DCL-08-032, Three-Month Response to NRC Generic Letter 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems
| ML081120112 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 04/10/2008 |
| From: | Becker J Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-08-001, OL-DPR-80, OL-DPR-82, PG&E Letter DCL-08-032 | |
| Download: ML081120112 (5) | |
Text
PacificGas and Electric Company' James R. Becker Diablo Canyon Power Plant Site Vice President and Mail Code 104/5/502 Station Director P. 0. Box 56 Avila Beach, CA 93424 April 10, 2008 10 CFR 50.54(f) 805.545.3462 Internal: 691.3462 Fax: 805. 545.4234 PG&E Letter DCL-08-032 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2
Subject:
Three-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" Reference 1: NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008.
Dear Commissioners and Staff:
The U. S. Nuclear Regulatory Commission (NRC) issued NRC Generic Letter (GL) 2008-01 (Reference 1) to request that each licensee evaluate its Emergency Core Cooling System, Residual Heat Removal System, and Containment Spray System licensing basis, design, testing, and corrective actions 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 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, X1, 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; A member of the STARS (Strategic Teaming and Resource Sharing) Afliance Callaway
- Comanche Peak o Diablo Canyon
- Palo Verde o South Texas Project
- Wolf Creek
Document Control Desk PG&E Letter DCL-08-032 April 10, 2008 Page 2 (b) A description of all corrective actions, including plant, programmatic, procedure, and licensing basis modifications that the licensee 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 is 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.
The enclosure to this letter contains the Pacific Gas and Electric Company (PG&E) 3-month response to the requested information in NRC GL 2008-01.
This letter contains the following new commitment:
"PG&E will perform any necessary confirmatory walkdowns of inaccessible piping in the DCPP Unit 1 containment during Unit 1 Refueling Outage Fifteen (1 R1 5), currently scheduled to begin in January 2009. Any corrective actions that are identified that PG&E determines can reasonably be performed during 1R1 5 will be completed during that refueling outage. Any other corrective actions that are identified during 1R1 5 which cannot be completed will be implemented prior to restart following Unit I Refueling Outage Sixteen.
PG&E will provide a supplemental submittal within 60 days of the completion of I R1 5 describing any corrective actions identified and their schedule for completion."
This response is submitted in accordance with 10 CFR 50.4.
If there are any questions or if additional information is needed, please contact Stan Ketelsen at 805-545-4720.
I state under penalty of perjury that the foregoing is true and correct.
Executed on April 10, 2008.
A member of the STARS . (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
Document Control Desk PG&E Letter DCL-08-032 April 10, 2008 Page 3 James 1. Becker---7--
Site Vice Presidentand Station Director mjrm/4557 A0716463AE02 Enclosures cc: Gary W. Butner, Acting Branch Chief, California Department of Public Health Elmo E. Collins, NRC Region IV Michael S. Peck,.NRC, Senior Resident Inspector Diablo Distribution cc/enc: Alan B. Wang, Project Manager, Office of Nuclear Reactor Regulation A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak e Diablo Canyon 9 Palo Verde 9 South Texas Project
- Wolf Creek
Enclosure PG&E Letter DCL-08-032 PG&E 3-Month Response to NRC Generic Letter 2008-01 NRC Generic Letter (GL) 2008-01, "Managing Gas Accumulation in Emergency Core Cooling [ECCS], Decay Heat Removal, and Containment Spray Systems [CSS]," dated January 11, 2008, was issued to address the issue of gas accumulation in the ECCS, Residual Heat Removal System (RHRS), and CSS.
The NRC issued the GL to request information from licensees regarding compliance with current licensing and design basis requirements, applicable regulatory requirements, and control measures in place for maintaining compliance.
The NRC has requested that each addressee evaluate its ECCS, RHRS, and CSS licensing basis, design, testing, and corrective actions 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.
This letter provides Pacific Gas and Electric Company's (PG&E) 3-month response to NRC GL 2008-01.
This response discusses:
- The required evaluations that will not be complete by October 11, 2008 (9 months from the date of GL 2008-01);
9 The alternative course of action planned; and
- The basis for the acceptability of the alternative course of action.
The requested information in NRC 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..." The requested description of all corrective actions pertaining to plant modifications would require the completion of a thorough physical walkdown of the system piping to confirm such things as adequate vent capability for system high points, and verification that the design drawings reflect the as-built piping.
