NL-25-0313, Request for Authorization of Inservice Testing Alternative to ISTC-3700 and Inservice Testing Alternative to Adopt Code Case OMN-32

Request for Authorization of Inservice Testing Alternative to ISTC-3700 and Inservice Testing Alternative to Adopt Code Case OMN-32

ML25238A190
Person / Time
Site:	Hatch
Issue date:	08/26/2025
From:	Coleman J Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-25-0313
Download: ML25238A190 (1)

Text

1.

3535 Colonnade Parkway Birmingham, AL 35243 205 992 5000 tel Regulatory Affairs August 26, 2025 Docket Nos.: 50-321 NL-25-0313 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Request for Authorization of Inservice Testing Alternative to ISTC-3700 and Inservice Testing Alternative to Adopt Code Case OMN-32 Ladies and Gentlemen:

In accordance with 10 CFR 50.55a, Codes and standards, Southern Nuclear Operating Company (SNC) requests NRC authorization of two proposed alternatives, RR-V-5 and RR-P-10, associated with the lnservice Testing (IST) Program for Edwin I. Hatch Nuclear Plant (HNP).

Alternative request RR-V-5 is provided in Enclosure 1 and proposes an alternative to the ISTC-3700 position verification requirements of the ASME OM Code.

Proposed alternative request RR-P-10 is provided in Enclosure 2 and would adopt American Society of Mechanical Engineers Operation and Maintenance of Nuclear Power Plants (ASME OM Code) Code Case OMN-32 for pump test instrumentation range and accuracy.

The proposed alternatives in the attached enclosures provide reasonable assurance of pump and valve operational readiness and provides an acceptable level of quality and safety.

SNC requests NRC authorization of proposed alternative RR-V-5 by December 31, 2025 to allow for processing the necessary procedure and program changes prior to the Unit 1 Spring 2026 refueling outage. SNC requests authorization of proposed alternative RR-P-10 within 12 months of acceptance review. These alternatives, upon authorization, will be implemented during the Code of Record Interval that uses the 2022 Edition of the ASME OM Code, which begins on January 1, 2026.

This letter contains no regulatory commitments. If you have any questions, please contact Ryan Joyce at 205.992.6468.

U. S. Nuclear Regulatory Commission NL-25-0313 Page 2 of 2 Respectfully submitted, Jamie M. Coleman Director, Regulatory Affairs Southern Nuclear Operating Company JMC/agq/cbg

Enclosures:

1.

RR-V-5: Proposed Alternative to ISTC-3700

2.

RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 cc:

Regional Administrator, Region ll NRR Project Manager - Hatch 1&2 Senior Resident Inspector - Hatch 1&2 R-Type: CHA02.004 Digitally signed by JAMIEMCO Date: 2025.08.26 08:56:26

-05'00'

NL-25-0313 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Request for Authorization of Inservice Testing Alternative to ISTC-3700 and Inservice Testing Alternative to Adopt Code Case OMN-32 RR-V-5: Proposed Alternative to ISTC-3700 to NL-25-0313 RR-V-5: Proposed Alternative to ISTC-3700 Page 1 of 2

1. ASME Code Components Affected All of the valves in the Inservice Testing (IST) program within the scope of ISTC-3700 are covered in this proposed alternative.

2. Applicable Code Edition and Addenda

American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants (OM) Code, 2022 Edition.

3. Applicable Code Requirement

ISTC-3700, Position Verification Testing Valves with remote position indicators shall be observed locally at least once every 2 yr to verify that valve operation is accurately indicated. Where practicable, this local observation should be supplemented by other indications such as use of flow meters or other suitable instrumentation to verify obturator position. These observations need not be concurrent.

Where local observation is not possible, other indications shall be used for verification of valve operation.

Position verification for active MOVs shall be tested in accordance with Division 1, Mandatory Appendix III.

10 CFR 50.55a(b)(3)(xi) OM condition: Valve Position Indication requires licensees to verify that valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation, to provide assurance of proper obturator position.

