ML20212G108

Forwards Adequacy of RHR Reservoir Freeze Over Problem for Plant Unit 2.Based on Evaluation,Staff Agrees That Deco Measures Will Ensure RHR Reservoir Operability During Extremely Cold Weather

ML20212G108
Person / Time
Site:	Fermi
Issue date:	01/17/1990
From:	Zwolinski J NRC (Affiliation Not Assigned)
To:	Greenman E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
TAC-M73832, NUDOCS 9711060029
Download: ML20212G108 (2)

Text

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3 UNITE 3 87 ATE 8 4 ,

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! k* J . . MEMORANDUM FOR: Edward G. Greenman, Director N, A Division of Reactor Projects Region !!!

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FRON: John A. Zwo11nski, Assistant Director iR for Region !!! Reactors F ., Divisten of Reactor Projects !!!,

M^ - fY, Y & Special Projects ip, Office of Nuclear Reactor Regulation Ih $UBJECT: TIA. RECUEST TOR TECHNICAL AS$1SMNCE REGARDING ADEQUACY ib 07 FERHI-2 RESCLUTION OF RHR RESERVOIR FREEZE-0VEF. FROBLEli ji (TAC 73832) l' 1984, you requested that we reviev the Detroit Ey letter Ediscn Cos:pany dated (DECe July)17 fir.a1 rt: port on measures taken to ensure the ope

'D of the Termi-2 residual hest renovel (Rl:R) reservoir during extrerely celd 1 seather. The request was ir. advertently a.isplactd thereby resbiting in the

long delay in eur response.

I 1' We have revitved the licensee's letter dated July 5,1984; licensee proce. dure NPP-23.208, "RHR Comples Service k'ater Systen;" and the licensee's revisee Residual Heat Removal Reservoir !cing Evaluation dated July 1 1985. The 4

ar.closedSafetyEvaluationprovidesthedetailed,NFRstaffrevIewofthe licensee's aralysis. Based en cur evaluttion the NRR staff agrees that CECO's n.easurer vill ensure RhR reservoir cper, ability curir.g extrer.ely r.ulo j weather.

i This s.emorandum ccerpletes our action on your July 17, 1984, reque .

i E John A. Zwolinski, Assistant Director i for Region !!!

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' DivisionofReactorProjects!!!,

IV, V & Special Projects q, Office of Nuclear Reactor Regulation Y

Enclosure:

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" 3 l [/ ADEQUACY OF RHR RESERVOIR FREEZE-0VER PROBLEM lf AT TERMI-2

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t The RHR reservoir serves as the ultir. ate heat sink for ferri 2 and as such is the source of supply for the safety-related diesel generator service water,

eurgency equiprent service kater and resitual heat reseval service water

, systers. These systess operate only during norsal shutdown or post-accident  !

'[ conditions. The pumps for these systems are vertical deep draft pusps which j are nomally en standby (not running), and are locsted in the reservoir.

l, Because there is r.o flow to the reservoir during nonnal power operation, ice

can form on the reservoir surface. Ice forzation in the reservoir can affect

, the opetattlity of the pur.ps by flow blockage or damage to the pump column.

l The licensee provides freeze prctectier, for the RHR Reservoir with the plant in i i normal power operation by running the erargency equipment coflir.g water syster and/or einergency diesel generator on indication that the RHR tuervoir ter.pera-j ture has dropped to 43'F. Instructicn of injecticn heat into the reservoir is- ,

i contained in license procedure fiFP-23.?O8, "RHR Complex Service Water System."

i Review of procedure NPP t3.208 revealed that the instructions are appropriate "

l and acceptable. The heat generated by the corponents in the en.er0*ncy *4uir-l ment coolirg water syster. or diesel generator would then be transferred to the.

) reservoir by the associated service water system, thus warritng it. While the l plant is shutdown, reacter decay heat can otovide the recessary reservoir freeze protectiot. by r.crr.a1 operation cf the RHR heat exchar.ger via the RHR service

! water syster.

l I Based on our reviev, we conclude that the licensee's approach is acceptable

! and stculd provide adequate freeze protection. We dc rot believe use of the ,

l above indicated syster.s atd cottponents to add heat to the RPR reservoir will i

ir. pact their ability to acccr.plish their intended safety functions. However, I because the propr, sed approach is not a norr. ally intended function for the f

effected safety-related systers, the licensee should ccnfirr. that operaticn of i the erergency equipn.ent cooling and service water systers, and diesel generator

!- and diesel generator service water systen in a r. ode to provide RHR reservoir i freeze prctectiot. Will ret violate existing technical specifications for ensuring operability of these systems and cor.ponents. Further, the licensee should confirm that measures are in place as necessary to ensure that the safety

! functions of the above systers and cotr.ponents will be accorplished if needed at l a time when they are being used to heat the reservoir. We would expect such i< time pericd to occur very rarely and for short durations during the life of the

!t- plant. If experience indicates the contrary, an alternative, more perr.anent i

and specific freeze protection design r.ay be apprcpriate. We would also expect l any diesel generator operation for purposes of heating the RNR reserveir to be

! accounted for consistent with the licensee's diesel generator reliebility pro-

'r gram per Regulatory Guide 1.9 which will be irplemented in the r. ear future.

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