DCL-10-128, Response to NRC Letter Dated September 13, 2010, Request for Additional Information (Set 23) License Renewal Application
| ML102940148 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon, Shoreham  |
| Issue date: | 10/12/2010 |
| From: | Becker J Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| DCL-10-128 | |
| Download: ML102940148 (10) | |
Text
Pacific Gas and Electric Company James R. Becker Diablo Canyon Power Plant Site Vice President Mail Code 104/5/ 601
- p. O. Box 56 Avila Beach, CA93424 805.545.3462 October 12, 2010 Internal: 691.3462 Fax: 805.545.6445 PG&E Letter DCL-10-128 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20852 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Response to NRC Letter dated September 13, 2010, Request for Additional Information (Set 23) for the Diablo Canyon License Renewal Application
Dear Commissioners and Staff:
By letter dated November 23, 2009 (Reference 1), Pacific Gas and Electric Company (PG&E) submitted an application to the U.S. Nuclear Regulatory Commission (NRC) for the renewal of Facility Operating Licenses DPR-80 and DPR-82, for Diablo Canyon Power Plant (DCPP) Units 1 and 2, respectively.
The application included the license renewal application (LRA), and Applicant's Environmental Report - Operating License Renewal Stage.
By letter dated September 13, 2010, the NRC staff requested additional information needed to continue their review of the DCPP LRA.
PG&E's response to the Requests for Additional Information is provided in Enclosure 1. PG&E has identified additional changes that are required in the LRA submitted in Reference 1. LRA Amendment 17 is included in Enclosure 2 showing the changed pages with line-in/line-out annotations.
PG&E makes a commitment in revised LRA Table A4-1, License Renewal Commitments, shown in Enclosure 2.
If you have any questions regarding this response, please contact Mr. Terence L. Grebel, License Renewal Project Manager, at (805) 545-4160.
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway . Comanche Peak . Diablo Canyon . Palo Verde . San Onofre . South Te x as Project . Wolf Creek
Document Control Desk PG&E Letter DCL-1 0-128 October 12, 2010 Page 2 I declare under penalty of perjury that the foregoing is true and correct.
Executed on October 12, 2010.
TLG/50342432 Enclosure cc: Diablo Distribution cc/enc: Elmo E. Collins, NRC Region IV Regional Administrator Nathanial Ferrer, NRC Project Manager, License Renewal Kimberly J. Green, NRC Project Manager, License Renewal Fred Lyon, NRC Project Manager, Office of Nuclear Reactor Regulation Michael S. Peck, NRC Senior Resident Inspector A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway. Comanche Peak. Diablo Canyon. Palo Verde. San Onofre. South Texas Project. Wolf Creek
Enclosure 1 PG&E Letter DCL-10-128 Page 1 of 5 PG&E Response to NRC Letter dated September 13, 2010 Request for Additional Information (Set 23) for the Diablo Canyon License Renewal Application RAI 2.1-2 (Follow-Up)
In the June 18, 2010, response to RAI 2.1-2, the applicant added additional systems to the scope of license renewal, which included the sanitary sewage system. The U.S. Nuclear Regulatory Commission (the staff) made the following observations:
- The system description for the sanitary sewage system was provided in the June 18, 2010, letter; however, the response was unclear in assisting the staff to identify the license renewal boundary to confirm that the correct components were captured in scope in the license renewal application (LRA) Table 2.3.3-18. The staff requests that the applicant provide supplemental information to identify the license renewal boundary for the sanitary sewage system.
- On license renewal boundary drawing LR-DCPP-15-106715-02, the applicant shows the service water loop at location 29-E through A in scope for license renewal. However, the heat exchanger in that loop was not identified in LRA Table 2.3.3-18. The staff requests that the applicant justify the exclusion of the heat exchanger from the scope of license renewal.
PG&E Response to RAI 2.1-2 (Follow-Up)
- A walkdown of selected plant design features performed on February 18, 2010, identified potentially adverse spatial interactions involving what appeared to be sewer piping extending into the Unit 2 diesel compartment. The subject sanitary sewer piping is not shown on a license renewal boundary drawing. Therefore, an extent of condition walkdown was performed to determine the extent of liquid-filled pipe in the diesel generator (DG) and other rooms in the turbine building containing safety-related equipment. Sanitary sewer piping was confirmed to be located in the Unit 2 emergency diesel generator (EDG) 2-3 DG room.
