ML20213E944

Forwards Reactor Sys Branch Sser Granting Temporary Relief from Tech Specs 3.4.1.2,3.4.1.3 & 3.7.1.3 During Natural Circulation & Boron Mixing Tests.Salp Input Also Encl. Overall Rating of Category 2 Assigned

ML20213E944
Person / Time
Site:	Diablo Canyon
Issue date:	07/30/1984
From:	Houston R Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
Shared Package
ML20213D572	List: ML20213D570 ML20213E944 ML20213F093 ML20213F114 ML20214R269 ML20214R304 ML20214R337 ML20214R407 ML20214R489
References
FOIA-84-741, FOIA-84-742 TAC-51638, NUDOCS 8408070158
Download: ML20213E944 (7)

Text

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r)TSTRIBUTION Docket File RSB R/F RSB P/F: Diablo Canyon Unit 1--SSER ND. 27 CIFn@F r:a TParsh BSheron AD/RS'Rdg.

JUL 3 0 1984 MEMORANDUM FOR:

Thomas M. Novak, Assistant Director for Licensing D1Yision of Licensing FROM:

R. Wayne Houston, Assistant Director for Reactor Safety Division of Systems Integration

SUBJECT:

,DIABLO CANYON UNIT 1--SSER NO. 27 Plant Name:

Diablo Canyon Unit 1 Docket No.:

50-275 Licensing Stage:

OL Responsible. Branch:

Licensing Branch No. 3 Project Manager:

H. Schierling Review Branch:

Reactor Systes:s Branch Review Status:

Complete In response to the verbal request from B. Buckley of your staff,titte P.eactor Systems 3rsach has completed its review of the applicant's request for temporary relief from Technical Specification 3.4.1.2, 3.4.1.3, and 3.7.1.3 during natural circulation and boron mixing tests.

The staff's safety input for the SALP is also enclosed.

Originsi signed by E. C?p.s Ec : sten' R. Wayne Houston, Assistant Director for Reactor Safety, DSI

Enclosures:

As stated cc:

D. Muller D. Eisenhut G. Knighton H. Schierling B. Buckley g

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CONTACT:

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ENCLOSURE 1 DIABLO CANYON UNIT 1 SSER NO. 27 (RSB) 19.

Natural Circulation and Boron Mixing Test By letters dated February 10 and August 16, 1983, the licensee requested one-time relief from Specifications 3.4.1.2, 3.4.1.3 and 3.7.1.3 in order to conduct a natural circulation and boron mixing test that the staff required the licensee to perform. The proposed relief would permit, during the performance of the test, all four reactor coolant pumps (RCP) and both residual heat removal pumps (RHR) to be de-energized for a period

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exceeding the current one hour limit while.in Mode 3 (hot standby) and Mode 4 (hot shutdown).

The proposed relief would also allow the condensate storage tank (CST) level to be below that specified in current technical specification 3.7.1.3.

With respect to the relief from specifications 3.4.1.2 and 3.4.1.3, the Diablo Canyon boron mixing and natural circulation tests will be conducted in accordance with staff reviewed and approved test procedures that assure l

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2 the core is continually cooled and an unsafe condition does not occur. The system temperatures and pressures will be carefully monitored and recorded throughout the test. The RCP and RHR pumps will be available for operation throughout the test and can be immediately started at any time should the need arise for forced reactor coolant system flow.

With respect to the CST level, the staff notes that one of the main purposes of the test is to determine the quantity of condensate required to cool the reactor coolant system to the RHR system entry conditions.

While detailed thermal hydraulic calculations have been performed to i

determine this quantity, the test will actually measure the amount of condensate necessary.

Thus, the test is both a verification of the 1

calculations and a check of the system performance.

It may be necessary i

to allow the CST level to go below the minimum normally required to derive an accurate measurement of the condensate actually 5xpended.

Absent the relief from this requirement, makeup to the CST would have to be continually aligned and flowing, thus adding uncertainty to the measure-1 ment of the condensate expended.

An alternate supply of makeup to the CST (and thus to the steam generators) will be available throughout the test.

1 Technical specification 3.7.1.3 has been modified to require that during the test, the fire water tank and its flow path to the auxiliary feedwater pumps shall be operable prior to and throughout the test.

The staff will ensure that the test procedures, which are under review, ensure no loss of suction to the auxilary feedwater pumps.

