ML113550209
| ML113550209 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 01/11/2012 |
| From: | John Lamb Plant Licensing Branch 1 |
| To: | Freeman P NextEra Energy Seabrook |
| Lamb J 301-415-3100 | |
| References | |
| TAC ME6901, TAC ME6902, TAC ME6903, TAC ME6904 | |
| Download: ML113550209 (8) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 11, 2012 Mr. Paul Freeman Site Vice President clo Michael O'Keefe Seabrook Station NextEra Energy Seabrook, LLC P.O. Box 300 Seabrook, NH 03874
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING THE SEABROOK STATION, UNIT 1 SECOND 10-YEAR INTERVAL INSERVICE INSPECTION FOR PROGRAM PLAN REQUESTS FOR RELIEF (TAC NOS. ME6901, ME6902, ME6903, AND ME6904)
Dear Mr. Freeman:
The U.S. Nuclear RegUlatory Commission (NRC) staff, with technical assistance from Pacific Northwest National Laboratory (contractor), has reviewed and evaluated the information provided by NextEra Energy Seabrook, LLC (the licensee) in its letter dated August 17, 2011 (Agencywide Documents Access & Management System (ADAMS) Accession Number ML11234A185).
The licensee submitted Requests for Relief (RR) 2IR-17, 21R-18, 2IR-19, and 21R-20 from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI for Seabrook Station, Unit 1 (Seabrook). The request for relief applies to the second 10-year inservice inspection (lSI) interval, in which the licensee adopted the 1995 Edition through the 1996 Addenda of ASME Code Section XI as the Code of Record.
The NRC staffs request for additional information (RAI) is contained in the enclosed contractor's RAI. A draft of these questions was previously sent to Mr. Paul Willoughby of your staff with an opportunity to have a teleconference to ensure that the licensee understood the questions and their regulatory basis; as welJ as, to verify that the information was not on the docket. On January 10, 2012, a teleconference was held between the NRC staff and Seabrook personnel and at the end of the teleconference Mr. Paul Willoughby of your staff agreed that NextEra Energy Seabrook, LLC would respond to the RAI by March 15, 2012. Please note that if you do not respond to the RAI by March 15,2012, the NRC staff may reject your request for relief under the provisions of Title 10 of the Code of Federal Regulations, Section 2.108, "Denial of application for failure to supply information."
P. Freeman
- 2 If you have questions. you can contact me at 301-415-3100 and/or John.Lamb@nrc.gov.
Iy. ia.,
f4/l
. ~#
. Lamb. Sen' r Project Manager Licensing Branch 1-2 Di. ion of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION ON THE SECOND 10-YEAR INSERVICE INSPECTION INTERVAL REQUESTS FOR RELIEF NEXTERA ENERGY SEABROOK, LLC SEABROOK STATION, UNIT 1 DOCKET NUMBER 50-443 1.0 SCOPE By letter dated August 17, 2011 (Agencywide Documents Access & Management System (ADAMS) Accession Number ML11234A185), NextEra Energy Seabrook, LLC (the licensee),
submitted Requests for Relief (RR) 21R-17, 21R-18, 21R-19, and 21R-20 from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code),Section XI, for Seabrook Station, Unit 1 (Seabrook). The request for relief applies to the second 1 O-year inservice inspection (lSI) interval, in which the licensee adopted the 1995 Edition through the 1996 Addenda of ASME Code Section XI as the Code of Record.
In accordance with Title 10 of the Code of Federal Regulations (10 CFR),
Section 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 1 DO-percent of the examination volumes, or surface areas, described in ASME Code,Section XI, Tables IWB-2500-1 and IWC-2500-1 be performed during each interval. The licensee stated that 1 ~O-percent of the ASME Code-required volumes, or surface areas, are impractical to obtain at Seabrook.
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 U.S. Nuclear Regulatory Commission (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 NRC staff, with technical assistance from Pacific Northwest National Laboratory (PNNL)
(contractor), has reviewed the information submitted by the licensee, and based on this review, determined the following information is required to complete the evaluation.
