ML20217K096

Forwards RAI Re RCS Flow Requirements to Allow Increased SG Tube Plugging.In Order to Expedite Staff Review,Response Requested by 980415

ML20217K096
Person / Time
Site:	Calvert Cliffs
Issue date:	03/30/1998
From:	Dromerick A NRC (Affiliation Not Assigned)
To:	Cruse C BALTIMORE GAS & ELECTRIC CO.
References
TAC-M97855, TAC-M97856, NUDOCS 9804070116
Download: ML20217K096 (5)

Text

. Mr. Charles H. Cruse Vice Prssident - Nuclair Energy March 30, 1998 B:ltimore Gts cnd Electric Comp:ny Calvert Clins Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - LICENSE AMENDMENT REQUEST CHANGE TO REACTOR COOLANT SYSTEM FLOW REQUIREMENTS TO ALLOW {

INCREASED STEAM GENERATOR TUBE PLUGGING (TAC NOS. M97855 AND l M97856)

Dear Mr. Cruse:

. By letter dated March 25,1997, and Jandary 22,1998, you provided information regarding your license amendment request regarding reactor coolant system flow requirements to allow increased steam generator tube plugging. The NRC staff has reviewed the information and has determined that additional information is required for us to complete our review. The information required is addressed in the enclosure.

In order to expedite our review, we request that you provide the information by April 15,1998. If you have any questions, please contact me at (301) 415-3473.

Sincerely, GRIGINAL SIGNED BY:

1 Alexander W. Dromerick, Senior Project Manager Project Directorate 1-1 Division of Reactor Projects 1/ll Office of Nuclear Reactor Megui. Son Docket Nos. 50-317 and 50-318 i

Enclosure:

Request for Additional Informstion cc w/ encl: See next page DISTRIBUTION:

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\,q,,,+/ March 30, 1998 Mr. Charles H. Cruse Vice President- Nuclear Energy Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20857-4702

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - LICENSE AMENDMENT REQUEST CHANGE TO REACTOR COOLANT SYSTEM FLOW REQUIREMENTS TO ALLOW l INCREASED STEAM GENERATOR TUBE PLUGGING (TAC NOS. M97855 AND M97856)

Dear Mr. Cruse:

By letter dated March 25,1997, and January 22,1998, you provided information regarding your license amendment request regarding reactor coolant system flow requirements to allow increased steam generator tube plugging. The NRC staff has reviewed the information and has determined that additionalinformation is required for us to complete our review. The infortnation required is addressed in the enclosuse.

In order to expedite our review, we request that you provide the information by April 15,1998. If you have any questions, please contact me at (301) 415-3473.

Sincerely,

. Alexa der W. Dromerick, Senior Project Manager Project Directorate 1-1 Division of Reactor Projects 1/II Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50 318

Enclosure:

Request for Additional information I

cc w/ encl: See next page j I

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Mr. Charles H. Cruse -

Baltimore Gas & Electric Company Calvert Cliffs Nuclear Power Plant cc:

President Mr. Joseph H. Walter, Chief Engineer l Calvert County Board of Public Service Commission of Commissioners Maryland 175 Main Street Engineering Division

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Prince Frederick, MD 20678 6 St. Paul Centre Baltimore, MD 21202-6806

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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 l

Shaw, Pittman, Potts, and Trowbridge Patricia T. Bimie, Esquire 1 2300 N Street, NW Co-Director Washington, DC 20037 Maryland Safe Energy Coalition P.O. Box 33111 Mr. Thomas N. Pritchett, Director Baltimore, MD 21218 NRM Calvert Cliffs Nuclear Power Plant Mr. Loren F. Donatell 1650 Calvert Cliffs Parkway NRC TechnicalTraining Center Lusby, MD 20657-4702 5700 Brainerd Road Chattanooga, TN 37411-4017 Resident inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. Richard I. McLean, Manager Nuc' ear Programs Power Plant Research Program Maryland Dept. of Natural Resources 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 CALVERT CLIFFS NUCLEAR POWER P' ANT Main Steam Line Break Accident (MSLB)

The manner in which radioactivity is released during the course of this accident is as follows.

