ML17252A723

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Forwards Safety Evaluation for SEP Topic VI-10.B,re Electrical Instrumentation & Control Portions of Shared Sys. Mods to Plant Sys & Tech Specs Recommended
ML17252A723
Person / Time
Site: Dresden Constellation icon.png
Issue date: 07/07/1981
From: Crutchfield D
Office of Nuclear Reactor Regulation
To: Abel J
COMMONWEALTH EDISON CO.
References
TASK-06-10.B, TASK-6-10.B, TASK-RR LSO5-81-07-006, LSO5-81-7-6, NUDOCS 8107130413
Download: ML17252A723 (6)
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Docket No. 50-237 Lsos..:s1-oz-006

  • Mr.* J. s. Abel
  • Direc*tor of Nuclear L 1cens1ng Connnon~~alth jfJ~ison Cornp~ny *

,Post,Ot:;ftc*e Bgx.767 Chica_~o, Illtno1s 60690

Dear Mr. Abel:

July 7, 1981.

SUBJBCT:

SEe TOPIC VI-10. B, ELECTRICAL,..INStRUMENTATION ANp CONTROL P.09tIONS OF SHARED SYSTEMS (DRESDEN 2 "NUCLEAR GENERATING STIITTON)

The enclosed staff sa-fety---eval uation is based on a contractor'$ document that has been made available to youfiprev1ously. This document supports the find-ings of the staff safety evaluation of Topic VI-10.B ~nd reconnnends modifica-tions to several plant systems and the Technical Specifications.

The need to actually implement these changes will be detennined during the integrated safety assessment. This safety evaluation may be revised in the future if your facility design 1s changed or if NRC criteria relating to this

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topic are modified before the integrated assessment is completed.

Enclosure:

As stated cc w/enclosure:

See next page

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  • See revious concurrence Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing_

OFFICE~ SEPB**

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NRC FORM 3181101801 NRt;:M.()240 Qf'f'lCIAL* B.£CQRD CQPY*

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'. :".USGPO: 198()..':329-824

OFFICE.

SURNAME..

ElATE~

Docket No. 50-237 LS05 Mr. J. S. Abel Director of Nuclear Licensing Conunonwealth Edison Company Post Office Box 767 Chicago, Illinois

  • 60690

Dear Mr. Abel:

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SUBJECT:

SEP TOPIC VI-10.B, ELECTRICAL, INSTRUMENTATION AND GONTROL PORTIONS OF SHARED SYSTEMS {DRESDEN 2 NUCLEAR GENERATING STATION)

The enclosed staff *Safety evaluation is based on a contractor's document that has been made available to you previously. This document supports the findings of the staff safety evaluation of Topic VI-10.B and recommends modifications to severe plant systems and the Technical Specifications.

The need to actually implement these changes will be determined during the integrated safety assessment. This safety evaluation may be revised in the future if your facility design is changed or if NRC criteria

  • relating to*this topic are modified before the integrated assessment is cornp,leted~

Enclosure:

As stated cc w/enclosure:

See next page.

.. ti SEPB:DL SL/SEPB:°* C/SEPB: or-Jk, RScholl :dn RHermann

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Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing ORB#5:DL C/ORB#5: DL AD-SA:DL P0 1 Connor DCrutchfield GCLainas 6/ /81

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NRC f'ORM 318 fle/801 NRCM il24V OFFICIAL RECORD COPY J

  • USGPO: 1980-329-824

.. _e Mr:-~ ~. S. Abel cc*

Isham, Lincoln & Beale

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  • c*ounsel ors at Law One First National Plaza1 42nd Floor Chicago, Illinois 60603 Mr. B. B.
  • Stepbenso:ri. -

Pl ant Supertnt*endent

  • o*resden Nuclear Power Station Rura 1 Route #L._

Morris1 Illinoi~ 60450.

Natural Resources Defense Council 917 15th Street,_N. w.

Washington, D. c.

20005

  • --u. s. Nuclear Regulatory Corrmission * * *
  • Re~ident Inspectors Offic~

Dresden Station RR #1 Morris, Illinois 60450 Mary Jo Murray -

Assistant Atiorney General Environmental Control Division

  • l.88 W. Randolph Street Suite 2315 Chicago, Illinois 60601 Morris Public Library 604 Liberty Street*

Morris, Illinois 60451 Chairman Board of Supervisors* of Grundy County Grundy" County Courthouse Morris, Illinois 60450 John F. Wolfe, Esquire 3409 Shepherd Street Chevy Chase, Maryland 20015 Dr *. Linda W~ Little 500 Hermitage Drive Raleigh, Nort.h Carolina 27612

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DRESDEN.2 Docket No. 50..:237

-111 i ncii s Oepart:rn~nt of Nu cl ear Safety.

l03S Outer P~rk:b~iVe, 5th Floor

  • . springf i e, d, 11 i.H1_oi s 62104 * -

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u. ~- Envi*r.~n1'.1_er.i.~h *Protection Agency F~eral Act1v1t1es Branch Regi o,n V Offi.ce. ***,

ATTN:

  • EIS COORDINATOR

~30 South Oe~rborri Street Chicago; Ill.ino~s'. 60604

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Dr.