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3 For the reasons discussed above, the staff concludes that the proposed one-time relief from specifications 3.4.1.2, 3.4.1.3 and 3.7.1.3 are acceptable.

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Et! CLOSURE 2 SALP !NPUT The pur;cse of this enciesure is :: co:unent our evaivation cf the iicensee's performance curing 051's Safety lvaluation Review.

The fellowin; :riteria f r:m NRC A::encix 05'.5 are the only ones releven

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This actiori was handied by cersonnel a the a:;r: ria e ievel of manecer,ent.

The utili y involvec the ne:essary in-house technical staff.*

Ratine:

Catecorv 2 2...

Accroach to Rescidtion of Technical.. issues The applicant performed the analytical work re:uired.

The c,uality of applicant's submittal, was satisf actory.

Rating:

Category 2 i

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-Resoonse to NRC initiatives The appiicar.t's res;ceses tc the NRC's Reevest f er Additional inf orr,ation (Rai) was satisf actery.

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'cr i. :r to be re.c.wd frc-the PHR suction isolatien valves during Modes 6, #/

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6 en e~nt, _b'e..w._i.l_l r.evies EFs inicntation to ensure that our concerns have

.m' In addititn, the Technical Specification 3.4.9.3 de ately acdres sed.

u.d c; otirg procr tre B-2:11 rust be charged within three r.cnths after the ira ilts alt.im is installed to require power to be available to the valvesq (y,

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Furtherr.re, in accordance with our letter iof ~ ' rn.ry p, M14 pu will update the FSAR by September 1934

'r'e request t' 5t ycu pr:. de us with the Ebeve requested ir.for ation within ene nek af ter r:cEspt of this letter zrd infort us w'.en the alarm has been installed.

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usly i:f;r. ed the Staf f th it the RJR System ;u?ps could be o ;.< c t :-d t o. ;+ r a '. e it': st r Qr.ifir.ar.t A 3;e fcr apprcxir.ately 15 :ainatr s lth 15.0,. ; .ct':. s ci.cs that at 1:w Eeactor Ceclant Systen (RCS) p.:ssure.

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In 143, FM p rp seal dar,.r:ge and a slightly b wed shaf t s ccurred of ter che f. cur's cperation; ho,,ever, hydraulic operaticn was within

(;ecificeticns tun thosgh the pump exhibited slightly high vitration and seal

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Mm wtitral Licersee Event Ee;c.rt 84-004-00, dated F. ' r aiy 2,155', prcsided additical ir.f:. mation concerning the 1983 event.

In a(dition to cur first-haad knowledge of RHR pump experience at Diablo C r,y:n, P er.cE has reviend I sac 52 - Resideal H:-at Re.moval Experier.ce review t d !? f:ty Ar.alysis Frest urf.ed i'ater Ecacters (PWR), dated Jacutry 1983 Cne r ?. c r.t. : s i e;;.rts d..' c re a ;. p.as c,

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Kindly e:tr:.rMd;e rect'pt cf this r.iterial en the en:lc3ed u.;y c.f 11:s letter and return it in '.!.e en:lesed addressed er.velcpe.

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s: rip tica c.f t' e ':w il:w 2' ~ ra.

In l'.e c'i scur si:n 'i ich 'cl':-s, plea se re fe r to the :ncic ed schematic.

In thc c r c ~ t u s '. en, flrn- -.dicatirg c:".trellers (FIC641 A end B) on the F.HR p cischarge pipine <;an t'c.e corresper.dir's recirculation valves (FC','64i A ar.d B) if the fl:w d ps belcw the setpcint f.90 cpr) a.nd close the recirculation v.h e s 2 n fl:x ri sc s t'. ;ve l'.03 cpm.

The ccntrol circuitry is Class IE, a.d

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'dk ati:n circuit is n:r-Class IE.

The :_cditicr.a1 systt, cc p:ner.ts which will provide the low ficw alara, are s':ca cn the cnched scl.-.atic and include the new time delay relays and

'rir ted wi ing.

If ;- 'r; t'.e re circulation valves does not result in a f'.,-

i se t' ve ' ' e s -t icint bef;re the tire Qlay relay " times cut"

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:(-i;r will ac tis ate, indicating low flow.

The new rekys cre Class IE, nd the al:nn circuit is ncn-class lE.

'he sys'e n ( n";0nents which will prc. vide the low flow alam are to be s' ;ile-d, tested, t nd functieral prior to Mode 1 creraticn.

