ML17354B316
| ML17354B316 | |
| Person / Time | |
|---|---|
| Site: | 07000048 |
| Issue date: | 02/17/1998 |
| From: | Elizabeth Ullrich NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| References | |
| 125353, NUDOCS 9809040344 | |
| Download: ML17354B316 (5) | |
Text
MEMORANDUMTO: Frederick J. Hebdon, Director Project Directorate II-3 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation FROM:
SUBJECT:
Ledyard B. Marsh, Chief Plant Systems Branch Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation REQUEST FOR ADDITIONALINFORMATIONRELATED TO THE GL 96-06 RESPONSE FOR TURKEYPOINT 3 AND 4 (TAC NOS. M96878 AND M96879)
Generic Letter (GL) 96-06, "Assuiance 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.
The Florida Power and Light Company (the licensee) provided its assessment of the waterhammer and two-phase flow issues for Turkey Point 3 and 4 in letters dated January 28 and March 24, 1997.
In order to complete our review of the licensee's resolution of these issues, we will require additional information as discussed in the attachment.
We ask that the licensee provide this information by September 30, 1998, in order to support our review schedule for GL 96-06.
Docket Nos.:
50-250 and 50-251
Attachment:
As stated CONTACT:
James Tatum, SPLB/DSSA/NRR (301) 415-2805 U
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I II PF PPL IIIF LMarsh GHubbard JTatum RCroteau Plant R/F BWetzel SPLB:DSSA LBMarsh
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ATTACHMENT REQUEST FOR ADDITIONALINFORMATIONFOR RESOLUTION OF
~
GL 96-06 ISSUES ATTURKEY POINT 3 AND 4 (TAC NOS. M96878 AND M96879)
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. The Florida Power and Light Company (the licensee) provided its assessment of the waterhammer and two-phase flow issues for Turkey Point 3 and 4 in letters dated January 28 and March 24, 1997. The licensee has determined that waterhammer could occur in the component cooling water system, which provides cooling water for the normal containment coolers and the emergency containment coolers.
The licensee indicated that actions would be taken to preclude steam formation in the CCW system, thus eliminating the potential for waterhammer.
In order to assess the licensee's resolution of these issues, the following additional information is requested:
Notes:
1.
Information that has been submitted previously may be referred to and supplemented as necessary to provide a complete response to the staffs questions.
2.
The following questions are applicable t'o the system configuration and analyses that are credited for resolution of the waterhammer and two-phase flow issues.
1.
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, and describe the minimum margin to boiling that will exist. For example, all waterhammer types and water slug scenarios should be con"'dered, as well as temperatures, pressures, flow rates, load combinations, and potential component failures.
2.
Describe in detail any testing that has been completed to confirm the analytical results, identify any shortcomings that exist, and explain how the test results assure conservatism in the analyses that have been completed.
3.
Describe and justify all assumptions and input parameters (including those used in any computer codes) that were used in the waterhammer and two-phase flow analyses.
Confirm that these assumptions and input parameters are consistent with the existing design and licensing basis of the plant. Any exceptions should be explained and justified.
4.
Explain and justify all uses of "engineering judgement" that were credited in the waterhammer and two-phase flow analyses.
Discuss specific system opera'ting parameters and other operating restrictions that must be maintained to assure that the waterhammer and two-phase flow analyses remain valid (e.g., surge tank level, pressures, temperatures),
and explain'why it would not be appropriate to establish Technical Specification requirements to acknowledge the importance of these parameters and operating restrictions.
Also, describe and justify use of any non-safety related instrumentation and controls for maintaining these parameters.
Implementing measures to assure that waterhammer willnot occur, such as establishing and maintaining system overpressure requirements, is an acceptable approach for addressing the waterhammer concern.
However, all scenarios must be considered to assure that the vulnerability to waterhammer has been eliminated.
Confirm that all scenarios have been considered, including those where the affected containment penetrations are not isolated (ifthis is a possibility), such that the measures that have been established (or will be established) are adequate to prevent the occurrence of waterhammer during (and following) all postulated accident scenarios.
7.
Confirm that the waterhammer and two-phase flow 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 a'nd fullydocumented FMEAwas not performed.
8.
Determine the uncertainty in the waterhammer and tw'o-phase flowanalyses, explain how the uncertainty was determined, and how it was accounted for in the analyses to assure conservative results.
9.
Provide a simplified diagram of the affected system, showing major components, active components, relative elevations, lengths of piping runs, and the location of any oriTices and flow restrictions.
- 10. 'escribe in detail any plant modiflicatioiis or procedure changes that have been made or-are planned to be mad~
to resolve the waterhammer and two-phase flow issues, including schedules for any changes that have not been completed.
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