ML20236R365

Forwards Request for Addl Info for Resolution of GL 96-06 Issues at Pilgrim Nuclear Power Station,Unit 1

ML20236R365
Person / Time
Site:	Pilgrim
Issue date:	07/14/1998
From:	Wang A NRC (Affiliation Not Assigned)
To:	Olivier L BOSTON EDISON CO.
References
GL-96-06, GL-96-6, TAC-M96851, NUDOCS 9807210409
Download: ML20236R365 (4)

Text

July 14,1998 Mr. Leon J. Olivier Vice President - Nuclear / Station Director Boston Edison Company Pilgrim Nuclear Power Station RFD #1 Rocky Hill Road Plymouth, MA 02360

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR RESOLUTION OF GENERIC LETTER (GL) 96-06 ISSUES AT PILGRIM NUCLEAR POWER STATION, UNIT 1 (TAC NO. M96851)

Dear Mr. Olivier:

In response to GL 96-06, Boston Edison Company provided its assessment of the waterhammmer and two-phase flow issues for the Pilgrim Nuclear Power Station in a letter dated

. ' January 28,1997. The Nuclear Regulatory Commission (NRC) has reviewed the response and determined that additional information is needd to complete the review. Enclosed is the staffs Request for Additional Information. We request that you respond by August 30,1998.

Questions regarding this request should be sent to my attention at the above address; or, you can contact me at (301) 415-1445.

Sincerely, Original signed by Alan B. Wang, Project Manager Project Directorate 1-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket No. 50-293

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Enclosure:

Request for Additional /

Information cc w/ encl: See next page

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DISTRIBUTION:

Docket File T. Clark J. Zwolinski ACRS PUBLIC A. Wang C. Cowgill, RI PDI-3 R/F OGC G. Galletti DOCUMENT NAME: G:\ PILGRIM \G9606.RAI To receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure *E" = Copy with attachment / enclosure "N" = No copy OfflCE LA:PDI-3_,g J/ { lE PM PDI 3 l ( A)DJPDb3 ((N l l NAME TLClarh } /\ / AWang /34. W C76 # /

DATE 07//4 /98 07//0/98 07/1998 3 0FFICIAL RECORD COPY

, !. YJ 9807210409 980714 PDR ADOCK 05000293 P PDR

Mr. Lson J. Olivisr

! Boston Edison Company Pilgrim Nuclear Power Station cc:

Mr. Ron Ledgett Ms. Nancy Desmond Executive Vice President Manager, Reg. Affairs Dept.

800 Boyleston Street Pilgrim Nuclear Power Station Boston, MA 02199 RFD #1 Rocky Hill Road Plymouth, MA 02360 Resident inspector U. S. Nuclear Regulatory Commission Mr. David F. Tarantino Pilgrim Nuclear Power Station Nuclear Information Manager Post Office Box 867 Pilgrim Nuclear Power Station Plymouth, MA 02360 RFD #1, Rocky Hill Road Plymouth, MA 02360 Chairman, Board of Selectmen 11 Lincoln Street Ms. Kathleen M. O'Toole Plymouth, MA 02360 Secretary of Public Safety Executive Office of Public Safety Chairman, Duxbury Board of Selectmen One Ashburton Place Town Hall Boston, MA 02108 878 Tremont Street Duxbury, MA 02332 Mr. Peter LaPorte, Director Attn: James Muckerheide Office of the Commissioner Massachusetts Emergency Management Massachusetts Department of Agency Environmental Protection 400 Worcester Road One Winter Street P.O. Box 1496 Boston, MA 02108 Framingham, MA 01701-0317 Office of the Attomey General Chairman, Citizens Urging One Ashburton Place Responsible Energy 20th Floor P.O. Box 2621 Boston, MA 02108 Duxbury, MA 02331 Mr. Robert M. Hallisey, Director Citizens at Risk Radiation Control Program P.O. Box 3803 Massachusetts Department of Plymouth, MA 02361 Public Health 305 South Street W.S. Stowe, Esquire Boston, MA 02130 Boston Edison Company 800 Boyleston St.,36th Floor Regional Administrator, Region l Boston, MA 02199 U. S. Nuclear Regulatory Commission 475 Allendale Road Chairman King of Prussia, PA 19406 Nuclear Matters Committee Town Hall Ms. Jane Fleming 11 Lincoln Street 8 Oceanwood Drive Plymouth, MA 02360 Duxbury, MA 0233 Mr. William D. Meinert Mr. Jeffery Keene Nuclear Engineer Licensing Division Manager Massachusetts Municipal Wholesale Boston Edison Company Electric Company 600 Rocky Hill Road P.O. Box 426 Plymouth, MA 02360-5599 Ludlow, MA 01056-0426

