ML092720936
| ML092720936 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 09/23/2009 |
| From: | Farideh Saba Plant Licensing Branch II |
| To: | |
| Saba F, NRR/DORL/LPL2-2, 301-415-1447 | |
| Shared Package | |
| ML092720937 | List: |
| References | |
| TAC ME1143, TAC ME1144, TAC ME1145, TAC ME1146 | |
| Download: ML092720936 (5) | |
Text
ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION ON THE THIRD TEN YEAR 10-YEAR INSERVICE INSPECTION INTERVAL REQUESTS FOR RELIEF RR-42, RR-43, RR-44, AND RR-45 CAROLINA POWER AND LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNIT 1 DOCKET NUMBER: 50-325 1.0 SCOPE By letter dated April 27, 2009, the licensee, Carolina Power and Light Company, submitted Requests for Relief (RR) RR-42, RR-43, RR-44, and RR-45, from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, for Brunswick Steam Electric Plant, Unit 1 (BSEP-1). The requests for relief are for the third 10-year inservice inspection (ISI) interval, in which the licensee adopted the 1989 Edition of ASME Code Section XI, No Addenda, as the Code of record.
In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii), the licensee has submitted the subject requests for relief for limited examinations in multiple ASME Code Examination Categories. The ASME Code requires that 100% of the examination volumes, or surface areas, described in ASME Code,Section XI, Tables IWB-2500 and IWC-2500 be performed during each interval. The licensee stated that 100% of the ASME Code-required volumes, or surface areas, are impractical to obtain at BSEP-1.
10 CFR 50.55a(g)(5)(iii) 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 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 Nuclear Regulatory Commission staff has reviewed the information submitted by the licensee, and based on this review, determined the following information is required to complete the evaluation.
2.0 REQUEST FOR ADDITIONAL INFORMATION A.
Request for Relief RR-44, ASME Code,Section XI, Examination Category B-A, Items B1.22 and B1.30, Pressure Retaining Welds in Reactor Pressure Vessel (RPV)
RPV Bottom Head Meridional Welds (1B11-RPV-J31 and 1B11-RPV-J42)
The licensee stated that no access was possible to the portions of the meridional welds located inside the vessel support skirt, and that control rod drive (CRD) housings would interfere with examinations in this area. However, access to this region (inside the RPV support skirt) is typically available through man-ways to enable maintenance work on the CRD housings to occur, as necessary. Further information is needed to provide an adequate basis for impracticality.
1.)
Provide further information (descriptions, sketches, measurements, etc.) to show that no access to these welds from the inside of the RPV support skirt area is possible.
2.)
State whether 100% of the accessible portion (outside of the vessel support skirt) of these welds was examined. If less than 100% of the ASME Code-required volume was examined for the accessible portion of the welds, provide cross-sectional coverage plots to show the volume coverage obtained for each of these welds.
3.)
In the written description, the licensee stated that [Ultrasonic Testing] UT examination was performed using personnel and examination procedures qualified to the ASME Code, Appendix VIII, as administered by the [Electric Power Research Institute (EPRI)] Performance Demonstration Initiative (PDI).
However, it is unclear what angles were used or if the examinations used shear or longitudinal waves.
4.)
Please clarify the ultrasonic sound beam modes and insonification angles used for all ultrasonic examinations.
5.)
State whether the accessible portions of the welds was examined from both sides.
6.)
State whether any indications were discovered as a result of these examinations, and how these indications were dispositioned.
B.
RPV Shell-to-Flange Weld (1B11-RPV-F1 and 1B11-RPV-F2)
The licensee stated that the design configuration/restriction makes compliance with the ASME Code-required examination coverage requirements impractical. However, this general statement is unclear and insufficient to adequately demonstrate impracticality.
1.) Provide detailed descriptions (text and supporting sketches with dimensions, as necessary) of the interferences to applied UT techniques.
2.) Based on the limited information in the sketch provided by the licensee, it is assumed that these examinations were performed from the outside surface of the RPV.
Discuss whether ASME Code volumetric coverage could be increased by applying nondestructive examination (NDE) from the inside surface of the RPV.
3.) On the coverage calculation sheet, the licensee provided some information pertaining to the UT techniques applied. However, it is unclear whether the angles shown represent shear or longitudinal waves. Please clarify the UT sound beam modes and insonification angles used for all UT examinations.
4.) State whether any indications were discovered as a result of these examinations, and how these indications were dispositioned.
C.
