ML14084A383
| ML14084A383 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/14/2014 |
| From: | Sartain M D Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 14-145, TAC MF2520 | |
| Download: ML14084A383 (10) | |
Text
Dominion Nuclear Connecticut, Inc.5000 Dominion Boulevard, Glen Allen, VA 23060 Web Address: www.dom.com March 14, 2014 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, DC 20555 DOMINION NUCLEAR CONNECTICUT.
INC.ADominiont Serial No.14-145 NLOS/WDC RO Docket No. 50-336 License No. DPR-65 MILLSTONE POWER STATION UNIT 2 RESPONSE TO SECOND REQUEST FOR ADDITIONAL INFORMATION FOR ALTERNATIVE REQUEST RR-04-16 FOR THE USE OF ENCODED PHASED ARRAY ULTRASONIC EXAMINATION TECHNIQUES (PAUT) IN LIEU OF RADIOGRAPHY (TAC NO. MF2520)In a letter dated August 1, 2013, Dominion Nuclear Connecticut, Inc. (DNC) requested relief from the requirements of the American Society of Mechanical Engineers (ASME)Boiler and Pressure Vessel Code Section III for Millstone Power Station Unit 2 (MPS2). Specifically, DNC requested approval to use encoded Phased Array Ultrasonic Examination Techniques as an alternative to radiographic examination for ASME Class 2 carbon steel circumferential pipe weld joints to satisfy nondestructive examination requirements.
In a letter dated October 1, 2013, the Nuclear Regulatory Commission (NRC) transmitted a request for additional information (RAI) to DNC related to the alternative request. In letters dated November 22, 2013 and February 27, 2014, DNC responded to the RAI. On March 12, 2014, the NRC transmitted a second RAI related to the alternative request.The attachment to this letter contains DNC's response to the RAI.If you have any questions regarding this submittal, please contact Wanda Craft at (804) 273-4687.Sincerely, Mark D. Sartain Vice President
-Nuclear Engineering
Attachment:
- 1. Response to Second Request for Additional Information for Alternative Request RR-04-16 Proposed Alternative to ASME Section III Commitments made in this letter: None A-0c47 Serial No.14-145 Docket No. 50-336 Page 2 of 2 cc: U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd Suite 100 King of Prussia, PA 19406-2713 James S. Kim Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C2A 11555 Rockville Pike Rockville, MD 20852-2738 Mohan C. Thadani Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 B 1 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Serial No.14-145 Docket No. 50-336 ATTACHMENT RESPONSE TO SECOND REQUEST FOR ADDITIONAL INFORMATION FOR ALTERNATIVE REQUEST RR-04-16 PROPOSED ALTERNATIVE TO ASME SECTION III MILLSTONE POWER STATION UNIT 2 DOMINION NUCLEAR CONNECTICUT, INC.
Serial No.14-145 Docket No. 50-336 Attachment 1, Page 1 of 7 Backqround In a letter dated August 1, 2013, Dominion Nuclear Connecticut, Inc. (DNC) requested relief from the requirements of the American Society of Mechanical Engineers (ASME)Boiler and Pressure Vessel Code Section III for Millstone Power Station Unit 2 (MPS2).Specifically, DNC requested approval to use encoded Phased Array Ultrasonic Examination Techniques (PAUT) as an alternative to radiographic examination for ASME Class 2 carbon steel circumferential pipe weld joints to satisfy nondestructive examination requirements.
In a letter dated October 1, 2013, the Nuclear Regulatory Commission (NRC) transmitted a request for additional information (RAI) to DNC related to the alternative request. In letters dated November 22, 2013 and February 27, 2014, DNC responded to the RAI. On March 12, 2014, the NRC transmitted a second RAI related to the alternative request. This attachment provides DNC's response to the RAI.Question 1 Describe the radiographic testing procedure used to characterize the specimens described in the letter dated February 27 in detail. Identify if the radiographic testing procedure used single or double wall viewing and how many shots and angles were taken per weld.DNC Response The radiographic examinations were performed with the examination personnel having no knowledge of the location or type of flaws implanted within the mockups. The radiographic testing procedure used to characterize the mockups consisted of ASME Section V, Article 2 radiographic examination techniques, typical of examinations performed in the plant. The examinations were performed using an Iridium 192 source with the direction of the central beam of radiation centered on the area of interest and perpendicular to the film, to the extent possible.
Each weld consisted of four film views;0 to 90 degrees, 90 to 180 degrees, 180 to 270 degrees, and 270 to 0 degrees, with adequate overlap to provide complete coverage of the entire weld length. Single wall viewing was used to interpret the film.
Serial No.14-145 Docket No. 50-336 Attachment 1, Page 2 of 7 Question 2 Did the radiographic testing procedure used to evaluate the specimens described in the letter dated February 27 meet the requirements of ASME Code Section V Article 2?DNC Response Yes, the radiographic testing procedure used to evaluate the specimens described in the letter dated February 27 meets the requirements of ASME Code Section V, Article 2.Question 3 Provide a table describing the implanted flaws used to qualify the ultrasonic inspection procedure.
Include the flaw types and dimensions.
The NRC staff understands that releasing this information may compromise the blind qualification testing. If this information is proprietary include the necessary affidavit for the NRC staff to treat the information as proprietary.
DNC Response To maintain the integrity of the test qualification material, the information will be made available for NRC review.Question 4 Provide examples of successful ultrasonic detection of planar flaws in the 0.28 inch thick test blocks.DNC Response The following Figures 1 through 5 provide examples of the ultrasonic data representing successful detections and characterizations of typical fabrication flaws from the Dominion procedure qualification data. These figures provide examples of lack of fusion defects, lack of penetration defects, and cracks, which were implanted into the 6 inch diameter, 0.28 inch thick welded mockups. These mockups represent the weld configurations and welding processes to be used for the replacement welds. The flaw map for each of these examples is included in the applicable figures. The planar flaws identified in Figures 2, 3, and 4 were not detected with the radiographic examination performed.
Serial No.14-145 Docket No. 50-336 Attachment 1, Page 3 of 7 Figure 1 Weld 4 -Flaw 3, Incomplete Penetration It= 4r--..,, -i %v- , .Upstream Detection Using First Leg.~IIII=Down Stream Detection Using First Leg Serial No.14-145 Docket No. 50-336 Attachment 1, Page 4 of 7 Figure 2 Weld 4 -Flaw 5, Crack*.."'P Down Stream (Near Side) Detection Using First Leg Serial No.14-145 Docket No. 50-336 Attachment 1, Page 5 of 7 Figure 3 Weld 5 -Flaw 2, Crack I,,...Down Stream (Near Side) Detection Using First Leg Serial No.14-145 Docket No. 50-336 Attachment 1, Page 6 of 7 Figure 4 Weld 5 -Flaw 4, Lack of Fusion Don S-.4 Down Stream (Near Side) Detection Using First and Second Leg Serial No.14-145 Docket No. 50-336 Attachment 1, Page 7 of 7 Figure 5 Weld 5 -Flaw 5, Crack FLAW 5 r- 0, 105" Down Stream Detection Using Second Leg