ML20216G945

Requests Addl Info Pertaining to GL 96-06 Dtd 980930,which Included Request for Licensees to Evaluate Cooling Water Systems That Serve Containment Air Coolers to Assure Not Vulnerable to Waterhammer & two-phase Flow Conditions

ML20216G945
Person / Time
Site:	Davis Besse
Issue date:	04/15/1998
From:	Hansen A NRC (Affiliation Not Assigned)
To:	Jeffery Wood CENTERIOR ENERGY, TOLEDO EDISON CO.
References
GL-96-06, GL-96-6, TAC-M96803, NUDOCS 9804200532
Download: ML20216G945 (6)

Text

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, g ,p NUCLEAR REGULATORY COMMISSION p 'E WASHINGTON, D.C. 2066H001 f

April 15, 1998 I

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Mr. John K. Wood

• l Vice President - Nuclear, Davis-Besse Centerior Service Company c/o Toledo Edison Company Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, OH 43449-9760

SUBJECT:

DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 - SUPPLEMENTAL REQUEST FOR ADDITIONAL INFORMATION PERTAINING TO GENERIC LETTER 96-06, " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS" (TAC NO. M96803) -

Dear Mr. Wood:

i Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment Integrity Ouring 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. You provided your assessment of the waterhammer and two-phase flow issues for the Davis-Besse Nuclear Power ,

Station in letters dated January 28, February 28, July 28, and September 30,1997. l In order to complete our review of your resolution of these issues, we requested by letter dated March 18,1998, that you address several questions posed by NRC Office of Nuclear Reactor  ;

Regulation (NRR) Division of Engineering staff. Since then, NRR Division of Systems Safety and Analysis staff have identified additional questions related to these issues, as follows. .

4 l (1) 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 for the Davis-Besse plant (typically accomplished through rigorous plant-specific modeling, testing, and analysis).

l (2) 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 g flow analyses and describe the methods used to benchmark the codes for the specific loading conditions involved (see Standard Review Plan Section 3.9.1).

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l (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 (for example, fluid structure interaction, flow induced vibration, erosion).

(c) Provide a detailed description of the " worst case" scenarios for waterhammer and two-phase flow, 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 examples include:

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

. the consequences of steam formation, transport, and accumulation; l

. cavitation, resonance, and fatigue effects; and  !

1

. erosion considerations.

NUREG/CR-6031, " Cavitation Guide for Control Valves," may be helpful in addressing some aspects of the two-phase flow analyses.

(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 judgment."

(3) 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 for the Davis-Besse plant.

(4) Confirm that the waterhammer 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. Also confirm that the system will continue to perform its design-basis functions as assumed in the safety analysis report for the facility.

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lI J. Wood l (5) Provide a simplified diagram of the system, showing major components, active L components, relative elevations, lengths of piping runs, and the location of any orifices I and flow restrictions. i l I 1 Please provide your response to the above request within 90 days of receipt of this letter. You may contact me at 301-415-1390 if you have any questions.

Sincerely, Allen G. Hansen, Project Manager l' Project Directorate lll-3

• Division of Reactor Projects til/IV Office of Nuclear Reactor Regulation

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Docket No. 50-346 cc

See next page 3

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1 J. Wood l (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.

Please provide your response to the above request within 90 days of receipt of this letter. You  ;

may contact me at 301415-1390 if you have any questions.

Sincerely, 1

Original signed by:

Allen G. Hansen, Project Manager Project Directorate ill-3 Division of Reactor Projects Ill/IV Office of Nuclear Reactor Regulation Docket No. 50-346 .

cc: See next page QLSTRIBUTION:

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DATE 7//f/98 4/15/98

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OFFICIAL RECORD COPY

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& J. Wood l-l (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.

Please provide your response to the above request within 90 days of receipt of this letter. You

! may contact me at 301-415-1390 if you have any questions.

I Sincerely, Original signed by:

Allen G. Hansen, Project Manager

! Project Directorate lll-3 l Division of Reactor Projects lil/IV l , Office of Nuclear Reactor Regulation Docket No. 50-346 cc: See next page DISTRIBUTION:

Docket File PUBLIC PD3-3 R/F

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DATE 7//i/98 ~ 4/15/98 OFFICIAL RECORD COPY

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, John K. Wood Davis-Besse Nuclear Power Station, Unit 1 Toledo Edison Company cc:

Mary E. O'Reilly Robert E. Owen, Chief FirstEnergy Bureau of Radiological Health Davis-Besse Nuclear Power Station Service 5501 North State - Route 2 Ohio Department of Health Oak Harbor, OH 43449-9760 P.O. Box 118 Columbus, OH 43266-0118 James L. Freels Manager- Regulatory Affairs

! Toledo Edison Company James R. Williams, Chief of Staff Davis-Besse Nuclear Power Station Ohio Emergency Management Agency

, 5501 North State - Route 2 2855 West Dublin Granville Road I

Oak Harbor, OH 43449-9760 Columbus, OH 43235-2206 Gerald Charnoff, Esq. Donna Owens, Director Shaw, Pittman, Potts Ohio Department of Commerce and Trowbridge Division of Industrial Compliance l

i 2300 N Street, NW. Bureau of Operations & Maintenance l Washington, DC 20037 6606 Tussing Road l P.O. Box 4009 Regional Administrator Reynoldsburg, OH 43068-9009 U.S. Nuclear Regulatory Commission 801 Warrenville Road Ohio Environmental Protection Agency Lisle, IL 60523-4351 DERR--Compliance Unit ATTN: Zack A. Clayton Robert B. Borsum P.O. Box 1049 Babcock & Wilcox Columbus, OH 43266-0149 Nuclear Power Generation Division 1700 Rockville Pike, Suite 525 State of Ohio Rockville, MD 20852 Public Utilities Commission 180 East Broad Street Resident inspector Columbus, OH 43266-0573 i U.S. Nuclear Regulatory Commission 5503 North State Route 2 Attomey General Oak Harbor OH 43449 Department of Attomey 30 East Broad Street James H. Lash, Plant Manager Columbus, OH 43216 Toledo Edison Company Davis-Besse Nuclear Power Station President, Board of County 5501 North State Route 2 Commissioner of Ottawa County Oak Harbor, OH 43449-9760 Port Clinton, OH 43252 l

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