ML20080G950
| ML20080G950 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 04/05/2020 |
| From: | Undine Shoop Plant Licensing Branch II |
| To: | Maza K Duke Energy Progress |
| Wentzel M | |
| References | |
| EPID L-2019-LLR-0035 | |
| Download: ML20080G950 (7) | |
Text
April 5, 2020 Ms. Kim Maza Site Vice President Shearon Harris Nuclear Power Plant Mail Code NHP01 5413 Shearon Harris Road New Hill, NC 27562-9300
SUBJECT:
SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 - RELIEF FROM THE REQUIREMENTS OF THE ASME CODE (EPID L-2019-LLR-0035)
Dear Ms. Maza:
By letter dated April 30, 2019, Duke Energy Progress, LLC (the licensee) submitted relief request I3R-19 to the U.S. Nuclear Regulatory Commission (NRC) for relief from certain American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPV Code),Section XI requirements at Shearon Harris Nuclear Power Plant, Unit 1.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii),
the licensee requested relief and to use alternative requirements for inservice inspection items on the basis that the Code requirement is impractical.
The NRC staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that Duke Energy Progress, LLC has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(g)(5)(iii). Therefore, the NRC staff grants the licensees relief request I3R-19 at Shearon Harris Nuclear Power Plant, Unit 1, for the third 10-year inservice inspection interval. All other ASME BPV Code,Section XI, requirements for which relief was not specifically requested and approved remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
If you have any questions, please contact the project manager, Tanya Hood, at 301-415-1387 or by email at tanya.hood@nrc.gov.
Sincerely,
/RA/
Undine Shoop, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-400
Enclosure:
Safety Evaluation cc: Listserv
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST I3R-19 FOR THIRD 10-YEAR INSERVICE INSPECTION INTERVAL DUKE ENERGY PROGRESS, LLC SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 DOCKET NO. 50-400
1.0 INTRODUCTION
By letter dated April 30, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19120A446), Duke Energy Progress, LLC (Duke Energy, the licensee) submitted Relief Request I3R-19 to the U.S. Nuclear Regulatory Commission (NRC, the Commission) requesting relief from certain provisions of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Inservice Inspection (ISI) requirements at Shearon Harris Nuclear Power Plant, Unit 1 for the third 10-year ISI interval.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii), the licensee requested relief for ISI on the basis that the Code requirement is impractical.
2.0 REGULATORY EVALUATION
By letter dated April 30, 2019, the licensee requested relief from the essentially 100 percent volumetric coverage requirements for several items pursuant to 10 CFR 50.55a(g)(5)(iii).
Adherence to Section XI of the ASME Code is mandated by the regulations at 10 CFR 50.55a(g)(4), which state, in part, that ASME Code Class 1, 2, and 3 components will meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in ASME Code,Section XI.
Paragraph 50.55a(g)(5)(iii) of 10 CFR states that if the licensee has determined that conformance with an ASME Code requirement is impractical for its facility, the licensee must notify the NRC and submit, as specified in the regulations at 10 CFR 50.4, information to support the determinations. Determinations of impracticality in accordance with this section must be based on the demonstrated limitations experienced when attempting to comply with the ASME Code requirements during the ISI interval for which the request is being submitted. Requests for relief made in accordance with this section must be submitted to the NRC no later than 12 months after the expiration of the initial or subsequent 120-month inspection interval for which relief is sought.
Enclosure
Paragraph 50.55a(g)(5)(iv) of 10 CFR requires that where an examination requirement by the ASME Code or Addenda is determined to be impractical by a licensee, the basis for this determination must be demonstrated to the satisfaction of the Commission not later than 12 months after the expiration of the initial 120-month period of operation from the start of facility commercial operation and each subsequent 120-month period of operation during which the examination is determined to be impractical.
Paragraph 50.55a(g)(6)(i) of 10 CFR states, in part, that the Commission will evaluate determinations, under paragraph 50.55a(g)(5) of 10 CFR, that ASME Code requirements are impractical. The Commission may grant such relief and may impose such alternative requirements as it determines is authorized by law.
Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request relief and the NRC to grant relief.
3.0 TECHNICAL EVALUATION
3.1 The Licensees Relief Request 3.1.1 Applicable Code Edition and Addenda The licensees third ISI interval is based on the ASME B&PV Code,Section XI, 2001 Edition through the 2003 Addenda.