The sanitary sewer piping is depicted on plumbing drawing 501418 and confirms that sanitary sewer piping does extend into the Unit 2 EDG 2-3 DG room. There is no corresponding sanitary sewer piping in the other Units 1 and 2 DG rooms or any other areas of safety-related components.
Enclosure 1 PG&E Letter DCL-10-128 Page 2 of 5 Therefore, the only portion of the sanitary sewer system that is in scope of license renewal is located in the Unit 2 EDG 2-3 DG room. A boundary drawing was not created from the plumbing drawing. License Renewal Application (LRA) Section 2.3.3.18 has been revised to include discussion of the portion of sanitary sewer drain piping that extends down through the turbine building floor into the Unit 2 DG area. See revised LRA Section 2.3.3.18 in Enclosure 2.
- The heat exchanger depicted on LR-DCPP-15-106715-02 is no longer in the system. It was removed by a plant modification. Boundary drawing LR-DCPP-15-106715-02 has been revised based on the latest version of the DCPP operating valve identification diagram, which no longer shows the heat exchanger on the drawing.
Enclosure 1 PG&E Letter DCL-10-128 Page 3 of 5 RAI 2.3-2 (Follow-Up)
In the June 18, 2010, response to RAI 2.3-2, the applicant stated that the guard pipe was within the scope of license renewal with a fire barrier intended function under Title 10 of the Code of Federal Regulations (10 CFR) 54.4(a)(3). The staff verified that on the revised license renewal boundary drawings the guard pipe was placed in scope and added to the LRA tables; however, on the revised license renewal boundary drawing for Unit 1 (LR-DCPP-08-106708-05), the manual regulator, an open diaphragm valve and closed diaphragm valve, were not depicted in scope for license renewal. On license renewal boundary drawing for Unit 2 (LR-DCPP-081077708-05), the same components are captured in scope for 10 CFR 54.4(a)(2). The staff requests that the applicant justify the exclusion of the above Unit 1 components from the scope of license renewal.
PG&E Response to RAI 2.3-2 (Follow-Up)
The guard pipe enclosing the hydrogen piping and valves has a fire barrier intended function, but the hydrogen piping and valves do not. The piping and valves do not need to have this intended function because of the presence of the guard pipe. The reason that the manual regulator and diaphragm valves in Unit 2 are in scope is due to the location of the seismic support on the piping containing these components. This piping is attached to a safety-related valve on the volume control tank, and these components are in scope only for structural integrity (attached). On Unit 1, the seismic support is located between these components and the volume control tank, and therefore they are not in scope.
Enclosure 1 PG&E Letter DCL-10-128 Page 4 of 5 RAI 2.3-3 (Follow-Up)
In the June 18, 2010, response to RAI 2.3-3, the applicant added the oily water and turbine sump system to the scope of license renewal. Indications in the license renewal boundary drawings and the Final Safety Analysis Report show that there are fluid-filled components (i.e., sumps, pumps, and piping) in the underground manholes for electrical systems and fuel oil transfer pump vaults.
These fluid-filled components are potentially in the same space as safety related systems, structures, and components (SSCs) in scope for license renewal and may need to be included in the scope of license renewal in accordance with 10 CFR 54.4(a)(2). The staff requests that the applicant justify its exclusion of the fluid-filled components located in the underground manholes from scope of license renewal.
PG&E Response to RAI 2.3-3 (Follow-Up)
There are no safety-related components in the underground manholes shown on the license renewal boundary drawings for the oily water and turbine sump system. For that reason, the fluid-filled components in the manholes serve no license renewal function and are excluded from the scope of license renewal.
For electrical pullboxes at Diablo Canyon Power Plant (DCPP), the drain is at a low point of the pullbox and any fluid drains, gravity driven, to a sump where it is pumped to the turbine building sump. The drain piping components and sump for electrical pullboxes are oriented such that fluids cannot spray or leak onto safety-related cables or conduits.
The drain piping and associated components for the fuel oil transfer pump vaults are oriented such that fluids can not spray or leak onto safety-related components. The drainage system is gravity driven and drains to the turbine building sump system. DCPP Final Safety Analysis Report, Section 9.5.4.3, states that the two transfer pumps are in separate, underground, reinforced concrete vaults with solid covers protected from surface runoff due to their location inside the west buttress and condensate polishing system structure. The vaults manway hatch covers are made of steel and are provided with concrete curbing to prevent water intrusion into the vaults. These vaults are drained to the building sump and are protected with backwater valves. The drain piping for the fuel oil transfer pump vaults and the backwater valves are included in the scope of license renewal for (a)(2) considerations.
