ML081430019
| ML081430019 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/15/2008 |
| From: | Ridenoure R Southern California Edison Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-08-001 | |
| Download: ML081430019 (4) | |
Text
JSOUTHERN CALIFORNIA EDISON An EDISON INTERNATIONAL Company Ross T. Ridenoure VP and Site Manager San Onofre Nuclear Generating Station May 15, 2008 U. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, DC 20555-0001
Subject:
Reference:
Docket Nos. 50-361 and 50-362 Three-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" San Onofre Nuclear Generating Station, Units 2 and 3 NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems,"
dated January 11, 2008
Dear Sir or Madam:
The Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 (Reference) to request that each licensee evaluate the licensing basis, design, testing, and corrective action programs for the emergency core cooling, decay heat removal, and containment spray systems to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified.
The NRC, in GL 2008-01, requested each licensee to submit a written response in accordance with 10 CFR 50.54(f) within 9 months of the date of the GL (October 11, 2008) to provide the following information:
(a)
A description of the results of evaluations that were performed pursuant to the requested actions of the GL. This description should provide sufficient information to demonstrate that you are or will be in compliance with the quality assurance criteria in Sections III, V, Xl, XVI, and XVII of Appendix B to 10 CFR Part 50 and the licensing basis and operating license as those requirements apply to the subject systems of the GL; Mail Drop D45 P.O. Box 128 San Clemente, CA 92672 949-368-6255 PAX 86255 Fax: 949-368-6183 Ross. Ridenoure@sce.com IkI5Y
Document Control Desk May 15, 2008 (b)
A description of all corrective actions, including plant, programmatic, procedure, and licensing basis modifications that you determined were necessary to assure compliance with these regulations; and, (c)
A statement regarding which corrective actions were completed, the schedule for completing the remaining corrective actions, and the basis for that schedule.
Additionally, the NRC requested that if a licensee cannot meet the requested response date, the licensee shall provide a response within 3 months of the date of the GL. In the 3-month response, the licensee was requested to describe the alternative course of action that it proposes to take, including the basis for the acceptability of the proposed alternative course of action. An extension to May 16, 2008, for the 3-month response was provided by Mr. J Wermeil, NRC Deputy Director of Safety Systems, to our Mr. T. Raidy on April 10, 2008.
The enclosure to this letter contains the San Onofre Nuclear Generating Station (SONGS) extended 3-month response to the requested information in GL 2008-01.
Should you have any questions, please contact Ms. Linda Conklin at (949) 368-9443.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on 6-, '
(Date) cc:
E. E. Collins, Regional Administrator, NRC Region IV N. Kalyanam, NRC Project Manager, San Onofre Units 2 and 3 C. C. Osterholtz, NRC Senior Resident Inspector, San Onofre Units 2 and 3
Enclosure Page 1 of 2 San Onofre Nuclear Generating Station Extended 3-Month Response to Generic Letter 2008-01 This letter provides Southern California Edison's (SCE's) extended 3-month response to NRC Generic Letter (GL) 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008. This response discusses: 1) the required evaluations that may not be complete by October 11, 2008 (9 months from the date of GL 2008-01); 2) the alternative course of action planned in the event the actions required are not complete by October 11, 2008; and 3) the basis for the acceptability of the alternative course of action.
The requested information in GL 2008-01 includes "...A description of all corrective actions, including plant, programmatic, procedure, and licensing basis modifications that you determined were necessary to assure compliance with these regulations..."
SCE conducted walkdowns of all safety-related, Seismic Category I, American Society of Mechanical Engineers (ASME) code piping (including the Emergency Core Cooling System) in response to IE Bulletin No. 79-14, "Seismic Analysis for As-Built Safety-Related Piping Systems." Inspections were performed and measurements were taken to ensure the piping was constructed as specified, and the isometrics were revised for "as-found" field conditions. SCE maintains the isometric drawings for design configuration control and to meet high seismic and stress analysis requirements.
An assessment of the system piping to confirm adequate vent capability will be performed in order to assure successful management of gas accumulation volumes.
Potential gas accumulation volumes will be determined by conservatively applying construction tolerances to the plant isometric drawings.
Where additional vent valves are deemed to be required, confirmatory walkdowns will be conducted to verify the need for additional vents. These confirmatory walkdowns may not be completed by October 11, 2008 for the following reasons:
" The restrictions on removal of insulation from piping on operating systems due to equipment qualification concerns;
- ALARA considerations for entry into radiation areas; and
" The requirement to erect scaffolding which may impact equipment operability.
SCE will submit a response within nine months of the date of the Generic Letter providing the results of the evaluation, identifying required confirmatory walkdowns that have not been completed, and providing the schedule for their completion.
SCE believes that the above-described approach is appropriate. First, the analytical assessment and pre-construction planning for any required additional venting can
Enclosure Page 2 of 2 proceed immediately rather than being delayed pending walkdown results. Second, by conducting walkdowns on an as-needed confirmatory basis, ALARA exposure and equipment unavailability are prudently managed.
SCE's alternative course of action is acceptable based on the adequacy of the current design, additional vent locations added as needed, plant-specific surveillance and analysis, and the results of previous system inspections. SCE believes that the subject systems are in compliance with the current licensing and design bases and applicable regulatory requirements, and that suitable design, operational, and testing control measures are in place for maintaining this compliance.