The accident occurs concunent with a loss of offsite power. The steam generator which experiences the steam line break (the affected or faulted steam generator) is assumed to release the entire contents of that steam generator when the steam line breaks. In addition, all of the primary to secondary leakage to the faulted steam generator is assumed to flash with a partition factor of 1 and to be released directly to the environment. This release pathway continues until the faulted steam generator is isolated. The March 17,1998, submittal indicated that the steam generator activity initially in the faulted steam generator at the start of the accident and all primary to secondary leakage to the faulted steam generator would be released into the main steam piping room and released via the main steam piping room vent.

The intact steam generator is utilized to remove decay heat from the reactor through the steaming or discharge through the nimospheric dump valves (ADVs). This pathway continues until residual heat removal (RHR) can be instituted. The March 17,1998, submittal also indicated that the radioactivity in the intact steam generator and the primary to secondary leakage was assumed to be released from the ADV of the intact steam generator with a partition factor of 1. Cooldown of the core requires 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />, if the above information is correct, then the additional information which is needed is:

1. The duration of primary to secondary leakage to the faulted steam generator and the time following the MSLB at which primary to secondary leakage no longer occurs in the faulted steam generator.

2. - The duration of primary to secondary leakage for the intact steam generator and the time following the MSLB at which RHR operation begins.

Steam GeneratorTube Ruoture (SGTR) Accident Analysis The manner in which radioactivity is released to the environment for this accident is as follows.

A tube rupture occurs in a steam generator (the faulted or affected steam generator). This results in the transfer of primary coolant activity to the secondary side of the faulted steam gener6 tor. Some of the break flow immediately flashes and is released to the environment with a partition factor of 1. That break flow which does not flash is mixed with the radioactivity already contained in the liquid in the steam generator. The radioactivity in the liquid in the faulted steam .

generator is released when the ADV on the faulted steam generator is opened. The ADV on the faulted steam generator is opened because the ADV on the intact steam generator has a leak -

and the faulted steam generator must be utilized to remove decay heat. The faulted steam generator is utilized to remove decay heat by opening and closing the ADV. After a certain period of time, the faulted steam generator is isolated from primary to secondary leakage but its '

ADV is still utilized to remove decay heat. Approximately 10 minutes after the faulted steam generator is isolated, the ADV of the intact steam generator is opened and it cycles open and close to remove decay heat. It was indicated that approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> elapsed before RHR operation begins.

Enclosure

, n 2-l'or the SGTR accident, the following information should be provided:

a. For the faulted steam generator

1. Mass of break flow from 0-2 hours,2-8 hours, and 9-24 hours

11. Duration of break flow 111. Mass of steam released from 0-2 hours,2-8 hours and 9-24 hours.

IV. Flashing fraction as a function of time.

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b. For the intact steam generator- '

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1. Mass of steam released from 0-2 hours,2-8 hours and 9-24 .-

hours.

II. Beginning and ending times of steaming i

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c. Clarification of when releases occur through the condensers and through I the ADVs (

Selzed Rotor Accident The manner in which radion-tivity is released to the environment for this accident is as follows.

A pump shaft of a reactor cooient pump seizes. This results in a reduction in core flow and some fuel pins will experience DNBR. These fuels pins will release their gap activity to the primary -

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coolant. The activity associated with the fuel pin failures and the initial primary coolant activity levels will be transferred to the cecondary side at normal technical specification value for primary to secondary leakage. The primary to secondary leakage is mixed with the radioactivity already contained in secondary coolant ira the steam generators. The two steam generators will be ,

utilized to remove decay heat form the core. The ADVs are utilized to remove the decay heat by )

opening and closing thereby releasing steam. It was indicated that approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> elapsed before RHR operation begins.

For the seized rotor accident, the following information should be provided:

a. Mass of steam released from 0 2 hr and 2-8 hr.

b. Beginning and ending times of steaming _

c. Clarification of when releases occur through the condenser and releases occur through the ADVs.

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