ML17313A443
| ML17313A443 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 06/24/1998 |
| From: | Fields M NRC (Affiliation Not Assigned) |
| To: | James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| TAC-M96845, TAC-M96846, TAC-M96847, NUDOCS 9806260133 | |
| Download: ML17313A443 (8) | |
Text
brune 24, 1998 Mr. James M. Levine Senior Vice President, Nuclear Arizona Public Service Company Post Office Box 53999 Phoenix, Arizona 85072-3999
SUBJECT:
REQUEST FOR ADDITIONALINFORMATIONREGARDING GENERIC LETTER 96-06, "ASSURANCE OF EQUIPMENT OPERABILITYAND CONTAINMENTINTEGRITYDURING DESIGN BASIS ACCIDENT CONDITIONS," FOR THE PALO,VERDE NUCLEAR GENERATING STATION (TAC NOS. M96845, M96846 AND M96847)
Dear Mr. Levine 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. Arizona Public Service (APS) Company provided its assessment of, the waterhammer and two-phase flow issues for the Palo Verde units in letters dated January 28 and May 30,,1997.
APS also responded by letter dated June 4, 1998, to a previous'request for additional information from the staff, dated March 31, 1998.
In order to complete our review of these issues, we will require additional information as discussed in the enclosure.
We ask that the requested information be provided Within 60 days of the date of this letter; in order to supp'ort our review schedule for GL 96-06.
Sincerely, Original Signed By Mel B. Fields, Project Manager Project Directorate IV-2
'ivision of Reactor Projects - III/IV Office of Nuclear Reactor Regulation Docket Nos. STN 50-528, STN 50-529 and STN 50-530
Enclosure:
Request for Additional Information ccw/encl: See next page D
B Docket File
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0une 24, 1998 cc w/encl:
Mr. Steve Olea Arizona Corporation Commission 1200 W. Washington Street Phoenix, Arizona 85007 Douglas Kent Porter Senior Counsel Southern California Edison Company Law Department, Generation Resources P.O. Box 800
- Rosemead, California 91770 Senior Resident Inspector USNRC P. O. Box 40 Buckeye, Arizona 85326 Regioriai Administrator, Region IV U. S. Nuclear Regulatory Commission Harris Tower 8 Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Chairman, Board of Supervisors ATTN: Chairman 301 W. Jefferson, 10th Floor Phoenix, Arizona 85003 Mr. David Summers Public Service Company of New Mexico 414 Silver SW, ¹1206 Albuquerque, New Mexico 87102 Mr. Robert D. Bledsoe Southern California Edison Company 14300 Mesa Road, Drop D41-SONGS San Clemente, California 92672 Mr. Robert Henry Salt River Project 6504 East Thomas Road Scottsdale, Arizona 85251 Terry Bassham, Esq.
General Counsel EI Paso Electric Company 123 W. Mills El Paso, Texas 79901 Mr. Robert Burt Los Angeles Department ofWater 8 Power Southern California Public Power Authority 111 North Hope Street, Room 1255-B Los Angeles, California 90051 Mr. Aubrey V. Godwin, Director Arizona Radiation Regulatory Agency 4814 South 40 Street Phoenix, Arizona 85040 Ms. Angela K. Krainik, Manager Nuclear Licensing Arizona Public Service Company P.O. Box 52034 Phoenix, Arizona 85072-2034 Mr. John C. Home, Vice President Power Supply'alo Verde Services 2025 N. Third Street, Suite 220 Phoenix, Arizona 85004
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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. Arizona Public Service Company (the licensee) provided its assessment of the waterhammer and two-phase flow issues for the Palo Verde units in letters dated January 28 and May 30, 1997. The licensee also responded by letter dated June 4, 1998, to a previous request for additional information from the staff, dated March 31, 1998. The licensee's response indicated that the containment cooling water systems at Palo Verde are not safety-related and are not susceptible to waterhammer or two-phase flow conditions.
In order to assess the licensee's resolution of these issues, the following additional information is requested:
Note:
The following questions are applicable to cooling water systems associated with the in-containment environmental heat removal function.
Implementing measures to assure that waterhammer and two-phase flowwillnot occur, such as controlling post-accident operation of systems that could be affected, is an acceptable approach for addressing these concerns.
However, all scenarios must be considered to assure that the vulnerability to waterhammer and two-phase flow 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 are adequate to prevent the occurrence of waterhammer and two-phase flowduring (and following)all postulated accident scenarios.
Identify the "worst-case" conditions that could occur within the licensing basis of the plant, such as event possibilities, system configurations, parameters, and component failures, in order to adequately assess the waterhammer and two-phase flow concerns.
As an example, the 1204ay response did not address the scenario where a thermal relief valve has lifted, possibly reducing the pressure of the affected cooling water system to below saturation.
2.
Confirm that the waterhammer and two-phase flowanalyses 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 fullydocumented FMEAwas not performed.
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Discuss specific system parameter requirements that must be maintained in order to assure that waterhammer and two-phase flowwillnot occur (e,g., expansion tank level, temperature, and pressure requirements), and state the minimum margin to boiling that exists, including consideration of measurement and analytical uncertainties.
Explain why it would not be appropriate to establish technical specification requirements for these parameters, and describe and justify reliance on any non-safety related instrumentation and controls for assuring that waterhammer and two-phase flowwillnot occur.
Explain and justify all uses of "engineering judgement" that are credited in the waterhammer and two-phase flowevaluations.
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.
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