ML25232A191
| ML25232A191 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 09/05/2025 |
| From: | Markley M NRC/NRR/DORL/LPL2-1 |
| To: | Coleman J Southern Nuclear Operating Co |
| Kalathiveettil D, NRR/DORL/LPL2-1 | |
| References | |
| EPID L-2025-LLR-0005 | |
| Download: ML25232A191 (1) | |
Text
September 5, 2025 Jamie M. Coleman Regulatory Affairs Director Southern Nuclear Operating Co., Inc.
3535 Colonnade Parkway Birmingham, AL 35243
SUBJECT:
EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 - AUTHORIZATION OF ALTERNATIVE REQUEST RR-P SIXTH INSERVICE TESTING INTERVAL (EPID L-2025-LLR-0005)
Dear Jamie Coleman:
By letter dated January 30, 2025, Southern Nuclear Operating Company (SNC, the licensee) submitted Alternative Request RR-P-1 for specific pumps during the Sixth Inservice Testing (IST) interval at the Edwin I. Hatch Nuclear Plant (Hatch), Unit Nos. 1 and 2, which is scheduled to begin on January 1, 2026.
The licensee requested Alternative Request RR-P-1 for Hatch, Units 1 and 2, on the basis that the proposed alternative provides an acceptable level of quality and safety for the IST activities for the American Society of Mechanical Engineers (ASME) pumps affected. The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review and concludes that SNC has adequately addressed the regulatory requirements set forth in Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a, Codes and standards, paragraph (z)(1) for this alternative. Therefore, pursuant to 10 CFR 50.55a(z)(1), the NRC staff authorizes the use of this alternative to the 2022 Edition of the ASME Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code), as incorporated by reference in 10 CFR 50.55a, for the Code of Record interval, as defined in 10 CFR 50.55a(y), Definitions, that implements the 2022 Edition of the ASME OM Code for Hatch, Units 1 and 2. Use of this alternative with other Codes of Record is not authorized.
All other ASME OM Code requirements as incorporated by reference in 10 CFR 50.55a for which relief or an alternative was not specifically requested, and granted or authorized (as appropriate), in the subject request remain applicable.
If you have any questions, please contact the Project Manager, Dawnmathews Kalathiveettil at Dawnmathews.Kalathiveettil@nrc.gov or 301-415-5905.
Sincerely, Michael Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366
Enclosure:
Safety Evaluation cc: Listserv MICHAEL MARKLEY Digitally signed by MICHAEL MARKLEY Date: 2025.09.05 13:40:58 -04'00'
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION AUTHORIZATION OF PUMP ALTERNATIVE REQUEST RR-P-1 SIXTH INSERVICE TESTING INTERVAL SOUTHERN NUCLEAR OPERATING COMPANY EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-321 AND 50-366
1.0 INTRODUCTION
By letter dated January 30, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25030A363), and supplemented by letter dated May 15, 2025 (ML25135A409), Southern Nuclear Operating Company (SNC, the licensee) submitted RR-P-1 to the U.S. Nuclear Regulatory Commission (NRC) requesting authorization for a proposed alternative for specific affected pumps in lieu of certain inservice testing (IST) requirements of the 2022 Edition of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code), as incorporated by reference in Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a, Codes and standards, for the Sixth Inservice Testing (IST) interval at the Edwin I.
Hatch Nuclear Plant (Hatch), Units 1 and 2.
The licensee submitted Alternative Request RR-P-1 pursuant to 10 CFR 50.55a(z)(1),
Acceptable level of quality and safety, on the basis that the proposed alternative will provide an acceptable level of quality and safety for IST activities applied to the specific affected pumps within the scope of this request.
2.0 REGULATORY EVALUATION
The NRC regulations in 10 CFR 50.55a(f)(4), Inservice testing standards requirement for operating plants, state, in part:
Throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the inservice test requirements (except design and access provisions) set forth in the ASME OM Code and addenda that become effective subsequent to editions and addenda specified in paragraphs (f)(2) and (3) of this section
[10 CFR 50.55a] and that are incorporated by reference in paragraph (a)(1)(iv) of
this section [10 CFR 50.55a], to the extent practical within the limitations of design, geometry, and materials of construction of the components.
The regulations in 10 CFR 50.55a(z), Alternative to codes and standards requirements, state, in part, that alternatives to the requirements of paragraphs (b) through (h) of 10 CFR 50.55a or portions thereof may be used when authorized by the Director, Office of Nuclear Reactor Regulation. A proposed alternative must be submitted and authorized prior to implementation.
The applicant or licensee must demonstrate that:
(1) Acceptable level of quality and safety. The proposed alternative would provide an acceptable level of quality and safety; or (2) Hardship without a compensating increase in quality and safety. Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
NUREG-1482, Revision 3, Guidelines for Inservice Testing at Nuclear Power Plants: Inservice Testing of Pumps and Valves and Inservice Examination and Testing of Dynamic Restraints (Snubbers) at Nuclear Power Plants (ML20202A473), July 2020.
