ML18066A206
| ML18066A206 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/18/1998 |
| From: | Robert Schaaf NRC (Affiliation Not Assigned) |
| To: | Haskell N CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| GL-96-06, GL-96-6, TAC-M96844, NUDOCS 9806250212 | |
| Download: ML18066A206 (5) | |
Text
- ~---
. Mr. Nathan L. Haskell
- Director, Licensing Palisades Plant 27780 Blue Star Memorial Highway Covert, MI 49043 June 181, *.1998
SUBJECT:
PALISADES PLANT - REQUEST FOR ADDITIONAL INFORMATION REGARDING CONSUMERS ENERGY COMPANY'S RESPONSE TO NRC GENERIC LETTER 96-06 (TAC NO. M96844)
Dear Mr. Haskell:
Generic Letter 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. Consumers Energy Company provided its assessment of the waterhammer and two-phase flow issues for Palisades in letters dated January 27, 1997, and January 29, 1998. In order to complete our review of your resolution of these issues, the staff requires additional information as discussed in the enclosure. In order to support the staff's review schedule, please provide a r~sponse to the enclosed questions by August 30, 1998. If you have any questions regarding this request, please contact me at (301) 415-1312.
Docket No. 50-255 Sincerely, ORIGINAL SIGNED BY Robert G. Scpa~f, Project Manager Project Dir~dorate 111-1 Division of ~eactor Projects - Ill/IV Office of Nuclear Reactor Regulation
Enclosure:
Request for Additional Information cc w/encl: See next page DISTRIBUTION:.
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PUBLIC PD#3-1Reading E. Adensam (EGA1)
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ACRS B. Burgess, Rill J. Tatum DOCUMENT NAME: G:\\WPDOCS\\PALISADE\\PAL96844.RAI To receive a copy of this document, indicate in the box C=Copy w/o attachment/enclosure E=Copy with attachment/enclosure N = No copy OFFICE PM:PD31 NAME RSchaaf:d DATE 6/ lC.0198 9806250212 980618 PDR ADOCK 05000255 p
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- Mr. Nathan L. Haskell Consumers Energy Company cc:
Mr. Thomas J. Palmisano Site Vice President Palisades Plant 27780 Blue Star Memorial Highway Covert, Michigan 49043 Mr. Robert A. Fenech, Sr Vice Pres Nuclear, Fossil, and Hydro Operations Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan *49201 M. I. Miller, Esquire Sidley & Austin 54th Floor One First National Plaza Chicago, Illinois 60603 Mr. Thomas A. McNish Vice President & Secretary Consumers Energy Company 212 West Michigan Avenue Jackson *. Michigan. 49201 Judd L. Bacon, Esquire Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan 49201 Regional Administrator, Region Ill U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Jerry Sarno Township Supervisor Covert Township 36197 M-140 Highway Covert, Michigan 49043 Office of the Governor P. o. Box 30013 Lansing, Michigan 48909 Palisades Plant U.S. Nuclear Regulatory Commission
- Resident Inspector's Office Palisades Plant 27782 Blue Star Memorial Highway Covert, Michigan 49043 Drinking Water and Radiological Protection Division Michigan Department of Environmental Quality 3423 N. Martin Luther King Jr Blvd P. 0. Box 30630 CPH Mailroom Lansing, Michigan 48909-8130 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, N. W.
Washington DC 20037 Michigan Department of Attorney
. General.
Special Litigation Division 630 Law Building P.O. Box 30212 Lansing, Michigan 48909 June 1998
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.j REQUEST FOR ADDITIONAL INFORMATION REGARDING CONSUMERS ENERGY COMPANY'S RESPONSE TO NRC GENERIC LETTER 96-06 PALISADES NUCLEAR PLANT DOCKET NUMBER 50-255 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 (CAC) to assure that they are not vulnerable to waterhammer and two-phase flow conditions. Consumers Energy Company (the licensee) provided its assessment of the waterhammer and tWo-phase flow issues for Palisades in letters dated January 27, 1997, and January 29, 1998. The staff also met with the licensee on October 16, 1997, to discuss an alternate approach for evaluating the consequences of waterhammer. While the licensee's 120-day response provides detailed information concerning the operability assessment that was completed, it is not clear to what extent the licensee's analysis is bounding for the worst-case conditions that could exist for waterhammer and two-phase flow (assuming component failures, etc.). In order to assess the licensee's resolution of these issues, the following additional information is requested:
Note: Information that has already been submitted may be referred to and supplemented as necessary to provide a complete response.
- 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 alternate methodology in detail. Also, explain why this methodology is applicable and gives conservative results (typically accomplished through rigorous plant-specific modeling, testing, and analysis).
Notes: a.
- b.
While the waterhammer analysis methodology that was presented to the staff during the meeting on October 16, 1997, is a viable approach, plant-specific modeling and extensive testing is required to assure conservative results before this approach can be credited.
Appendices A, B, and C were referred to but not included in the 120-day
- response to GL 96-06.
- 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 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 ).
Enclosure
11.--t-o
- b.
2 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). For example, based on a review of the 120-day response, the following assumptions require explanation:
check valves are assumed to prevent backflow to the lake; service water piping is assumed to be heated up such that incoming service water is heated to saturation; piping system runs full when the Froude number is ~0.1 (i.e., this value is much less than the generally accepted value of 1.0);
a Froude number of ~0.1 can be used to establish the onset of steam bubble condensation; and waterhammer does not occur in vertical piping segments.
- 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 (which does not appear to have been done for the Palisades plant}, as well as temperatures, pressures, flow rates, load combinations, and potential component failures. For example, based on a review of the 120-day response, confirmation is needed that the following assumptions are "worst case":
60% of service water pump output is assumed to go to the critical cooler inlet piping; 85 °F service water temperature; the vapor void length and slug length are equal;
- . determination of CAC flow rate; and degree of service water preheat prior to entering CACs (i.e., thermal inertia of piping must be considered);
Additional examples of two-phase flow considerations that must be addressed include:
the effects of void fraction on flow balance and heat transfer;
3 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 concerns that must be addressed.)
- 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." For example, the 120-day response states that the design of the CACs makes it unlikely to have any steam.