ML20054B824
| ML20054B824 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 04/08/1982 |
| From: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| NUDOCS 8204190231 | |
| Download: ML20054B824 (7) | |
Text
I
~
}
to k
south CAROLINA ELECTRIC a gas COMPANY p
g post orrict non re4 h{gtil/ED CotuMeta, south CAROLINA 29218 9
p T C. NICHOLs,Ja.
April 8, 1982 g R 1 6 JgS h.
v,ae....
....c
.c="v"*
u m...on m..
ca 5
NO Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Conmission j,
- 3 Washington, D.C.
20555
Subject:
Virgil C. Sumter Nuclear Station Docket No. 50/395 Cold Overpressure Protection
Dear Mr. Denton:
South Carolina Electric and Gas Cortpany (SCE&G) herein responds to the request by your staff regarding pressurizer PORV variable setpoints and adherence to 10 CFR 50 Appendix G limits, by providing a mark-up of FSAR Section 5.2.2.5.
These changes will be incorporated into Anendment 31 to the FSAR.
Additionally, in response to concerns from your Materials Engineering Branch, SCE&G provides the following:
1.
The expected fast neutron fluence at the peak location on the reactor vessel wall prior to startup after first refueling is estimated to be 2.0 x 10 18 n/cm2, 2.
The number of expected full power years (EFPY) prior to first refueling is estimated to be 1.07 years EFPY.
If you have any questions, please let us know.
Very truly yours, a
l T. C. Nichols, Jr.
APJ:'ICN:lkb Attachment cc:
V. C. Sumrer (w/o attach.)
O. S. Bradham G. H. Fischer (w/o attach.)
A. R. Koon H. N. Cyrus M. N. Browne T. C. Nichols, Jr.
(w/o attach.)
G. J. Braddick M. B. hhitaker, Jr.
J. C. Ruoff J. P. O'Reilly J. L. Skolds H. T. Babb J. B. Knotts, Jr.
D. A. Nauman B. A. Bursey C. L. Ligon (NSRC)
NICF W. A. Willians, Jr.
File R. B. Clary b\\
N(@\\
8204190231 820408 PDR ADOCK 05000395 A
f inclusion of Icak detection criterie in the Technical Specifications is
.I 5
unt necessary with respect to these check valves sinca th2y are tested l
8 during the plant startup following'a refueling shutdown.
Should a valve l
17 be found leak excessively, it will be repaired and retested prior to a 5
return to normal ope' ration.
Check valves on the discharge side of the high head safety injection, r43 Y) charging and boron injection systems, which are classified as Category 0
AC, are tested an described in Sec tion 6.2.6.3.
Acceptance criteria for such tes ts are discussed in Sec tion 6.2.6.2.4.
Scheduling and reporting of such tects are addrensed in Sec tion 6.2.6.4.
o,
- 5. 2. 2. 5 RCS Pressure Control During Low Temperature Operation Administrative procedures are developed to' aid the operator in control-11 ling RCS pressure during low temperature operation, llowever, to provide a backup to the operator and to ninimize the frequency of RCS over-ousepressee,vrio~ nrrocww y;
pressurization, an au tomaticAsystem is provided t'o maintain pressures C OM S)
\\
within allouabic limits.
-r (foRVU
(/
Pressurizer power operated relief valvesAare used to provide protection 3l against exceeding 10CFR50 Appendix G limits, as defined by Virgil C.
Summer Nuclear Sta 'on Technical Specifications, during periods of water p,;-
N solid operation.*
nalysehDAt&tG y[
have shown that one PORV is sufficient to sout prevent violation of eeee. limits due to anticipated mass and heat input I
However, redundant protection against such over-pressurization event l
1s provided through use of two PORV's to mitigate any potential pres-18 sure transients.
The protection system is required only during low temperature water solid operation and is., automatically enabled.mI 3f reseroe e.colear systen te~ ten rures belo.o S o0 *P.
