ML19257A441
| ML19257A441 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/18/1979 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Roe L TOLEDO EDISON CO. |
| References | |
| IEB-79-05C, IEB-79-5C, NUDOCS 8001040295 | |
| Download: ML19257A441 (5) | |
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December 18, 1979 j
Docket No. 50-346 Mr. Lowell E. Roe Vice President, Facilities Devel opment Toledo Edison Company Edison Plaza 300 Madison Avenue Toledo, Ohio 43652
Dear Mr. Roe:
SUBJECT:
AUTOMATIC REACTOR COOLANT PUPP TRIP DURING SMALL BREAK LOSS-OF-COOLANT ACCIDENTS (LOCA)
The long-term requirement of IE Bulletin 79-05C requires the B&W licensees to submit a design which will assure automatic tripping of the operating reactor coolant pumps (RCPs) under all circumstances in which this action may be needed. -It-has been showirthrough analysis that this t"rfp 1s needed for a certain spectrum of small break LOCAs.
In order to assure that the operating RCPs are tripped during LOCA conditions yet minimize the pcssi-bility of tripping the RCPs during non-LOCA transients (such as severe overcooling events), the B&W licensees have proposed a conceptual safety-grade trip circuit which would utilize coincident input signals of low pressure ESFAS actuation combined with low RCP current / power.
The use of these coincident signals was discussed in detail during a meeting held in Bethesda, Maryland on November 8,1979, between the staff, the B&W Owners' Group and B&W. The staff expressed two concerns with the proposed design.
First, while the staff agrees that a decrease in RCP current / power will occur if voiding takes place in the reacter coolant system, the relationship of RCP current / power versus void fraction has neither been fully documented by the licensees nor demonstrated through full scale testing.
Secondly, absent the above information, the staff is nct convinced that the proposed setpoint of 20% decrease in RCP current is the proper setpoint for that portion of the coincidence logic.
Although these matters must be resolved as part of the final design acceptance, we believe that the proposed design contains sufficient flexibility and can be expected to meet its intended function. Therefore, the B&W licensees should proceed with equipment procurement and development of a final design based on the proposed concept.
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. Prior to final design acceptability, the following conditions must be satisfied:
1.
Characteristic curves for RCP current / power versus void fraction must be fully demonstrated and documented based upon existing test data and supplemented as necessary with confinnatory data obtained from future tests such as LOFT, full scale testing, etc. ;
2.
Justification for the RCP current / power setpoint must be shown; and, 3.
Satisfactory responses to the enclosed request for additional infor.aation must be received.
It is requested that within 30 days of receipt of this letter, licensees shall provide a schedule for responding to items 1 through 3 above.
In addition, a proposed schedule for installing the automatic RCP trip circuitry shall also be p rovi ded. Your installation schedule should include the expected reactor down time associated with the final hookup and testing of this circuitry.
If any additional information is needed, please contact your NRR Operating Reactor Project Manager, Mr. Daniel Garner on (301) 492-7435.
Si ncerely,
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a Robert W. Reid, Chief Operating Reactors Branch #4 Divisior of Operating Reactors
Enclosure:
Reuest for Additional Information - Automatic RCP Trip cc w/ enclosure:
See next page 1684 134
Toledo Edison Company cc w/ enclosure (s):
Mr. Donald H. Hauser, Esq.
Director, Technical Assessment The Cleveland Electric Division Illuminating Company Office of Radiation Programs P. O. Box 5000 (AW-459)
Cleveland, Ohio 44101 U. 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.
20036 Region V Office ATTN:
EIS CCORDINATOR Leslie Henry, Esq.
230 South Cearborn Street Fuller, Seney, Henry and Hodge Chicago, Illinois 60604 -
300 Madison Avenue Toledo, Ohio 43604 Mr. Robert B. Borsum Babcock & Wilcox Ohio Department of Health Nuclear Power Generation Division ATTN:
Director of Health Suite 420, 7735 Old Georgetown Road 450 East Town Street Bethesda, Maryland 20014 Columbus, Ohio 43216
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g-President, Board of County
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Ccanissioners of Ottawa County Port Clinton, Ohio 43452 Attorney General Department of Attorney 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
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Industrial Commission State of Ohio 2323 9est 5th Avenue Columbus, Ohio 43216 Mr. Tec Myers Licensing Engineer Toledo Edison Cemcany Edison Olaza j 6 8 4
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3C0 Madison Avenue Toisda, Ohio a3652
Enclosure ADDITIONAL INFORMATION REOUIRED FOR AUTOMATIC TRIP CIRCUITRY FOR THE REACTOR COOLANT PUMP MOTORS We have reviewed the preliminary design descriptions of the automatic ~
trip circuitry for the subject motors which have been provided by the B&W plant licensees. Since it has been concluded that this action is required to perform a safety function, the added circuitry should conform to specified safety criteria.
When submitting the proposed final design for the automatic trip circuitry, provide responses to the follcwing. questions:
1.
For your proposed design, state the degree of confonnance with the applicable acceptance criteria listed in Column 7.2 of Table 7-1 of the Standard Raview Plan. Also, provide justification for any non-conformance.
2.
Provide a discussion of the following:
conformance of the design with the design requirements of Section 4 a.
of IEEE Std. 279-19711 and, b.
confomance of the design with the principal design criteria of Section 4 of IEEE Std. 308-1974.
3.
Provide a detailed description of any changes to and/or interfaces; with the existing protection systems.
Include diagrams (block, location, functional, and/or elementary wiring), as necessary, to clearly depict the changes and/or interfaces.
In addition, provide an analysis which demonstrates that these changes and/or interfaces will not degrade the existing protection systems.
4 Identify equipment which is identical to equipment utilized in existing safety-grade systems.
For the equipment which is not identical, briefly describe the differences.
5.
In general, the equipment shall be seismically and environmentally qualified.
Therefore, provide the following descriptive information for the qualification test programs:
equipment cesign specification requirements; a.
b.
test plan; c.
test setup; d.
test precedures; and, accepta:ility goals and requirements.
e.
1684 136
2 ADDITIONAL INFORMATION REQUIRED FOR AUTOMATIC TRIP CIRCUITRY FOR THE REACTOR COOLANT PUMP MOTORS (CONTINUED)
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When submitting your final design for approval, if all of the above information is not available, provide a schedule for its submittal.
6.
Provide the criteria for the overall trip circuitry installation testing which will demonstrate that this circuitry has been installed properly.
When submitting your final design for approval, if this information is not available, provide a schedule for its submittal.
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