ML19257B416

Forwards Safety Evaluation Re Preliminary Design for safety- Grade Anticipatory Reactor Trips on Loss of Main Feedwater &/Or Main Turbine Generator

ML19257B416
Person / Time
Site:	Davis Besse
Issue date:	12/20/1979
From:	Reid R Office of Nuclear Reactor Regulation
To:	Roe L TOLEDO EDISON CO.
References
TASK-2.K.2.10, TASK-TM TAC-45184, TAC-45188, NUDOCS 8001160039
Download: ML19257B416 (2)

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• M December 20, 1979 Docket No. 50-346 Mr. Lowell E. Roe Vice President, Facilities Development Toledo Edison Company Edison Plaza 300 Madison Avenue Toledo, Ohio 43652

SUBJECT:

PRELIMINARY DESIGN APPROVAL FOR THE SAFETY-GRADE ANTICIPATORY REACTOR TRIP SYSTEM (ARTS)

We have reviewed your submittals of May 21 and October 3,1979, in which you forwarded a preliminary design for upgrading the present control-grade anticipatory reactor trip system (ARTS) for loss of main feedwater and turbine trip to safety-grade.

A copy of the staff safety evaluation approv-ing your preliminary design is included as an enclosure to this letter.

As summarized on Attachment 1 to this safety evaluation, additional infor-mation will need to be submitted prior to final design approval by the staff.

Therefore, assure that this information is submitted for review in sufficient time to allow staff review prior to system operation.

If you have any questions regarding this matter, please contact your NRR Operating Reactor Project Manager, Mr. Daniel Garner, on (301) 492-7435.

Sincerely, m

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Robert W. Reid, Chief Operating Reactors Branch '4 Division of Operating Reactors

Enclosure:

Safety Evaluation cc: w/ enclosure l[bb 2bb' See next page 8 001160 Q3$

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Toledo Edison Company cc w/ enclosure (s):

Mr. Donald H. Hauser, Esq.

Cirector, Technical Assessrent The Cleveland Electric Division Illuminating Company Cffice of Radiation Prograr.s P. O. Box 5000

( AW-459)

Cleveland, Ohio 44101 C. S. Environmental Protection Agency Crystal Mall #2 Gerald Charnoff, Esq.

Arlington, Virginia 20460 Shaw, Pittman, Potts and Trowbridge U. S. Environmental Protection Agency 1800 M Street, N.W.

Federal Activities Branch Washington, D.C.

20335 P.egion V Office A TH:

EIS COORDINATOR Leslie Henry, Esq.

230 South Dearborn Street Fuller, Seney, Henry and Hodge -

Cnicago, Illinois 60604 300 Madison Avenue Toledo, Ohio 43634 Mr. Robert B. Borsum Babcock & Wilcox Chio Der'rtment of Health Nuclear Power Generation Division ATTH:

U1 rector of Health Suite 420, 7735 Old 3eargetown Road 450 East Town Street Bethesda, Marylanc 20014 Columbus, Ohio 43216 Ida Rupp Public Library 310 Madison Street Port Clinton,0hio 43452 President, Board of County Commissioners of Cttawa County Port Clinton, 0 hic 43452 Attorney General Department of Atterr.ey General 30 East Broad Street Columbus, Ohio 43215 Harold Kahn, Staff Scientist Power Siting Commission 361 East Broad Street Columbus, Ohio 43216 Mr. Rick Jagger Industrial Commissicn State of Ohio 2323 est 5:n averus Colurtus, Ohio 422: 9 "r

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'% V SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION EVALUAITON OF PRELIMINARY DESIGN FOR SAFETY GRADE ANTICIPATORY REACTOR TRIPS (ARTS) ON LOSS OF MAIN FEEDWATER AND/0R MAIN TURBINE GENERATOR FOR DAVIS-BESSE, UNIT NO. 1 DOCKET NO. 50-346 I Background Following the accident at Three Mile Island, Unit No. 2, an assessment of feedwater transients in the Babcock & Wilcox (B&W) designed pressurized water reactors was performed.

The results of that review were reported in NUREG-0560.

This report highlighted a concern regarding the challange rate to the power-operated relief valve (PORV) in the B&W design.

In response to I&E Bulletin 79-05B, Toledo Edison Company (TECO or licensee) lowered the existing setpoint for the high pressure reactor trip and raised the setpoint of the PORV.

By inverting these setpoints the challenge rate to the PORV opening, and thus the likelihood of it not reseating following actuation was reduced.

To provide additional margin to the automatic opening setpoi.t of the PORV, the licensee proposed design provisions for direct reactor trip on loss of main feedwater or turbine trip.

This design modification was incorporated as part of the short-term and long-term requirerents of the Comissions' May 16, 1979 Confinnatory Shutdown Order.

In order to achieve a timely implementation of this modification, it was determined that a control-grade design was sufficient for the short-term.

This was implemented by the licensee by installing hardwired, control-grade trips for loss of main feedwater and turbine trip which were independent of the reactor protection system (RPS).

For the long-term, an upgrading of this system to safety-grade is required.

The licensee submitted its proposed safety-grade design in a letter dated May 21, 1979, from J. S. Grant (TECO) to J. G. Keppler (NRC) and later supplemented the design in a letter dated October 3,1979, from L. E. Roe (TECO) to R. W. Reid (NRC).

The following evaluation addres = + M

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b preliminary design of. the Antic Davis-Besse, Unit'No. 1.

DUPLICATE DOCUMENT Entire document previously entered into system under:

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