ML20236F750
| ML20236F750 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 06/30/1998 |
| From: | Pulsifer R NRC (Affiliation Not Assigned) |
| To: | Kingsley O COMMONWEALTH EDISON CO. |
| References | |
| GL-96-06, GL-96-6, TAC-M96856, TAC-M96857, NUDOCS 9807020314 | |
| Download: ML20236F750 (6) | |
Text
..
June 30, 1998 Mr. Oliver D. Kingsley, President l
Nuclear Generation Group j
Commonwealth Edison Company.
L Executive Towers West lil 1400 Opus Place, Suite 500 ~
Downers Grove,IL 60515 i
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO GENERIC LETTER 96 QUAD CITIES, UNITS 1 AND 2 (TAC NOS. M96856 AND M96857)
Dear Mr. Kingsley:
f.
~ 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 water hammer and two-phase flow conditions.
Commonwealth Edison Company (Comed) provided its assessment of the water hammer and two-phase flow issues for Quad Cities Nuclear Power Station, Units 1 and 2, in letters dated January 28, May 2 and May 16,1997.. In order to complete our review of Comed's resolution of -
these issues, we will require additional information as discussed in the enclosure. Please I
provide this information by August 30,1998, in order to support our review schedule for fI g GL 96-06.-
l Sincerely,.
ORIG. SIGNED BY Robert M. Pulsifer, Project Manager M
Project Directorate 111-2.
Division of Reactor Projects - lil/IV
.. - Meir Office of Nuclear Reactor Regulation c Docket Nos. 50-254, 50-265 DISTRIBUTION:
DOCKET FILE CMoore
Enclosure:
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l June 30, 1998 Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West til 1400 Opus Place, Suite 500 Downers Grove, IL 60515 -
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO GENERIC LETTER 96 QUAD CITIES, UNITS 1 AND 2 (TAC NOS. M96856 AND M96857)
Dear Mr. Kingsley:
Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions," dated September 30,1996, included a l
. request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to water hammer and two-phase flow conditions.
Commonwealth Edison Company (Comed) provided its assessment of the water hammer and two-phase flow issues for Quad Cities Nuclear Power Station, Units 1 and 2, in letters dated j
January 28, May 2 and May 16,1997. In order to complete our review of Comed's resolution of these issues, we will require additional information as discussed in the enclosure. Please provide this information by August 30,1998, in order to support our review schedule for GL 96-06.
Sincerely, f-obert M. Pulsifer, Project Manager Project Directorate ill-2 Division of Reactor Projects - llillV Office of Nuclear Reactor Regulation I
Docket Nos. 50-254, 50-265
Enclosure:
RAl L
cc w/ encl: See next page
i l
l O. Kingsley Quad Cities Nuclear Power Station.
Commonwealth Edison Company Units 1 and 2 l
l cc-1 l
Michael I. Miller, Esquire Commonwealth Edison Company l
Sidley and Aust; Site Vice President - Quad Cities l
One First National Plaza 22710 206th Avenue N.
Chicago, Illinois 60603 Cordova, Illinois 61242-9740 Commonwealth Edison Company Document Control Desk-Licensing Quad Cities dtation Manager Commonwealth Edison Company 22710 206th Avenue N.
1400 Opus Place, Suito 400 l
Cordova, Illinois 61242-9740 Downers Grove, Illinois 60515 U.S. ft. clear Regulatory Commission Mr. David Helwig Quad Cities Resident inspectors Office Senior Vice President 22712 206th Avenue N.
Commonwealth Edison Company Cordova, Illinois 61242 Executive Towers West lli 1400 Opus Place, Suite 900 Chairman Downers Grove,IL 60515 Rock Island County Board of Supervisors Mr. Gene H. Stanley 1
1504 3rd Avenue PWR's Vice President Rock Island County Office Bldg.
