '. '
- l "For small breaks in the discharge 1tne of the recirculation system.
the most 11'miting single failure originally identified by the app'Itcant was the high, pressure coolant injection failure which leaves four low pressure coolant injection pugs, two core spray
, pumps, and the automatic depressurization system operable. For intennediate breaksi the most Itaiting'stngle failurt originally identified by the applicant was the low pressure coolant infection system injection valve failure which leaves two low prussure core spray systems and the high pressure coolant injection and automatic depressurization systems available. We note, however, that during a study of low pressure coolant injection, diversion the applicant identified the failure of the d c power so'urce.comon to the high pressure coolant injection, one core spray pump, and one low pressure coolant injection pure as the worst single failure for small breaks.
[
{
While small breaks are not limiting with respect to peak clad teger-ature and were not expected to become Itaiting with the d c power
" failure, additional,information was requested from the applicant with regard to the overall effect of this d-c failure on small and intermediate breaks. The' applicant provided technical discunston
,.c, d-on the effects of the d c failure and presented a curve showing the
![U estimated effect on peak cladding tesperature for the spectrum of break sizes in the rtetreulation system piping. This infonnation shows that the worst small break peak cladding tegerature increased approximately1000F (to about 1H00F) which we find acceptable. In addition, the worst intermediate break and the large breaks (which p
are the Ifmiting breaks) are not affected by this d.c failure.
l,,,
Therefore, we find the effects of this failure acceptable."
i
- s h... h O l
k
')... f....:; a,:,k.) -
i
- .r..jf.
u'i..v r
....;w t, d: i, '
.,,i lC,-
,'v.
~
u ( w $. /-(. y : f.i $,_,*'
~
.I
.. a... d ', :
...,.S t
- if -
,.>>f,',)
a.y h w. INiirt 5..
LPCT Ofversion Followin's LOCA' '
,,.., ;..., y v / ' <-
This change closes out an open item related to LPCI diversion to r
.,.f ' '.,
containment spray on the basis that automatic diversion is not 3
C.
I.
- ',,, 7. '
read as follows:ge the first complete paragraph on page 6 42 to necessary. Chan
~
.g s
3q, M.,- ;
p hyl'R*-
,......m
-l "The loss-of-coolant accident analysis presented in the Final Safety 1,f -
Analysts Report states that after 10 minutes (following loss-of.
4 coolant accident initiation) the core f a reflooded and two of the residual heat removal pumps can be dtysrted'to the containment spray mode in the event'that high containmen't pressure exists. Additional j
evaluation and, technical justification were requested from the app 11-
). -
cant to show that the loss-of-coolant accident analysis over the entire 5
spectrum of break size and location is valfd with low pressure coolant i;l-Injection diversion cons'idering a single failure. The applicant has provided an evaluation of the ef'fect on peak cladding t,,
temperature resulting from low pressure' coolant injection i),.
diverston for various break locations and sizes, including various S-single failures. The worst case presented is low pressure coolant
[
fnjection diverston at 10 minutes for a break in a core spray system Ifne coupled with a failure of the d c power source comon to the
.')
high pressure, coolant injection, one core spray pump, and one low pressure coolant injection pung. For this worst case, results of the appiteant's analysts show a peak cladding temperature of approximately 17000F for diversion of two low pressure coolant p *,y injection puses. While we find this peak cladding temperature acceptable, we note that the Shorthan emergency core cooling system o
design uttitres a two thirds core height interlock which negates the capahtlity to provide low pressure coolant injection diversion during accident conditions if the core is not sufficiently covered.
i
~
If the design or operation of this interlock is modified for Shoreham, or if automatic diversion of low pressure coolant injection
~.
.'-] -'
,(
~
.I?$hhDI*
.m, s
i).CMdh9 (@*f@f..!;['I.'[.'. ' -
d?Mf.".j$hT@.Yrj$,[.f.*l,','M,['f[,Y.2,f.[Q%};fyhi,.n.y
. :k :;,
.:1* r >
'
- r; ' y.:-
' ','.is 'i ; alled we would require addit
'i
.;y. _~ c,s.
.9
' fff. ' ' ' C nst
, 'ispplic' ant' 'relat'edf to' the fida'c't' df'the,chinge,.on ' core' cooling 5E['Ji
. capability. Regardless"of which design'.is,adopfed the applicant's
- p
~
$, b'c, - l}
. operating procedures.w.hich if st the condi..tions.for'which the operator
?
g.
can bypass the two-thirds core height interlock,should in'clude y'
r '.