P ancE ill

-fo..a t!.e i::C 4.cn '. Lc ria nn is installed.

Ur.dly ect.cwledge rcceipt of this raterial cn the enclosed copy of this let'er ind ret;rn it in the er.clcsed addressed cr.velope.

S i r. r. r ely,

V. A. Raytond for sl. O. Schuyler

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Cht:>ctcii::tica Secti:n 5.5 of t? e Ditblo Ctry:n FSAR describes the autoclosure interlock for t'.e TeR coction lir.e is olation *.alves (E701 Erid E7C2). Section 3.4.9. I(a) of-the Chllo Ct jcn Te:hr.ical Specificatfor.s rec.uires ; ser to be r+:.:ved from these iroitti:n.alve cper *,crs during Mode 4 (h:t stetd:-n, te', s ett re is le:s than 2<3*F), Mcde 5 (cold s N_' d:en) end l'.:de S (rei ali ;)i.e This. :;.ir..<nt defeats the function of auto:les are ir.terlock for the saiits.

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37, 38, 39, 40, 41, 42, 43,177, 261, 610, 611,- 612, E? 6, E19, 523, 523

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T';.t C-sien. C:nstructi:n. cr 0;eration Tc' tit t'j n -d in fi;Rs 21 Erd 22.

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siticr. cf t he F. actor f r':c'.t nt v. sign d.as r 31 co: f t rr, to tie Err nch T-chnical Po-

s Era ch, P53 5-1, Pcsition B.I.C., for the require-i m.t of i s' ar bs are f r 'crhk.

Ey '.. i g ;m ir ::. a il eM e t o the is ci atic r.

va'se d_.*ng a 5att -n t-

rcs that n ir.tcrrysten LOCA will r. t etcur es a r.-s uit cf t' cpe r.tsr failir.g to clete L.oth is clation valvas d rirg a return t o 7

-.. e r.

With poter en the isolation valses, a spurices cicsure of the is ola-tion salves veuld resuit in a 1 cts of sucticn. flew to the RHR purps.

t'.e RMR 1:w flow altre vould r nible rapid eptrater detection and c.itigatien.

H:wtver, F_rth:r 3 ? cf f dbr. tsien en this all' 7 ticn is ;.;&,ided in References 14 nd 2.

i i

In 'SE R F2 tha riktf sisted that it is the staff posit'fon that power be avail-ible to the T:.iR hot leg section isolation valves when in a shutdcwn condition to provide protectica egrir.st intersystem LOCA.

the liccnsce confir;ed that the corp;nsnis which provide the low flew alarmIn a let c:.r e 0.s te iled E nd f r c ted.

The PJ:R systta Icw flev elarrt is nw fenctional.

">;icn V to s ins;5ct-d tad verified the installation of the-low ficw alarm t.hrou;5 the r:.etite in>;ecticn progrt (NRC Repcrt 50-275/E*-11).

The licensre pt:vided the altre description and the basis of the clare retpoint in it s 1, t iers re t:-d !'ty 24, 15E3 tnd July 2, 1954.

In the currant system, i

r Diablo Canyon $.SER 26 A.4-45.1 9

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If opning the recirculation velves d:es st. t uit 'n c f kw h.crea se (Seve 503 sp:: within 20 seconds cf tira delty, the h s fi

'c.r.a.-it h r vill activate.

tiith re prd to pet (ntie.1.:.HR pu p dara;e, the vorst case is an inzdsertent cle-i st:re of t'.e ~-:R hot leg isolutica valse (s) when the RCS pressure is leser than

--t'.c T.-:R pu p :h.'t:1 f head.

Eased cn the cperating experien:es, the. licensee his rt.**.ed itst the RRR pu ;(s) ccuid run fcr a rinice. of 15 cinutes without

.-p ng fl id +nd still retain cretable. Vith the above assurance, the staff fir.ds t'st there is resscr.Eble. tir-e tvailable for operator action to trip EiR

;.(r) fc. h,eir.g the t.vencit. tion cf RER los ficw alarm 'and, therefore, the d s Qn

f t!.e T.,R k g fica alcrn is ecceptable.

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PGandE Letter No. : DCL-84-301-D& 9WW $.

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Mr. George W. Knighton, Chief 1

01 ino icen r$g Office of Nuclear Reactor Regulation

[h lM g d H(,

j U. S. Nuclear Regulatory Coarnission J

Wm.thington, D.C.

