ML18067A440

LER 97-003-00:on 961101,four Piping Lines Were Determined to Be Potentially Susceptible to Pressurization Due to Containment Temperature Increase During an Accident.Cac Discharge Piping Will Be verified.W/970321 Ltr

ML18067A440
Person / Time
Site:	Palisades
Issue date:	03/21/1997
From:	Kozup C, Thomas J. Palmisano CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-97-003-01, LER-97-3-1, NUDOCS 9703270234
Download: ML18067A440 (5)

Text

A.CMS Energy Company Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert. Ml 49043

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• March 21, 1997

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U.S. Nuclear Regulatory Commission

• ATTN: Document Control Desk

• Washington, De 20555 DOCKET 50-255 - LICENSE DPR PALISADES* PLANT ' *.- - * :* * <'-'~ > ,

_INFORMATIONAL LICENSEE EVENT REPORT 97-003-POTENTIAL'FOR STEAM

. VOIDING AND WATER HAMMER IN CONTAINMENT AIR COOLER SYSTEM AND .

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"FOR OVERPRESSURlzATION OF CLOSED PIPING SYSTEMS.

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..iritormational Licensee Event Report 91-003 is attached. This repo'it was generatecf** :_. .

due to *our continuing revie.w of Gene*ric Letter 96-06, .dated September 30, .1996.

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SUMMARY

OF COMMITMENTS*:

• . Th_is le_tter contains no ne.w cc>~mitments *and _no revisiC?ns to existing eommitrrients .

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Thomas J. Palmisano Site Vice President .

CC Administrator', Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector - Palisades .', '-,

Attachment 9703270234 970321 PDR ADOCK 05000255 S PDR

• • NRC FORM 388 U.S. NUCLEAR REGULATO~Y COMMISSION APPROVED BY OMB NO. 3150*4l104

<4195> .. EXPIRES 4130198. ,f" '~. :_. - ........

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ESTIM.\TB> IUIDBI P£R RESPONSE TO COllPI.Y Willi THIS llNCIATORY INFORMATION COUB:'T10N REQUEST: 50.0 HRS. REPORTED LESSONS I.EARNED ARE NCORPORATED LICENSEE EVENT REPORT (LER) INTO TlfE UC0ISING PROCESS N1D FED BACll TO INDUSTRY. FORWARD COllllENTS REGARDING BUIDEN ESTIMATE TO TlfE INFORMATION N1D RECORDS llANAGEllEHI' llRNICH (T.t F33). U.S. MICLEAR REGUIATORY COlllllSSION, WASHINGTON. DC -

0001. NID TO TlfE PAPERWORK REDIJC'.llON PROJECT (.1150-01CM, OFflCE Of (See reverse for required number of digits/characters for each block) llANAGEllBl1' NID BUDGET, WASHNGTON, DC 20503

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PAclUTYNAMl!(1) CONSUMERS POWER COMPANY DOCKET NUMBER (2) Page (3)

PALISADES NUCLEAR PLANT 0501)0255

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.TITLE (4)1NFORMATIONAL LICENSEE EVENT R~PORT 97-003- POTENTIAL.FOR STEAM VOIDING AND WATER HAMMER IN CONTAINMENT AIR CO.OLER SYSTEM, AND FOR OVERPRESSURIZATION OF CLOSED PIPING SYSTEMS .* . . ... * * .

EVENT DATE (5) LER NUMBER (6) REPORT DATE.m .

• OTHER FACILmES INVOLVED (8)

MONTH DAY

• YEAR

• YEAR

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I SEQUENTIAL NUMBER REVISION NUMBER MONTH

• DAY YEAR FACILITY NAME DOCKET NUMBER 05000' FACILITY NAME DOCKET NUMBER 11 .01 96 97 ~ ob3 - *oo 03 *21 97 05000

• .OPERATING . THIS REPORT IS SUB!"'ITTED PURSUANT TO THE ~QUIREMENTS OF 10 CFR§: (Check one or monl) (11)

• MODE (9) N 20.Z?01(b) 20.2203(a)(~)(v)_* 50.73(a)(2)0) 50.73(a)(2)(1ll)

. *POWER. 20.2203(a)(1_) 20.2203(a)(3)0>: .. : 50.73(a)(2)0Q ...

