ML20059H519

Application for Amends to Licenses DPR-58 & DPR-74,modifying Tech Spec 4.7.5.1.a to Reduce Control Room Temp Limit to 95 F

ML20059H519
Person / Time
Site:	Cook
Issue date:	09/10/1990
From:	Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20059H523	List: ML20059H519 ML20059H524
References
AEP:NRC:0398U, AEP:NRC:398U, NUDOCS 9009180035
Download: ML20059H519 (7)

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cN Pows.' Company dM N -.. .P.O. Box 10631 -

i Jh V' l Cdumbus. OH 43216 ?

E M INDIANA

' AlfCNIGAN -

J POWER 7

AEP:NRC:03980'. .,

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Donald C. Cook Nuclear Plant Units 1-& 2:

License Nos. DPR-58 and DPR 74

. Docket Nos.-50 313-and 50 316- i p M -TECHNICAL SPECIFICATION CHANGE:

CONTROL ROOM TEMPERATURE LIMIT U.ES.~ Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

~ Attn: T. E - nurley 't September 10, 1990-

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Dear Dri.Murley; s

'This letter and_its attachments constitute an application for "y '

amendmen~ to the Technical Specifications (T/Ss) for Donald C.

= Cook. Nuclear-Plant Units 1 and 2. Specifically, we propose'to ,

modify T/S 4.7.5.1.a such that the control room temperature limit is-conservatively: reduced from 120 F to 95 F. We are also . ]

proposing a change to the associated Bases Section that-elaborates on the reason for the temperature that we have proposed. ,

The reasons for the. proposed changes and our analyses concerning.

significant hazards considerations -.aro contained in Attachment- I

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to this letter. The proposed revised T/S pages are contained in' Attachment 2.

Additional changes to the control room ventilation system T/Ss have been proposed in our letter AEP:NRC:0398R,' dated June 29, "

1989. The changes proposed in this letter are in addition to those changes 'ad ao not supersede them.--

We believe that the proposed changes will not result in (1) -a significant change in the types of effluents or a significant l

increase in the amounts of any effluent that may be released offsite, or (2) a significant increase in individual or cumulative ~ occupational radiation exposure. ,

LThese changes have been reviewed by the Plant Nuclear Safety Review Committee and will be reviewed by the Nuclear Safety and Design Review Committee at their next regularly scneduled

. meeting.

I 9009180035 90091o hDR ADOCK 05000315 phi PDC I"1 m .

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Dr. T. E. Murley- 2- 'AEPiNRC:0398U i .

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f . In compliance with the requirements of 100FR50.91(b)(1), copies of

.,3 this letter and its attachments have been transmitted to Mr. J. R.

Padgett of the Michigan Public Service Commission and to the Michiga.n Department of Public Health.

This document has been prepared following Corporate procedures that incorporate-a reasonable set of controls to ensure its

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accuracy and completeness prior to signature by the undersigned.

Sincerely, i

"J c,

. M. . Alexich Vice President

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.o cc: D. H, Williams , Jr. ,

.A; A. Blind:- Bridgman J..R..Padgett G. Charnoff A. B. Davis - Region III NRC Resident Inspector - Bridgman NFEM Section Chief h

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ATTACHMENT 1 TO'AEP:NRC:0398U. .

t g -y. REASONS AND 10CFR50,92 ANALYSES FOR CHANGES TO THE n.. -.

DONILD C.' COOK NUCLEAR PLANT' UNIT NOS.~1.AND 2 ,

T- i TECHNICAL SPECIFICATIONS ,

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ATTACIMENT 1 TO AEP:NRC:0398U Page 1 Introduction and Background This license amendment request proposes to modify T/S 4.7.5.1.a ,

such that the control room temperature limit is conservatively reduced from 120 F to 95 F.

During<the period of September 15 19, 1986, a survey was conducted of the control room ventilation system at the Cook Nuclear Plant, i; The survey team was led by J. Hayes of NRR, with assistance from contractors from Argonne National Laboratory. The team's review 4

L' included control room habitability Technical Specification (T/S) changes that we had submitted in July 1986 as a result of NUREG 0737 Item III.D.3.4 and the subsequent Generic Letter 83 37.

l: 'The. team found problems with our T/S submittal and with the control room. habitability analyses that supported the ~ chnge. As l a result, we withdrew our proposed T/S changes by lette dated l April 29, 1988. By letter dated October 11, 1988, we provided lc revised control room habitability analyses, and by letter dated-L June 29, 1989, we provided proposed revised control room habitability T/S changes.