20555 Re: Docket No. 50-275, OL-DPR-76 D}

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Docket No. 50-323 Diablo Canyon-Units 1 and 2 RHR System Suction Line Isolation Yalves 3

W

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Dear Mr. Knighton:

As requested in your letter, G. W. Knighton to J. O. Schyyler, dated May 21,

@-3.. s e ri e s~ to 7eq_ui r_ag eE 4.4.5. 2 2Gan dE ' ha s modi fied'i ts 't)p 1984, and SSER 26, p modes 4.(with the.JHf sy. stem aligfed_to.theJCS)fSifand.6./ The plant is being operated in a mode that complies with existing Technical Specifications,

~

in that'with power appliod to the suction valve operators, ~in modes 4 (below-3230F), S and 6 with the head on the vessel, the reciprocating, charging pump will not be operated. Therefore, the change to Technical Specification letter, is not imediately requi red. "' O '; "'." r. ' ; -

21,'.1984 4.4.9.3.1, which was also requested in the May

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As stated in PGand's ietper.of August 15,*1.984, PGand does not believe power should be app; fed to the valves because potential inadvertent valve closures could'rE01t' n-'(T) Tnterruption of' decay heat reinoval, (2).RHR' letdown isolation resulting in RCS pressure spiking and PORY challenge, and (3)

Nuclear. Service Divi.sion Technical Bulletin 7h71ic~opyfenc]osed),(a,nd,Ej puttenLlal for RilR pump. damage. Moreover, both Westinghouse (in V ctjnghoUife-hSWAcport_62~date'd.Januar,y_1961) advocate operating with power remavad fenes the' suction valves when the RCS is incapable of being prussurized, j'

Although not a safety concarn, the charging system throttling valves will incur increased wear because of the inability to operate the reciprocating charging pump with RCS tefnperatura lett than 323oF in accordance with the existing Technical Specifications..This will result'in an increased plant maintenance requirement, increased personnel exposure, and lower overall ga t 9 reliability.

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.y PGandE Letter No. DCL-84-301 Septe.-ber 5, 1984 Page 2 I

PGandE plans to propose modifications to the R!!R suction valve circuitry which, in accordance with discussions.with the NRC Staff in a' meeting-conducted at Diablo Canyon on August 21, 1984, would modify the closing

i circuitry to make the RHR suction valves less susceptible to inadvertent closure. These are long-tem modifications that PGandE will develop with Westinghouse.

PGandE is requesting pemission to operate in modes 4, 5, and 6 with power removed from the operators of the RHR suction. valves.to preclude inadvertent valve closure Fntf3 the long-tem modification can be implemented. iWhen girit'infwithy,_pobrJri_oFedfrom theWalve m

ra ot' rs.,Tthe%1]owEg ;ac yug@c_A37 1

s Ei.P.riugusiFby M,n, ago.r.edugng'probio ber g-1.

The addition of a step to Operating Procedure L-1 and OP B-2:IY requiring (pd_epintaprit Ver$ficJLtianftliat 8cth MifuKop23_.EucTiroft%1vessarleTc30sc -

prior to removing power from the valve operators, as required by Technical Specification Surveillance Requirement 4.5.2.a.

P.f5 virid'operit5r~_t' raining oncinter'3y.s_temlLpCAii7rstressing the impor-tance 2.

of properly isolating a icw-pressure system from the RCS.

The occurrence of an inter-system LOCA because of failure to close both RHR suctiun isolation valves under existing circumstances is unlikely because the Technical r,pecif.ications siso require that the. power be removed from these valves in operating modes,1, 2,' and 3 for fire protection.

It is unlikely that power would be removed from a valve that was.in..the incorrect position.

Burvet11asc~sTis~tWoefddrs%1 A-(s hi ft' checklist)*a. (saty'requifysfg 1

9tr'f ficitf o;n otyal.ves?8701;in'd'.8 n Abe.fclostdmos,itioD'with

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fr.cm.the.cperator.s in. modes.1FJ!

is.pr.ocedure-1

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• '#f" B'ecause'of tid disadYMde's' otedearifierofope ting with wer on the yelvat, PrandE requests prompt action on this request.