3.0 TECHNICAL EVALUATION
The applicable Code of Record for the Hatch, Units 1 and 2, Sixth IST interval is the 2022 Edition of the ASME OM Code. The Hatch, Units 1 and 2, Sixth IST interval, is scheduled to begin on January 1, 2026.
3.1 Licensees Alternative Request RR-P-1 3.1.1 Applicable ASME OM Code Requirements The requirements in the ASME OM Code, Subsection ISTB, Inservice Testing of Pumps in Water-Cooled Reactor Nuclear Power Plants - Pre-2000 Plants, as incorporated by reference in 10 CFR 50.55a, related to Alternative Request RR-P-1 are as follows:
Paragraph ISTB-3500, Data Collection and ISTB-3510, General, requires, in part:
a) Accuracy. Instrument accuracy shall be within the limits of Table ISTB-3510-1. If a parameter is determined by analytical methods instead of measurement, then the determination shall meet the parameter accuracy requirements of Table ISTB-3510-1 (e.g., flow rate determination shall be accurate to within +/-2% of actual). For individual analog instruments, the required accuracy is percent of full-scale. For digital instruments, the required accuracy is over the calibrated range. For a combination of instruments, the required accuracy is loop accuracy.
b) Range (1) The full-scale range for each analog instrument shall not be greater than 3 times the reference value.
Table ISTB-3510-1, Required Instrument Accuracy, provides the required instrument accuracy for pump tests conducted in accordance with the requirements of Subsection ISTB.
3.1.2 Components for Which Alternative is Requested The alternative was proposed for the following components:
Component ID Pump Description / Pump Type ASME Code Class ASME OM Code Category 1E11-C002A Residual Heat Removal Pump 2A /
Centrifugal 2
Group A 1E11-C002B Residual Heat Removal Pump 2B /
Centrifugal 2
Group A 1E11-C002C Residual Heat Removal Pump 2C /
Centrifugal 2
Group A 1E11-C002D Residual Heat Removal Pump 2D /
Centrifugal 2
Group A 2E11-C002A Residual Heat Removal Pump 2A /
Vertical Line Shaft 2
Group A 2E11-C002B Residual Heat Removal Pump 2B /
Vertical Line Shaft 2
Group A 2E11-C002C Residual Heat Removal Pump 2C /
Vertical Line Shaft 2
Group A 2E11-C002D Residual Heat Removal Pump 2D /
Vertical Line Shaft 2
Group A 3.1.3 Licensees Proposed Alternative and Basis for Use In its January 30, 2025, submittal, the licensee states in part:
Plant Hatch proposes to use the existing installed instrumentation during Group A pump testing. Even though 1(2)E11-PI-R003A-D exceed the Code allowable range limit of three times the reference value, this additional gage range coupled with the better-than-Code required accuracy of 0.5% results in only a 3 psi (600 x 0.005) maximum variance compared with the Code allowable variance of 10.26 psi (513 x 0.02).
Using other (temporary) instrumentation during Group A testing is not justifiable considering the difficulty and dose associated with such a requirement. The installed pressure indicators will provide data that is sufficiently accurate to allow assessment of pump condition and to detect degradation during the performance of the Group A IST pump testing. Highly accurate M&TE [Measuring and Test Equipment], which meets all Code requirements, will be installed during Comprehensive and Baseline testing.
The above proposed alternative provides an acceptable level of quality and safety since the variance in the actual test results is less than the maximum variance allowed by the Code. Based on the determination that the use of installed instrumentation provides an acceptable level of quality and safety; this proposed alternative should be authorized pursuant to 10 CFR 50.55a(z)(1).
By letter dated December 30, 2015 (ML15310A406), a similar alternative request was authorized for Hatch, Units 1 and 2.
In a letter dated May 15, 2025 (ML25135A409), the licensee confirmed that Pump Periodic Verification Tests are not within the scope of this alternative request.
3.1.4 Licensees Reason for its Request In its January 30, 2025, submittal, the licensee states in part:
Pursuant to 10 CFR 50.55a(z)(1), relief is requested from the requirements of the ASME OM Code, 2022 Edition, Subsection ISTB-3510(b)(1) which requires that full-scale range for each analog instrument shall not be greater than three times the reference value. The Residual Heat Removal (RHR) system pump discharge pressure indicators 1(2)E11-PI-R003A, 3B, 3C and 3D, exceed this Code range limit.
This alternative request is a re-submittal of NRC approved 4th and 5th Intervals Relief Request RR-P-3, previously submitted and approved for use for these instruments. There have been no substantive changes to this alternative or to the basis for use, which would alter the previous NRC Safety Evaluation conclusions for previous IST Intervals for Plant Hatch. (See Precedents for SERs)
The original installed instrumentation associated with the RHR pumps was not designed with the instrument range limits of OM Code ISTB-3510(b)(1) taken into consideration. The actual instrument ranges are itemized below.
