ML17194A116
| ML17194A116 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/26/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Delgeorge L COMMONWEALTH EDISON CO. |
| References | |
| TASK-07-06, TASK-7-6, TASK-RR LSO5-81-08-060, LSO5-81-8-60, NUDOCS 8109030073 | |
| Download: ML17194A116 (4) | |
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Docket No. 50-237 LS05 08-060
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Mr. L. DelGeorge Director of Nuclear Licensing Cormnonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690
Dear Mr. DelGeorge:
August 26, 1981
SUBJECT:
SEP TOPIC VII-6, FREQUENCY DECAY SAFETY EVALUATION FOR DRESDEN 2 The enclosed Slaff safety evaluation is based on a contractor document that has been made available to you previously. This evaluation is the staff's position regarding design of your facility in the subject area.
With regard to the referenced toptc, the staff has concluded that your facility meets current licensing criteria.
Enclosure:
As stated cc w/enclosure:
See next page Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
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Mr. L. De1George cc Isham~ Lincoln & Beale Counselors at law One First National Plaza, 42nd Floor*
Chicago, Illinois 60603 Mr. B. B. Stephenson
- Plant Superintendent Dresden Nuclear Power Station Rural Route #1 Morris, Illinois 60450 Natural Resources Defense Council 917 15th Street, N. w.
Wa~hington, o. c *. 20005 U. S. Nuclear Regulatory Connnission Resident Inspectors Office Dresden Station RR #1 Morris, Illinois 60450 Mary Jo Murray..
Assistant Attorney General Environmental Control Division 188 W. Randolph.Street Suite 2315 Chicago, Illinois 60601 Morris Public Library 604 Liberty Street Morris, Illinois 60451 Chairman Board of Supervisors of Grunqy County Grunqy County Courthouse Morris, Illinois 60450' John F. Wolf, Esquire 3409 Shepherd Street Chevy Chase, Maryl and 20015 Dr~ Linda Ww little 500 Hermitage Drive
. _Raleigh, North Carolina 27612
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DRESDEN 2*
Docket No. 50-237 Illinois Department of Nuclear Safety 1035 Outer Park Drive, 5th Floor Springfield, Illinois 62704 U *. S. Environmental Protection Agency Federal Activities Branch
. Region V Office ATTN:
EIS COORDINATOR 230 South Dearborn Street Chicago, Illinois 60604 Dr. Forrest J. Remick 305 East Hamilton Avenue State College, Pennsylvania 16801 The Honorable Tom Corcoran United States House of Representatives Washington, D. c.
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SYSTEMATIC EVALUATION PROGRAM TOPIC VII-6 DRESDEN.2 TOPIC VII-6 FREQUENCY DECAY
. I. Introduction*
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Issue 9 of NOREG-0138 states that.the staff should req~ire that a post-ulated rapid decay of the* *frequency of the offsite power system be included in the accident analysis and that the r~sults be demonstrated to be acceptable. Altetnatively, the reactor coblant pump (RCP) circutt breakers should be designed to protection system criteria and tripped to separate.the pump motors from the offsite power system because rapid decay of the frequency of offsite*power system has the potential for slowing down or braking the RCP thereby reducing the coolant f1ow rates to l~vels not considered in previotis analysts.**.~
. II. Review Criteria
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The review criteria for reactor trip systems are: presented in Table 7-1 of the Standard Review Plan.
- III; Related Safety Tooics and Interfaces*
Set Poirits (topic VII-1,A) and Degraded Gri~ (Topic VIII-1.A) are relat-ed review areas that are outside the.scope of thjs Topic *
. Although Topic VIII-1.A is not dependent o.n *the present topic for comp-letion, the concl~sions with regard to frequency decay should be compat-ab le.
IV.
Review Guidelines Issue 9 of NUREG-0138, "Staff Discussion Of Fifteen Technical *issues Usted in Attachment to November 3, 1976 Memorandum from Di~ector, NRR to NRR Staff," provides suitable guidance for this review.
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Eva1uation
- Oak Ridge National Laboratory (ORNL), under a technical assistance program, reviewed the frequency decay rate phenohitna and its effects on RCP's.
The results of the review are presented in Section 4 of NUREG CR 1464, "Review of Nuclear Power Plant Offsite Power *source Reliability and Related Recom-mended Changes to the NRC Rules and Regulations.~' In surrmary, the report**
_shows that the conditions required for dynamic b~aking:of reactor cool*nt ~~*
pumps are a sustained and rapid decrease in frequency \\1hile maintaining bu~ voltage. These conditions are only realized in a bighly capacitive
.. *.. ---~ystern. using large amounts of buri_ed transmission cab_les.J~uch_as. Lqng __ '**
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The Commonwealth Edison system dbes not use large amounts of buried transmissi6n cable.
VI.
- Conclusion The conditions necessary for an unacceptable frefjuency decay rate are not present in the Dresden 2 offsite electrital ijistribution syst~m.
Accordingly, the. staff c6nsider~ this issue not to be applicable to Dresden 2.
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