ML17194A623
| ML17194A623 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/22/1982 |
| From: | Oconnor P Office of Nuclear Reactor Regulation |
| To: | Delgeorge L COMMONWEALTH EDISON CO. |
| References | |
| TASK-06-07.C1, TASK-06-10.B, TASK-07-03, TASK-6-10.B, TASK-6-7.C1, TASK-7-3, TASK-RR NUDOCS 8204260099 | |
| Download: ML17194A623 (6) | |
Text
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Docket No. 50-237 uosr2-oflS
) Mr. L. DelG~orge Dh*ctor of Nuclear L 1cens1ng Commonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690 Dear\\
2~. DelGeorge:
April 22, 1982 A
- ~*
SUBJECT:
SEP TOPIC VI-10.B, ELECTRICAL, INSTRUMENTATION AND~ONTROL PORTIONS OF SHARED SYSTEMS {DRESDEN 2 NUCLEAR GENERATING STATION)
The. enclosed staff safety evaluation is a revision of a repof~ forwarded by D *. M. Crutchfield's letter of July 7, 1981.
The report has been revised to reflect addi tiona 1 information developed during our review.
of your ventilation systems and completion of Topics VI-7.C.1 and VII-3.
We continue to recommend modifications to several plant systems and the Technical Specifications.
We also recommend additional analyses of electrical load distribution and diesel generator loading and modifica-tion of the divisional assignments for some ;l)~hared *systems.
The need to actually implement these changes will be determined2,1luring 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 completed.
Enclosure:
As stated cc w/enclosure:
- See n~xt page Sincerely, Paul O'Connor, Project Manager Oper~ting Reactors Branch No. 5 Division of Licensing A.tbi:Y.1. ~
pSti ().SI. t'f{i/,)
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. NRCFORM316(10-sO)NRCM0240 OFFICIAL RECORD COPY USGP0:1981-335-960
Docket No. 50-237 LS05-82 Mr. L. DelGeorge Director of Nuclear Licensing Co1TUTJOnwealth Edison Company Post Office Box 767 Chicago, 111fno1s
~0690
Dear Mr. DelGeorge:
~
- 0
SUBJECT:
SEP TOPIC VI-10.B, ELECTRICAL, INSTRUMENTATION AND CONTROL PORTIONS OF SHARED~YSTEMS (DRESDEN 2 NUCLEAR GENERATING STATION)
The enclosed staff safety evaluation is a revision of a report forwarded by fl\\Y* letter of July.7, 1981. The report has been revised to reflect additional 1nfonnat1on developed during our review of your ventilation systems and completion of Topics VI-7. C.1 and VII-3.
We continue to recommend modifications to several plant systems and the Technical Specifications.
We also reconunend additional analyses of-
. electrical load distributfon and diesel generator loadf ng and *modifica-tion of the divisional assignments for some shared systems.
~
The need to actually implement(~ese ~hanges will be determined during the integrated safety assessment. This safety evaluation may be revised 1n the future ff your facility.design is changed or if NRC criteria relating to this topic are modified before the integrated assessment ts completed.
Enclosure:
As stated cc w/enclosure:.
See next page Sincerely, Paul.O'Connor, Project Manager Operating Reactors Branch No. 5 Qfvision of Licensing OFFICE...
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NRC FOAM 318 (10-80) l\\IACM 0240 OFFICIAL RECORD COPY USGPO: 1981-335-960
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Mr. L. DelGeorge cc Isham, Lincoln & Beale..
Illirtois* Departfue~t of Nuclear* Sa-fety..
Coun~elors at Law~-
1035 Outer Park Drive, 5th Floo~ *
- one First Nati.onaLPlaza, 42nd Floor Springfield, Illinois 62704..
- ~ :... _.. <:.
Chi ca go, 111 i noi s 6_Q60_3
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- _ u ~ ~*s. Env~~~n~~~ia; *--~~b*~~~~~:j~~; ~~~~-cy:*:' *_. ~ :-.
Mr. Doug.Scott ___
Federal-.Activit:ies... Branch--:-:c~ **-.~-::--~-:::.
Plant.Superintenden:t--:: : ~-* *... *_
- :_ 7- :~Region :v OffiCe ".: *-_--* " * -- --~
... ~: - * - * -
Dresden Nuclear Power Station * -- -
- 'ATTN: - Regional Radiati.on Representative Rural Route #1.
.... 230 South.
Dearborn-Street --**.. -".*:
Morri~.- Iliinois 6*0450*. *
- Ch1cago; Ill!noi:s_:~q6o4~<----* --~, - ***-.-
- The.Honorable Tom Corcoran _ _
United States Hous~ of Represent.atives.
Washington, D. c.
20515 * *
- u *. s. Nuclear Regulatory Commission Resident Inspectors Office
- Mary Jo Murray Assistant Attorney General Environmental Control Division~-
188 W. Randolph Street
- Suite 2315 Chicago, Illinois -:60601..
Chairman Board of Supervisors of
.:.Grundy County Grunay*tounty Courthouse Morris, Illinois 60450 John F. Wolf, Esquire
- 3409.Shepherd Street Chevy Chase, Maryland 20015 Dr. Linda W. Little 500 Hennitage Drive Raleigh, North Carolina 27612 Judge Forrest J. Remick
.The Carriage House - Apartment 205 2201 L Street, N. W.