4. Reason for Request

Pursuant to 10 CFR 50.55a(z)(1), an alternative to the requirements of the ASME OM Code, 2022 Edition, Subsection ISTC-3700 is requested. In addition, the frequency of these tests, along with NRC Condition 10 CFR 50.55a(b)(3)(xi), would be performed every four (4) years.

Resulting from an industry event where a valves stem-disc connection failed (NRC Information Notice (IN) 2012-14), the NRC placed Condition 10 CFR 50.55a(b)(3)(xi) on OM Code Subsection ISTC-3700 to require licensees to verify that the valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation to provide assurance of proper obturator position for valves with remote position indication.

This alternative simplifies the implementation instructions for remote position indication verification. The existing requirement to verify valve operation is accurately indicated includes local verification of indication that the valve is either in or out of its required safety position(s). The requirement to verify all indicated positions is unaltered by this proposed alternative.

In addition, extending the frequency of these tests would support a divisional outage strategy in which only one division of safety systems is removed from service during an outage. This strategy would improve safety system availability during outages, reduce the potential for human performance issues, and reduce personnel radiation exposure.

to NL-25-0313 RR-V-5: Proposed Alternative to ISTC-3700 Page 2 of 2

5. Proposed Alternative and Basis for Use

As an alternative to ISTC-3700 and the condition in paragraph 50.55a(b)(3)(xi), SNC proposes the following for Position Verification Testing:

Valves with remote position indicators shall be exercised to verify valve operation is accurately indicated for both the open and closed positions. Observation shall be supplemented by other indications such as use of flow meters or other suitable instrumentation to verify obturator position. These observations need not be concurrent.

The position verification test may be extended from at least once every 2 yr to a frequency of once per four (4) years, unless historical data requires more frequent testing.

Position verification for active MOVs, shall be performed in accordance with Mandatory Appendix III.

The alternative clarifies implementation instructions for definitive verification of obturator to stem connection integrity in conjunction with valve position indication as required by the condition in 10 CFR 50.55a(b)(3)(xi). Normal valve operations, other IST testing such as stroke time testing, and diagnostic testing are not changed by this alternative and will also provide assurance of proper component operation and valve position. This alternative also provides a benefit that eliminates the need for local observation which reduces radiation exposure (ALARA). This approach provides reasonable assurance that valve position indication and obturator to stem connection integrity is verified.

This alternative also provides an approach to extend the test frequency from 24 months to 48 months. The decision to extend the position verification frequency will be based on historical data consistent with similar methodology as applied to pressure relief valves in ASME OM Code Division 1, Mandatory Appendix I. This approach provides reasonable assurance that a loss of position indication, including obturator to stem connection, is detected.

The above proposed alternative provides an acceptable alternative in quality and safety in lieu of ISTC-3700 and the condition in 10 CFR 50.55a(b)(3)(xi) and should be authorized pursuant to 10 CFR 50.55a(z)(1).

6. Duration of Proposed Alternative

This Code alternative will be implemented during the Code of Record Interval that uses the 2022 Edition of the ASME OM Code.

7. Precedents

None

NL-25-0313 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Request for Authorization of Inservice Testing Alternative to ISTC-3700 and Inservice Testing Alternative to Adopt Code Case OMN-32 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 to NL-25-0313 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 Page 1 of 6

1. ASME Code Components Affected Component ID Pump Description ASME Class ASME OM Code Category 1E11-C002A Unit 1 Residual Heat Removal Pump A 2

Group A 1E11-C002B Unit 1 Residual Heat Removal Pump B 2

Group A 1E11-C002C Unit 1 Residual Heat Removal Pump C 2

Group A 1E11-C002D Unit 1 Residual Heat Removal Pump D 2

Group A 2E11-C002A Unit 2 Residual Heat Removal Pump A 2

Group A 2E11-C002B Unit 2 Residual Heat Removal Pump B 2

Group A 2E11-C002C Unit 2 Residual Heat Removal Pump C 2

Group A 2E11-C002D Unit 2 Residual Heat Removal Pump D 2

Group A 1P41-C001A Unit 1 Plant Service Water Pump A 3

Group A 1P41-C001B Unit 1 Plant Service Water Pump B 3

Group A 1P41-C001C Unit 1 Plant Service Water Pump C 3

Group A 1P41-C001D Unit 1 Plant Service Water Pump D 3

Group A 2P41-C001A Unit 2 Plant Service Water Pump A 3

Group A to NL-25-0313 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 Page 2 of 6 Component ID Pump Description ASME Class ASME OM Code Category 2P41-C001B Unit 2 Plant Service Water Pump B 3

