ML20029A648

LER 91-002-00:on 910128,essential Svc Water Flow to Containment Cooling Units Below TS 4.6.2.3 Requirements of 4,000 Gpm.Caused by Inaccurate Flow Readings Provided by Local Annubars.Surveillance Procedure revised.W/910226 Ltr

ML20029A648
Person / Time
Site:	Wolf Creek
Issue date:	02/26/1991
From:	Bailey J, Mike Williams WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-002, LER-91-2, NO-91-0070, NO-91-70, NUDOCS 9102280187
Download: ML20029A648 (7)

Text

. . . _ _ ______- . - . . . _ . . . . . . _ . . . . - . . . . _ _ _ _

t r p

_. g W44.F CREEK NUCLEAR OPERATING CORPORAT10N John A. Bailey Vice President t . Operations ,

f February 26,1991

NO 91-0070. ,

i U. S. Nuclear Regulatory Conmission

' ATTN Document Control Desk-Mail Station P1-137 Washington,-D. C. .20555-

Subject:

Docket No. 50-462: Licensee Event Report 91-002-00 Gentlemen:

The attached Licensee. Event Report (LER) is being submitted pursuant to-10 CFR 50.75 (a) (2) (1) concerning a Technical Specification violation.

Very truly yours, 7

I John A. Bailey.

'Vice President Operations JAB /jra

~ Attachment ce s- A. T. Howell (NRC), w/a.

-R. D. Martin 1(NRC),.w/a D.- V.EPickett (NRC),'w/a L 'M.-E.-Skow:(NRC), w/a ll 9102280187 Y10226 PDR ADOCK O'5000482 5 PDP RO. Box 411/ Burhngton, KS 66839 / Phone: (316) 364 8831 i\\

An Equal Opportunity Ernployer M r/HCsVET

-_ _ _ _ _ . _ _ ._- ~ - -

4

)

NaC ,evei see ~ u 8 Nuctica nioutotoav CopMesarch APPaQvlo OMS No 3100 04

• , LICENSEE EVENT REPORT (LER) 'a'***"

,aciur, Na. i, noen i No..ia m eaa a Wolf Creek Generating Station 01610 Rl 014 l_812 I lor l016 Technical Specification Violation - Essential Service Water Flow To Containment Ccoling Units Below limits Because Of inaccurate EquipmtDt in 'NT oaf t St Le R NUM.i m . a:PoafDate17* ofulli f ACnttial INVDLviD (Si MONtw . DAY ve&a vtAa ! " ,$ h 2,'y*,N MONTH oat ,iAt ' ' ' ' W ' N " "l 5 M 4 I NV8I" 8' 0 161010101 -1 I Oli 2l8 9 1 9l1 0 l 0l2 0l0 O!2 2l 6 9] 1 o1 6 1 0 1 0 1 0 1 1 i inii ai, oat is su..it rio evasu,Ni vo 1 i ii oviai uiNii o, io c, a , re..,. ,-, .. ..,, ,, , ,,4.. ,, n i, j o,,,,,,,

4

" '* 1 a *om aam u n+m<* n "mi pom a n ammw so x,.im .o n,.nsim unm NEo 019 0 aammm se um a n+mm, omi a is-+ e um T n awo n.a [ un+mm son.ww.m n, ~~' **::> '" ~ '"' " ' **

20 4064alH HM SO 731st(2iNI to 73teil24vum.)

n 406tand hvi to 73+(2Hast 60 Ph.t!2Hal teciNils CONT ACT Foa THl Lin (ill NAME_ iltienONE NuMeia Af*E A CDOi Merlin G. Williams - Manager Plant Support 31116 3 1614l- 1818 13 11-coe.u n o~e uni ,oa eacu couroNm sanuai encaco m tais ainoar no causi svsuu cov,o e t

• • %f "

• 3,' an '

, cause muv coveo~ m *;"WlF "' g,' an '

1 I I l' i l I ,,__,

I i 1 1 I I I I I l l l I i 1  ! ! I I I I sunuum*L ainoar ex,ieno n., e,w pa, una g su..

.oN 45 litsee compiere ik,8C7tO $v06H3310N Onill kO l l -l ce a r a ac1 m ..a = , e ,- , 1.. _ . -- , ~,- ,,. .-. e. . w..< o s .