Welded components included in the relief request are described in Table 1, below:
Table 1 Nominal Exam Percent Component ID Component Description Material Pipe Size Category Coverage Thickness Shell: SA-533 Reactor Pressure B-A/ II-RV-001FTHW- GR B Cl. 1; Vessel (RPV) Shell-to- N/A (7) 71.7 percent B1.30 RV-18FA, B, C Flange: SA-Flange Weld 508, CL. 2 Weld Steam Generator (SG)
B-B II-SG-0001SGB- 70.1 percent; Tubesheet to-Head SA-508-CL 3a N/A (5.26)
B2.40 TSTHW-06-01 Base Metal Weld 75.2 percent Nozzle SA-Pressurizer Safety N/A B-D II-PZR-01NTHW- 508 CL 2; Nozzle to-Upper Head (minimum 67.14 percent B3.110 10 Shell SA-533 Weld 2.09)
Gr A CL 2 Nozzle SA-Pressurizer Safety N/A B-D II-PZR-01NTHW- 508 CL 2; Nozzle to-Upper Head (minimum 67.14 percent B3.110 11 Shell SA-533 Weld 2.09)
Gr A CL 2 Nozzle SA-Pressurizer Safety N/A B-D II-PZR-01NTHW- 508 CL 2; Nozzle to-Upper Head (minimum 67.14 percent B3.110 12 Shell SA-533 Weld 2.09)
Gr A CL 2
Nominal Exam Percent Component ID Component Description Material Pipe Size Category Coverage Thickness Nozzle SA-Pressurizer Spray N/A B-D II-PZR-01NTHW- 508 CL 2; Nozzle to-Upper Head (minimum 67.14 percent B3.110 9 Shell SA-533 Weld 2.69)
Gr A CL 2 Nozzle SA-Pressurizer Relief N/A B-D II-PZR-01NTHW- 508 CL 2; Nozzle to-Upper Head (minimum 69.26 percent B3.110 13 Shell SA-533 Weld 2.09)
Gr A CL 2 Nozzle SA-Pressurizer Surge N/A B-D II-PZR-01NTHW- 508 CL 2; Nozzle to-Lower Head (minimum 59.1 percent B3.110 08 Shell SA-533 Weld 2.74)
Gr A CL 2 A Residual Heat II-RHR-C-A/ Removal (RHR) Heat SA-240-TP 01RHRACSW-02 0.696 75 percent C1.10 Exchanger Shell 304 A, B, C Circumferential Weld Nozzle: SA-Safety Injection Boron C-B/ II-BIT-01NTHW- 182 F304 Injection Tank Inlet 2.0" 78.6 percent C2.21 04 Shell: SA-240 Nozzle to-Head Weld TP304 Nozzle: SA-Safety Injection Boron C-B/ II-BIT-01NTHW- 182 F304 Injection Tank Outlet 2.0" 76.5 percent C2.21 03 Shell: SA-240 Nozzle to-Head Weld TP304 3.1.2 Applicable Code Requirements The extent of examination requirement for Examination Category B-A, Item Number B1.30, per Table IWB-2500-1, requires a volumetric examination of essentially 100 percent of the weld length for shell-to-flange welds as shown in Figure IWB-2500-4. The extent of examination requirement for Examination Category B-B, Item Number B2.40, per Table IWB-2500-1, requires a volumetric examination of essentially 100 percent of the weld length for tubesheet-to-head welds, as shown in Figure IWB-2500-6. The extent of examination requirement for Examination Category B-D, Item Number B3.110, per Table IWB-2500-1, requires a volumetric examination of all pressurizer nozzle-to-vessel welds, as shown in Figure IWB-2500-7(b). The extent of examination requirement for Examination Category C-A, Item Number C1.10, per Table IWC-2500-1, requires a volumetric examination of essentially 100 percent of the weld length of the shell circumferential welds, as shown in Figure IWC-2500-1.
The extent of examination requirement for Examination Category C-A, Item Number C1.10, per Table IWC-2500-1, requires a volumetric examination of essentially 100 percent of the weld length of the shell circumferential welds, as shown in Figure IWC-2500-1. The extent of examination requirement for Examination Category C-B, Item Number C2.21, per Table IWC-2500-1, requires a volumetric and surface examination of the nozzle-to-head welds, as shown in Figure IWC-2500-4(a).
The licensee has adopted ASME Code Case N-460, Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1, which defines essentially 100 percent as greater than 90 percent coverage of the examination volume or surface area, as applicable.
The greater than 90 percent minimum coverage was applied to all surface and volumetric examination required by ASME Code,Section XI.
3.2 NRC Staff Evaluation The licensee has requested relief from the essentially 100 percent volumetric coverage requirements described in ASME Code,Section XI and their ISI program. However, the design configurations of the subject welds limit access for volumetric inspection. In order to effectively increase the examination coverage to meet ASME Code requirements, the welds would require design modifications. This would place a burden on the licensee.
Weld II-RV-0001FTHW-RV-18FA, B, C is an Examination Category B-A, Item Number B1.30 RPV shell-to-flange weld which joins low-alloy steel materials. The RPV shell material is approximately 7-inches thick and is composed of SA-533 Grade B Class 1 ferritic material. The flange is constructed from SA-508 Class 2 material. The examination obtained coverage of 71.1 percent using 45-degree and 60-degree shear waves during the ultrasonic testing examination. The coverage achieved represents a large sample, such that, if significant degradation were present in the weld, it is likely that the degradation would have been detected.
Evidence of significant service-induced degradation in the weld, if it were to occur, would likely be detected in the portions of the welds that were examined, because the examined volume is the same material as the unexamined volume, is under the same loading conditions, and is exposed to the same reactor coolant environment. This provides reasonable assurance of the structural integrity and leak tightness for weld II-RV-0001FTHW-RV-18FA, B, C.
