ML17318A561

Safety Evaluation Supporting Amends 35 & 16 to Licenses DPR-58 & DPR-74,respectively

ML17318A561
Person / Time
Site:	Cook
Issue date:	12/20/1979
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML17318A560	List: ML17318A559 ML17318A561 ML17318A562
References
NUDOCS 8001170057
Download: ML17318A561 (7)

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UNITED STATES NU ~EAR REGULATORY COMMISSION

, WASHINGTON, D. C. 20555 SAFETY EVALUATING)i BY THE OFFICE OF NUCLEAR REACTOR REGULATION "REL'ATED TO AMEHDI' IT HO 35 TO FACILITY OPERATING LICEHSE HO DPR 58 AND AMENDMENT I!0.

16 TO FACILITY OPERATING. LICENSE NO.

DPR-74 It:DIANA AND MICHIGAN ELECTRIC COMPANY DOtiALD C.

COOK NUCLEAR PLANT UNIT NOS.

1 AND 2 DOCKET NOS.

50-315 AND 50-316 Introduction

, By 'letter dated August 9, 1979,,Indiana and Michigan Electric Company (the licensee) submitted

=roposed Technical Specification changes for the Donald C.

Cook Nuclear Plant, I:n-'t Nos.

1 and 2.

The proposed changes would (1) add a moto'r driven auxil:ary feedwater (AFW) 'pump to each unit to enhance the availability of Units

'. and.2 by e'liminating shared equipment dependency, (2) add an additiona'.

O'C battery system; and (3) eliminate dependency on alternating current

-n the turbine drive auxiliary feedwater train.

1 The Unit 2 Facility Operating License No.. DPR-74 cohtains a license condition, 2.C. (3) (k';, which requires the c'onversion of the AC electrical dependency to DC before return to power following the first Iefueling outage.

Unit 2 is currently in the first'refueling outage and since the addition of the moto." criven auxiliary feedwater pumps has not progressed as originally schedulIed, this safety evaluation addresses only the proposed changes of AC to DC..i.e evaluation has been done specifically for Unit 2,

however, the informa:ion provided by the licensee is for both Units 1

and 2.

Because these un.ts are essentially identical and the proposed changes and commitments appl.'oually to Units 1

and 2, this evaluation and the resulting conclusions and Technical Specifications are for Units 1

and 2.

Existin Turbine Driven Auxiliar Feedwater Train.- Unit 2 The turbine driven a.xiliary feedwater (TDAFW) pump is connected to all four steam generators in Un-:t 2.

Steam is supplied redundantly from Steam Generator Hos.

2 and 3 and taken upstream of the main steam isolation valves.

The steam supply isolation valves to the TDAFW pump are MCH 221 and HCM 231; (refer ".o Figure 1)..

These 4-i nch motor operated gate valves are normally open, allowing steam pressure to be available up to the trip and throttle (T8T) valve.

The motor operated steam isolation valves MCM-221 and 231 can be opened or, closed from the control room and on loss of power thev f=-il as-is.

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~ 1 The TAT valve is normally closed and opens automatically when the TDAFW pump receives a start signal, however, it is AC powered and fails as-is.

Auxiliary feedwater is supplied to the four steam generators through 4-inch motor

'operated valves (HOY), FMO-211, 221,

231, and 241.

These globe type MOVs are normally open, but each may be closed by the control room operator in the event of a feedwater or steam line break at the steam generator it feeds.

Each HOV can be throttled to regulate steam generator level.

In the event of a steam line break and rapid depressurization of a steam generator, or upon detection of a high flow at the TDAFW pump, these HOVs are automatically driven to an intermediate position to prevent pump runout.

On loss of power, these HOVs fail as-is.

The TDAFW pumps and associated valves are presently powered from the Class IE AC power system train B.

Upon loss of all AC both onsite and offsite the AFWS could not perforn its intended function.

Therefore, the staff has found it necessary and the licensee has committed to eliminate dependence of the TDAFW pump train upon alternating current by converting to a direct current source of power.

Descri tion of Desi n Modification At the present time, Unit 2 has two safety-related station batteries.

However, when the additional motor driven auxiliary feedwater (NDAFW) pump (proposed for future installation by the licensee) is installed, the use.,of either of these batteries for the TDAFW pump train will not be possible.

At that time, each of the two NDAFW pumps will be served by its own ESF electrical train and associated station battery.

Hence, the licensee has installed a third station

battery, designated as train "N".

This new train "N" station battery is considered to be part of the ESF system.

The turbine driven auxiliary feed pump control bus and associated MOV motors will be peered from the "H" train battery.

The following is a list of loads on the "N" train:

valve - FHO - 211, 221, 231 and 241 (1.6 Hp) each; the trip and throttle valve (0.33 Hp); test valve -

FRV - 256; emergency leak off valve-FRV - 258; AFW=Turbine Auto Start; AFW turbine trip; and the overspeed monitor.

Two battery chargers are connected to the "H" train battery bus.

When AC power is available, each charger has sufficient capacity to supply all steady state "N" train loads and recharge the batter from full discharge (1.75 volts per cell) to full charge in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Only one of the chargers will be in service at any one time.

The battery is capable of serving all of the electrical needs of the TDAFW pump trai p for at least four hours upon loss of all AC power.

Evaluation We have reviewed the i.".forr~tion provided by the licensee concerning the change of the TDAFM purp train from AC to DC power..

This included information provided in Amendment lio. 84 (also provided in a letter dated August 9, 1979) which provided a brief description o

the proposed modification, additional documentation by the 1:censee in response to our requests. for additional information, and funct onal logic diagrams.

Our evaluation is presented bel ow.

The two new battery ch=-rcers would b powered rom separate and independent Class IE power buses.