On May 26,-1989, a post-accident Essential Service Water alignment flow test was conducted. 'ihe test results indicated that flows to the Containment Cooling Units were below Technical Specification 4.6.2.3 requirements of

- 4000 gallor.s per minute. On June 2 and-3, 1989, flow was adjusted based on the conservative indications provided =in this flow test.

An evaluatico conducted during Refueling IV (March-May 1990) revealed that-this event cccurred as the result of inaccurate flow readings provided by-local annubars. Review of previous normal flow test results revealed two-instances in which adequate norm 1 flow was below Technical Specification 4.6.2.3 limits because of reliance on the annubars. Ultrasonic flow masurunent test equipnent has been used to perform the associated surveillance procedure since Refueling IV. On January 28, 1991, following-an engineering evaluation of test results, it was determined that the low-post-accident Essential Service Water flow to the Containment Cooling Units is reportable pursuant to 10 CFR 50.73(a)(2)(1) concerning a condition- j prohibited by the plant's 'Ibchnical Specification.

l l

1 l

N MC D orim MS

-Y ~ , , n .....,.n . .~, . , , . ---

..-._...m _- . - - . - _ . . - ,

_ ._...._m . m_.-- - ..m_ _ - . . _ . - - _ _ . . . . . - . . -,

e kXC FOAM 3saA .US huCLE AR fil0VLATORY COMMIS5tOh t s*this 4 30'92 LICENSEE EVENT REPORT (LER) L50'o?,%'#RWr"o"'jR*3,"),o*f 7.fi ,*#.'J! -

TEXT CONTINUATlON $**,'l01,'$ o^"$"sOU'*.1"C7^,'!# UMfA PAPt.WO Rt T 60N 84 I 60 i Of DF V AN AGEMENT A.JD OvDGE f.W A3HtNGTON, DC ,0boj FACettf Y NAME tu DOClkti NUM5tR W ggg ggggg g ggi pAgg (3,

~-

unw . W:,r:

Wolf-Creek Generating Station o Is l o l o l o l4 l 812 9 11 010 l 2 -

0IO O l2 0F 0 l6 ru, --. . r. ~ w w.n m IMm3XCPIGi On January 28,-1991, following an engineering evaluation, it es detemined that Essential Service Water (ESW) [BI] flows to the containment Cooling Units (SGN01A, B, C, and D) (BK-CLR] were below Technical Specification 4.6.2.3 limits prior. to June 3,1989. 'Ibchnical Specification 4.6.2.3 requires that the cooling water flow rate be at least 4000 gallons per minute to each cooling unit gmup on a Safety Injection Signal. Also, a review of previous normal flow test results using a conservative error of 20 percent for the annubar revealed two instances in which nomal flow was bclow'Ibchnical Specification 4.6.2.3 lbnits because of reliance on the annubars (Figure 1). %is event is being reported pursuant to 10 CFR 50.73(a)(2)(1) concerning a condition prohibited by the plant's Technical Specifications.

DESOLIPTIGi GP EVEMP te design-of the Containment Cooling Systs incorporates two redundant trains containing two Containment Cooling Fans per train [ Figure 2).

'Ibchnical Specification 3.6.2.3 applicable for Mode -1, Power Operation,,

through Mode 4, Hot Shutdown, requires two independent groups of Containment Cooling Units to be oparable with two fan systes included in each group.

Technical Specification 4.6.2.3 requires d m onstration of operability once per 18 nonths by verifying that on a Safety Injection test signal, the cooling flow rate increases to at least 4000 gallons per minute to each cooling unit group. %e anount of ESW flow to the cooling units is maximized upon receiving a Safety Injection Signal, l

An Essential Service Water Systs flow test was perfomed on May 26, 1989, to measure system flow on a Safety Injection valve alignment. This test was

-conducted to resolve differences in the results of previous flow tests perfomed on the system. Temporary procedure TP-TS-15, " Essential Service Water Punp Test", Revisicn 0 was used to record differential pressure at various locations in the system for conversion to flow rate.

