ML20149J184

Forwards Request for Addl Info Re 970131 & 0416 Proposed Technical Changes to Reactor Coolant System Flow Limit, Calvert Cliffs Nuclear Power Plant,Units 1 & 2

ML20149J184
Person / Time
Site:	Calvert Cliffs
Issue date:	07/25/1997
From:	Dromerick A NRC (Affiliation Not Assigned)
To:	Cruse C BALTIMORE GAS & ELECTRIC CO.
References
TAC-M97855, TAC-M97856, NUDOCS 9707280103
Download: ML20149J184 (4)

Text

__ _

duly 25, 1997 r

Mr. ' Charles H. Cruse' /

Vice President ~- Nuclear. Energy.

Baltimore Gas and Electric Company:

O Calvert Cliffs NuclearJPower Plant:

11650.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-o ' CLIFFS NUCLEAR POWER PLANT,- UNIT NOS. 1:AND 2 (TAC NOS. M97855 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. This request supplements our request for additional information dated June 9,1997.

1- In order to meet your schedule, the staff requests that the additional information be~provided by August 15, 1997.

4

.If you have'any questions regarding this letter, please contact me~at (301)

415-3473.

i  : Sincerely, 0RIGINAL SIGNED BY:

Alexander W. Dromerick, Senior 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 See next page cc w/ encl:

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..,J f July 25, 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 2065'7-4702 i

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - PROPOSED TECHNICAL CHANGES TO

REACTOR COOLANT SYSTEM FLOW LIMIT REGARDING REACTOR SYSTEMS, CALVERT  !

CLIFFS NUCLEAR POWER. PLANT - UNIT NOS. 1 AND 2 (TAC NOS. M97855 AND M97856) j

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 .

c reactor systems. Based on our review, we have determined that additional t information is required for us to complete our review. The information requested is addressed in the enclosure. This request supplements our request for additional.information dated June 9, 1997.

In. order to meet your schedule,- the staff requests that the additional

information be provided by August 15, 1997.

If you have any. questions regarding this letter, please contact me at (301)

, 415-3473.

" Sincerely, l

Alexander W. Dromerick, Senior Project Manager i 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-l cc w/ enc 1: See next page-J J

d

, r- +-- -- , - --

k Mr. Charles H. Cruse ~ Calvert Cliffs Nuclear Power Plant Baltimore Gas & Electric Company Unit Nos. I and 2' cc:

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 '

Baltin.'re Gas :..id Elcetric Company Maryland People's Counsel

.P.O. Box 3475 6 St. Paul Centre Baltimore, 60 21203 Suite 2102 Baltimore, MD 21202-1631 Jay E. Silberg, Esquire 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 NRM Calvert Cliffs Nuclear Power Plant Mr. Loren F. Donate 11 1650 Calvert Cliffs Parkway NRC Technical Training Center Lusby, MD. 20657-4702 5700 Brainerd Road Chattanooga, TN 37411-4017 Resident Inspector U.S. Nuclear Regulatory Commission i P.O. Box 287 1 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 4

REQUEST FOR ADDITIONAL INFORMATION CALVERT CLIFFS STEAM GENERATOR TUBE PLUGGING LICENSE AMENDMENT REQUEST OF JANUARY 31, 1997 Address concerns associated with reactor coolant pump loop-seal clearing and break orientation, and compliance with the requirements of 10 CFR 50.46(b),

including concerns regarding metal / water reaction, and long-term cooling. A non-proprietary submittal by Framatome Technologies Incorporated (FTI) provided additional information to describe the concern and associated phenomena.

The small-break loss-of-coolant accident (SBLOCA) scenario involving the principal safety concern involves long term cooling conditions in which the break size and orientation would be such that the primary system would not depressurize, limiting the emergency core cooling system injection flow rate to that only capable of matching the core boiloff rate due to decay heat.

Also in this scenario a column of water in the reactor coolant system pump suction loop seal would inhibit the vent path to the break and exert enough additional pressure to the steam space above the core that the level in the core would be depressed below the top of the core. Should this condition  ;

exist as an equilibrium condition, core uncovery would be indefinite, since i the attendant decay heat rate would be small and virtually constant. Under these circumstances, the cladding oxidation criteria of 10 CFR 50.46 could be violated.

To address this concern in the near term, the licensee should provide information to assure that the Calvert Cliffs plants, in their present configurations (including plant design, technical specifications, procedures, analyses) will operate such that the criteria of 10 CFR 50.46 will not be violated for its SBLOCA analyses in consideration of the scenario (s) of concern. To confirm its near term assessment and addrets longer term concerns associated with this SBLOCA scenario, and the capability of this model to quantify the scenario (s) of concern for ongoing operation and future cor. figurations, the licensee should describe its action plan to update its licensing basis SBLOCA model with noding and correlations to explicitly simulate the phenomena for the scenario (s) and plant configurations of concern as required by 10 CFR 50.46.

Information supplied by ABB/CE in support of its forthcoming updated SBLOCA evaluation model (S2M) confirms the potential for the scenario (s) of concern for some plant designs, and addresses, both near term and long term, the

. associated concerns for all designs licensed with the model. This model awaits NRC approval; however, vendor assistance may be available to respond to this question for the model used in the Calvert Cliffs SBLOCA analyses.

Enclosure