Enclosure
- 2 2.0 REQUEST FOR ADDITIONAL INFORMATION 2.1 Request for Relief 21R-17, ASME Code,Section XI, Table IWC-2500-1, Examination Category C-A, Items C1.10 and C1.30, Pressure Retaining Welds in Pressure Vessels The licensee has included Residual Heat Removal (RHR) Heat Exchanger Circumferential Shell Weld RH E-9B 01 B and Containment Building Spray (CBS) Heat Exchanger Tubesheet-to-Shell Weld CBS E-16B 01 in this request. From the limited sketches and text provided, it is unclear which portion and how much of the ASME Code-required volumes have been completed, compared to the listed coverage percentages shown in Table 21R17-01 of the licensee's submittal dated August 17, 2011.
(a) Please submit detailed cross-sectional drawings showing volumetric coverage for each of the ultrasonic (UT) angles/techniques applied. Please include written descriptions of the ASME Code-required volumes and areas of completed coverage for each of the techniques used over the length of these welds.
(b) The licensee stated that manual UT methods using, "the most recent technology available," was applied to maximize volumetric coverage. Please describe the specific technology that was used, e.g., phased array, composite transducers, or other.
(c) State whether procedures, personnel and equipment used on these welds were qualified through ASME Code,Section XI, Appendix VIII methods. If not, describe the qualification methodology, and provide a discussion on why the techniques applied would result in "best effort" coverage achieved on the near-and far-side of the subject weld volumes.
(d) For Weld CBS E-16B 01, include information to better describe the welded support attachment and its impact on the examination, as this limitation could not be fully determined from Figure 2IR-17-02 contained in the licensee's submittal dated August 17, 2011.
2.2 Request for Relief 21R-18, ASME Code,Section XI. Table IWC-2S00-1, Examination Category C-B, Item C2.21, Pressure Retaining Nozzle Welds in Vessels The licensee has included two CBS heat exchanger nozzle-to-shell welds in this request.
From the limited sketches and text provided, it is unclear which portion and how much of the ASME Code-required volumes have been completed compared to the listed coverage percentages shown in Table 2IR-18-01 contained in the licensee's submittal dated August 17, 2011.
(a) Please submit detailed cross-sectional drawings showing volumetric coverage for each of the UT angles/techniques applied. Please include written descriptions of the ASME Code-required volumes and areas of completed coverage for each of the techniques used over the length of these welds.
-3 (b) The licensee stated that manual UT methods using, "the most recent technology available," was applied to maximize volumetric coverage. Please describe the specific technology that was used, e.g., phased array, composite transducers, or other.
(c) State whether procedures, personnel and equipment used on these welds were qualified through ASME Code,Section XI, Appendix VIII methods. If not, describe the qualification methodology, and provide a discussion on why the techniques applied would result in "best effort" coverage achieved on the near-and far-side of the subject weld volumes.
(d) For "B" CBS Heat Exchanger Inlet Nozzle-to-Shell Weld, the weld identification in Tables 2IR-18-01 and -02 (CBS E-16 N1) in the licensee's submittal dated August 17, 2011, is differentfrom the weld identification in Figure 21 R-18-01 (CBS E-16B N 1) contained in the August 17, 2011, submittal. Please specify the correct identification for this weld.
2.3 Request for Relief 21 R-19, ASME Code,Section XI. IWC-2500-1, Examination Category C-F-1! Items C5.11 and C5.21! Pressure Retaining Welds in Austenitic Stainless Steel or High Alloy Piping The licensee's submittal summarizes limited examinations performed during the second 1 O-year lSI interval, and provides calculated examination coverage for each piping weld.
However, the licensee's submittal provides only "typical" figures that do not describe or depict the specific limitations for each weld listed in Table 2IR-19-01 of the licensee's submittal dated August 17, 2011.
(a) Please submit detailed and specific information to support the basis for each limited examination in Request for Relief 2IR-19, and therefore, demonstrate impracticality.
Please include descriptions (written and/or sketches, as necessary) of the interferences to applied nondestructive examination (NDE) techniques. As applicable, describe NDE equipment, show accessibility limitations, and discuss whether alternative methods or advanced technologies could be employed to maximize ASME Code coverage.
(b) The licensee's submittal states that the subject weld areas were interrogated with a combination of 45-, 60-, and/or 70-degree shear waves, and in some cases, 60- and 70-degree longitudinal waves (L-waves) were applied to detect circumferentially oriented flaws. The licensee's submittal further states that examinations were performed in accordance with ASME Code,Section XI, Appendix VIII (performance demonstration initiative (PDI>>, and consisted of single-sided examinations from the pipe side of the welds.