Enclosure 1 PG&E Letter DCL-10-128 Page 5 of 5 RAI 2.3-5 (Follow-Up)
In the June 18, 2010. response to RAI 2.3-5,. the applicant added long term cooling as a system intended function for the condensate. makeup water. and fire protection systems. The applicant revised the systems' scoping boundaries to include additional components into the scope of license renewal required to perform this system intended function of long term cooling. Some of the systems' components required to perform this function were already in scope of license renewal, and assigned a component intended function of "leakage boundary."
In order to support the long term cooling system intended function. certain SSCs in the flow paths now have additional component intended functions. For example, strainers in the makeup water system should now have a component intended function of "filter," in order to maintain the flow path for long term cooling. The staff requests that the applicant evaluate all components in the above systems included in the revised long term cooling flow paths and provide any additional intended functions.
PG&E Response to RAI 2.3-5 (Follow-Up)
Components in the condensate, makeup water, and fire protection systems that support the long term cooling function were evaluated for additional component intended functions. Strainers in the makeup water system were identified that support long term cooling. These strainers are periodically cleaned and inspected on 24 month frequency by preventative maintenance activities. Other components in the long term cooling flow paths will be evaluated to ensure additional components and intended functions are managed by the Fire Water System Aging Management Program B2.1.13.
Table A4-1 has been revised to state that DCPP will update the PM basis documents for strainers in the makeup water system that support long term cooling to require that they are cleaned and inspected on a 24 month frequency during the period of extended operation. These PM activities will be performed as part of the Fire Water System Aging Management Program, B2.1.13. Other components in the long term cooling flow paths will be evaluated to ensure additional components and intended functions are managed by the Fire Water System Aging Management Program B2.1.13. See revised LRA Table A4-1 in .
PG&E Letter DCL-10-128 Page 1 of 3 LRA Amendment 17 LRA Section RAI 2.3.3.18 2.1-2 Table A4-1 2.3-5 Section 2.3 PG&E Letter DCL-10-128 SCOPING AND SCREENING RESULTS:
Page 2 of 3 MECHANICAL SYSTEMS 2.3.3.18 Miscellaneous Systems In Scope ONLY for Criterion 10 CFR 54.4(a)(2)
Sanitary sewage The sanitary sewage system transfers sewage from site facilities to the sewage treatment plants.
The sanitary sewage system consists of a breaker, motors, pumps, relays, switches, piping and valves. Most of these components are located in the yard and in various yard pumping stations. Piping in the power block transfers sewage from that area to the yard. A portion of sanitary sewer drain piping extends down through the turbine building floor into the Unit 2 diesel generator area.
Portions of the sanitary sewage system are in the scope as nonsafety affecting safety-related components based on the criterion of 10 CFR 54.4(a)(2) due to spatial interaction.
Secondary Sampling System The secondary sampling system is a nonsafety-related system that provides sampling and analysis of secondary plant systems.
The central sample panel for each unit is located in the auxiliary building. Each unit has another sample panel located in the buttress area west of the turbine building. Most of the sample points and lines are in the turbine building but the lines leading to the central sample panels are in the auxiliary building. Portions of the secondary sampling system piping and piping components in the turbine building contain high energy fluids.
Portions of the secondary sampling system are in scope as nonsafety affecting safety-related components based on the criterion of 10 CFR 54.4(a)(2) due to spatial interaction and structural integrity. High energy portions of the Secondary Sampling System in the turbine building could prevent the satisfactory accomplishment of a safety-related function associated with certain safety-related cables. These portions of the Secondary Sampling System are within the scope of license renewal as nonsafety affecting safety-related components based on the criterion of 10 CFR 54.4(a)(2).
Table A4-1 PG&E Letter DCL-10-128 LICENSE RENEWAL COMMITMENTS Page 3 of 3 Table A4-1License Renewal Commitments Item # Commitment LRA Implementation Section Schedule 49 DCPP will update the PM basis documents for strainers in the makeup water B2.1.13 Prior to the period system that support long term cooling to require that they are cleaned and of extended inspected on a 24 month frequency during the period of extended operation. operation