Washington, o. c.
20037
. James _G.*Keppl_er; -~egiona1 *:Administrator-:
- Nli'clear Regulatory Commission,. Region III 799 Roosevelt Street Glen Ellyn, Illino.is,601_37 4
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e SYSTEMATIC EVALUATION PROGRAM **
TOPIC VI-10.B DRESDEN 2*
TOPIC::.VI-10.B~ ELECTRICAL~ INSTRUMENTATION AND:CONTROt PORTIONS OF SHARED SYSTEMS I.
INTRODUCTION*
- - *=.. *-
The sharing of engineered :-safety features *.*systems": (ESF).- systems,: irtc;l udi ng 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~site *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.0117J,
'.'Electrical Instrumentation and Control Portions of Shared Systems."
I I I.
RELATED SAFETY TOPICS AND INTERFACES The scope of review fo~ thi~ topic was limited to avoid duplication of effort since some aspects of the review-were_performed*under..related:
t6pics.
Related~topics and the subject_matter are identified bel6w~'.
- Each of the,related topic reports contain the acceptance*criteria and review guidance for its subject matter.
- =
VI-7.A~.3_-
ECCS Actuation VI-7.C.l
.Independe~ce of Onsite.Power,
~ VI-7~C.2 Single *Fai'lures VII-2 Isolation of ECCS and Control Systems VI I-.3 Safe Shutdown VIII-2 Diesel Generators Topics VI-7.C~J, VI-7.C.2 and VII-3 are dependent in the present topic information for their completion.
IV.
.REVIEW GUIDELINES The re~tew guidelines are presented in Section 2 of Repo~t Oll7J.
V.
EVALUATION As rioted 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 features of shared systems.
They include:
- 1.
Si'ngle failures could result in the inability to provide power to the requtred safe shutdown loads upon a loss.. of offsite power coincident with an accident in Unit 2.
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. 2. There are no physical or electrical interlocks or LCQ preventing parallel operation of the shared 125V and 250V DC battery systems.
Such operation, combined with a single failure, would resuit in a loss ~f capability to supply accident or safe shutdown* loads following.
- 3.
There are no LCO requirements or interlocks preventing the normal/
bypass switches for the DG2/3 from being in ~'bypass".during *operation of either*: unit< Such *operation, c_ombined with a single -failure,
-*. *could render the required accident and safe sh~tdown load~ inoperable
.~--~-_following a loss of offsite power.
- 4.
Complete information of the status of the shared DC batteries, chargers and.buses is not available to operators of each unit.
- 5.
- The l 25V-ahCI 250V_ QC. systems* are sh*ared~ whic~ is no~ Jri compliance w*ith current* 1 i~ensing requirements. * =
- 6.
Stored energy for DG operation does not meet the sevef1 *day mfnimum.. bt:
time to replenish, which ever is longer) required by currentlicensing criteria~.
- 7.
The 2SOV DC battery; chargers are not capable of *restoring the ba.ttery to its fully-charged conditi-on from minimum:charge.conditions during normal and post_-aGc.ident steady state loads.
In additton to th.e work: done by EGtcG, a second contractor (Franklin Rese*
Lab-oratories l has in_fonned us that at least one snared ~engineered safety feature (ESFI -i's powered from diesel generator. 2/3.
F-r~m.Fra.nkltn'*s :review.o-f the ventilation-systems,* ~it was deterrriined tha.~
. part of one_ standby* Gas Treatnienu System (SBGTS) is powered from Bus 28-
- (Untt 21 and. di"esel 2/3, >
.*The other SBGTS is powered from diesel 3 in Unit 3, If there is a LOCA Uni"t 3 and offsite power.i's lost and dtesel generator 3 fai"ls, both SBGl' will fail. (oecause diesel 2/3 will swing to Unit 3).
The staff i's concerned that similar problems may exl:st wtth the shared cooling systems, The staff does not have *suffktent, current drawings of Untts 2 and 3 shared systems to resolve thi*s :oncern.
VI, "'CONCtUS!-ONS.
Tt'ie Dresden 2 DC.systell\\S should be modified to prevent parallel operation*
of DC fiattertes, The Techntcal Spectfication. C.ha.pge witti regard.to DG2/3 bypass.switch shout~:
be completed as s*oon as~ po~stble.. *.
.. 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 1-o's~ of po\\'.ler to valve 2-1303-3 is not a safety.problem for.-*safe shut-
- -~ ~ _* - down because_ it __ can be operated manually.__
~:- _ * * -_
0 The partial loss.of shutdown cooling capacity will. not prevent safe shut-down.
Although the present level of sharing of 125V and 250V DC systems is not in agreement with current criteria (and is prohibited by the recommendations of NUREG-0666}, thestaff has determined that the design satisfies the single fail tire criterion and is, therefore, acceptable.
The distribution of safety loads assigned to diesel generator 2/3 must be reviewed and revised by the licensee.
The situation that exists with* regard to the SBGTS failing if the* diesel swings to a unit with a failed diesel
- is unacceptable.. *If, as in the case of the SBGTS, it is necessary to mov.e loads to diesel 2 or diesel 3; new diesel generator loading calculations must also be made by the licensee to assure compliance with Regulatory
- Guide 1.9.
The licensee should complete the-load distribution and diesel generator loadfog reviews within 60 days and submit the results and supporting electrical schematics for ~taff review.