PG'an'd

%pects -tof f

.odng.the-ssuance.cf.the spropo's_e a'.3omi.gensol$n11' pow [ic; operating 1 cen,gn,yith10.1_hr_qqumonth sei.; The implemen

'eveht',**!GFieq0) gent on plant conditions necessary to accomp11sn it.ent't6'you will be contir In any prior to conclusion of the first refueling outage.

Kindly acknowledge receipt of this material on the enclosed copy of this letter. and return it in the enclosed. addressed env. elope.

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Sincerely, N'O*.k.aymond.u.co rc..:.

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H. E. Schierling Service List

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.J00 1100182 0S:80 ST/60 PGandE Letter No.:

DCL-54-301 ENCLOSURE Westinaiouse Nuclear i

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Service Technical Bulletin

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Division 1

s An edvisory rtotics of a recent te hr.c.at deceicoment pertaining to the inrt4flation or operation crf Westirghovse. supplied Nuclear Plant equipment. Recipients sh utJ evalvete the information and recommeridation. and initista sciaori where saproprista.

P.S. &ea.*7as, rimane,yn. PA 15330

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r;ummer Residual Heat Re w/a1 Pumo Nsc Tc. 77-7

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Residual Heat Re io al System July 15, 1977 Asi:::e: r.ati s.o.ast ALL 215 i

Rt!&ftnLt!

$htet Of Plant Ooeratiens Es gineering Letter Oated May 5.1977 1

2 A review of the t ui rent, standard Westinghousa,'two suction line, RHR system i

revealed the potential for RHR pump damage due to inadvertent suction isola-tion valve elesu: e.

The above potential for RHR pump damage also exists for.

l single suction 1 ne plants. For a two line suction system the concern is s

the inadvertent !HL suction valve closure initiated by spurious actuation of i

the RHR autoclost ri it.terlock. The actuation of the interlock could occur as a result of a sirgle pressure transmitter failure or a single histable fail-ure resulting in tre closure of a suction valve in each line of a two line RHR suction system witt. the potential for RHR pump damage depending upon plant conditions. Curt er t plant designs include a RHR low flow alann which would alert the operater to inadvertent closure of a suction valve on a running RHR pump.

If RCS pressurt is greater than the shutoff head of the RHR pump (approximate-i ly 200 psi), the RHR pumps should not be daraged by closure of the suction valves since they c:erate satisfactorily on miniflow. Also, steam generators would be available.'or decay heat removal if it became necessary under the above ' set of conet t f orts. Thwrtfurr for tflis plant condition, no action is e

recoernended.

i l

If RCS pressure is less than the shutoff head of the RHR pumps and the RCS is closed, the p ter.tiil for FJiR pump dar. age due to inadvertent closure of the suction isolation vsives exists. Howver, since the time the plant is in this condition is typi: ally short and since the steam generators would be available for decay heat rt no.'al if it becomes necessary, no action is recorcended for this plant conditlo1.

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~1100182 19:80 81/60 Westinghouse

$ Nue ax-r M@Dj Service Technical Su!Ietin Divissori An adviwry notice o a recent tsc mical development pertaining to the imtanation or operation o' Wertinghouwapphed Nuclear front equtoment. Realpisatt t to ;ld svsluate the informstron and rs:cmmendation. and initista estion where appr:grlatt.

P.o. Sea 27.*t.Petuwy, PA 1g*,23 If the RCS is oci n to atmosphere with the reactor vessel heed on, the potential for RHR pumo d s ge exists due to inadvertent closure of the sucticn isolatien valves. Makeup to the RCS could be used for decay heat removal in this case; however, it wo.ild M limited by the availability of borated water and would be difficult to c introl. To preclude a single event (suction valve closure) re-sulting in RHR p:*p damage under the above plant conditions. it is recomended that electrica power be locked out to the suction isolation valve in each suttien line wihn is powered from an emergency power source different from tnat of its reipsctive pump. The above reconcendation also applies if the RCS is in a refueling condition with the reactor vessel head off and the refuel.

ing canal full.

For a single s action 1ine plant, spurious actuation of the autoclosure inter-lock, any fall are mechanism which results in closing of either suction iso-lation valve t i a concern for single suction line plants, since damage to both RHR pumps could occur.

The various pl ant conditionc eensidered absve for' the tw suctiaa lina appliac to the single 11.,e system. The recomendations are the same except the elec-trical power s toald be locked out for both suction valves and that only one RXR pump should be, operated when.the RCS is open.

