ML20140E090
| ML20140E090 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/09/1997 |
| From: | Dromerick A NRC (Affiliation Not Assigned) |
| To: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| References | |
| TAC-M97855, TAC-M97856, NUDOCS 9706110234 | |
| Download: ML20140E090 (5) | |
Text
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Mr. Charles H. Cruse June 9,1997
. Vice President - Nuclear Energy
- Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - PROPOSED TECHNICAL CHANGES TO REACTOR COOLANT SYSTEM FLOW LIMIT REGARDING REACTOR SYSTEMS, l
CALVERT CLIFFS NUCLEAR POWER PLANT - UNIT NOS. 1 AND 2 (TAC NOS. M97855 AND M97856)
Dear Mr. Cruse:
l The NRC staff has reviewed your submittals of January 31, 1997, and April 16, i
1997, regarding changes to the reactor system flow limit amendment related to reactor systems.
Based on our review, we have determined that additional information is required for us to complete our review. The information 4
requested is addressed in the enclosure.
In order to meet your schedule, the staff requests that the additional information be provided by June 21, 1997.
i If you have any questions regarding this letter, please contact me at (301) 415-3473.
i Sincerely, I
ORIGINAL SIGNED BY:
Alexander W. Dromerick, Sr. Project Manager Project Directorate I-1 i
Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-317 i
and 50-318 i
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Enclosure:
Request for Additional Information 1
cc w/ encl:
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June 9,1997 Mr. Charles H. Cruse Vice President - Nuclear Energy Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - PROPOSED TECHNICAL CHANGES TO REACTOR COOLANT SYSTEM FLOW LIMIT REGARDING REACTOR SYSTEMS, CALVERT CLIFFS NUCIEAR POWER PLANT - UNIT NOS. 1 AND 2 (TAC NOS. M97863 AND M97856)
Dear Mr. Cruse:
The NRC staff has reviewed your submittals of January 31, 1997, and April 16, 1997, regarding changes to the reactor system flow limit amendment related to reactor systems.
Based on our review, we have determined that additional information is required for us to complete our review. The information requested is addressed in the enclosure.
)
In order to meet your schedule, the staff requests that the additional information be provided by June 21, 1997.
)
j If you have any questions regarding this letter, please contact me at (301) 415-3473.
Sincerely, Alexan er W. Dromerick, Sr. Project Manager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318
Enclosure:
Request for Additional Information cc w/ encl:
See next page i
I 1
Mr. Charles H. Cruse Calvert Cliffs Nuclear Po~ er Plant w
t Baltimore Gas & Electric Company Unit Nos. I and 2 cc:
4 President Mr. Joseph H. Walter, Chief Engineer Calvert County Board of Public Service Commission of Commissioners Maryland 175 Main Street Engineering Division Prince Frederick, MD 20678 6 St. Paul Centre Baltimore, MD 21202-6806 James P. Bennett, Esquire Counsel Kristen A. Burger, Esquire Baltimore Gas and Electric Company Maryland People's Counsel P.O. Box 1475 6 St. Paul Centre Baltimore, MD 21203 Suite 2102 Baltimore, MD 21202-1631 Jay E. Silberg, Esquire 4
Shaw, Pittman, Potts, and Trowbridge Patricia T. Birnie, Esquire 2300 N Street, NW Co-Director Washington, DC 20037 Maryland Safe Energy Coalition P.O. Box 33111 Mr. Thomas N. Prichett, Director Baltimore, MD 21218 I
i NRM Calvert Cliffs Nuclear Power Plant Mr. Loren F. Donate 11 1650 Calvert Cliffs Parkway NRC Technical Training Center Lus'y, MD 20657-4702 5700 Brainerd Road o
Chattanooga, TN 37411-4017 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. Richard I. McLean Administrator - Radioecology Department of Natural Resources 580 Taylor Avenue Tawes State Office Building, B3 Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406
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REQUEST FOR ADDITIONAL INFORMATION l
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2
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1.
Please provide a basis for the 3-second delay of loss-of-offsite power (LOOP) assumed in the main steamline break (MSLB) analyses described in l
the amendment request. The original submittal identified thtt this assumption represents a change in the Calvert Cliffs licensing basis
~
methodology for this event, i.e. is not justified by Calvert Cliffs licensing precedent. The response to this question included in its April 16, 1997, submittal indicated that BGE knows of no other licensee
~ hose approved MSLB analyses include an assumed delay in LOOP, i.e. the w
assur.ption is not justified by precedent for any plant MSLB licensing analyses. The response also attempted to draw an analogy between the delay allowed for certain CE System 80 plant locked rotor analyses and using this assumption for Calvert Cliffs MSLB analyses. There is sufficient dissimilarity between these two events that we do not find this justification acceptable at this time. Use consistent with the guidance given in Standard Review Plan 15.1.5. is one way to justify the LOOP delay assumption. That guidance states:
Assumptions as to the loss of offsite power and the time of loss should be made to study their effects on the consequences of the accident. A loss of offsite power may occur simultaneously with the pipe break, or during the accident, or offsite power may not be lost. Analyses should be made to determine the most conservative assumption appropriate to the particular plant design.
The analyses should take account of the effect that loss of offsite power has on reactor coolant pump and main feedwater pump trips and on the initiation of auxiliary feedwater flow, and the effects on the sequence of events for these accidents.
Experience would indicate that, if the sensitivity study described in the guidance were performed, a LOOP occurring simultaneously with the pipe break would likely be idtitified as the most conservative assumption for DNB-related cri oria.
As identified in the original submittal, a change in the LOOP assumption (including the means of identifying the worst case) represents a model change. As may be inferred from SRP 15.1.5 guidance, the change could affect all aspects of the model and its calculated scenarios.
Therefore, the entire model, and its performance for all applicable criteria, must be reviewed for approval. Another criterion that must be explicitly addressed in calculations with the model is low temperature overpressure which could occur with primary system cooling, refilling, and repressurization. The methodology must also be used to calculate mass and energy release information to be used in the analyses to address containment conditions and dose criteria for MSLB events.
Enclosure
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i 2.
Several places in the April 16, 1997, submittal indicate that a positive moderator temperature coefficient (MTC) was used in the analyses, and refer to a March 28, 1996, letter (Reference 4) as justification for its use. What MTC value was approved? If so, is the value used in the analyses the same as the one that was approved? If not, what is the licensing status of the analysis value? Is that the reason for Reference 4? Discuss use of the positive MTC in analyses and how a conservative 4
MTC is used for all analyses (including ATWS).
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