~
J.' ' -
provisions.for the operator.to verify that acco'ptable core ' ooling c
capability will be available,fter low pressure coolant injection a
~ fs diverted." s.
. p...1.,:p -
t a
t t
t o
6
~
'\\
.5 t-i
+
+h*
e%
4
$v '.. h
_ Y yi..;,
y yyu,r;;,.
' v.,a 8 r,f,v,Tf!,.'
a k
h
?
?'k.*k'p$~)fhkh'.,>y;$$ yaw?!?$$hw rar.n v !r. h,p: f; W-$. a :' * ~.
f
. t. < t.h. p;. shy.
1y r
.s.r,y.d.j,...x...;,.%.y.pq;p:....s.,,..
.d.-
< :. s. r. 4..a. 3.p< v.,.. ~. >..~.a ;.'
y
.p.:
q
. g.
- a. s,,.
t...:..
. s..
,.t.,..
,.1..u. '.,.;.;
v.
~
h....(]./y..a.
y,n ;
..p.+
ps e b[,NE00I,10502.Mn.@th% y.t,..
.;5, s.
.:,,..};,c';.b..aQ sK l; ?k..n. m.-
- 3
%g.'
.%g 73W,.14's,4..'
]k... >.!..D.. r.*J In'ss'rt '6..
~
This hang:e notes.that the...
.m.,.L, s.y '...... z.use of.NE0010602;.for.tra W
.:~ V e.
- A r. :'..-
- s '~ '
.v -
- t
- . e',..
c l '> ts generic open item appitcable to Shoreham. < Replace the last
.Y. '
sentence of the second complete paragraph on page 15 2 with the
, 4.::
.lli.-
.' f011ow1ng1. ;;.,:
.,.,.:".;.m,?,. :,,..
Q j S, y. c.q,.. -;...n..
, ;:.:., f., ;
...t.
~;
y
.,,'1 s.g
.s
- .,'( ~,:4.,'..f y ;
. +,
.*...t..d.
e "The staff is tesolving this" issue ~ on a ge.nerte ba. sis with the General Electric Company. We'regiire the, applicant to confors
.I to the generic resolution as' applicable to Shoreham Nuclear Power Station befort power operation."
a
.g 4
t l
l 6
I l
i l
a l
l l
g 6f
.(
,.f P.
- b',
Y l
.,4, y, A,,\\ $. 8 '.f 'G * 'dtY,, '
yy
$ f.M 'P,',y* T ', y" D
l
}'j,T:. ll ~ O .
f O Q:%j, ) ? C:' K.'l, i
~'
~
.i k.f';'.],. ;
3.N,, ::
- ~
.t
,o i.t :
. f.
r 9
i
.?~
f N,..
' l^
Inse h 7.
Peclassiffestion of TTWOSP
.;y',y
,?
J,.
'.,,,... l This change acknowledoes that the $NPS F14 has been changed to
- f.'
reflect that reclassification of TTWOBP Land other transients)
.~
. has not been approved by the staff. Rep'see the second couplete
, cf.
paragraph on page 15 3 with the following l,'. Y "For turbine trip and generator load rejection without bypass events, shoreham has proposed a frequency classification which is difforent than that previously accepted by the staff for bot 1trg water reactors.
The new classificatton would remove these events from the anticipated 1
operational occurrence category and place them inte an accident category, with aseociated less stringent acceptance criteria. This recategorfattion ts currently under evaluatten by the staff and has not yet been approved. The applicant has supplemented the Final safety Analysis Report with a revised transient analysts based on a frequency classification previously accepted by the staff, Accordingly, turbine trip and generator load rejection without bypass events are considered to be antfefpated operetter.41 occurrences for detamining the nintsus critical power ratto (MCpR) operating Ilmit.
The applicant's revised transtant analysts for Shoreham is acceptable to the staff."
4 i
f-l
.h '
k' 4
dd. 4E6:
~ - -....
~L, 1 w, n~-a..
~m, ~ ~ :.x
. ~ ~
a
. rg.e..?*,,.,,, i y. ;;,. u. e.,.~
+
-c po e.H+,,,) A,.- <...
9.,.. ;a.r.
- 1.,.s.
- , a.
..,
- o J.
r
.',;,,.-.,
- 9..:
- a...a..