"It is requeste t that operating plants should review their individual plant tief.slyris Lo ess tss whether the recomended octions are both na:essary and suf.

fi ci ent.

In a fdition, those operating plant customers with plants which do not have RHR law flow alam ecy wish to add the alarm to alert the operator-cf an inadvertent RRR suction valve closure.

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?.e_ C I F : C Cr A S 4 N 'O E L E C T R.I C 'C C 2v PA.N Y 77 ot Att statti, sam reancesec, cattream A 94104 TELEDWONE :415) 7884711

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September 5,1984 i

PGand Letter No.: OCL-64-301 4

alua xvw { g.e.Q D

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Mr. George W. Knighton, Chief Of si n o icens1[ig M

V Office of Huclear Reactor Regulation d Gy, U. S. Nuclear Regulatory Comission

[kq.o gm p k hington, D.C.

20555 a

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Re: Docket No. 50-275, OL-DPR-76 Oqcket_ No. 50-323 H=

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.OtR dysum aiuon ine iso.ation Valves 3

W N(h)

Dear Mr. Knighton:

As requested in your letter, G. W. Knighton to J. O. Schqyler, dated May 21, 1984, and SSER 26, page A.4.-45.2,@Gand'has modified its Opela.tingfrocedure i]E2. series trrequire that poweriraWTisdTOheDin'sTution valves'when in.

modes 4 (with the_RHR sy. stem aligned to the.RCS), 5, and.6.,- The plant is being operated in a mode that complies with existing Technical Specifications, in that with power applied to the suction valve operators,.in modes 4 (below 323oF), 5, and 6 with the head on the vessel, the reciprocatin1 charging i

pump will not be operated. Therefore, the change to Technical Specification 4.4.9.3.1, which was also, requested,in the May 21,. 1984 letter, is not irmediately requir.ed.: ~.

s As stated in PGand's letter of August 15,'1984, PGand does not believe power should be, app;ied to the valves because potential inadvertent valve closures i

cuuld'rBOTt'< n'(T)*' interruption of'5ecay heat reinoval, (2) RHR' letdown isolation ~ resulting in RCS pressure spiking and PORY challenge, and (3) pulential for RilR pump damage. Moreover, both Westinghouse (in.WestinghoGiie-Nuclear Service Div.{s on Technical Bulletin.7]-73 ~ copy cnclosed) and.EPRC(b; hSAG'Repott 52,~ dated { January.198'J) advocate operating with power recinvari f'roen the suction valves when the RCS is incapable of being pressurized.

Although not a safety concern, the charging system throttling valves will l

incur increased wear because of the inability to operate the reciprocating charging pump with RCS tefnperatura latt than 323oF in accordance with the existing Technical Specifications. This will result in an increased plant maintenance requirement, increased personnel exposure, and lower overall reliability.

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.ir. G. W. Knighton 1

PGandE t.stter No. OC'.-N-301 Smeter 5,12M Pa:;e 2 PGancE plans to propose modifications to the RHR suction valve circuitry which, in accordance with discussions with the NRC Staff in a meeting conducted at Diablo Canyon on August 21, 1984, would modify tne closing circuitry to make the RHR suction valves less susceptible to inadvertent f

closure. These are long-tem modifications that PGandE will develop with Westinghouse.

PGandE is requesting pemission to operate in modes 4, 5, and 6 with power i

removed from the operators of the RHR suction valves to preclude inadvertent valve closure l ntilithe,long-term modification can be implemented. Dihen !

i piierating ~with jiowir?r'emoved from the valve operators.^the following actions t fi.FCugupd]JJfiiincf to., reduce'Ine p,r,ocaoility urgeryypp1,$0cAs..-

~

1.

The addition of a step to Operating Procedure L-1 and 0P 8-2:1Y requiring independent verification'that~both-HHRJoop 4_,, suction _ Valves are'closK i

prior to removing power from the valve operators, as required by l

Technical Specification Surveillance Requirement 4.5.2.a.

2.

Provide ~ operitoritraining on_.in,ter-sy.s. tem lL,0CAsistressing the importance

~

of properly isolating a icw-pressure system from the RCS.

i t

t The occurrence of an inter-system LOCA because of failure to close both RHR suction isolation valves under existing cirtumstances is unlikely because the i

Technical Specifications also require that the power be removed from thes*

valves in operating modes 1, 2, and 3 for fire protection.

It is unlikely

}

that power would be removed from a valve that was in the incorrect position.