PG&E has reviewed the GL for applicable piping at Diablo Canyon Power Plant (DCPP) that will be inaccessible prior to the 9-month due date. PG&E previously performed plant walkdowns as part of INPO Significant Operating Experience Report (SOER) 97-01 (Reference 1) efforts. However, PG&E believes that confirmatory walkdowns are a prudent measure to revalidate the piping configuration for ECCS piping segments in containment that connect to the accumulators whose pressurized nitrogen cover blanket represents a potential gas source to the ECCS. PG&E has determined that additional walkdowns will not be necessary to complete the evaluations requested in the GL for RHRS and CSS piping.
1
- V Enclosure PG&E Letter DCL-08-032-During Unit 2 Refueling Outage Fourteen (2R1 4), a confirmatory walkdown was performed on ECCS piping segments with potential configurations for gas accumulation.
DCPP 2R1 4 walkdown results indicate that all of the potential gas-trapping locations have adequate vent locations and that the as-built piping configurations are consistent with the isometric drawings. The Unit 1 ECCS piping configuration is similar to Unit 2.
Unit 1 ECCS piping in containment is considered inaccessible while at power due to the containment environment being one with excessive heat, poor lighting, and increased radiation levels, which makes accessing the piping more hazardous as compared to non-outage periods. In addition, access to ECCS piping requires the erection of scaffolding which would result in additional personnel dose.
In order to perform confirmatory walkdowns of the containment as part of a complete GL response, Unit 1 will need to be in a shutdown condition. Therefore, the walkdowns for inaccessible piping in the Unit 1 containment will not be complete by October 11, 2008.
PG&E will perform any necessary confirmatory walkdowns of inaccessible piping in the DCPP Unit 1 containment during Unit 1 Refueling Outage Fifteen (1 R1 5), currently scheduled to begin in January 2009. Any corrective actions that are identified that PG&E determines can reasonably be performed during 1R1 5 will be completed during that refueling outage. Any other corrective actions that are identified during 1 R1 5 which cannot be completed will be implemented prior to restart following Unit 1 Refueling Outage Sixteen. PG&E will provide a supplemental. submittal within 60 days of the completion of 1R1 5 describing any corrective actions identified and their schedule for completion.
References:
- 1. INPO Significant Operating Experience Report (SOER) 97-01, "Potential Loss of High Pressure Injection and Charging Capability from Gas Intrusion," dated December 6, 1997.
2
Text
PacificGas and Electric Company' James R. Becker Diablo Canyon Power Plant Site Vice President and Mail Code 104/5/502 Station Director P. 0. Box 56 Avila Beach, CA 93424 April 10, 2008 10 CFR 50.54(f) 805.545.3462 Internal: 691.3462 Fax: 805. 545.4234 PG&E Letter DCL-08-032 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2
Subject:
Three-Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" Reference 1: NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008.
Dear Commissioners and Staff:
The U. S. Nuclear Regulatory Commission (NRC) issued NRC Generic Letter (GL) 2008-01 (Reference 1) to request that each licensee evaluate its Emergency Core Cooling System, Residual Heat Removal System, and Containment Spray System licensing basis, design, testing, and corrective actions 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 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, X1, 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; A member of the STARS (Strategic Teaming and Resource Sharing) Afliance Callaway
- Comanche Peak o Diablo Canyon
- Palo Verde o South Texas Project
- Wolf Creek
Document Control Desk PG&E Letter DCL-08-032 April 10, 2008 Page 2 (b) A description of all corrective actions, including plant, programmatic, procedure, and licensing basis modifications that the licensee 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 is 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.
The enclosure to this letter contains the Pacific Gas and Electric Company (PG&E) 3-month response to the requested information in NRC GL 2008-01.
This letter contains the following new commitment:
"PG&E will perform any necessary confirmatory walkdowns of inaccessible piping in the DCPP Unit 1 containment during Unit 1 Refueling Outage Fifteen (1 R1 5), currently scheduled to begin in January 2009. Any corrective actions that are identified that PG&E determines can reasonably be performed during 1R1 5 will be completed during that refueling outage. Any other corrective actions that are identified during 1R1 5 which cannot be completed will be implemented prior to restart following Unit I Refueling Outage Sixteen.
PG&E will provide a supplemental submittal within 60 days of the completion of I R1 5 describing any corrective actions identified and their schedule for completion."
This response is submitted in accordance with 10 CFR 50.4.
If there are any questions or if additional information is needed, please contact Stan Ketelsen at 805-545-4720.