Instrument Range Reference Value
- Allowed Range Accuracy 1E11-PI-R003A-D 0-600 psig 171-185 psig 0-513 psig
+/-0.5%
2E11-Pl-R003A-D 0-600 psig 180-195 psig 0-540 psig
+/-0.5%
- Allowed Range corresponds to 3 times the lowest reference value
[psig = pounds per square inch gauge]
3.2
NRC Staff Evaluation
In RR-P-1, the licensee has proposed an alternative approach to the OM Code instrumentation requirements of ASME OM Code, Subsection ISTB, paragraph ISTB-3510(b)(1), for pressure gauges that are used to measure the discharge pressure of the RHR pumps. Paragraph ISTB-3510(b)(1) requires that the full range of each instrument be no greater than three times the reference value.
The installed discharge pressure gauges for the RHR pumps at Hatch, Units 1 and 2, have a range of 0 to 600 psig and an accuracy of +/-0.5%. The typical value or reference value for the discharge pressure of the RHR pumps during Group A testing is 171 psig for Unit 1 and 180 psig for Unit 2. To meet the requirement of ISTB-3510(b)(1), the pressure gauge must have a range limit of 0 to 513 psig (3 x 171) for Unit 1 and 0 to 540 psig (180 x 3) for Unit 2.
Therefore, the installed pressure gauge with a range of 0 to 600 psig does not meet the ASME
OM Code requirements. In lieu of the ASME OM Code requirements, the licensee proposed to use the installed instrumentation with a range 0 to 600 psig, but with a required instrument accuracy of +/-0.5% during Group A testing, which is better than the ASME OM Code accuracy requirement.
Based on the ASME OM Code requirements for range and an ASME OM Code requirement for an accuracy of +/-2%, the NRC staff has determined that the ASME OM Code would allow up to a maximum variance of 10.26 psig (513 x 0.02) for Unit 1 and 10.8 psig (540 x 0.02) for Unit 2 in the measured parameters. Although the installed pressure gauges exceed the ASME OM Code allowable range limit of three times the reference value, the maximum variance allowed by the higher installed gauge range of 0 to 600 psig and the better than required accuracy of +/-0.5%,
would be only 3 psi (0.005 x 600), which is more conservative than the ASME OM Code requirements (10.26 psi for Unit 1 and 10.8 psi for Unit 2). Based on the above, the NRC staff finds that the proposed alternative will provide a more accurate measured value of the parameters than required by the ASME OM Code, and, therefore, is acceptable.
The use of the existing instruments is supported by NUREG-1482, Revision 3, Guidelines for Inservice Testing at Nuclear Power Plants, paragraph 5.5.1, which addresses NRC approval when the combination of range and accuracy yields a reading at least equivalent to that achieved using instruments that meet the ASME OM Code requirements.
Based on the above, the NRC staff has determined that Alternative Request RR-P-1 may be authorized pursuant to 10 CFR 50.55a(z)(1) on the basis that the proposed alternative provides an acceptable level of quality and safety in lieu of the applicable pump instrument accuracy requirements in the ASME OM Code.
The NRC staff notes that the applicable code of record for the Hatch Units 1 and 2, Sixth IST interval, is the 2022 Edition of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a. The Hatch Units 1 and 2, Sixth IST interval, is scheduled to begin on January 1, 2026.
The ASME OM Code (2022 Edition), Subsection ISTA, General Requirements, paragraph ISTA-3120, Inservice Examination and Test Interval, as incorporated by reference in 10 CFR 50.55a, requires that licensees implement 10-year intervals for their IST programs. Although not requested, the NRC regulations in 10 CFR 50.55a allow licensees to implement the same ASME OM Code as their Code of Record for two consecutive IST program intervals.
4.0 CONCLUSION
As set forth above, the NRC staff has determined that Alternative Request RR-P-1 for Hatch, Units 1 and 2, provides an acceptable level of quality and safety for IST activities for the specific affected pumps within the scope of the request. Accordingly, the NRC staff concludes that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1) for this proposed alternative. Therefore, pursuant to 10 CFR 50.55a(z)(1), the NRC staff authorizes Alternative Request RR-P-1 for the Sixth IST Interval for the specified pumps within the scope of the request in lieu of the applicable IST requirements in the 2022 Edition of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a, for Hatch, Units 1 and 2, for the code of record interval, as defined in 10 CFR 50.55a(y), Definitions, that implements the 2022 Edition of the ASME OM Code. Use of this alternative with other codes of record is not authorized.
All other ASME OM Code requirements as incorporated by reference in 10 CFR 50.55a for which relief or an alternative was not specifically requested, and granted or authorized (as appropriate), in the subject request remain applicable.
Principal Contributors: N. Hansing, NRR T. Scarbrough, NRR G. Bedi, NRR Date: September 5, 2025
ML25232A191 NRR-028 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DEX/EMIB/BC NAME DKalathiveettil KZeleznock SBailey DATE 08/19/2025 08/25/2025 08/19/2025 OFFICE NRR/DORL/LPL2-1/BC NAME MMarkley DATE 09/05/2025