RS-09-144, Additional Information Supporting the Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirements for Piping Replacements, Relief Request No. 1203
| ML092960499 | |
| Person / Time | |
|---|---|
| Site: | Clinton, LaSalle  |
| Issue date: | 10/22/2009 |
| From: | Hansen J Exelon Corp, Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RS-09-144, TAC ME1878 | |
| Download: ML092960499 (5) | |
Text
Exelon Generation www.exeloncorp.com 4300 Winfield Road Warrenville, IL 60555 RS-09-144 October 22, 2009 U. S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington, DC 20555-0001 Clinton Power Station, Units 1 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374 Exellon Nuclear 10 CFR 50.55a Subject :
Additional Information Supporting the Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirements for Piping Replacements, Relief Request No. 1203 (TAC No. ME1878)
References :
1.
Letter from J. L. Hansen (Exelon Generation Company, LLC) to U. S. NRC, "Request for Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirements for Piping Replacements (Relief Request No.
1203)," dated May 5, 2009
- 2.
Letter from U. S. NRC to Mr. C. G. Pardee (Exelon Generation Company, LLC), "Clinton Power Station, Unit No. 1 - Request for Additional Information Related to Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirement for Piping Replacements, Relief Request No. 1203 (TAC No. ME1878)," dated October 14, 2009 In Reference 1, Exelon Generation Company, LLC (EGC) requested relief from certain Inservice Inspection program requirements related to post weld heat treatments.
In Reference 2, the NRC requested that EGC provide additional information in support of their review of Reference 1. The NRC's request for additional information and the specific EGC responses are provided in the attachment to this letter.
October 22, 2009 U. S. Nuclear Regulatory Commission Page 2 There are no regulatory commitments contained within this letter.
If you have any questions concerning this letter, please contact Mr. Mitchel A. Mathews at (630) 657-2819.
Jeff rey I-Mnsen Manag - Licensing and Regulatory Affairs Exelon Generation Company, LLC
Attachment:
Additional Information Supporting the Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirement for Piping Replacements, Relief Request No. 1203 (TAC No. ME1878)
Additional Information Supporting the Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirement for Piping Replacements, Relief Request No. 1203 (TAC No. ME -1878)
In reviewing the Exelon Generation Company's (Exelon's) submittal dated May 5, 2009 (Agencywide Documents Access and Management System Accession No.
ML091260459), related to Relief Request 1203, for the Clinton Power Station, Unit No. 1 (Clinton), the Nuclear Regulatory Commission (NRC) staff has determined that the following information is needed in order to complete its review.
1. What minimum preheat temperature will be applied for all of this welding?
Response :
All welds will be preheated to 400°F minimum in accordance with Welding Services, Incorporated's (WSI's) welding procedure specification (WPS) WPS-5A-5A-TS-200, Revision 3.
- 2. What method is to be used for the preheat application?
Response :
ATTACHMENT Exelon Nuclear Training and Reference Material (T&RM) CC-AA-501-1011, "Exelon Nuclear Welding Program Preheat, Interpass, Temperature and Postweld Heat Treatment of Welds,"
requires the Work Planner to determine the required preheat temperature requirements for each welding job in accordance with the applicable Code. This T&RM also requires the welder assigned to the work to follow the work package instructions for preheat temperature requirements. In this instance the work package will specify the temperature, method of application, and duration of preheating. As previously discussed, the material will be preheated to a minimum of 400°F. The method of preheat application is inductive or resistive heating.
- 3.
Will the preheat be maintained from the start of welding until the completion of welding?
Response :
The work package instructions supporting the performance of these welds will specify that preheating shall be maintained from the commencement of welding through weld completion in accordance with the requirements of CC-AA-501-1011.
4. How will the preheat and interpass temperature maintenance be measured?
Response
Preheat and interpass temperatures will be verified using temperature indicating crayons, contact pyrometers, magnetic thermometers, or thermocouples in accordance with CC-AA-501-1011.
Additional Information Supporting the Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirement for Piping Replacements, Relief Request No. 1203 (TAC No. ME1878)
- 5.
Will the preheat for the procedure qualification be performed at the 300°F temperature and not at 400°F as allowed by American Society of Mechanical Engineers (ASME)
Section IX QW-4XXXX?
Response :
ATTACHMENT The WPS that is to be used for these welds, WPS-5A-5A-TS-200, was qualified using three different procedure qualification records : PQR-5A-5A-TS-001, PQR-M05253-256, and PQR-M05002. PQR-5A-5A-TS-001 was qualified with a preheat temperature of 63°F, PQR-MO5253-256 was qualified with a preheat temperature of 400°F, and PQR-M05002 was qualified with a preheat temperature of 400°F. While the WPS was qualified at additional preheat values, the WPS requires a preheat temperature of 400°F.
- 6. Describe the system of electrode control and storage to be used for this welding.
Response :
Electrodes are controlled in accordance with Exelon Nuclear T&RM, CC-AA-501-1004, "Exelon Nuclear Welding Program Filler Material Control." This T&RM establishes the requirements for the storage and disbursement of welding materials at Exelon Nuclear sites.
These requirements are applicable to all working groups using welding materials at all EGC Nuclear sites.
In summary, electrodes will be received on site in accordance with the quality receiving requirements and then issued to Maintenance for rod control. The F-6 filler material that will be utilized for these welds will be locked in a designated rod storage area and will be issued to qualified welders per a rod issue ticket. The issue ticket will specify the type of rod required, the work order number, and the welder that is qualified to perform the weld.
The F-4 filler material that will be utilized during this project will be locked in a rod storage area until the sealed containers are opened. Once the F-4 containers are opened the rod will be placed in locked rod ovens and maintained at a temperature between 250°F and 400°F. The F-4 filler material will only be issued to qualified welders in accordance with a rod issue ticket that will specify the type of rod that is required, the work order number, and the welder that is qualified to perform the weld. Once issued to the qualified welder, the F-4 filler material will be maintained in portable heated rod caddies. A copy of the rod issue ticket must be kept with the weld filler material at all times after the filler material is removed from the rod issue area until it is used or disposed of.
ATTACHMENT Additional Information Supporting the Request for Approval of Proposed Alternative to 10 CFR 50.55a Post Weld Heat Treatment Requirement for Piping Replacements, Relief Request No. 1203 (TAC No. ME1878)
- 7.
What is the actual thickness of the base metal at the welded joint for each material, including the ASME SA-217, Grade WC9 valve?
Response :
Post-weld heat treatment will be applied where required by the Code. The material has yet to be received by the station, but the design specification thickness of the 4-inch schedule 120 piping is 0.438 inches. The only way to determine the actual thickness is to measure each piece once the material is prepped for welding. If it is determined that the base metal for a piece exceeds the allowed 0.5 inches, post-weld heat treatment will be applied as required by Code, and in accordance with CC-AA-501-1011.
- 8. The exemption for the ASME SA-217, Grade WC9 valve cannot be included in the relief request authorization until all the particulars, i.e., base metal chemistry, etc. of the certified material test report are produced for NRC review.
Response :
As the valve has not been received by the station, EGC will apply post-weld heat treatment to welds associated with the valve as required by Code.