ML13178A190
| ML13178A190 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/27/2013 |
| From: | Boska J Plant Licensing Branch II |
| To: | Alter K Duke Energy Carolinas |
| Boska J | |
| References | |
| TAC MF0648, TAC MF0649 | |
| Download: ML13178A190 (3) | |
Text
From:
Boska, John Sent:
Thursday, June 27, 2013 1:14 PM To:
Alter, Kent R (Kent.Alter@duke-energy.com)
Cc:
Gray, Corey A (Corey.Gray@duke-energy.com)
Subject:
Oconee Units 1 and 2, NRC Request for Additional Information on Relief Requests 12-ON-001 and 12-ON-002 Importance:
High By letters dated January 31, 2013 (Agencywide Document Access and Management System (ADAMS) Accession No. ML13038A152 and ML13038A150), Duke Energy Carolinas, LLC (Duke Energy, the licensee), submitted Requests for Relief (RR) 12-ON-001 and 12-ON-002 from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, for Oconee Nuclear Station, Units 1 and 2 (ONS 1 and 2). The request for relief applies to the fourth 10-year inservice inspection (ISI) interval, in which the licensee adopted the 1998 Edition through the 2000 Addenda of ASME Code Section XI as the code of record.
In accordance with 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 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 ONS 1 and 2.
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 Staff has reviewed the information submitted by the licensee, and based on this review, determined the following additional information is required to complete the evaluation. The questions are found below. On June 25, 2013, the Duke staff indicated that a response to this request for additional information would be provided within 45 days of the date of this email.
- 1. Request for Relief 12-ON-001, Part A, Examination Category B-B, Item B2.51, Pressure Retaining Welds in Vessels Other than Reactor Vessels, ONS 1:
The Letdown Cooler N32389-1 Inlet and Outlet Channel Body-to-Chemical Connector Welds WJ-32 and WJ-35 required preservice examination.
Briefly describe nondestructive examinations that were performed on the subject welds during the replacement process, including examinations for construction code acceptance and/or preservice inspection in accordance with ASME Code Section XI. Please state whether any indications, discovered as a result of ASME Code-required construction and/or preservice examinations, could interfere with inservice ultrasonic examinations of the subject welds, and if these exist, how these flaws will be accounted for during inservice inspection.
- 2. Requests for Relief 12-ON-001and 12-ON-002, Part B, Examination Category B-D, Items B3.110 and B3.150, Full Penetration Welded Nozzles in Vessels, ONS 1 and 2:
The Letdown Coolers N32389-1 and 1-N-37804-2 Inlet and Outlet Nozzle-to-Channel Body Welds WJ-33 and WJ-36 required preservice examination.
Briefly describe nondestructive examinations that were performed on the subject welds during the replacement process, including examinations for construction code acceptance and/or preservice inspection in accordance with ASME Code Section XI. Please state whether any indications, discovered as a result of ASME Code-required construction and/or preservice examinations, could interfere with inservice ultrasonic examinations of the subject welds, and if these exist, how these flaws will be accounted for during inservice inspection.
- 3. Requests for Relief 12-ON-001and 12-ON-002, Part C, Examination Category B-J, Item B9.11, Pressure Retaining Welds in Piping, ONS 1 and 2:
The licensee stated that these relief requests are specific to examination volume coverage limitations only. All other Code requirements were satisfied.
Verify and state specifically whether a full surface examination was performed on each of the circumferential piping welds and describe any indications that were detected as a result of the surface examinations.
- 4. Requests for Relief 12-ON-001and 12-ON-002, Part D, Examination Category C-F-1, Items C5.11 and C5.21, Pressure Retaining Welds in Austenitic Stainless Steel or High Alloy Piping, ONS 1 and 2:
The licensee stated that these relief requests are specific to examination volume coverage limitations only. All other Code requirements were satisfied.
Verify and state specifically whether a full surface examination was performed on each of the Class 2 austenitic stainless steel or high alloy circumferential piping welds, and describe any indications that were detected as a result of the surface examinations.
- 5. Request for Relief 12-ON-001, Part E, Examination Category C-F-2, Item C5.51, Pressure Retaining Welds in Carbon or Low Alloy Steel Piping, ONS 1 The licensee stated that these relief requests are specific to examination volume coverage limitations only. All other Code requirements were satisfied.
5.1 Verify and state specifically whether a full surface examination was performed on each of the Class 2 carbon steel or low alloy steel circumferential piping welds, and describe any indications that were detected as a result of the surface examinations.
5.2 The text of the licensees submittal states that the subject weld areas were interrogated with a combination of 45-and 60-degree shear waves, but in the data sheet the licensee also listed 0-, 45-, and 60-degree longitudinal waves (L-waves) being applied to detect circumferentially-oriented flaws. The licensees submittal further states that examinations were performed in accordance with ASME Code Section XI Appendix VIII (performance demonstration), and consisted of single-sided examinations from the pipe side of the welds.
Clarify and confirm the insonification angles and wave modalities used to examine each of the subject welds.
John Boska Oconee Project Manager, NRR/DORL U.S. Nuclear Regulatory Commission 301-415-2901 email: john.boska@nrc.gov