Commonwealth Edison Company RockIsland, Illinois 61201 Executive Towers West lil 1400 Opus Place, Suite 900 lilinois Depdrtment of Nuclear Safety Downers Grove,IL 60515 Office of Nuclear Facility Safety 1035 Outer Park Drive Mr. Steve Perry Springfield, Illinois 62704 BWR's Vice President Commonwealth Edison Company Regional Administrator Executive Towers West lli
~ U.S. NRC, Region ill 1400 Opus Flace, Suite 900 801 Wanrenville Road Downers Grove,IL 60515 Lisle, Illinois 60532-4351 Mr. Dennis Farrar William D. Leach Regulatory Services Manager Manager-Nuclear Commonwealth Edison Company MidAmerican Energy Company Executive Towers West til 907 Walnut Street 1400 Opus Place, Suite 500 P.O. Box 657 Downers Grove,IL 60515 Des Moines, Iowa 50303 Ms. Irene Jonnsen, Licensing Director Vice President - Law and Nuclear Regulatory Services Regulatory Affairs Commonwealth Erdison Company i
Mic';mericten Energy Company Executive Towers West lil
. One River Center Place 1400 Opus Place, Suite 500 106 E. Second Street Downers Grove,IL 60515 P.O. Box 4350
)
Davenpod, Iowa 52808
O. Kingsley Quad Cities Nuclear Power Plant Commonwealth Edison Company Uni'.s 1 and 2 Commonwealth Edison Company Reg. Assurance Supervisor-Quad Cities 22710 206th Avenue N.
Cordova, Illinois 61242-9740 Mr. Michael J. Wallace Senior Vice President Commonwealth Edison Company Executive Towers West lil 1400 Opus Place, Suite 400 Downers Grove,IL 60515 l
l l
i
.I REQUEST FOR ADDITIONAL INFORMATION FOR RESOLUTION OF GL 96-06 ISSUES AT QUAD CITIES, UNITS 1 AND 2 1
Generic Letter (GL) 96-06, " Assurance of Equipr sent operability and Containment integrity During Design-Basis Accident Conditions," dated September 30;.1990, included a request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to water hammer and two-phase flow conditions. Commonwealth Edison Company (Comed, the licensee) provided its assessment of the water hammer and two-phase flow issues for Quad Cities, Units 1 and 2, in letters dated January 28, May 2 and May 16,1997.
l The licensee indicated that the drywell cooling system (DCS) at Quad Cities is non-safety related nnd is not assumed to operate under postulated accident conditions. However, the licensee also incncated that the Emergency Operating Procedures (EOPs) allow plant operators to use the DCS as an option following an accident. In crder to assess the licensee's resoluSon of the water hammer and two-phase flow issues, the following additional information is requca.ted:
Note: To the extent that positive measures are implemented to eliminate the potential for water hammer 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 water hammer and two-phase flow that could occur in the DCS within the constraints imposed by the EOPs, taking into consideration the complete range of event possibilities, system configurations, and parameters. For example, all water hammer 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; a
cavitation, resonance, and fatigue effects; and e
erosion considerations.
a Licensces may find NUREG/CR-6031, " Cavitation Guide for Control Valves," helpful in addressing some aspects of the two-phase flow analyres. (Note: it is important for licensees to realize that in addition to heat transfer considerations, twofhase 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 Water hammer," was used in evaluating the effects of water hammer, 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).
i 3.
For both the water hammer and two-phase flow analysas, provide the following information:
- a. Identify any computer codes that were used in the water hammer and two-phase flow analyses and describe the methods used to bench marx ine codes for the specific loading conditions involved (see Standard Pcvitrw Plan Section 3.9.1).
- b. Describe and justify all assumptiot.s and input parameters (inc.luding those used in any computer codes) such as amplifications due to fluid structure ir teraction, cushioning, ENCLOSURE
_ _ _ _ _ - - _ _ _ 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 water hammer and two-phase flow analyses, explain how the uncertainty was deterrained, and how it was accounted for in the analyses to assure conservative results.
4.
Confirm that the water hammer 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; 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 for water hammer and two-phase flow con:titions in the DCS, such as placing restrictions on use of the DCS following an acciderd. Describe the worst-case scenario and how much begin will exist to boiling.
6.
Implementing measures to assure that water hammer will not occur, such as restricting post-accident operation of the affected system, is an acceptable approach for addressing the water hammer and two-phase flow concems. Pwevser, all scenarios must be considered to assure that the vulnerability to water hamer 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 water hammer 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.
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 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 coaponents, 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 water hammer and two-phase flow issues, including schedules for completing these actions.