Weld II-SG-001SGB-TSTHW-06-01 is an Examination Category B-B, Item Number B2.40 SG tubesheet-to-head weld. This weld is constructed of SA-508 Class 3 steel. The required volumetric examinations are limited due to the design configuration of the SG inlet nozzle and by four SG support pads. In order for the licensee to perform the ASME Code required examinations, the subject components would have to be redesigned and replaced. The examinations were performed with angle beam (45-degree shear and 60-degree shear) scans to achieve the weld examination volume of 70.1 percent and base metal examination volume of 75.2 percent. Based on these volumetric coverages of the subject weld and considering the licensees performance of ultrasonic examination techniques employed to maximize this coverage, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed. Based on the materials and the coverage obtained, there is reasonable assurance of structural integrity and leak tightness for weld II-SG-001SGB-TSTHW-06-01.
For the six Exam Category B-D, Item Number B3.110 welds listed in Table 1, the licensee achieved between 59.1 and 69.26 percent of the required examination volume. The applicable Code requirements are based on ASME Code,Section XI, Table IWB-2500-1, Class 1, Examination Category B-D, Item No. B3.110, which requires a 100 percent volumetric examination of the nozzle-to-vessel welds for all pressurizer nozzles. As described in the licensees submittal, the coverages of these welds are limited due to geometric configurations of the pressurizer safety nozzle transitions to the upper/lower head. The NRC staff determined that obtaining the ASME Code required examination volume is impractical because of the nozzle-to-head configurations of the subject welds. Based on the materials and the coverage obtained, there is reasonable assurance of structural integrity and leak tightness for welds II-PZR-01NTHW-10, II-PZR-01NTHW-11, II-PZR-01NTHW-12, II-PZR-01NTHW-9, II-PZR-01NTHW-13, and II-PZR-01NTHW-08.
Weld II-RHR-01RHRACSW-02 A, B, C is an Examination Category C-A, Item Number C1.10 RHR heat exchanger shell circumferential weld. The RHR heat exchanger is constructed using SA-240-TP 304 stainless steel and is approximately 0.7 inches thick. The examination was conducted using 45-degree shear waves for the circumferential scans for axial flaws with no restrictions and using 60-degree shear waves for axial scans for circumferential flaws, with inspections being limited to one side of the weld. The combined inspection obtained 75 percent coverage. The entire wetted surface of the weld was inspected. Based on the materials and the coverage obtained, there is reasonable assurance of structural integrity and leak tightness for weld II-RHR-01RHRACSW-02 A, B, C.
Welds II-BIT-01NTHW-04 and II-BIT-01NTHW-03 are the Boron Injection Tank Inlet and Outlet Nozzle-to-Head Welds, respectively. The boron injection tank has a nominal thickness of 2 inches and was inspected using 45- and 60-degree shear and longitudinal waves. The use of 45- and 60-degree longitudinal waves provides reasonable assurance that the examination will be able to identify significant cracks through a 2-inch thick weld. Based on the materials, the low operating temperatures and pressures, and the coverage obtained, there is reasonable assurance of structural integrity and leak tightness for welds II-BIT-01NTHW-04 and II-BIT-01NTHW-03.
In addition to the volumetric examinations, the licensee conducts the normal VT-2 examinations for signs of leakage during each outage. While this does not ensure leak tightness, it does contribute to component integrity by providing means to detect possible future leakage if it should occur.
The licensee has shown that it would be a burden to meet the ASME Code-required 100 percent volumetric examination coverage for the subject welds due to their design. Based on the volumetric coverage obtained for the three welds, the resistant material, and the low operating temperatures and pressures, the NRC staff concludes that there is reasonable assurance of structural integrity of the subject components. Thus, relief request I3R-19 meets the requirements for relief for impracticality described in the regulations at 10 CFR 50.55a(g)(6)(i).
4.0 CONCLUSION
As set forth above, the NRC staff determines that granting relief pursuant to 10 CFR 50.55a(g)(6)(i) is authorized by law, will not endanger life or property or the common defense and security, and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in the regulations at 10 CFR 50.55a(g)(5)(iii). Therefore, the NRC staff grants the licensees relief request I3R-19 at Shearon Harris Nuclear Power Plant, Unit 1 for the third 10-year ISI interval.
All other ASME Code,Section XI requirements for which relief was not specifically requested and authorized herein by the NRC staff remain applicable, including the third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributors: C. Fairbanks S. Cumblidge Date: April 5, 2020
ML20080G950 *by memorandum **by e-mail OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LA NRR/DNRL/NVIB/BC(A)
NAME MWentzel BAbeywickrama GCheruvenki DATE 03/25/2020 03/23/2020 12/26/2019 OFFICE NRR/DNRL/NPHP/BC DORL/LPL2-2/BC NAME MMitchell UShoop DATE 12/26/2019 04/05/2020