Group A 2P41-C001C Unit 2 Plant Service Water Pump C 3

Group A 2P41-C001D Unit 2 Plant Service Water Pump D 3

Group A 2P41-C002 Unit 2 Standby Diesel Generator Service Water Pump 3

Group B 1E11-C001A Unit 1 Residual Heat Removal Service Water Pump A 3

Group A 1E11-C001B Unit 1 Residual Heat Removal Service Water Pump B 3

Group A 1E11-C001C Unit 1 Residual Heat Removal Service Water Pump C 3

Group A 1E11-C001D Unit 1 Residual Heat Removal Service Water Pump D 3

Group A 2E11-C001A Unit 2 Residual Heat Removal Service Water Pump A 3

Group A 2E11-C001B Unit 2 Residual Heat Removal Service Water Pump B 3

Group A 2E11-C001C Unit 2 Residual Heat Removal Service Water Pump C 3

Group A 2E11-C001D Unit 2 Residual Heat Removal Service Water Pump D 3

Group A 1E41-C001 Unit 1 High Pressure Coolant Injection Pump 2

Group B 2E41-C001 Unit 2 High Pressure Coolant Injection Pump 2

Group B to NL-25-0313 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 Page 3 of 6 Component ID Pump Description ASME Class ASME OM Code Category 1E51-C001 Unit 1 Reactor Core Isolation Cooling Pump 2

Group Aug-B 2E51-C001 Unit 2 Reactor Core Isolation Cooling Pump 2

Group Aug-B 1C41-C001A Unit 1 Standby Liquid Control Pump 2

Group B 1C41-C001B Unit 1 Standby Liquid Control Pump 2

Group B 2C41-C001A Unit 2 Standby Liquid Control Pump 2

Group B 2C41-C001B Unit 2 Standby Liquid Control Pump 2

Group B

2. Applicable Code Edition and Addenda

American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants (OM) Code, 2022 Edition.

3. Applicable Code Requirement

ISTB-3510(a), from ISTB-3500, Data Collection and ISTB-3510 General paragraphs (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 requirement 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 of each analog instrument shall not be greater than 3 times the reference value.

(2) Digital instruments shall be selected such that the reference value does not exceed 90% of the calibrated range of the instrument.

NOTE: ISTB-3510(b)(3) pertains to vibration instruments and is not covered by Code Case OMN-32 Revision 1 or included in this alternative request.

to NL-25-0313 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 Page 4 of 6 Table ISTB-3510-1, Required Instrument Accuracy provides the accuracy requirements for gauges used for Group A and Group B Testing for pumps.

NOTE: Speed and vibration listed in Table ISTB-3510-1 are not covered by Code Case OMN-32 Revision 1 or included in this alternative request.

Pump Periodic Verification Tests (PPVTs) are not covered by Code Case OMN-32 Revision 1 or included in this alternative request since instrument accuracies for PPVTs are not explicitly listed within Table ISTB-3510-1. Although Table ISTB-3510-1 does not specify instrument accuracy or ranges for PPVTs, Table ISTB-3510-1, Note 1 requires instrument accuracies to be accounted for in the test acceptance criteria. Therefore, alternate range and accuracy gages are permitted to be used for PPVTs as long as the required instrument accuracy is taken into account for the PPVT flow and pressure.

4. Reason for Request

Pursuant to 10 CFR 50.55a(z)(1), an alternative that provides an acceptable level of quality and safety is proposed to the requirements of the ASME OM Code, 2022 Edition, Subsection ISTB-3510(a), ISTB-3510(b)(1), ISTB-3510(b)(2), and Table ISTB-3510-1 for the accuracy and range of pressure, flow rate, and differential pressure.