3,1f.
- 57.;,,.i n.:....
.....4
.p ;.
. ;~.
'..- '.b s.
. ;y,.
s, ;,...,,.,
> Insert'8.
Inadvertent opentno~of a $/R alve~. '
[.. ;,'
This change altatnates an open ltes'Nyalve. Our concerns w sting additional infonnation
.related to inadvertent opening of an be covered by Containment Systems Branch revtew of information to be provided by the applicant. Delete the third paragraph on page 15 5.
O 9
b t
9 i
r
\\
9 I
b t
1 i
s
\\
i
s g
s*
g
.,?;@4@,-, Jh",. " % :$! Cfi. * < v*.i- ,fI, h,.F',M r. g.. p.y'l. _. n + ~, '7.,' ' j,,. 9t ' Insert '9. Rectreulation Pump Missiles
- v. :
,This change closes out ari open item on recirculation pump '.'(* missiles because this item is being handled on a generic basis. Change the last two paragraphs of Section 3.5.2 (page39)toreadasfollows: i "The temperature element assemblies were identified as the only credible source of jet propelled missiles from high energy Ifnes. Studies by the applicant show that the safe shutdown of the plant will not be i impaired by the generation of such a missile. The control rod housings are restrained by supports which are designed to allow a maximum displacement of three inches. Missiles may result from destructive overspeeding of a recirculation pump and motor following a postulated break in a recirculation loop. The generation of such missiles from overspeed of both the motor and igeller of the recirculation pump is,an issue which is under review by the staff i on a generic basis. During the interia, we believe that the probability of an event that would result in damage to safety-i related equipment is acceptably small. In addition, with regard to pug ige 11er missiles, the applicant has stated that a generic study has been performed which confirmed that no unacceptable damage consequences can occur as a result of a potential rectreulation pug missile. $hould'the results of our generte evaluation indicate i the need for additional resolution on $horeham, the appitcant will be required to respond at that time." 'i, I I ' ', ', +; ' ' u.,f,. 2c, I
$fS',*'C@.*i,'.'YNl;.l'..*VlECmi..q&y,~,, . :. ~f. :.' Y.b'*OY ' ' ^ ,c,
- ~ '?,
- c
- .
,j:,: ' n,f.. .s.... a . *.. ;f.
- 3 r...r
..,.o.,' y j\\;.- .,,J..'. . h ' k.h f:,;p;'a..(; y,b.l lh k.k% f. d .y;n',.fl(,tv- . y *:- ,. _ i q. :* 4%$ ,i,Mu'" ,. ; ) ' '.L. l 1 ' :.' t... - ' C: ' Q' Insert 10.'. 0veroressure Pio't'ectic'n ;.)...'o.'. '.. ' #. *.,' YJ -l \\ 3 .c 4 h a.: ', j , This'resoonse ' closes out'an open' item on the overpressure protection Jh'.WJ. I,y' : '.i analysis based 'en the draft' SRP change. Q V; ' ';:. ...,,y. y' (A) Change the first complete paragraph on page 5-10 to read 6 as follows:~ d 3.,. - A h.I.. ~ analytical. assumptions may not be sufficiently ' conservative: "The staff expressed.two concerns to the applicant that certain (1) the assumed value of. initial operating: pressure, and (2) the exclusion of 'ecirculation' pump motor. generator trip in the analysis. r The applicant has conducted sensitivity studies which demonstrate that changes in initial operating pressure up to the present scram .setpoint of 1060 pounds per square inch guage would result in minor changes in maximum pressure. For a flux scram,,these studies show that an increase in the initial operating pressure from 1020 pounds j per square inch gauge to 1060 pounds per square inch gauge would result in approximately a 20 pounds per square inch gauge increase-in maximum pressure.- For e pressure scram, however, an increase in the operating pressure would cause a decrease in the maximum pressure due to the shorter delay to the scram setpoint. In addition, not including the trip of the motor generator sets for the recirculation pumps (used in Choreham to mitigate the consequences of anticipated transientswithoutscram)wasshownbytheapplicanttobeasmall effect in the calculated values of the maximum pressure. The postulated transient for this sensitivity study was the closure of main steam line i. isolation valves with a high neutron flux scram. Trip of the motor ~ generator sets was initiated at 1135 pounds per square inch gauge vessel dome. pressure. Th's calculated pressure increase was approxi-mately 20 pounds per square inch with only 8 safety reitef valves assumed operable. With additional valves assumed operable, the pressure increase would be less. 9ese two areas of concern do not compromise the acceptance' criteria of maximum allowed pressure.