3urvel11anfe1 Test Procedure 4-1 A1 shift ~ checklict)31rea(y requires. j yet1f.fcation.~.of_ val.ves'8701..and'8702'in,.th4 ' closed postti.on wi,th powc.r_ remov,cd, Ante ri ng ; ope r,a,tirig.go de,,Lfrom, mo de-Ca n'd.at il, ej p[gncj!p[ry from.the operators.in modes.1 ~J/ 2This. procedure'is. performed r to -

)

89FAl43fr.i -

2 B'ecause of tN disadvabagis n'oted earlier of operating with,dkower on the i

val va;<, PGanctE requests prompt action on this request. PGin aicpects tof

propose WJ6ng~-Jem so)utfSD yithip thrgg months. pff )lowjng thedsagnee.of.thg l

full;oower.' operating. license.; The implem_entation; of the long-range solfutio,n 1

will be contir) gent on plant conditions necessary to accomp11sn it.

In any the'1ong-term change will be implemented "eMRt',!GHsqbent't6 your approval, fueling outage.

prior to conclusion of the first re i

Kindly acknowledge receipt of this material. on the enclosed copy of thf s letter and return it in the enclosed addressed envelope.

Sincerely, N'b'.d.aymond m.,.,rist<r*

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J. B. Martin H. E. Schierif ng Service List 1

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• %c et Of Plant Ooerations Es gineering Letter Cated May S.1977 1

2 A review of the i ui rsent, standard Westinghouse, two suction line, RHR system revealed the pote nt.ial for RHR pump dar. age due to inadvertent suction isola-tion valve closu: e.

The above potential for RNR pump da.iage als 2 exists for.

single suction 1 ne plants. For a two line suction system, the concern is the inadvertent !Hl. suction valve closure initiated by spurious actuation of the RHR autoclostrt irterlock. The actuation of the interlock could occur as a result of a sirgle pressure transmitter failure or a single bistable fail-ure resulting in ste closure of a suction valve in each line of a two line RHR suction system w*,tr. the potential for RHR pump damage depending upon plant conditions. Curr er: plant designs include a RHR low flow alarm which would alert the eperater to inadvertent closure of a suction valve on a running RHR pump.

If RCS pressure is greater than the shutoff head of the RHR pump (approximate-ly 200 psi), the Rht pumps should not be dar. aged by closure of the suction valves since they c erate satisfactority on miniflow. Also, steam generators would be availabit for decar heat rem: val if it becar e necessary under the

""'l above set of conet s!uris. Tire rt furt, for this plant condition, no action is i

recorrended.

If RCS' pressure is less than the shutoff head of the RHR pumps and the RCS is closed, the p ter. tis 1 for PJiR pump dar. age due to inadvertent closure of the suction isolatfor. vs1ves exists. However, since the time the plant is in this condition is typi:a'1y short and since the steam generators would be available for decay heat rt no >al if it becomes necessary, no action is recoceended for this plant conditlot.

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If the RCS is oc n to at: osphere with tne reactor vessel head on, the p tential for RHR pumc d a se exists cae tc inadvtsrteent closure of the suction isolatien valves. Makeu s.o the RCS could be used for decay heat removal to this case; however, it we ll J be limited by the availability of borated water and would be dif ficult to c introl. To preclude a single event (suction valve closure) re-Sulting in RHR p;mo damage under the above plant eenditions. it is recomended that electrica xa.er be locked out to the suction isolation valve in each suction line wit :n is pcwered from an emergency power source different from tnat of its resp ctive pump. The above recom.endation also applies if the RCS is in a refueling condition with the reactor vessel head off and the refuel-ing canal full.

For a single s action line plant, spurious actuation of the a_utoclosure inter-lock, any fall are mechanism which results in closing of either suction iso-lation valve ii a concern for single suction line plantc. since damage to both RHR pusps c:vid occur.

The various plin; conditionr. considered above for'the two suct on line appliet i

to the single 11.1e system. The recomendations are the same except the elec-trical power s soJld be IcCked cut for both suction valves and that only one RHR pump shoulf be, operated when,the RCS is open.

Ot is requestei that operating plants should review their individual plant walyns to ass ess whether the rectmended actions arc both na:essary and suf-ficient. In a fdttion, those operating plant customers with plants which do not have RHR 1:w flow alam may wish to add the alam to alert the operator of an inadvert ent RNR suction valve closure.

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