(c) Please confirm the insonification angles and wave modalities used to examine each of the subject welds. Discussions with the industry's PDI administrator, the Electric Power Research Institute (EPRI), indicate that Supplement 2 qualifications require refracted longitudinal wave methods to be applied, if possible. If only shear wave techniques were used to examine the subject stainless steel welds, please explain
- 4 why refracted longitudinal wave techniques were not used as part of a "best effort" examination. The L-wave method has been shown capable of detecting planar inside diameter gD) surface-breaking flaws on the far-side of wrought stainless steel welds. Studies1, recommend the use of both shear and L-waves to obtain the best detection results, with minimum false calls, in austenitic welds.
(d) For Elbow-to-Pipe Weld CS-0371-03-08, limitations were caused by the width of the weld crown. Please discuss any efforts that were used to correct the weld crown condition in order to maximize coverage.
2.4 Request for Relief 2IR-20, Risk Informed lSI (RI-ISI), Category R-A, Items R1.11! R1.16 and R1.20, Risk Informed Piping Examinations The licensee's submittal summarizes limited examinations performed during the second 10-year lSI interval, and provides calculated examination coverage for each piping weld.
However, the licensee's submittal provides only "typical" figures that do not describe or depict the specific limitations for each weld listed in Table 2IR-20-01 of the licensee's submittal dated August 17, 2011.
(a) Please submit detailed and specific information to support the basis for each limited examination in Request for Relief 21R-20, and therefore, demonstrate impracticality.
Please include descriptions (written and/or sketches, as necessary) of the interferences to applied NDE techniques. As applicable, describe NDE equipment, show accessibility limitations, and discuss whether alternative methods or advanced technologies could be employed to maximize ASME Code coverage.
(b) The licensee's submittal states that the subject weld areas were interrogated with a combination of 45-, 60-, and/or 70-degree shear waves, and in some cases, 60- and 70-degree longitudinal waves (L-waves) were applied to detect circumferentially oriented flaws. The licensee's 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.
(c) Please confirm the insonification angles and wave modalities used to examine each of the subject welds. Discussions with the industry's PDI administrator, EPRI, indicate that Supplement 2 qualifications require refracted longitudinal wave methods to be applied, if possible. If only shear wave techniques were used to examine the subject stainless steel welds, please explain why refracted longitudinal wave techniques were not used as part of a "best effort" examination. The L-wave method has been shown capable of detecting planar inside diameter (ID) surface-breaking flaws on the far-side of wrought stainless steel welds. Studies (see footnotes)
- 1.
F. V. Ammirato, X. Edelmann, and S.M. Walker, Examination ofDissimilar Metal Welds in BWR Nozzle-to Safe End Joints, 8th Intemational Conference on NDE in the Nuclear Industry, ASM International, 1987.
- 2.
P. T. Lemaitre, P., T.D. Koble, and S.R. Doctor, PISC 11/ Capability Study on Wrought-to-Wrought Austenitic Steel Welds: Evaluation at the Level ofProcedures and Techniques, Effectiveness ofNondestructive Examination Systems and Performance Demonstration, PVP-Volume 317, NDE-Volume 14, ASME, 1995.
- 5 recommend the use of both shear and L-waves to obtain the best detection results, with minimum false calls, in austenitic welds.
(d) The licensee has requested relief from examining 100-percent of the ASME Code required volumes for 15 ASME Code, Class 1 piping welds covered under a risk informed lSI program.
(1) Please state the total number of ASME Code, Class 1 piping welds included in the overall risk-informed program so that the 15 limited examinations can be assessed within the scope of all examinations being implemented.
(2) Please confirm that all other ASME Code, Class 1 piping examinations in the RI-ISI program have been completed in accordance with ASME Code volumetric requirements.
(3) Further discuss whether additional welds could have been examined to augment the reduced volumetric coverage resulting from the limited examinations of the subject welds.
P. Freeman
- 2 If you have questions, you can contact me at 301-415-3100 and/or John.Lamb@nrc.gov.
Sincerely, lraJ John G. Lamb, Senior Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:
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