~orrest J. Remick

.304 East Hamilton Avenue

    • '.Chica.go, I1linois 60604

ENCLOSURE.

TOPIC:. VI-1 o~ B ~ ELECTRICAL,.INSTRUMENTATION AND CONTROL PORTIONS *

  • oF SHARED SYSTEMS I:

INTRODUCTION

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The sharing of 'engineered* safety f~atur~s: systems ( ESF) systems,

  • including on-site emergency power systems, and *service systems for a multiple unit facility can result in a reduction of the number**

and of the capacity of on..:si.te systems to below that which normally is provided for.the same. number of units located at separate sites.

II.

REVIEW CRITERIA The review criteria are presented in Section 2 of EG&G Report Oll7J, "Electrical Inst.rumentation and Control Portions of Shared Systems."

III, RELATED SAFETY TOPICS AND INTERFACES The s~ope of review for this topic was limited to avoid duplication ;

of effort since some aspects of the review were performed under related topics. *Related topics arid the subject matter are identi-fied below.

Each of the related topic reports contain the acceptance criteria and review guida~ce for its subject matter.

VI-7.. A.3 VI-7:C. l VI-7.C.2 VI I-2 VII-3 VI!l,..2 ECCS Actuation -

Independence of Onsite Power Single Failures Isolation of ECCS and Control Systems Safe Shutdown Diesel Generators topics VI-7.C.l ~ VI-7.C.2 and VII-3 are dependent in the present topic information for their completion.

IV.

REVIEW GUIDELINES The review guid~lin~s are presented in Section 2 of Report Oll7J.

  • V.. EVALUATION

.As noted in EG&G Report 0117J,.the Dresden Nuclear Station Unit 2

. is not in-compliance with current licensing requirements with regard to some of the EI&C featur.es of shared systems.. They* include:

l. Single failures could result in the inability to provide power to the required safe shutdown loads upon a loss of offsite power coincident with an accident in Unit 2.

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2.

There are rio physical or electrical interlc::icksiior.LCO

  • .preventing parallel operation of the sh~~ed.125V and 250V DC battery systems.

Such operation, combined with a single failure, would resuJt in a loss..'.pf.

capability to supply atci dent orl'safe -sht.itdow~/'l cads fo 11 owing a loss of offs i te power~

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., *< >*A J. *. Th er~ :are no LCO requirements o.t."1 n.terl eeks preventing

  • the* normal/bypass switches for.'the jDG2/3 from b~ing in 11 byp~ss 11 d~ring o~erat1on"9,f ei'ther unit.*Such,opera~ion, comb med w1 th a s rngl e f~lure, could render the. requ1 red i~cident arid safe shutdow~ lo~ds ihoperable fo1Jowing a loss of offsite power.*
4.

Complete ~nformation of the stat~s of *the shared DC batteries, chargers, ~*nd buses-is not available to operators of each unit..

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5.

The l 25V and 250V*'DC systems are shared, which *is not in compliante with cur~ent licensin~ r~quirements.

6.

Stored energy for DG operation does not meet the seven-day minimum (or time to replenish, whichever is longer) required by current licensing criteria.

7.

The 250V DC battery chargers are.not capable of restoring the battery to its fully-charged coridition from minimum charge conditions during normal-and :oost-accident. steady state loads.

VI.

CONCLUSIONS The Dresden 2 dcsys'tems should be-modified to prevent parallel operation of de batteries, The Technical Specificati6n Change with regard to DG2/3 bypass switch should be completed as soon as possible.

The battery status indication should be modified as outlined in SEP Topic VIII-3.B.

Additional onsite fuel oil storage should be provided.

The 250V battery charger capacity should be increased.

The loss of power to valve 2-1303-3 is not a safety problem for safe shutdown because it can be operated manually.

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The partial loss of shutdown cooling capacity will not orevent safe shutdown.

Although the present level* of* sharing of l25V ~rid 2sov de systems is not*in agreement with current criteria (and is prohibited by the recommendations of NUREG-0666); the staff is postponing a decision.of the safety impact of thi~ issue until we tomplete

  • topics VI-7.C.l and VII~3 for Dresden'U~it 2.

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