I state under penalty of perjury that the foregoing is true and correct.
Executed on April 10, 2008.
A member of the STARS . (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
Document Control Desk PG&E Letter DCL-08-032 April 10, 2008 Page 3 James 1. Becker---7--
Site Vice Presidentand Station Director mjrm/4557 A0716463AE02 Enclosures cc: Gary W. Butner, Acting Branch Chief, California Department of Public Health Elmo E. Collins, NRC Region IV Michael S. Peck,.NRC, Senior Resident Inspector Diablo Distribution cc/enc: Alan B. Wang, Project Manager, Office of Nuclear Reactor Regulation A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak e Diablo Canyon 9 Palo Verde 9 South Texas Project
- Wolf Creek
Enclosure PG&E Letter DCL-08-032 PG&E 3-Month Response to NRC Generic Letter 2008-01 NRC Generic Letter (GL) 2008-01, "Managing Gas Accumulation in Emergency Core Cooling [ECCS], Decay Heat Removal, and Containment Spray Systems [CSS]," dated January 11, 2008, was issued to address the issue of gas accumulation in the ECCS, Residual Heat Removal System (RHRS), and CSS.
The NRC issued the GL to request information from licensees regarding compliance with current licensing and design basis requirements, applicable regulatory requirements, and control measures in place for maintaining compliance.
The NRC has requested that each addressee evaluate its ECCS, RHRS, and CSS licensing basis, design, testing, and corrective actions 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.
This letter provides Pacific Gas and Electric Company's (PG&E) 3-month response to NRC GL 2008-01.
This response discusses:
- The required evaluations that will not be complete by October 11, 2008 (9 months from the date of GL 2008-01);
9 The alternative course of action planned; and
- The basis for the acceptability of the alternative course of action.
The requested information in NRC 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..." The requested description of all corrective actions pertaining to plant modifications would require the completion of a thorough physical walkdown of the system piping to confirm such things as adequate vent capability for system high points, and verification that the design drawings reflect the as-built piping.
PG&E has reviewed the GL for applicable piping at Diablo Canyon Power Plant (DCPP) that will be inaccessible prior to the 9-month due date. PG&E previously performed plant walkdowns as part of INPO Significant Operating Experience Report (SOER) 97-01 (Reference 1) efforts. However, PG&E believes that confirmatory walkdowns are a prudent measure to revalidate the piping configuration for ECCS piping segments in containment that connect to the accumulators whose pressurized nitrogen cover blanket represents a potential gas source to the ECCS. PG&E has determined that additional walkdowns will not be necessary to complete the evaluations requested in the GL for RHRS and CSS piping.
1
- V Enclosure PG&E Letter DCL-08-032-During Unit 2 Refueling Outage Fourteen (2R1 4), a confirmatory walkdown was performed on ECCS piping segments with potential configurations for gas accumulation.
DCPP 2R1 4 walkdown results indicate that all of the potential gas-trapping locations have adequate vent locations and that the as-built piping configurations are consistent with the isometric drawings. The Unit 1 ECCS piping configuration is similar to Unit 2.
Unit 1 ECCS piping in containment is considered inaccessible while at power due to the containment environment being one with excessive heat, poor lighting, and increased radiation levels, which makes accessing the piping more hazardous as compared to non-outage periods. In addition, access to ECCS piping requires the erection of scaffolding which would result in additional personnel dose.
In order to perform confirmatory walkdowns of the containment as part of a complete GL response, Unit 1 will need to be in a shutdown condition. Therefore, the walkdowns for inaccessible piping in the Unit 1 containment will not be complete by October 11, 2008.
PG&E will perform any necessary confirmatory walkdowns of inaccessible piping in the DCPP Unit 1 containment during Unit 1 Refueling Outage Fifteen (1 R1 5), currently scheduled to begin in January 2009. Any corrective actions that are identified that PG&E determines can reasonably be performed during 1R1 5 will be completed during that refueling outage. Any other corrective actions that are identified during 1 R1 5 which cannot be completed will be implemented prior to restart following Unit 1 Refueling Outage Sixteen. PG&E will provide a supplemental. submittal within 60 days of the completion of 1R1 5 describing any corrective actions identified and their schedule for completion.
References:
- 1. INPO Significant Operating Experience Report (SOER) 97-01, "Potential Loss of High Pressure Injection and Charging Capability from Gas Intrusion," dated December 6, 1997.
2