As originally proposed, either charger could have been connected to the 'N" train battery under normal conditions.

During our review we identified the potential for unacceptable parallel operation of both chargers which co ld connect redundant sa=ety load groups in violation of Regulatory Guide l.:.

n'e required that at least one interlock (mechanical or electrical) be prov ded to preven:

an operator error that would parallel these chargers.

The 1;censee modified its design to incorporate an accept-able electrical interl'.ck which will prevent this potential problem.

Likewise, during our review we identified another potential for paralleling two standby circuits f"on the existing station batteries (AB and CD) in violation of Regulator Guide 1.6.

Me required that at least one interlock be provided to prevent operator error from tying these batteries together.

To meet our requirenen-.,

the licensee disabled the backup feeders from the AB and CD batteries (by d>sconnecting and insulating the ends of the interconnecting cables).

These cables w re disconnected at the "N" train distribution cabinet and at the dis=ribution cabinets for the AB and CD batteries.

With the incorporation o-..hese modifications we conclude that the design of the TDAFW pump trai~ co;,plies with the provisions of Regulatory Guide

~ 1.6.

The electrical equipment to be installed for the "N" train is qualified in accordance with IEE= 323-1971.

This includes the battery, battery

chargers, distribution cabinets, and valve control centers.

The installation also meets the provisions of Regulatory Guide 1.75 with the exception of the annunciation circui.s which are non Class IE.

The "N" train batteries

-.or each unit will each be housed in a new room.

Each room will be fully enclosed by'wo hour fire rated barriers with l-l/2 hour rated (Class B) doors and ventilation darqers.

In addition, the licensee will provide-u=aaatic fire detection and manual fire suppression equipment.

Also the v n:ilation system is designed to maintain hydrogen concentration well bel~

2 volume percent and alarms in the control room are provided to ann nciate if either redundant ventilation fan fails.

The licensee has performed a fire hazards analysis for the new battery being installed in each unit.

In this analysis, the licensee concludes that no unacceptable safety-related consequences would result from a postulated fire in these rooms.

This conclusion is based primarily on containing the fire within the room and because of. the separation, diversity and redundancy in the auxiliary feedwater system.

We agree with this evaluation and find that the fire protection meets the requi rements of Appendix A to Branch Technical Position APCSB 9.5-1.

Technical S ecificaticns The changes to the,echnical Specifications proposed by the licensee on August 9, 1979 for the addition of the "N" train batteries are consistent with the current Techrical Specifications for Units 1

and 2.

Nowever, the action statement for -;he "i" train batteries is being revised to refer to the operability of he unit's turbi ne driven auxiliary feedwater pump.

With the "N" train battery inoperable, the related TDAFW pump is to be declared inoperable and the TD~Ri pump Action Statement would apply.

The changes to the Un;t 2 Technical Specifications should be effective immediately to satisfv 1 icense condition 2. C.(3)(k) which requi res elimi na-tion of AC dependency i n the TDAFM pump train during the first refueling outage.

Similar changes to the Unit 1 Technical Specifications should

~e made effective as soon as

he licensee can complete the modifications described above.

The licensee has committed to completing these modifications before returning to power frcm the next refueling outage of Unit 1.

Therfore, we find that these changes for the Unit 1 Technical Specifications should be made effective no later than during the next Unit 1 refueling outage or sooner if at all poss ble.

~Summar Based on the information presented in FSAR Amendment No. 84 and the additional information requested we have concluded that:

(1)

The design bases information provided gives reasonable assurance that the new DC train can be satisfactorily implemented into the exi sting AFWS.

(2)

The "N" battery:rain is physically and electrically independent from the other ESF electrical trains.

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(3)

The conversion of the TDAFW pump train from AC to DC meets the Commission's requirements and is acceptable.

(4)

The "N" battery.rain is capable of serving the TDAFW pump train for at least four hours without either charger in'operation.

This feature satisfies the staff position that at least one AFW flow path and associated instr~mentation and controls be capable of being operated without AC power for at least two hours.

(5)

The fire protection for the rooms containing the "N" battery train meets the requiremen s of Appendix A to Branch Technical Position APCSB 9.5-1.

Environmental Consideration We have determined hat tho amendnents do not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environental impact.

Having made this determination, we have further conclude" that the amendments involve an action which is insignificant from the standpoint of, environmental impact and, pursuant to 10 CFR $51.5(d)(4), that an environmental impact statement or negative declaration and environmertal impact appraisal need not be prepared in connection with the issuarce of these amendments.

Conclusion We have concluded based on the considerations discussed'above, that:

(1) because the amendments do not involve a significant increase in the probability or consequences of accidents previously considered and do not involve a significant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed

manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.

Date:

December 20, 1979

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LEGEND:

= MOTOR OPERATED GLOBE VALVEOPEN MOTOR OPERATED GLOBc VALVECLOSFD iVIOTOR OPERATED BUTTcRFLY VALVEOPEiU

= iVIQTQR OPERATED BUTTERFLY VALVECLOSED MOTOR OPERATED GATE VALVEOPEN MOTOR OPcRAT=D GATE VALVE CLOSED fOC] = MANUALGATE VALVEOPEN

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= MANUALGLOBE VALVEOPEN

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= MANUALGLOBE VALVECLOSED

= MANUALBUTTEr..FLY VALVEOPEN i>lANUALBUTTc FLY VALVE CLOSED

= CHcCKVALVc FO

= FAILS OPEN FC

= FAILS CLOS=D LO

= LOCKED QPcN (LOCK AiND KEY)

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= LOCKED CLOSED (LOCK AND KFY)

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= SEAI ED OPEN iDETENT)

~ g Auxiiiery Feec;vater System D.. Cook Ficure 1 {Sheet 2 oi 2)