! l l On June 1,-1989, a review of the test results.of t mporary procedure TP-TS-L 15, " Essential Service Water Pump Test", Revision 0 indicated that ESW flows ,

to the Containnent Cooling Units were less than design values. However, Li surveillance procedure STS EF-925, " Containment Coolers Flow Verification",

utilizing the local test annubars for flow measurement indicated that )

Containment Cooling Unit ESW flows were acceptable. ' Resolution of the flow '

l discrepancy could not occur until Refueling IV (March-May 1990). It was I subsequently determined that the conservative hxiication fram the differential pressure measurments should be used to determine ESW flow to the cooling units. In accordance with this decision, STS EF-925,

" Containment Coolers Flow Verification", was revised to utilize the differential pressure measurements.

.NRC Perm 366A 4896

l NMC 70 AM 36aA u s NUCLL AR Riout ATORY COMMik&80N APmtiv ED nue p.O 3160 0:04 EU t mP6hl3 4 30W LICENSEE EVENT REPORT (LER) M,%^u",%'d!Od',"#A;OL'(ff*f# ,*0."d"2 '

TEXT CONTINUATlON 27n',*P0n';'."u'2"$lEU'Udf','h'? UiMMi "fa Apt O HitUCit P JE T !3 to O I OF WAN AGE ML N't ANO BUDull.W ASHINGTON DC 7t%J F ACl48 t

• 8. Art 113 DOCIL i f NUMBi n (2 6 gg n ouvegn to, ra OS (3-u-  % U;; r T4r:

Wolf Creek Generating Station n p lo j o j o l 4l8l2 9l 1 -

0l0l? -

0 !0 0l3 or 0l6 nu %.t. . - uc i- e nn Temporary procedure TP-TS-15, " Essential Service Water Pump Test", Revision 1 and revised surveillance procedure STS EF-925, "Contairemt Coolers Flow Verification", were perfo e d on June 2 and 3, 1989 to adjust the ESW flow to the cooling units. 'Ihis testing consisted of adjusting the associated valves with the Service Water pumps (KG-P] and ESW pumps (BI-P] in service to obtain the required flow. 'Ihis testing was perfomd on both trains, crd when cmpleted, both trains were providing pu+er ESW flow.

During Refueling IV flow balancing, cmparison data was taken between ultrasonic flow masurent test equipment and the local test annubars. 'Ihe results of this testing indicated that the differential pressure measurements w re accurate while the local annubare gave inaccurate high flow readings. Ch January 28, 1991, it was determined that ESW flows were below Technlcal Specification 4.6.2.3 limits prior to the perfornance of tmporary procedure TP-TS-15, " Essential Service Water Pump Test", Revision 1 on June 2 and 3, 1989.

IYX7P CAUSE NO CmfUUflVP. ACTKNS

'Ihis event occurrtd as the result of inaccurate flow readings provided by local annubars. Although the exact cause of the inaccuracy could not be determined, the installation of the annubars adjacent to pipe elbows which created flow turbulence is thought to be a mjor contributor. 'Ihis was the only situation in which the local annubars were used to provide flow measurments. Surveillance procedure STS EF-925, " Containment Coolers Flow Verification", wac revised to conservatively use the differential pressure masurments instead of the local annubars after the flow discrepancies are discovered on June 1. 1989. Ultrasonic flow measurment test equipuent has been used to perfom surveillance procedure STS EF-925, "Containmnt Coolers Flow Verification", since Refueling IV.

NETTIfEAL INPCIDMTIOi While ESW flows to the Containment Cooling Units w re below Technical Specification 4.6.2.3 limits, the unit operated in all mdes of operation frm Mcde 6, Refueling, to Mode 1, Power Operation.

A review of the results of surveillance test STS EF-925, "Containmnt Coolers Flow Verification", has revealed two instances of a failure to verify adequate normal flow as required by 'Ibclutical Specification 4.6.2.3 because of reliance on the local annubars. A cmparison of data obtained frm the local annubars and the ultrasonic fh.; measument test equipuent has indicated that a 20 percent error could be obtained with the annubar results.

NRC Fem 366A (683r

.. ,-.-a . . . - - . - - - . . - - . . . - . . - - ~ ~ ~ - . - ~ . - . . . .