Each of the two PORV's is supplied with an independent, seismically designed supply of nitrogen which is sized to assure that no operator l
action is required to terminate the transient to 10 cinutes.
The nitro-gen supply is shown on FSAR Figure 5.2-8a.
High pressure nitrogen will f
be regulated down to the required operating pressure for the PORV actua-tors.
Relief valves ens provide 4 protection against over-pressurizing h
13 the actuators due to regulator f ailure.
.11 AMENDMENT 1Eir-3.2 4h Mr.l if 9 2.
g
(
5.2.2.5.1 System operation Two pressurizer power operated relief valves are supplied with actuation logic to ensure that a completely automatic and independent RCS pressure control backup feature is rovided for the operator during low' tempera-
~
TM e s
- .:i 3I ture operations.
"T i: ;7: *- provides the capability f or additional RCS i
inventory letdown, thereby maintaining RCS pressure within allowable limits.
Refer to Sections 5. 5. 7, 5. 5.10, 5. 5.13, 7. 6. 6 and 9.3.4 f or additional information on RCS pressure and inventory control during 11 other modes of operation.
CMS 31 l The basic function of the cy:::
logic is to continuously monitor RCS temperature and pressure conditions whenever plant operation is at a
3ce*r 3' ll temperature below RNPT.
An auctioneered system temperature will be continuously converted to an ailowable pre,ssure and then compared to the actual RCS pressure.
This comparison would provide an actuation signal to the power operated relief valves when required to prevent pressure temperature conditions from exceeding allowable limits.
I
.L l
l (s
(
5.2-45aa JI DMT w Afro I, (18 %
N,' die 5r
P l
+.
7 p
.e o,
1
' _ _. _ _ _. - _ _ _ _ -__.T_pS.e._e.r._ A. _. +_ a f4f e _5, ? - 4 Tz __
l
%d.MS v1detu 1Ae P 9 Vs 41, semans_th+ y.y 7
dsf.sadsj_an f h'e werap _reactoc ccolaur_ sy.stea
~
feftLtut%-.&vy.) -
-IS2 t h M G.S W,
'+t
$ t.,
));LN th t ' t _kja ^ 'Y.. st tf 1kl51 0 4.As v -.__._ de F,; eLhy-Esy vee. v. 2.-J.S~
- i _
il 4 4 i i g I -.e. 9 .__-.+-._._%.4 m .-.~-e,__ e ..-__--eee. -o.- = =. _ - - - - - -
- -^* mms' 4
-._.-.- m. = 4 _. - -. _... h,- - ___~.. _ - . - - + -. t +g ~4
5.2.2.5.2 Evaluation of Low Temperature Overpressure Transients Pressure Transient Analyses ASME Section III, Appendix G, establishes guidelines and limits for RCS Pressure primarily for low temperature conditions (<350 F). The relief system discussed in 5.2.2.5 satisfies these conditions as dis-cussed in the following paragraphs. "Dg' *# --> w n, Transi t ana ses was erforme to termin the ximum ressure for' th postui ted wors case m s in t and at i put. eve s. t I h The ass in trans' nt an ysis w per rmed as ing the in vertent tuation of a sa ty in" ction p p, w ch, in ombination v'th other f b diisop ation, ressur" es the S. e result show that maxim f pr sure o 575 ps' will be reac d. 12 heat in analys* was rformed f an inco ect rea or coo ant T pump sta assumine that t e RCS was ater sol" attheinitiationof) A the e nt and tha 50*F mismatch existed between the RCS (250*F) =- + pserT o 1 c. and the secondary side of the steam generators (300 F). (At lower temperatures, the mass input case is the limiting transient condition.) prssureofa/40Mihi11[e/apAfe e s s w t at a axi
- t. [
gry' the CS or is p rtic ar ranst l Both analyses took into account the single failure criteria aEs e md there-w 3; fore, the operation of one N u Op = ::d Reli=# m'"- { PORV)fwas assumed to be available for pressure relief. The above events have been evaluated against the allowable pressure / temperature limits established in Figures 5.2-13 and 5.2-14. The evaluation of the transient results l conclude that the allowable limits will not be exceeded and therefore will not constitute an impairment to vessel integrity and plant safety. l b 3/ 5.2-45b AMENDMENT R AfAl 195L -F; u;An, teiie
a' n i'! n ..,. +.. .-.....qe. ....A. _ I~ as e r.: 6 jo _ P y< 5, _t '15 L
- 2. -
...r.. .go y.., ,l T*rc~'uc~r_ s.es! pes _.wscs._g<1ked to-s n a k la d _ a.