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20.2203(a)(2)(U) .20.2203(a)(4) :- 50.73(a)(2)(iv) x . OTHER Vol~ntary

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... 20.2203(a)(2)(1v) . .50.36ic)(2) 50.73(a)(2lMll In NRC. Forni 366A .

UCENSEe: CONTACT fOR.THIS LEk (12) . ' **

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.NAME TELEPHON~ NUMBER.(lnclude Area Code) .*

• Charles-S: Kozup;. Licensing Engin~er * * (616) 764-2009.

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

• CAUSE SYSTEM. COMPONENT MANUFACTuRER REPORTABLE CAUSE coMPoNENT

• MANUFACTURE.R . REPORTABLE

.. TONPRQS .TONPfUls.

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MONTH. DAY** YEAR'

.. lYES SUPPLEMENTAL REPORT EXPECTED (14)

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• *I If ves. COMPLETE EXPECTED COMPLETION DATE X

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. EXPECTED SUBMISSION DATE (15).*

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ABSTRACT (Umlt to 1400 spaces. I.e., approximately 15 slngle-si)aCed typewritten iln~) O6): ... \*

The-Palisades review of Generic"tetter 96-06, *has* determined the following:** * ** ,

• *1) \A/aterhammer.coulq occur in-the*ServiceWater (SW)"reti.mi plpi.ng downstream ofthe.CACs (VHX-1, 2 *. &-3) whiCh ar~ ln-:-service. * . . .* . . . . .. .. .. . .

' 2) .. While* CAC VHX-4~.is isolated during a D.BA; itwas~ detenni"ne~:Hhat a stearrrbub.~le could * * .*

• fonn.' * .: * * * * * .. **

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• The CACs (VHX-1, 2, &:3) were: determined to be-susceptit;>le to short-tenn tWo-phase flow:

dt,1ring*a*o0A. * ... ::. :: : *.: . " .* . * * . . -: * * * . . .- . - .* :: : : . . -.:

4). Simplified, bounding_an.alyses show.ad th~t the li_nes Y{~>Uld r.emain.:oper~ble .. Detailed ..... *

• analyses :are lri progress to verify .that _FSA~ *d:~sign _criteria: a.re. sat!sfieq ... *. :. -: . ..

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Four piping 1.ineswere determined to be potentially suseeptible to pres~urization due to a ._

containment:temper~ture increase during an accident These four-piping line*s are the clean waste receiver tank fill and drain lines (2 lines) arid the reactor cavi~y fill and drain lines (2 lines).

Analyses were not performed *to predict pressures in the line*s be~use the plant was in a refueling outage. - Instead, modifications *or procedure changes .were completed pefore startup to elimi.nate the potential for overpres.surization. * .. * * * * * ** * * .*.: * *. . *

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NRC FORM 368a J:==============n** *:~.*:.

• • NUCLEAH. REGULATORY COMMISSION 4195 LICENSEE EVENT REPORT (LER) .. . *.* * *. *:<~°'>;: -~*> ;.:>;~. :1 TEXT CONTINUATION YEAR REVISION NUMBER 20F4

• 05000255 PALISADES NUCLEAR PLANT 97 - 003 - 00 TEXT (If more space is required, .use additional copies of NR~ Form 366A) (17)

EVENT DESCRIPTION On November 1, 1996, the Palisades Plant was shutdown to begin a refueling outage. During the .

refueling outage, the review of Generic Letter 96-06, "Assurance of Equipment Operability and:

Containment Integrity During Design Basis Accident. Conditions" eontinued. Evaluations were

• done to determine the susceptibility of the containment air cooler (CAC) cooling wat~r .systern to either w~ter hammer or two-phase flow conditions during any postulated design basis ~cci~ent *