4 1

C PO%M 3644 U t huCLE AR REGULAf 0RV Commission APPAOvtP OMS NC.3160 0104 (MP!Nt$ ef30M7 LICENSEE EVENT REPORT ILER) 'J,'lfn'd'E/d80,n"n0'#R,it ,'i!f0l ,*J,"J'A's TEXT CONTINUATION 27/*n"!1^Afd5;'Of'.%I"c',T'i!J l,".'"'Ef"fA

",'at,lo".'Ji"N#ina^ne?!?%?&P#' ta???

0F MA4 TGTMg NT AND LIVOQ(f, W A8641NCTON, DC 30601 PLCibaf v hAME t); DOCKE T NV4tsim (2) qq hvuggn ggi PAge g3, ta ae m i." 3*,t; Wolf Creek Generating Station 016 l o 1010 l4 l812 911 1 01012 -

0 10 014 0F 0l6 TLET tot more noece a reqored, use achtsenord MC form Jti6As' t (1h Subsequent engineering analysis has concluded chat adequate heat rmoval ,

would have been accmplished with ESW flow '.imited to 2000 gallons per minute to each cooling unit group in a safety Injection valve alignment.

Assuming the conservative error of 20 percent for the local annubar results, ESW flow to the Containment Coc, ling Units was substantially above this 112 nit. Therefore, there was no threat to the health and safety of site personnel nor the public.

'Ihere have been no previous similar occurrences.

NRC Form 364A 1649)

. - . . . - , - - ~ , .. , - , - - . . - - - - - . . - , . .

NHC f onM 3e4A - U 8 NUCLE AA PluutA1084Y COMMinbloh

. . . n, .wo ,

uCENSEE EVENT REPORT (LER) ',5,'s",'o',',94"M'R,7,"o"5,0*1',,'%'f"Ul ,"J// 'j,"'

' Ofl"fj

!"d,',",'J,ll',3^24'i$lll"f',*,D,'!,U,'h'f t,",'

TEXT CONTINUATlON

%?",,'i0fr.ra,i"A%",'!:"",n?"in:2 0?!?

Of MANAGE M(N! AND BUC A T.W A9HNGlDN. DC 20h01 9 AC4Lif v hAME til DOCRET huMet A L2l (th hUMR(R164 PAQt 42

'<aa " C'.;;'." Q.aT.I Wolf Creek Generating Station 911 o ll O ls M nk 01510'lo lo l 41S l 2 0.lfd2 iEX1 f# anwe ape is revvant, was esewW NAC Ferm #441/ (14 FIGURE 1 - ANNUBAR 10

- m U _ (. \

Instrument connections AMF with valves l:1 1-:1

t

+ e e 'I Packing i j gland j p j. j Insert-1 i retract i:

i.

mechanism Cage 3_

E

j,g, ~~

nipple'  :

(:i i N Unit Valve Closo nipple

. g m .,

.b nac - , Sensor 316S S kj NaC f arm E4A (649)

l

, NAC 70KM 3MA - U S. NUCt t AR Rigut AYOR Y COMMistiON E NP8RES 4W92 LICENSEE EVENT REPORT (LER) f,$,'s",^4',%5MM ?J',"00 'lig$i ,'o,jf *lJ,' ,*o',".',Ts TEXT CONTINUATlON 10"4",'A';!'4!,?ni 'Of(" !!,'#'.'l2 u'"' "Z't "f4 i i P apt hWO K REDUC IDN J (36o I O f lC Of MAN 40tMtNT AND DVDOt Y,W ASHINGTON, DC 20f,03, !l t Aciktiv NAMI ill V4n ti NUMalm (Js LE R NUM8t R 16e PA0413t  !

18Am " f j, ,* k  ?,y2 Wolf Creek Generating Station o ls lo lo io l 4l8l2 9l 1 -

0l0l2 -

0l0 0l6 0F 0 l6 rist w m., ,,u. . w. .w ew ue rom, m ,,iin '

FIGURE 2 - ESW FLOW TO CONTAINMENT COOLING UNITS I SGN01D N EF HV048 IP EF HV032 EF HV034 EF HV046 O ~*

-%  % X u Vm ANNUBAR EF HV050 II h

U 3 l

SGN019 ESWFLOW "B" TR AIN i

i SGN01A N

y ~

EF HV047 EF HV031 EF HV033 EF HV045 -C>4- ~*-

-x x x o ANNUBAR EF HV049 h

U L

SGN01C ESWFLOW i

"A" TR AIN l

NRC f orm 366A (6-891