ML082610134

Palo Verde Nuclear Generating Station, Unit 2, Request for Additional Information, Second 10-Year Interval Inservice Inspection for Program Update and Relief Request 38 (TAC No. MD8328)

ML082610134
Person / Time
Site:	Palo Verde
Issue date:	09/24/2008
From:	Singal B K Plant Licensing Branch IV
To:	Edington R K Arizona Public Service Co
Singal, Balwant, 415-3016, NRR/DORL/LPL4
References
TAC MD8328
Download: ML082610134 (8)

Text

September 24, 2008

Mr. Randall K. Edington Executive Vice President Nuclear/CNO Mail Station 7602 Arizona Public Service Company P. O. Box 52034 Phoenix, AZ 85072-2034

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION RE: SECOND 10-YEAR INSERVICE INSPECTION PROGRAM INTERVAL FOR PROGRAM UPDATE AND RELIEF REQUEST 38 (TAC NO. MD8328)

Dear Mr. Edington:

By letter dated March 14, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML080920639), Arizona Public Service Company (the licensee) submitted Relief Request 38 for its second 10-year inservice inspection program interval for Palo Verde Nuclear Generating Station, Unit 2.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided and determined that additional information is required in order to complete the evaluation. As discussed with Russell Stroud of your staff, the NRC staff is requesting a response within 30 days of the date of this letter.

If you have any questions, please contact me at 301-415-1306.

Sincerely,

/RA/ Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-529

Enclosure:

Request for Additional Information cc w/encl: See next page Mr. Randall K. Edington Executive Vice President Nuclear/CNO Mail Station 7602 Arizona Public Service Company P. O. Box 52034 Phoenix, AZ 85072-2034

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION RE: SECOND 10-YEAR INSERVICE INSPECTION PROGRAM INTERVAL FOR PROGRAM UPDATE AND RELIEF REQUEST 38 (TAC NO. MD8328)

Dear Mr. Edington:

By letter dated March 14, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML080920639), Arizona Public Service Company (the licensee) submitted Relief Request 38 for its second 10-year inservice inspection program interval for Palo Verde Nuclear Generating Station, Unit 2.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided and determined that additional information is required in order to complete the evaluation. As discussed with Russell Stroud of your staff, the NRC staff is requesting a response within 30 days of the date of this letter.

If you have any questions, please contact me at 301-415-1306.

Sincerely, /RA/

Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket No. STN 50-529

Enclosure:

Request for Additional Information cc w/encl: See next page DISTRIBUTION

PUBLIC LPLIV Reading RidsAcrsAcnwMailCTR Resource ResourceRidsNrrDorlDpr Resource RidsNrrDorlLpl4 Resource RidsNrrDciCvib Resource RidsNrrPMBSingal Resource RidsNrrLAJBurkhardt Resource RidsOgcRp Resource RidsRgn4MailCenter Resource TMcLellan, NRR/DCI/CVIB DNaujock, NRR/DCI/CPNB ADAMS Accession No. ML082610134 (*) RAI input memo OFFICIAL AGENCY RECORD OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/DCI/CVIB/BC NRR/LPL4/BC NRR/LPL4/PM NAME BSingal JBurkhardt MMitchell* MMarkley BSingal DATE 9/23/08 9/18/08 8/26/08 9/24/08 9/24/08 Palo Verde Nuclear Generating Station 7/2/2008 cc: Mr. Steve Olea Arizona Corporation Commission 1200 W. Washington Street Phoenix, AZ 85007 Mr. Douglas Kent Porter Senior Counsel Southern California Edison Company Law Department, Generation Resources P.O. Box 800 Rosemead, CA 91770 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 40 Buckeye, AZ 85326 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 Chairman Maricopa County Board of Supervisors 301 W. Jefferson, 10th Floor Phoenix, AZ 85003 Mr. Aubrey V. Godwin, Director Arizona Radiation Regulatory Agency 4814 S. 40th Street Phoenix, AZ 85040 Mr. Scott Bauer, Director Regulatory Affairs Palo Verde Nuclear Generating Station Mail Station 7636 P.O. Box 52034 Phoenix, AZ 85072-2034 Mr. Dwight C. Mims, Vice President Regulatory Affairs and Plant Improvement Palo Verde Nuclear Generating Station Mail Station 7605 P.O. Box 52034 Phoenix, AZ 85072-2034 Mr. John C. Taylor Director, Nuclear Generation El Paso Electric Company 340 E. Palm Lane, Suite 310 Phoenix, AZ 85004 Mr. James Ray Public Service Company of New Mexico 2401 Aztec NE, MS Z110 Albuquerque, NM 87107-4224 Mr. Geoffrey M. Cook Southern California Edison Company 5000 Pacific Coast Hwy., Bldg. D21 San Clemente, CA 92672

