ML20217G032

Forwards Request for Addl Info Re Licensee Resolution of Water Hammer & two-phase Flow Issues in Response to Generic Ltr 96-06.Info Requested by 980630

ML20217G032
Person / Time
Site:	Calvert Cliffs
Issue date:	03/20/1998
From:	Dromerick A NRC (Affiliation Not Assigned)
To:	Cruse C BALTIMORE GAS & ELECTRIC CO.
References
GL-96-06, GL-96-6, TAC-M96792, TAC-M96793, NUDOCS 9804020155
Download: ML20217G032 (5)

Text

[ f' Mr. Charles H. Cruse .

-March 20, 1998

,A Vice President - Nuclear Energy

+

. Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant

~1650 Calvert Cliffs Parkway '

Lusby, MD . 20657-4702

SUBJECT:

RE(. JEST FOR ADDITIONAL INFORMATION RELATED TO THE GL 96-06.

' RESPONSE FOR CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS.1 AND 2 (TAC NOS. M96792 AND M96793)-

Dear Mr. Cruse:

Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment integrity During Design-Basis Accident Conditions," dated September 30,1996, included a request for

' licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to water hammer and two-phase flow conditions. Baltimore Gas and

' Electric Company (the licensee or BGE) provided its assessment for Calvert Cliffs, Unit Nos.1 and 2 in letters dated January 28, and May 2,1997, and February 20,1998. In order to complete '

our review of the licensee's resolution of the water hammer and two-phase flow issues, we will

.zrequire additional information as discussed in the enclosure. The staff requires that BGE provide this information by June 30,1998, in order to support our review schedule for GL 96-06.

J Sincerely, ORIGINAL SIGNED BY:

i Alexander W. Dromerick, Senior Project Manager

' Project Directorate I-1_

Division of Reactor Projects - 1/Il Office of Nuclear Reactor Regulation Docket Nos. 50-317 i and 50-318

Enclosure:

Request for Additional Information cc w/ encl: See next page DISTRIBUTION:  ?  !

Docket File: S. Bajwa ACRS T) \ o \ I PUBLIC S. Slittle C. Hehl, Region I j PDl-1 R/F A. Dromerick i OGC I

- J. Zwolinski (A) l DOCUMENT NAME: G:\CC1-2\M96792,RAI ,

l To receive a copy of this document, Indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with '

ctttchment/ enclosure "N" = No copy w OFFICE PM POM4/ // lE LAtP01 1 J Q ,, l 0:P0l*1,pyk l l l-16AME A0rdr@/W sLittleM 58ebse WA DATE' 03/? d 96 - 03/ M 196 03/ 10 /96

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%g # March 20,1998 Mr. Charles H. Cruse Vice President - Nuclear Energy Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant

.1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE GL 96-06 RESPONSE FOR CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS.1 AND 2 (TAC NOS, M96792 AND M96793)

Dear Mr. Cruse:

Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment integrity During Design-Basis Accident Conditions," dated September 30,1996, included a request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to water hammer and two-phase flow conditions. Baltimore Gas and Electric Company (the licensee or BGE) provided its assessment for Calvert Cliffs, Unit Nos.1 and 2 in letters dated January 28, and May 2,1997, and February 20,1998. In order to complete our review of the licensee's resolution of the water hammer and two-phase flow issues, we will require additionalinformation as discussed in the enclosure. The staff requires that BGE provide this information by June 30,1998, in order to support our review schedule for GL 96-06.

Sincerely, f lc1L p ~N Alexander W. Dromerick, Senior Project Manager Project Directorate 1-1 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318

Enclosure:

Request for Additional Information cc w/ encl: See next page

,e V..

'N, Mr. Charles H. Cruse Baltimore Gas & Electric Company Calvert Cliffs Nuclear Power Plant

,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 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

. 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. 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 a St. Leonard, MD 20685 Mr. Richard I. McLean, Manager Nuclear 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 p .

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= - - - - . _ - - .

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9 .

n s-REQUEST FOR ADDITIONAL INFORMATION FOR RESOLUTION OF GL 96-06 ISSUES AT CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS.1 AND 2 (TAC NOS. M96792 AND M96793) -

Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment Integrity -

During Design-Basts Accident. Conditions," dated September 30,1996, included a request for licensees to evaluad cooling water systems that serve containment air coolers to assure that.~

they are not vulnerable to water hammer and two-phase flow conditions. Baltimore Gas and Electric Company (the licensee) provided its assessment for Calvert Cliffs, Unit Nos.1 and 2, in letters dated January 28, and May 2,1997, and February 20,1998; In order to adequately

- assess the licensee's resolution of the water hammer and two-phase flow issues, the following additional information is requested:

1. If a methodology other than that discussed in NUREG/CR-5220, " Diagnosis of Condensation-

' Induced Water hammer " was used in evaluating the effects of water hammer, describe this alternate methodology in detail.~ Also, explain'why this methodology is applicable and gives

- conservative results for the Calvert Cliffs units (typically accomplished through rigorous plant-specific modeling, testing, and analysis).

2. For both the water hammer and two-phase flow analyses, provide the following information:

. a. Identify any computer codes that were used in the water hammer and two-phase flow analyses and describe the methods used to bench mark the codes for the specific loading conditions involved (see Standard Review Plan Section 3.9.1).

b. Describe and justify all assumptions and input parameters (including those used in any 4 computer codes) such as amplifications due to fluid structure interacticn, cushioning, )

speed of aound, force reductions, and mesh sizes, and explain why the values selected give conservative results. Also, provide justification for omitting any effects that may be ]

l relevant to the analysis (e.g., fluid structure interaction, flow induced vibration, erosion). j

c. Provide a detailed description of the " worst case" scenarios for water hammer and two-phase flow, taking into consideration the complete range of event possibilities, system configurations, and parameters. For example, all water hammer types and water slug scenarios should be considered, as well as temperatures, pressures, flow rates, load combinations, and potential component failures. Additional examples include:

• the effects of void fraction on flow balance and heat transfer; a

the consequences of steam formation, transport, and accumulation!

+ cavitation, resonance,' and fatigue effects; and 4 *

• erosion considerations.

J l Licensees may find NUREG/CR-6031, " Cavitation Guide for Control Valves," helpful in {

addressing some aspects of the two-phase flow analyses.-

l i

Enclosure

1

d. Confirm that the analyses included a complete failure modes and effects analysis (FMEA) for all components (including electrical and pneumatic failures) that could impact performance of the cooling water system and confirm that the FMEA is documented and available for review, or explain why a complete and fully documented FMEA was not performed.

e. Explain and justify all uses of " engineering judgement."

3. Determine the uncertainty in the water hammer and two-phase flow analyses, explain how the uncertainty was determined, and how it was accounted for in the analyses to assure conservative results for the Calvert Cliffs units.

4. Confirm that the water hammer and two-phase flow loading conditions do not exceed any design specifications or recommended service conditions for the piping system and components, including those stated by equipment vendors; and confirm that the system will continue to perform its design-basis functions as assumed in the safety analysis report for the facility,

5. Provide a simplified diagram of the system, showing major components, active components, relative elevations, lengths of piping runs, and the location of any orifices and flow restrictions.

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