ML16162A291
| ML16162A291 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/17/1979 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Parker W DUKE POWER CO. |
| References | |
| NUDOCS 8001030590 | |
| Download: ML16162A291 (8) | |
Text
DISTRIBUTION:
RReid DECEMBER. 1 7 197 NRC POP (3)
ORB#4 PI L PDR RIngram TERA Gray File N1SI C AEOD Dockets Nos.
Rdh RCapr Pocke s No.
r f'RR Rdg DEisenhut RVollmer Gammill, W Mr. William 0. Parker, Jr.
IBGRimes Vice President, Steam Production Duke Power Company JRMiller P. 0. Box 2178 WRussell 422 South Church Street TJCarter Charlotte, North Carolina 28242 OE LD I&E
Dear Mr. Parker:
SUBJECT:
AUTOMATIC REACTOR COOLANT PUMP TRIP DURING SMALL BREAK LOSS-OF COOLANT ACCIDENTS (LOCA)
The long-term requirement of IE Bulletin 79-05C requires the B3W licensees to0 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 shown through analysis that this trip is 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. possi 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 reactor 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 not 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 8&W licensees should proceed with equipment procurement and development of a final design based on the proposed concept.
-2 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 confirmatory 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 information 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 provided. 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. Morton B. Fairtile on (301) 492-7435.
Sincerely, Robert W. Reid, Chief Operating Reactors Br anch #4 Division of Operating Reactors
Enclosure:
Reuest for Additional Information - Automatic RCP Trip cc w/enclosure:
See next page
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NUCLEAR REGULATORY COMMISSION 00
.WASHINGTON, D. C. 20555 December 18, 1979 Docket No. 50-312 Mr. J. J. Mattimoe Assistant General Manager and Chief Engineer Sacramento Municipal Utility District 6201 S Street P. 0. Box 15830 Sacramento, California 95813 Dear Mr. Mattimoe
SUBJECT:
AUTOMATIC REACTOR COOLANT PUMP TRIP DURING SMALL BREAK LOSS-OF COOLANT ACCIDENTS (LOCA)
The long-tenn 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 shown through analysis that this trip is 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 possi 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 reactor 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 not 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.
-2 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 confirmatory 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 information 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 provided. 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.
Sincerely, Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors
Enclosure:
Reuest for Additional Information - Automatic RCP Trip cc w/enclosure:
See next page
P Christopher Ellison, Esq David S. Kaplan, Secretary and Dian Grueuich, Esq GeneralCounselCalifornia Energy tonmmissiO General Counsel 11 oeAeu 6201 S Street Ho anue P. 0. Box 15830 Sacramento, California 95813 Sacramento CountyCalifornia State Office Bardmeof S uvior 600 Pennsylvania Avenue, S.E., 1n. 201 Board of Supervisors 827 7th Street, Room 424
-Washington, D.C.
20003 Sacramento, California 95814 Docketing and Service Section Thomas A. Baxter, Esq.
office of the Secretary Shaw, Pittman, Potts & Trowbridge U. S. N r555 1800 M Street, N.W.
- Washngto, DC. 2036Michael L. Glaser, Esq.
Washington, D.C. 20036 Director, Technical Assessment 15 h tr,.20 Division Office of Radiation Programs Dr. Richard F. Cole (AW-459)
Atomic Safety and Licensing Board U. S. Environmental Protection Agency Panel Crystal Mall #2 Aryltn Virini 2046 U. S. Nuclear Regulatory Commnission Arlington, Virginia 2046020555 U. S. Environmental Protection Agency Mr. Frederick J. Shon
-Region IX Office Atomic Safety and Licensing Board ATTN:
EIS COORDINATOR Panel 215 Fremont Street San Francisco, California 94111 W. S. N ryC s
Mr. Robert B. Borsum Timothy V. A. Dillon, Esq.
Babcock & Wilcox Suite 380 NUclear Power Generation Division 1850 K Street, N.W.
suite 420, 7735 Old Georgetown Road r£nthesda, Maryland 20014 James S. Reed, Esq.
Michael H. Remy, Esq.
Reed, Samuel S Remy
-717 K Street, Suite 405 Sacramento, California 95814 Herbert H. Brown, Esq.
Mr. Michael R. Eaton Lawrence Coe Lanpher, Esq.
Energy Issues Coordinator H4-i!-, Christopher and PhilliCps, P. C.
Sierra Club Legislative Office 1900 M St., NW 1107 9th St., Room 1020 Washington, D. C. 20036 Sacramento, CA 95814
Sacramento mcipal Utility District Atomic Safety and Licensing Board Panel U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Atomic Safety and'Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Mr. Richard D. Castro 2231 K Street Sacramento, California 95814 Mr. Gary Hursh, Esq.
520 Capital Mall Suite 700 Sacramento, California 95814 California Department of Health ATTN:
Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814
Enclosure
-ADDITIONAL INFORMATION REQUIRED 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 following questions:
- 1. For your proposed design, state the degree of conformance with the applicable acceptance criteria listed in Column 7.2 of Table 7-1 of the Standard Review Plan. Also, provide justification for any non conformance.
- 2. Provide a discussion of the following:
- a. conformance of the design with the design requirements of Section 4 of IEEE Std...279.1971; and,
- b. conformance 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:
- a. equipment design specification requirements;
- b. test plan;
- c. test setup;
- d. test procedures; and,
- e. acceptability goals and requirenents.
-2 ADDITIONAL INFORMATION REQUIRED FCR AUTOM'!I-TRIP CIRCUITRY FOR THE REACTOR COOLANT PL' ? MOTORS (COrTI UED)
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 subrittal.