Mr. Robert Henry Salt River Project 6504 E. Thomas Road Scottsdale, AZ 85251

Mr. Jeffrey T. Weikert Assistant General Counsel El Paso Electric Company Mail Location 167 123 W. Mills El Paso, TX 79901 Mr. Eric Tharp Los Angeles Department of Water & Power Southern California Public Power Authority P.O. Box 51111, Room 1255-C Los Angeles, CA 90051-0100 Mr. Brian Almon Public Utility Commission William B. Travis Building P.O. Box 13326 1701 N. Congress Avenue Austin, TX 78701-3326 Ms. Karen O'Regan Environmental Program Manager City of Phoenix Office of Environmental Programs 200 W. Washington Street Phoenix, AZ 85003

REQUEST FOR ADDITIONAL INFORMATION ARIZONA PUBLIC SERVICE COMPANY, ET. AL.

PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. STN 50-529 1.0 SCOPE By letter dated March 14, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML080920639), Arizona Public Service Company (the licensee), submitted Request for Relief (RR) 38 from requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, for Palo Verde Nuclear Generating Station (Palo Verde), Unit 2. The request for relief applies to the second 10-year inservice inspection (ISI) interval, in which Palo Verde, Unit 2 adopted the 1992 Edition, with the 1992 Addenda, of ASME Code Section XI as the Code of record.

In accordance with Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(g)(5)(iii), the licensee has submitted RR 38 for certain Class 1 and Class 2 component weld examinations. The ASME Code requires that 100 percent of the examination volumes described in Tables IWB2500-1 and IWC-2500-1 be completed. The licensee has claimed that 100 percent of the ASME Code-required volumes are impractical to obtain at Palo Verde, Unit 2. Paragraph 50.55a(g)(5)(iii) of 10 CFR states that when licensees determine that conformance with ASME Code requirements is impractical at their facility, they shall submit information to support this determination. The U.S. Nuclear Regulatory Commission (NRC) will evaluate such requests based on impracticality, and may impose alternatives, giving due consideration to public safety and the burden imposed on the licensee.

The NRC staff reviewed the information submitted by the licensee, and based on this review, determined the following additional information is required to complete the evaluation. For the ease of tracking various reliefs for the different ASME Code,Section XI, Examination Categories, the staff has divided the reliefs into parts.

2.0 REQUEST FOR ADDITIONAL INFORMATION

2.1 Part A, Examination Category B-A, Item B1.22, Pressure Retaining Welds in Reactor Vessel The licensee stated that the reactor pressure vessel (RPV) lower head meridional weld examination is limited to approximately 22 percent of the Code volume coverage, due to geometric constraints of the in-core instrumentation penetrations and flow skirt. The licensee provided a schematic of the subject (Figure 1) depicting in-core instrumentation penetrations and the flow skirt configuration depicting the interferences that create the limitations. The ASME Code states that essentially 100 percent of the "accessible length" of the subject weld must be volumetrically examined.

Note: The ASME Code Committees, when implementing the above requirement in the ASME Code, considered the various obstacles (e.g., control rod drives (in some cases), Enclosure RPV support skirt, instrument lines, etc.) that prevent the volumetric examination of the full length of the subject weld. For this particular ASME Code requirement, the examinations are limited to the accessible length of the RPV lower head weld.

The licensee is requested to:

(a) Define the accessible length of the RPV bottom head meridional weld and state whether the reported 22 percent volumetric coverage represents essentially 100 percent of this accessible length. If the reported 22 percent volumetric coverage represents essentially 100 percent of this accessible length, provide reasons for requesting for the relief. If essentially 100 percent of the accessible weld length was not achieved, continue to question 2.1(b).

(b) The licensee stated that, given presently available technology, no additional coverage can be obtained. In order to demonstrate impracticality, provide a brief description of the technology deployed and discuss the specific reasons that limit coverage using this technology.

2.2 Part B, Examination Category B-D, Item B3.110, Full Penetration Welded Nozzles in Vessels Please clarify the following statement regarding the examination of pressurizer nozzle-to-vessel welds 5-10 and 5-13:

Pressurizer nozzle Zone 5 welds 5-10 and 5-13 were limited to an average of 83% Code volume coverage because of limited access based on geometric constraints of the nozzle. The radius portion of the nozzle and the curvature of the Pressurizer head limited some angles of sound to portions of the inside diameter.

Note: General references to geometric constraints, nozzle radius portion, and curvature of the pressurizer head are not adequate to demonstrate impracticality. In addition, the impact of these conditions on ultrasonic beam propagation and coverage are not well defined.

The licensee is requested to:

(a) Provide detailed information to support the basis for the limited examinations of pressurizer nozzle-to-vessel welds 5-10 and 5-13 and the basis for demonstrating impracticality. Include detailed descriptions (with sufficient explanation, and lay-out or cross-sectional drawings/sketches) to enable the staff to understand the causes of ultrasonic scan limitations and their impact on examination volume coverage.

(b) List the type of nozzles included in the subject request (e.g. surge, safety, relief, spray, etc.) and describe the nozzle dimensions and the materials used in the fabrication of these nozzles.

2.3 Part C, Examination Category B-H, Item B8.20, Integral Attachments for Vessels The licensee is requested to: (a) Provide a cross-sectional sketch showing the pressurizer support skirt weld. Include in this sketch a depiction of how the volumetric technique was applied and coverage obtained.

(b) Confirm that 100 percent of the surface examination was performed on the outside surface of the pressurizer support skirt weld.

2.4 Part D, Examination Category B-J, Items B9.11, Pressure Retaining Welds in Piping It is not apparent that the following general statements demonstrate impracticality for the ASME Code,Section XI, Examination Category B-J piping welds.

Several [ASME Code, Section XI] category B-J and C-F-1 butt welds were only accessible from one side of the weld due to configuration. Only 50% Code volume coverage was credited due to single sided examination of austenitic stainless steel welds e.g.; obstruction from valves. The licensee is requested to:

(a) Describe the configuration (e.g., pipe-to-valve, pipe-to-elbow, etc.), materials and dimensions of each of the ASME Code,Section XI, Examination Category B-J piping welds.

(b) Provide detailed information to support the basis for each limited ASME Code,Section XI, Examination Category B-J weld and, therefore, demonstrate impracticality. Include detailed descriptions (with sufficient explanation, and lay-out or cross-sectional drawings/sketches) to enable the staff to understand the causes of ultrasonic scan limitations and their impact on examination volume coverage.

(c) Describe the ultrasonic techniques (shear wave and angles, and refracted L-wave and angles) applied to maximize coverage when examining from a single side of these welds.

(d) In addition to the basis for impracticality, state whether any outside diameter surface feature, such as weld crown, diametrical weld shrinkage, or surface roughness conditions caused limited volumetric coverage during the subject piping weld examinations. Discuss the efforts that were used to address these conditions.

(e) Confirm that ASME Code-required surface examinations were completed for the subject welds.

2.5 Part E, Examination Category C-C, Items C3.20 and C3.30, Integral Attachments for Vessels, Piping, Pumps, and Valves The licensee is requested to:

(a) Confirm that component support SI-107-H-022 is located on the safety injection system piping.

(b) Provide a sketch or photograph depicting the stated configuration of welded attachments on component supports 116-1B and 116-1C. Also, list the high-pressure safety injection pump designation for the subject supports.

2.6 Part F, Examination Category C-F-1, Items C5.11 and Item C5.21, Pressure Retaining Welds in Austenitic Stainless Steel or High Alloy Piping It is not apparent that the following general statements demonstrate impracticality for the ASME Code,Section XI, Examination Category C-F-1 piping welds.

Several [ASME Code, Section XI]

category B-J and C-F-1 butt welds were only accessible from one side of the weld due to configuration. Only 50% Code volume coverage was credited due to single sided examination of austenitic stainless steel welds e.g.; obstruction from

valves. The licensee is requested to:

(a) Describe the configuration (e.g., pipe-to-valve, pipe-to-elbow, etc.), materials and dimensions of each of the ASME Code,Section XI, Examination Category C-F-1 piping welds.

(b) Provide detailed information to support the basis for each limited ASME Code,Section XI, Examination Category C-F-1 weld and, therefore, demonstrate impracticality. Include detailed descriptions (with sufficient explanation, and lay-out or cross-sectional drawings/sketches) to enable the staff to understand the causes of ultrasonic scan limitations and their impact on examination volume coverage.

(c) Describe the ultrasonic techniques (shear wave and angles, and refracted L-wave and angles) applied to maximize coverage when examining from a single side of these welds.

(d) In addition to the basis for impracticality, state whether any outside diameter surface feature, such as weld crown, diametrical weld shrinkage, or surface roughness conditions caused limited volumetric coverage during the subject piping weld examinations. Discuss the efforts that were used to address these conditions.

(e) Confirm that ASME Code-required surface examinations were completed for the subject welds.