The June 29, 1989 T/S c'bmittal addressed the T/S concerns of the y survey team except for one item regarding the maximum control room

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temperature. The temperatureto120{/Sshavealwayslimitedthecontrolroom F. This value remained unchanged throughout our various T/S'submittals. The survey. team, in their report, asked two questions concerning the adequacy of this temperature, specifically: (1) Is the temperature consistent with equipment qualification temperatures? and (Q Does the temperature limit consider that tempercturea inside various panels may be much higher than the ambient room temperature?

l In our June 29, 1989 submittal, we committed to perform a study of

, the control room temperature limit, and to propose any necessary changes by September 1990. Orr study has been completed and, a: a result, we have determined that a temperature limit of 95 F is more-appropriata. We note that (ur June 29, 1989 T/S submittal remains under NRC review. The changes proposed in this letter are in addition to those changes aH do not supersede them.

Evaluation As discussed in the Bases for T/S 3/4.7.5.1, the , arpose of d,e w ntrol room temperature limit is to ensure that the ambient air l 1

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, i if ATTACRMENT 1 TO AEP:NRC:0398U Page 2

. temperature does not exceed the alle 'able temperature for the continuous duty rating for the equipa nt and instrumentation 1 cooled by the control room ventilation system.

t In researching the adequacy of the 120*F limit, we have considered both parts of the survey team's concern, which are the sensor  :

location and the temperature.  ;

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Temperature Sensor Location i

The non-Westinghouse critical instruments ars located in open racks and not enclosed panels. These devices'are all -

I continuous duty rated above 120 F. The control room temporacure probe used for determining the T/S temperature (the DTU panel .

probe) is nested in the open rack behind the control room DTU i i panel. The temperature measured at ht is probe location was found '

to be within 1 1/2 degrees of the temperatures measured at the  ;

other critical locations within the racks.

The Westinghouse panels are temperature rated as a complete unit based on the control room ambient temperature, not the temperature  !

inside the panel. As the ambient temperature rises, the rated life of the equipment in the panel decreases. During the testing, ,

the ambient temperature measured at each Westinghouse panel was at or below the control room temperature at the DTU panel probe. The ,

DTU panel indicates a temperature very close to the ambient temperature surrounding the Westinghouse panels. The DTU panel readout, therefore, provides the appropriarc relevant temperature to be used to determine T/S temperature. It should be noted that the panels are well ventilated and during testing, temperature rises through the panels were observed to be low. l T/S Temperature Limit' As discussed above, the critical non Westinghouse equipment is continuous duty rated for room ambient temperatures above 120 F.

Regarding the Westinghouse equipment, the panel with the highest expected ambient temperature would have a gated life of approximately 15,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> at 95 F. At 80 F, equipment life ,

exceeds the life of the plant. The control room ventilution l system typically maintains the control room at an average temperatureofapproximatelyf5Fyearround. The control room temperature has been above 80 F as measured at the DTU panel only on rare occasions, for limited time periods.

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ATTACHMENT 1 TO AEP:NRC:0398U Page 3 We are' proposing to chagge the control room temperature limit from-the present 120 F to 95 F. . Although higher than the corcinuous duty rating for the Westinghouse equipment - rated equip'aent life ,

at this temperature (15,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />) is sufficiently long,to provide ,

reasonable assurance that the rated life will not be etceeded. -

(Because we have redundant control room air gondition systems, we j would expect temperature excursions above 80 F [the continuous 'l duty temperature) to be liuited in ngaber and very short in '

duration.) Equipment lifetime at 95 F would be sufficiently long-to preclude the need to log temperature excursions above the ,

continuous duty temperature.

. Bases Changes In addition to changing the 120 F T/S limit, we are also proposing to modify.the Bases Section for T/S 3/4.7.5. The revised Bases discusses the relationship between the T/S limit and the continuous duty rating.

10CFR50.92 Evaluation Per 10CFR50.92, a proposed ameniment will not involve significant hazards consideration if the proposed amendment does not: ,

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(1) involve a significant increase in the probability or +

consequences of an accident previously analyzed, (2) create the possibility of a new or different kind of L U accident from any accident previously analyzed or  :

evaluated,-or  !

i (3) involve a significant reduction in a margin of safety, i l' criterion 1 The change to the T/S temperature limit is in the conservative

! direction. The temperature selected is consistent with ASHRAE guidance on heat stroke protection and was developed considering qualified life of control room equipment. We therefore conclude f

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j l' ATTACHMENT 1 TO AEP:NRC:0398U Page 4 that the change will not involve a.significant increase in the probability or consequences of a previously evaluated accident.

Criterion 2 The change involves no physical changes to the plant nor any new-modes of plant operation. The change will not. therefore, create the possibility of a new or different kind of accident from any accident previously analyzed or evaluated.

Criterion 3 The change is in the conservative direction, placing additional y restrictions on 1lant operation. Therefore, the change should 1 increase, rather than decrease, the margin of safety.. i>

Lastly, we note that the Commission has provided guidance ,

concerning the determination ot significant hazards by providing examples (48FR14870) of amendments considered not likely to involve significant hazards consideration. The second example .

refers to changes that constitute additional limitations, restrictions, or controls not presently included in the T/Ss.

Since this change reduces the maximum allowable T/S temperature for which operation may continue, we conclude that the example cited is applicable, and that the change should not involve significant hazards consideration.

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