Request for Relief RR-42, ASME Code,Section XI, Examination Category B-D, Item B3.90, Full Penetration Welded Nozzles in Vessels, RPV Nozzle-to-Vessel Welds The licensee stated that Due to the design of these welds it was not feasible to effectively perform a volumetric examination of "essentially 100 percent" of the required volume. The nozzle-to-vessel welds are accessible from the vessel plate side of the weld and are examined to the extent practical. In addition, the licensees table only lists examination limited due to nozzle configuration as a basis. However, these general statements are not adequate to fully demonstrate impracticality.
1.) Provide full and detailed descriptions of how the nozzle designs limit examinations to the shell side, and why 100% of the ASME Code-required volumes from the accessible side could not be performed.
2.) On the coverage calculation sheets, the licensee provided some information pertaining to the UT techniques applied. However, it is unclear whether the angles shown represent shear or longitudinal waves. Please clarify the UT sound beam modes and insonification angles used for all ultrasonic examinations.
3.) State whether any indications were discovered as a result of these examinations, and how these indications were dispositioned.
D.
Request for Relief RR-45, ASME Code,Section XI. Examination Category B-H, Item B8.10, Integral Attachments for Vessels, Reactor Pressure Vessel 1.) Include a detailed description (text or sketches, as needed) of the interference caused by the stabilizer ring, demonstrating lack of access to the bottom of these lug welds.
2.) As applicable, discuss any additional NDE techniques that could be used to verify structural integrity of the welds. For example, discuss whether a visual VT-1 examination could have been performed to augment the limited surface examinations.
3.) State whether any indications were discovered as a result of these examinations, and how these indications were dispositioned.
E.
Request for Relief RR-43, ASME Code,Section XI, Examination Category R-A, Item R1.20, Pressure Retaining Piping Welds The licensee has requested relief from examining 100% of the ASME Code-required volumes for thirty-two (32) ASME Code Class 1 piping welds covered under a risk-informed ISI (RI-ISI) program.
1.) State the total number of ASME Code Class 1 piping welds included in the overall risk-informed program and the number of welds scheduled for examination so that the 32 limited examinations can be assessed within the scope of all examinations being implemented.
2.) Confirm that all other ASME Code Class 1 piping examinations in the risk-informed ISI program have been completed in accordance with ASME Code volumetric requirements.
3.) A number of the welds in RR-43 state that the weld was examined multiple times during the third inspection interval and/or that this is an additional weld not originally scheduled for examination. Please clarify the reason for each examination of these welds during the third inspection interval (i.e. normally scheduled ISI examination, sample expansion, supplemental examination coverage, etc.).
For Request for Relief RR-43, the licensee has provided only general information regarding the impracticality of obtaining ASME Code-required volumetric coverage by stating due to configuration this is a one-sided examination. Other limited descriptions are provided for each weld, such as configuration, however, insufficient information has been included to adequately demonstrate impracticality.
1.) Include descriptions (written and/or sketches, as necessary) of the interferences to applied volumetric techniques for each weld in RR-43.
2.) State the ultrasonic sound beam modes and insonification angles used for all ultrasonic examinations.
3.) Show cross-sectional coverage plots to describe ASME Code volumes examined.
4.) State whether any indications were discovered as a result of these examinations, and how these indications were dispositioned.
F.
For Welds 1B2142-4-FWRFWB6 And 1B21PS2A3A3-24-SWJ Contained In Request for Relief RR-43 ASME Code,Section XI, Examination Category R-A, Item 1.20, Elements not subject to a damage mechanism, requires a volumetric examination as specified in Table 1 of ASME Code Case N-578-11 Risk-Informed Requirements for Class 1, 2, 3, Piping Method B,Section XI, Division 1. Magnetic particle examination (MT) is not an approved volumetric NDE method. It is unclear why the licensee has submitted the subject welds, and the limited MT examinations, as part of RR-43. Please clarify the intent of including these examinations in ASME Code,Section XI, Examination Category R-A.
If a volumetric examination was performed in addition to the MT examination:
1.) Describe the volumetric NDE (UT or Radiography (RT)) with equipment used, details of the listed obstructions (size, shape, proximity to the weld, etc.) to demonstrate accessibility limitations.
2.) If UT examination was applied, state the UT sound beam modes and insonification 1 ASME Code Case N-578-1 has not been approved for use in Regulatory Guide 1.147, Revision 15 Inservice Inspection Code Case Acceptability. Licensees use Table 1 of ASME Code Case N-578-1 as guide to establish their inspection sample and examination categories for their RI-ISI programs.
angles used for all UT examinations.
3.) Show cross-sectional coverage plots to describe ASME Code volumes examined.
4.) State whether any indications were discovered as a result of these examinations, and how these indications were dispositioned.