This alternative request is to allow for implementation of ASME OM Code Case OMN-32 Revision 1, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests. This ASME OM Code Case is not listed in Regulatory Guide 1.192, Revision 5, Operation and Maintenance Code Case Acceptability, ASME OM Code, issued March 2024.

5. Proposed Alternative and Basis for Use

Plant Hatch proposes to use ASME OM Code Case OMN-32 Revision 1, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests, in lieu of ISTB-3510(a), ISTB-3510(b)(1),

ISTB-3510(b)(2), and Table ISTB-3510-1, so that the following requirements may be applied to instruments used to measure pump pressure, flow rate, and differential pressure.

1. Required Instrument Accuracy and Range a) Accuracy. The analog or digital instrument(s) shall be calibrated within the limits specified in Table 1 for the respective test quantity. For an instrument loop, the required accuracy is instrument loop accuracy as defined in ISTA-2000. If a parameter is determined by analytical methods instead of measurement, then the determination shall meet the parameter accuracy requirements of Table 1.

b) Range. The analog or digital instrument(s) shall be designed and calibrated in the range for use at the expected reading to be measured or recorded during the test (e.g., reference value and applicable acceptance criteria).

to NL-25-0313 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 Page 5 of 6 Table 1 Required Instrument Accuracy Quantity Group A and Group B Tests, %

of Reading Comprehensive, Baseline, and Preservice Tests

% of Reading Pressure

+/-6

+/-11/2 Flow Rate

+/-6

+/-6 Differential pressure

+/-6

+/-11/2 The basis behind this code case is that the maximum allowed full-scale range for an analog instrument is three times the reference value per ISTB-3510(b)(1). The ASME OM Code Group A and Group B Pump test accuracy requirements for pressure, flow rate, and differential pressure are +/-2% of full-scale for analog instruments per ISTB-3510(a) and Table ISTB-3510-1. Therefore, the maximum error allowed by the ASME OM Code at the reference value (reading) for Group A and Group B pump test parameters would be up to

+/-6% of the reference value (reading). Similarly, based on the comprehensive, baseline, and preservice accuracy requirements for pressure (+/-1/2%), flow rate (+/-2%), and differential pressure (+/-1/2%), the second column represents the maximum error allowed by the ASME OM Code at the reference value for comprehensive, baseline, and preservice pump tests.

Revision 1 of this code case incorporated the requirements for the Table 1 accuracies to apply to the expected reading to be measured or recorded during the test (e.g., reference value and applicable acceptance criteria). More information is provided within the white paper for Code Case OMN-32, Revision 1 (ASME Record 24-48).

The original installed instrumentation used for pump testing was not designed to meet the instrument accuracy and/or range limits of the OM Code ISTB-3510. Hatch has several longstanding Code alternatives for this instrumentation, specifically due to the instrument range exceeding three times the reference value or instrument accuracy exceeding Table ISTB-3510-1. However, this instrumentation does meet the alternative range and accuracy requirements of Code Case OMN-32 Revision 1. Upon authorization of this Code alternative to use OMN-32 Revision 1, it is intended to be used in lieu of the previously submitted relief requests RR-P-1, RR-P-2, RR-P-5, and RR-P-6 under NL-24-0421 (ML25030A363).

The above proposed alternative will provide adequate indication of pump performance and continue to provide an acceptable level of quality and safety.

6. Duration of Proposed Alternative

This Code alternative will be implemented during the Code of Record Interval that uses the 2022 Edition of the ASME OM Code.

7. Precedents

The following alternative to use Code Case OMN-32 Revision 0 was authorized in December 2024. Code Case OMN-32 Revision 1 was issued in February 2025 and includes requirements for when a parameter is determined by analytical methods instead of to NL-25-0313 RR-P-10: Proposed Alternative to Adopt Code Case OMN-32 Page 6 of 6 measurement. SNCs proposed alternative request RR-P-10 is seeking authorization to use Code Case OMN-32 Revision 1.

Constellation Energy Generation, LLC (CEG) SER for all of their nuclear sites to use ASME OM Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests,

[ML24344A274]

8. References

1. ASME OM Code Case OMN-32 Revision 1, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests