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

-* '. * .. . 'j .,. A.CMS Energy Company Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert. Ml 49043 -*-.. * . . . . -.

• March 21, 1997 . ' -. . ' ... U.S. Nuclear Regulatory Commission

• ATTN: Document Control Desk *Washington, De 20555 . '._. DOCKET 50-255 -LICENSE DPR-20 -PALISADES*

PLANT ' *.--* :* *

> ,, _INFORMATIONAL LICENSEE EVENT REPORT 97-003-POTENTIAL'FOR STEAM . VOIDING AND WATER HAMMER IN CONTAINMENT AIR COOLER SYSTEM AND . "FOR OVERPRESSURlzATION OF CLOSED PIPING SYSTEMS. * < *_ .:*. ,* '" -* :' . . ..::: ... ' -*, -. i,, . *-,. .. ,(" * ;_ -.**-* .. 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. ,

SUMMARY

OF COMMITMENTS*:

• . Th_is le_tter contains no ne.w

• and _no revisiC?ns to existing eommitrrients . .. *, . , .. .: *:' :--.. -*-;;---'---*-*{'*

• -;,* ,*.***j**.-

.;***:*,--.1.

--*----*'_ -* ........ -:' . -*' -. ---. . '

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 .---;--**t-..,, .', '-,

• • NRC FORM 388 <4195> .. U.S. NUCLEAR COMMISSION APPROVED BY OMB NO. 3150*4l104 EXPIRES 4130198. ,f" :_. LICENSEE EVENT REPORT (LER) (See reverse for required number of digits/characters for each block) "*:'..-* 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 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 llANAGEllBl1' NID BUDGET, WASHNGTON, DC 20503 . . PAclUTYNAMl!(1)

CONSUMERS POWER COMPANY PALISADES NUCLEAR PLANT DOCKET NUMBER (2) 0501)0255 Page (3)

• 1*of 4* .TITLE (4)1NFORMATIONAL LICENSEE EVENT 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 I SEQUENTIAL

• . NUMBER REVISION NUMBER MONTH

• DAY YEAR FACILITY NAME DOCKET NUMBER 05000' 11 .01 96 97 ob3 -*oo 03 *21 97 FACILITY NAME DOCKET NUMBER 05000 *.OPERATING MODE (9) N . THIS REPORT IS SUB!"'ITTED PURSUANT TO THE OF 10 CFR§: (Check one or monl) (11)

• 20.Z?01(b) 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

... *>:' "... 50.73(a)(2)(x)

.. " .

........ ,......,......, LEVEL(10) 0 20:2203(a)(2)(1)

_-20.2203(a)(3)(U) 50.73(a)(_2)(liQ 73.71 . . . --20.2203(a)(2)(U)

.20.2203(a)(4)

-50.73(a)(2)(iv) x . OTHER

... 20.2203(a)(2)(1v) . .50.36ic)(2) 50.73(a)(2lMll In NRC. Forni 366A . .NAME UCENSEe: CONTACT fOR.THIS LEk (12) . ' * *

• Charles-S:

Kozup;. Licensing

• NUMBER.(lnclude Area Code) .* (616) 764-2009.

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

• CAUSE SYSTEM. COMPONENT MANUFACTuRER REPORTABLE TONPRQS CAUSE coMPoNENT

• MANUFACTURE.R . REPORTABLE .TONPfUls.

.. . . ' SUPPLEMENTAL REPORT EXPECTED (14) MONTH. . . . . DAY** YEAR' .. lYES . . . . .

I NO . *: *I If ves. COMPLETE EXPECTED COMPLETION DATE X . EXPECTED SUBMISSION DATE (15).* .. ABSTRACT (Umlt to 1400 spaces. I.e., approximately 15 slngle-si)aCed typewritten O 6): ... \* :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 ln-:-service.

• . . . * . . . . . . . . . . . .

' 2) .. While* CAC isolated during a D.BA; a

could * * . * *fonn.' * .: * * * * * . . *

• 3) -* 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 the li_nes

.. Detailed ..... *

• analyses :are lri progress to verify .that

_criteria:

a.re. sat!sfieq

... *. :. -: . . . . . . . Four piping 1.ineswere determined to be potentially suseeptible to due to a . _

increase during an accident These four-piping line*s are the clean waste receiver tank fill and drain lines (2 lines) arid the reactor fill and drain lines (2 lines). Analyses were not performed

• to predict pressures in the line*s the plant was in a refueling outage. -Instead, modifications

• or procedure changes .were completed pefore startup to elimi.nate the potential for overpres.surization.

• . . * * * * * * * * * . *.: * *. . * .. -....... . * . .:. *, .I J:==============n**

• • NUCLEAH. REGULATORY COMMISSION NRC FORM 368a 4195 LICENSEE EVENT REPORT (LER) . . . *.* * *.

