ML14143A408
| ML14143A408 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/20/2014 |
| From: | Mark D. Sartain Dominion, Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 14-228, TAC MF1405 | |
| Download: ML14143A408 (9) | |
Text
Dominion Nuclear Connecticut, Inc.
5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion' Web Address: www.dom.coni May 20, 2014 U.S. Nuclear Regulatory Commission Serial No.14-228 Attention: Document Control Desk NLOS/MAE RO Washington, DC 20555 Docket No.
50-336 License No.
DPR-65 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2 EXAMINATION
SUMMARY
AND COVERAGE RESULTS ASME SECTION XI INSERVICE INSPECTION PROGRAM ALTERNATIVE REQUEST RR-04-15, LIMITED ONE-SIDED ULTRASONIC EXAMINATION TECHNIQUE (TAC MF1405)
By letter dated April 9, 2013, as supplemented by letter dated February 7, 2014, Dominion Nuclear Connecticut, Inc. (DNC) submitted a request to the Nuclear Regulatory Commission (NRC) and proposed an alternative to the requirements of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Case N-770-1 "Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities." The requested alternative applies to the fourth 10-year inservice inspection interval at Millstone Power Station, Unit 2 (MPS2).
By letter dated March 31, 2014, the NRC authorized the request for relief RR-04-15 for the fourth 10-year inservice inspection interval at MPS2, which began on April 1, 2010, and is scheduled to end on March 31, 2020.
In the DNC submittal dated February 7, 2014, DNC stated the following in Attachment 1, section 4, Reason for Request: "Examination summary and coverage results will be provided to the NRC following completion of these examinations." The purpose of this letter is to provide the above mentioned information. provides examination summary and coverage results.
If you have any questions in regard to this submittal, please contact Wanda Craft at (804) 273-4687.
Sincerely, Mark D. Sartain Vice President - Nuclear Engineering AbWý
Serial No.14-228 Docket No. 50-336 Page 2 of 2 Commitments made in this letter: None
Attachment:
Examination Summary and Coverage Results cc:
U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd Suite 100 King of Prussia, PA 19406-2713 Mohan C. Thadani Senior 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.14-228 Docket No. 50-336 ATTACHMENT 1 EXAMINATION
SUMMARY
AND COVERAGE RESULTS MILLSTONE POWER STATION UNIT 2 DOMINION NUCLEAR CONNECTICUT, INC.
Serial No.14-228 Docket No. 50-336, Page 1 of 6 By letter dated April 9, 2013, as supplemented by letter dated February 7, 2014, Dominion Nuclear Connecticut, Inc. (DNC) submitted a request to the Nuclear Regulatory Commission (NRC) and proposed an alternative to the requirements of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Case N-770-1 "Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities." The requested alternative applies to the fourth 10-year inservice inspection interval at Millstone Power Station, Unit 2 (MPS2). By letter dated March 31, 2014, the NRC authorized the request for relief RR-04-15 for the fourth 10-year inservice inspection interval at MPS2, which began on April 1, 2010, and is scheduled to end on March 31, 2020.
In the DNC submittal dated April 9, 2013, DNC stated the following in Attachment 1, Section 4, Reason for Request: "Examination summary and coverage results will be provided to the NRC following completion of these examinations."
This attachment provides DNC's results.
The following table provides Examination Summary and Coverage Results:
Serial No.14-228 Docket No. 50-336, Page 2 of 6 Examination Summary and Coverage Results Alloy 600 and Carbon Steel Base Material Wetd Surace Cast Stainless Steel Material Composite Weld #
Coverage e
e Coverage Examination Axial Beam Circumferential Beam Axial Flaw Circumferential Axial Beam Circumferential Volume Direction (%)
Direction (%)
(
Flaw (%)
Direction (%)
Beam Direction (%)
Coverage (%)
P-4-C-1 94.7 92.6 94.7 94.7 94.7 46.6 86.2 P-5-C-3 94.7 100 100 94.7 94.7 100 97.5 P-8-C-1 94.7 92.6 94.7 94.7 94.7 46.6 86.2 P-9-C-3 94.7 100 100 94.7 94.7 100 97.5 P-13-C-1 95.6 93.5 95.6 95.6 95.6 48.5 86.5 P-14-C-3 98.7 100 100 98.7 88.8 100 98.7 P-17-C-1 95.6 93.5 95.6 95.6 95.6 48.5 86.5 P-18-C-3 100 100 100 100 96.4 100 99.3 Notes:
- 1) Examination coverage is limited for each of the suction welds due to longitudinal weld seams on the elbow that restricts the phased array probe from maintaining adequate contact for approximately 6" of total weld length in the region of the longitudinal weld seams. See Figure 1 for typical examination coverage plots in regions without the longitudinal seam obstructions.
- 2)
Examination coverage is limited for discharge welds P-5-C-3 and P-9-C-3 in the region of the spray nozzle located at top dead center, which prevents the phased array probe from maintaining adequate contact for approximately 6" of weld length for the axial scans. The scan plan was adjusted to reduce the scan distance and use lower beam angles to obtain the maximum amount of coverage in the region of the spray nozzle.
See Figure 2 for typical examination coverage plots for the discharge welds in regions without the nozzle obstruction.
- 3) Non-encoded phased array ultrasonic examination techniques (PAUT) and manual conventional UT techniques were evaluated to determine if additional examination coverage could be obtained. Due to the surface condition or access it was determined that neither of these techniques would be capable of providing additional coverage. The welds were examined to the maximum extent possible.
Serial No.14-228 Docket No. 50-336, Page 3 of 6 Figure 1 Typical Coverage Plots for Welds P-4-C-1, P-8-C-1, P-1 3-C-1, and P-1 7-C-1 Non-Cast Portion of Examination Volume Cast Portion of Examioon Volume Carbon Steel Elbow Stainless Steel Clad Examination Volume Axial Scan Extent 30 37T5 45 52.5 60 Axial Beam Direction Coverage
Serial No.14-228 Docket No. 50-336, Page 4 of 6 Figure 1 (continued)
ýv 45 degree refracted beam angle with 0 to 30 degree skew 55 degree refracted beam angle with 0 to 30 degree skew Circumferential Beam Direction Coverage
Serial No.14-228 Docket No. 50-336, Page 5 of 6 Figure 2 Typical Coverage Plots for Welds P-5-C-3, P-9-C-3, P-14-C-3, and P-1 8-C-3 Examination Volume 60 Axial Beam Direction Coverage in Region of Sprav Nozzle (Welds P-5-C-3 and P-9-C-3)
Axial Beam Direction Coverage in Regions Without Spray Nozzles
Serial No.14-228 Docket No. 50-336, Page 6 of 6 Figure 2 (continued) 55 degree refracted beam angle with -30 to +30 degree skew 45 degree refracted beam angle with -30 to +30 degree skeN Circumferential Beam Direction Coveraqe from Weld Surface
_Q/
A 55 degree refracted beam angle with -30 to +30 degree skew 45 degree refracted beam angle with -30 to +30 degree skew Circumferential Beam Direction Coveraae from Base Material Surface Circumferential.Be..
Direction.C.v..aa from Bse.Maerial.u..ac