(OBA) conditions. 'While both a Main Steam Line Break (MSLB) and a Loss of Coolant'Aceident (LOCA) were considered, the LOCA w~s determined to be limiting when coinciding with a Loss of Offsite Power (LO.OP) event. At Palisades, three of the four CACs *are in service during ~ OBA:

The fourth required a .separate.evaluation since it is valved ~ut during a OBA. *

.. lJie evallJations* determined that water hammer could occur in th.e Service* Water ($W)~ret~m :. ,* -

piping downstream of the CACs (VHX-1, 2, & 3) which are in-service following.*a OBA. The water hammer loading was Qounded by a case where the system*refillis initiated at times later ttian the diesel generator start times assumed -for a LOOP .. It was determined that water hammer. would not .

. . occur. in ttie CACs for-the case of *a LOCA coincident with* a LOOP, wh!ch is ttie desig*n basis. for .*

Pali.sades. Howe.ver,*_if the refill occurred at a later time: the\vater slug from *refill would cqllide.

. . with the water slug in ttie 6-incti discharge line. The water hammer loading at this location was.

determined to be acceptable. *

• While CAC VHX-4 is isolated during a OBA, it was determined that a* steam bubble could form. If a steam .bubble formed, then a water hammer coul_d result due to a steam bubble .c0llap.se wheri SW is reinitiated. Because a modification was readily available that could prevent the '.Nater_h~mmer from*o6curring, and thecost and man-hours to perform the detailed analyses'. were significant, the

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• detailed analyses~were not performed to determine the loading rn~gnitude and the impact on

• piping. The water hammer potential was resolved by a modification to. ch~n-ge )he ..isolatlo~ri-valve --

to the inl~t side of the CAC from the outlet side. **

The CAC cooling water syst_erns for the operable (VHX-1,2, & 3) CACs were suseeptible to water hammer and two-phase flow during certain OBA events. However, neither ofthese conditions has

• been determined.to cause these systems to be inoperable. Only the CAC discharge piping is susceptible to water hammer and this piping was determined, through a simplified, bounding analysis, to be operable with respect to the water hammer loads. The two-phase flow was shown to* exist for only a fradion of the time that would-be necessary to cause an unacceptable temperature increase within containment. *

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NRC FORM 388a

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• NUCLEAR REGULATORY' COMMISSION 4195 ..

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• LICENSEE. EVENT REPORT (LER)

TEXT CONTINUATION

- ... YEAR REVISION' 05000255 NUMBER 30F4 PAUSADES NUCLEAR PLANT 97 003 - . 00'

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TEXT (If more spa?8 ls required, use additional copies of NRC Fonn 366A)_ (17)

The c6ntainment piping systems were reviewed to identify sections which contained fiuid and could.potentially expand and pr~ssurize the *piping as temperature increased during a OBA. Most containment piping ~ys.tems were screened out b.ecause they were not susceptible to large - .

• pressure increases thafcould ovefpressurize the line.s .. Only fo*ur iin.es were determined to_ be.-

. pote~tially susceptible tooverpressurization: These fo~r lines were nonsafety_related except for.:

very short sections associated with. c6ntainmerit penetrations. Because changes to* remove the**: - .

.pot~ntlal for overJ?ressurization ciould be.made q*ui~ly and inexpensively, thQse:cha11*ges w~re

• made in lieu of expending resources:on *analyses to*determine whether overpressurizafionwould actually o~t: All fou_r of these. lines werE:t re.splved prior to the plant startup-form ~he refue!ing *.. :

outage: the clean waste r~ceiver tank fill and drain lines (2 lines) were modified by adding_ sur~ie:

pots. to alleviate that possibility. The reactor- ~vify fill.and .drain linf3S- (2 lines) are being controlled*

by procedure.tq ensure.that the.line~*are ~rained during operation.*

e~s1s FOR CONTINUED QPE_RAe1uri OF *AEFECTEP svsT~Ms ANP coMpoNENTS

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f>rior.to~therestart ot the plant from th.e retue1ing*ci~:t~9e. ~a1i~acies~ad an *operabi1ity.as~es~m~nt

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c0mp1eted for the CAC cooling wate~ system and for piping suseeptible to. overpressurizati~n .

during D.BA eonditions. This assessment, titled "Operability _As~essment for: Jransi~nt Cqr:lditioris

.. atP.alisade$*Nuclear Plant In Response:to Generic.Letter 96~;','*is Sargent *&L1:.1n.dy's Report_ .. , * -...