- .' 4;.S t
e' j L )R& W,. a,
.] l (f., r._.,e,$$%Q$..fW;, '3WMYr!.W~$fMOLTW ' MEW ' $ *'
- i
. ? ->.a .:' M.p;. w.: .9 ~;.<., i ej %..... :. .,. ;..,... r...;G -, . m;, ,e W.
- u *
- l,2. ' '., ' '
.;V RsWQd ' P,. 'H O s '.. y :, p,..:., ~: t']; #, M,<; ' -:, ; ;(.0; 4 ', P.,f'the safety relief valves.' ThErNyalves will be pilot-operated l - 7 ;... 1More recently, however, the applicant' elected to modify the design h{,5;,,L' , of Target Rock manufacture., SomeI'qualificatign testing of these $,/'*' ". valves has been completed and additional testing is underway. The ~ i 2 results of these tests wt11 be submitted to the s'taff prior.to power operation.' ' Additional discussion is necessary with,the i applicant related to the design and testing of these valves. We will document our findings' in a future supplement to.tht's report." o (B) Change the first complete paragraph on psge 5-11 to read as follows: "Shoreham has based the statng of their safety valves (initial design and current design) on the failure of the direct position scram and subsequent shutdown by high neutron flux scram. Our current position in the Standard Review Plan is that the safety valve capacity should be determined assuming that scram is initiated by the high pressure signal or by the second signal from the reactor protection system, whichever is later. However, the current Standard Review Plan requirements have been determined to be too restrictive and a revision is warranted. If the failure of two' safety. grade RPS scram signals is postulated to occur Ithere 1 Itttle assurance that the remaining safety signals will be operative due to the potential for comon mode fatture. Failure of all the Rp3 signals would be analogous to an ATWS event for which the staff is currently developing criteria. Accordingly, with regard to credtt for reactor scram, the current position is that the reactor scram ts to be initiated by the second l safety-grade signal from the reactor protection system. This require-ment, coupled with the fact that the pressure is Itmited to 110 percent l of the design pressure, provides adequate assurance that reactor vessel integrity will be maintained for the itetting transtut event. ( , l/ ', ". ; ;,(. 7, ' ), 1 /
$ b$!h,h$ kk$ Sth.k Y. Y Y h $ 5 Y b.D t W Lit. %.r;.?.'y &:.f,' %,d.,,t4'&: N
- p..,.?.?$?.. &..gl?.Q,.<.NEN A
c .v ' ; :..... ; % y a
- a.'i-M +
- u.:3:. -
~
- x.
.1 .. :f,".*... m'. ~: r v ' s ':..t g,(NW)-.,$%w,4Tgfh.?,TO',.)I.DMl,0}e.a., 'Y:,3 : d b..'5 i 2 4.y dk. py:s. ;.;;b,[. It. is al s,o re,4g.4,yqg..y.g'.,w.,.74.gtwvfWg.
- ,s.,.. g.
st'/ cogni:edl.that it.f.acc.ep. table.qualifica. tion testing a.
- s...
-;.;..M, g.,i..' 3,'.. of the',new safet.y-valves..f.or,.Sho,r. e am,.an assessment o.f svelve-1 e
- g,
~it availability would. indicate that'cimbining worst' case power,' worst-r. l ' case pressure,jatfure 6f 25 percen't,'ptlot@p ad safety valves, ~ .[g/h: Y" s and failure of.two safety-grade resitor., protection system trips %.5.k,:$ wouldnotNwar'rdte'd'.:2.The applicant has provide'd information W[. ' ' demonstrating that press 0re is' limited to 110 percent of the design ~ pressure when credit is'taken for only'three fourths of the total ^' ' rated valve discharge' capacity and failure'of the first safety grade trip. We find that this' overpressure protection capability meets ASME requirenants and is acceptable to'the staff.' ,: \\'. (C) Change the last paragraph in Section 5.2.8 to read as follows: ( "In sumary, insufficient information exists on the Shoreham docket for us to cocplete our evaluation of overpressure protection because additional discussion is necessary with the applicant related to the reliability of the new Target Rock valve design." }.d ? ..o..i.. -} I,- f' Wi 6.5. ~. .}}