1 TEXT CONTINUATION PALISADES NUCLEAR PLANT 05000255 TEXT (If more space is required, .use additional copies of Form 366A) (17) EVENT DESCRIPTION YEAR 97 -003 -REVISION NUMBER 00 20F4

• 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 .systern to either hammer or two-phase flow conditions during any postulated design basis

• (OBA) conditions.

'While both a Main Steam Line Break (MSLB) and a Loss of Coolant'Aceident (LOCA) were considered, the LOCA 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 during a OBA. * .. lJie evallJations*

determined that water hammer could occur in th.e Service* Water

. ,* -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 CA Cs 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 from*o6curring, and thecost and man-hours to perform the detailed analyses'.

were significant, the -*

• detailed not performed to determine the loading and the impact on

• piping. The water hammer potential was resolved by a modification to. )he ..

--to the 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.

• .. . *

• NUCLEAR REGULATORY' COMMISSION NRC FORM 388a 4195 PAUSADES NUCLEAR PLANT *LICENSEE.

EVENT REPORT (LER) TEXT CONTINUATION

-... YEAR 05000255 REVISION' NUMBER 97 003 -. 00' . ' TEXT (If more spa?8 ls required, use additional copies of NRC Fonn 366A)_ (17) .. . *.*-. 30F4 The c6ntainment piping systems were reviewed to identify sections which contained fiuid and could.potentially expand and the *piping as temperature increased during a OBA. Most containment piping 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.-.

susceptible tooverpressurization:

These lines were nonsafety_related except for.: very short sections associated with. c6ntainmerit penetrations.

Because changes to* remove the**: -. .

for overJ?ressurization ciould be.made and inexpensively, thQse:cha11*ges

• made in lieu of expending resources:on

• analyses to*determine whether overpressurizafionwould actually All fou_r of these. lines werE:t re.splved prior to the plant startup-form refue!ing

• .. : outage: the clean waste tank fill and drain lines (2 lines) were modified by adding_

pots. to alleviate that possibility.

The reactor-fill.and .drain linf3S-(2 lines) are being controlled*

by procedure.tq ensure.that during operation.*

FOR CONTINUED QPE_RAe1uri OF *AEFECTEP ANP coMpoNENTS ot the plant from th.e an c0mp1eted for the CAC cooling system and for piping suseeptible to. . . ** .. during D.BA eonditions.

This assessment, titled "Operability for:

Cqr:lditioris . . atP.alisade$*Nuclear Plant In Response:to Generic.Letter Sargent *&L1:.1n.dy's Report_ .. , * -... C-PAL-96-1063.-01.

The conciuded:the CAC:cooli_ng*water:system pipin*g was ope.rable:

..... In addition, an interim evaluation of 'the heat eapability ot' the CACs.

for flow condi.tions was This evaluation demonstrated.

tile heat

• -* .. capability*

was* acceptable. ' -._,-*, E*ven though the CAC eoolingwater system.piping*has*been determined to be, operable, additional 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 was used as .: .. :-:* .... .-:: . ' .. guida_nce for determinations:

• *. * * * * * * *. * ._* * *. _ * ."

• For the four containment-piping lines suseeptible.to overpressurization, detailed analyses to predict pipin_g system pressures were not' 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 (containment jntegrity)'

.. would not be compromised.

Prior to the.startup from the-refueling outage, the clean

... 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 now*

by .

to ensure that the lines are drained during operatiol"!.

.:" * * -*

. *. ' . -*-...

' NRC FORM 366a 4195 ** NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATION PALISADES NUCLEAR PLANT 05000255 TEXT (If more si>ace is required, use additiOnal coPies of NRC Form 366A) (17) CORRECTIVE ACTIONS YEAR REVISION 'NUMBER 97 -003 -. 00 40F4 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

.. 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, as containment is cooled. . * ** *.,. *_As-part of the Facility.Changettiat modifted theVHX-4-isolafiqn*point, were also changed to r_eflect *the: revised: operation of this*

• * * (2) -Surge pots have been added to-clean.waste receiver tank fill .and drain._ piping to minimize the .. ,. . ... possibility of qverpressurization

• ., * :* _. ;_ *** ,. t * . . ,; *. . (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.

• .. * * ._. * * ' * ..

• In addition, -out .120 day response to Generic Letter 96-06, dated January 27, 1997, c6ntained qne . 'additional action. . . : .. : .. _* . . . . . . . . . .

.. *. . . . . : .

• . . . . . , . . . ' '! --. . -* ' ' ' . *-. * (4) . Compliance with the FSAR piping design for the CAC discharge piping will be verified prior to the completion-of the 1998 refueling outage. * * **-*---------*** ---**:*: *-*--------,..-..

• .--------------------.-.;;--, ....

' -...