- PoA V l ?r i
. a:. ('o410 ,s m, . pcope ' fe; O < ous.eg <.n.oe Mir..htdy 2prm ~ , ~ .tcrparar ..e.~. Vo bc rpt.heJ_Ju.any durJews? y <<a.r a d th<.pl-~.t,_ U.& _m<. v. .c. f.L.ayran_.na:w t sles_. csse1,r.e o e I<~r.sy s r<s.. p<<ssur<..wii W accep % Le tin **r-S.II. i y_ II eceditte o ue.cp_ce_s.s vasrcroa _ oseid<-rs_a ee eboy ..fc~p e<<~rar e,.w 1ee..r !.*iop!<~no~. i~ th e_ pla ~ r Jasn !* w yJ
- w a.J - pseforw'*l XhL.Ao.s3 sN uT ft*~sc~r *."sI I
f ~ s s u ~ T~y._H = ~.o s c_ sc v_c.es <. v< ~ r lvol kay a...s<*7 c c = ~ rio F-y ! / eh<<3oby f aep.. 5pelCo' II.,.s Iess_.e1._.o1e_ iueileer-Is y .-to stu Is.r*J_, wkeaet.y f see_.FI_.w__e o e reoI y s I_v s __ a,s _ +.h _ e k a ey os, _I&< isiIt ap se. o.n.I, s t rwI +-racas l _,_tk_< J to w_eanreal_.vsIve y .on fk* I er dow e Iiss isiIs. closcd. -..= I i t .i.... ....Tess e r. C lo fsp e _S.t <tf b i __,f,_._ .. - 0 c. h s s i sh oT._. h.* c h e N ss e cons ldersh (*<- s ** s I ysl2 f 1 inolv.La.- Acs-e. e sr cree ; oe I.., n w a a.~ d f* ef *ea toe c.
- a. s 3yM n e try. b u>sfce 1 o h*L c a n.cl_!.tio s < r s cra c_e. Ia ~r_sy s ren,M.=tdy th <.
sr<< ~. y.e<<<ro<s W T. e C __9. T' A $ a*p h te. f4M[tes f v/ C NEN b *.. f'cd**fM E e _ o I f l,4. _. t ..,. - - _ ~ _...... - + -. _. ~ _ - -,. . _ _ _. ~. - - t __ _ _ _ -.. __.r l ee
(2% 33)D) ' c.c. l ^ ~ttl teale Sr-Tha c~ ve 1,r n ; c e ~ o e.e. pened uf fo 3 2 EFfy'. -rzooo - W ~ 'w uj 5 5~ 6 w k 1500 - C (250,1480) tu L. 5 b i 5 i i L-% C I' a o %G 1000-(2OD9M8) j M %hv t . uJ T (tsopo) 5# # ' (loo,500) ~ (70,465) 2.o o O lbo 3ho 200 A VERAGE (t E R CTOR Cool frHT SYSTEr1 TEroPEKAPAE (*F). .u.. SOUTH CAROLINA ELECTRIC & GAS C0,.'. VIRGIL C. SUMMER NUCLEAR STATION Lov iEt1PER&TvnE RCS PRESSURE CONTROL Figure 5.2-f 5 nnx1mm m eo re v t t r7-s E7~Po ouT.T}}