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a REQUEST FOR ADDITIONAL INFORMATION (RAI)

PILGRIM NUCLEAR POWER STATION. UNIT 1 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 waterhammer and two-phase flow conditions. Boston Edison Company (the licensee) provided its assessment of the waterhammer and two-phase flow issues for Pilgrim Unit 1 in a letter dated January 28,1997. The containment air coolers at Pilgrim are cooled by loop B of the reactor building closed cooling water (RBCCW) system. Although the -

containment air coolers are not required for accident mitigation, they can be used in response to plant events if they are available. In order to assess the licensee's resolution of these issues, the following additional information is requested:

Note: To the extent that positive measures are implemented to eliminate the potential for waterhammer and two-phase flow conditions, question numbers 1, 2, 3, and 4 may not be applicable.

1. Provide a detailed description of the " worst case" scenarios for waterhammer and two-phase flow that could occur in the RBCCW system within the constraints imposed by the EOPs, taking into consideration the complete range of event possibilities, system configurations, and parameters. For example, all waterhammer types and water slug scenarios should be considered, as well as temperatures, pressures, flow rates, load combinations, and potential component failures. Additional two-phase flow considerations include:

the consequences of steam formation, transport, and accumulation; cavitation, resonance, and fatigue effects; and erosion considerations.

Licensees may find NUREG/CR-6031,

• Cavitation Guide for Control Valves," helpful in addressing some aspects of the two-phase flow analyses. (Note: it is important for licensees to realize that in addition to heat transfer considerations, two-phase flow also involves structural and system integrity concems that must be addressed).

2. If a methodology other than that discussed in NUREG/CR-5220, " Diagnosis of Condensation-Induced Waterhammer," was used in evaluating the effects of waterhammer, describe this attemate methodology in detail. Also, explain why this methodology is applicable and gives conservative results (typically accomplished through rigorous plant-specific modeling, testing,

! and analysis).

! 3. For both the waterhammer and two-phase flow analyses, provide the following information:

a. Identify any computer codes that were used in the waterhammer 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).

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b. Describe and justify all assumptions and input parameters (including those used in any computer codes) such as amplifications due to fluid structure interaction, cushioning, speed of sound, force reductions, and mesh sizes, and explain why the values selected give conservative results. Also, provide justification for omitting any effects that may be relevant to the analysis (e.g., fluid structure interaction, flow induced vibration, erosion).

c. Determine the uncertainty in the waterhammer and two-phase flow analyses, explain how the uncertainty was determined, and how it was accounted for in the analyses to assure conservative results.

4. Confirm that the waterhammer and two-phase flow loading conditions do not exceed any i design specifications or recommended service conditions for the piping system and i 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 and that the containment isolation valves will remain operable.

5. Describe positive measures that have been taken (or will be taken) to eliminate the potential I for waterhammer and two-phase flow conditions in the RBCCW system, such as placing restrictions on use of the RBCCW system following an accident. Describe the worst-case ,

scenario and how much margin will exist to boiling. j l

6. Implementing measures to assure that waterhammer will not occur, such a' s restricting post- I accident operation of the affected system, is an acceptable approach for addressing the waterhammer and two-phase flow cesncems. .However, all scenarios must be considered to assure that the vulnerability to waterhammer has been adequately addressed. Confirm that all scenarios have been considered such that the measures that have been established are adequate to address all situations.

7. Discuss specific system operating parameters that must be maintained in order for the waterhammer and two-phase flow analyses to be valid (e.g., head tank pressure and level),

and explain why it would not be appropriate to establish Technical Specification requirements for these system parameters. Also, describe and justify reliance on any non-safety related instrumentation and controls in this regard.

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8. Confirm that a complete failure modes and effects analysis (FMEA) was completed for all components (including electrical and pneumatic failures) that could impact performance of 4 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.

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

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

11. Describe in detail any plant modifications or procedure changes that have been made or are  :

planned to be made to resolve the waterhammer and two-phase flow issues, including schedules for completing these actions. '

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