C-PAL-96-1063.-01. The ~~port conciuded:the CAC:cooli_ng*water:system pipin*g was ope.rable: :. ....

In addition, an interim op~*rability evaluation of 'the heat r~moval eapability ot' the CACs. a~unting.

for two-ph~~e. flow condi.tions was eo_mpl~ted. This evaluation demonstrated. tile heat remov~i *- *..

capability* was* acceptable. ~ '

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E*ven though the CAC eoolingwater system.piping*has*been determined to be, operable, additional

~nalysis of the CAC c0oifng water systerri piping wfli be.eompleted to-ensure.that i=SAR design** - -*--*+---

criteria for piping :are met arid to assess the potential need .for additional modifications. Generic *.

• Letter 91-18, "Information to Licensees RegardingTwo NRC lnspectionManual Se.ctions on _* _

Resolution of Degraded and Nonconforming Conditions and on Operability;~ was used as .: .. :- :* .....- :: . ' ..

guida_nce for op~rability determinations: * *. * * * * * * *. * ._* * *. _* ."

• For the four containment-piping lines suseeptible.to overpressurization, detailed analyses to predict pipin_g system pressures were not' perfor~ed. However, review of the functions and configurations of the lines showed* that even if they were: assumed to_ be susceptible to overpressurization, reasonable assurance existed that their safety f~.mctions (containment jntegrity)' ..

would not be compromised. Prior to the.startup from the-refueling outage, the clean waste.receiv~r. :: ...

tar:ik fill and drain lines were modified by adding surge pots.to minimize the susceptibility to * *. . "*

• overpressurization. In addition, the reactor cavity fill and drain lines ~re now* ~nfrolled by .

procedur~ to ensure that the lines are drained during operatiol"!. .:" * * - *

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' NRC FORM 366a ** NUCLEAR REGULATORY COMMISSION 4195 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR REVISION

'NUMBER 05000255 40F4 PALISADES NUCLEAR PLANT 97 - 003 -. 00 TEXT (If more si>ace is required, use additiOnal coPies of NRC Form 366A) (17)

CORRECTIVE ACTIONS Prior to the restart of the plant from the recent refueling outage, several actions were taken as a result of conditions found during the study of Generic Letter 96-06. These were: *

(1 )

• The CAC VHX-4 cooling water system piping was modified to change *the isolation point

• during a OBA from the outlet piping to th_e Inlet piping; This change prevents th~ con~ition ..

where a *steam bubble may form in the CAC, and then suddenly collapse due to the*sw being reinitiated. The CAC will be isolated from.SW flow in either direction during a OBA*

since the-discharge piping is pro_tected by *a notJ-return che*ck valve. :The steam bubble will;

• therefore, _collaps~-slowly as containment is cooled. . **

• .,.

• _As-part of the Facility.Changettiat modifted theVHX-4-isolafiqn*point, p~ocedur.es were also ,; *.

changed to r_eflect *the: revised: operation of this* s_yste~. * * *

(2) - Surge pots have been added to-clean.waste receiver tank fill .and drain._ piping to minimize the

..,. .... possibility of qverpressurization d~ring ~OBA. * ., * :* _. ;_

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(3) - Procedures controlling the reactor cavity fill and drain piping have.been Ghanged.to ens1,mf -~ : .* ,*~.. *.

• *that the piping will be drained prior to operation. * . * * ._. * *' *

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• In addition, -out .120 day response to Generic Letter 96-06, dated January 27, 1997, c6ntained qne .

'additional action. . .  : .. : .. _* . . . . . . . . . . : .. *. . . . . : . *. . . .

., . . .

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. * (4) . Compliance with the FSAR piping design ~riteria for the CAC discharge piping will be verified prior to the completion-of the 1998 refueling outage. * *

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