ML24011A002

Final Safety Evaluation by the Office of Nuclear Reactor Regulation for the Nuclear Energy Institute Topical Report NEI 16-03, Revision 1, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools Project No. 689; Docket No. 99

ML24011A002
Person / Time
Site:	Nuclear Energy Institute, 99902028
Issue date:	01/31/2024
From:	Leslie Fields Office of Nuclear Reactor Regulation
To:	Gerond George Licensing Processes Branch
Shared Package
ML24011A001	List: ML24011A002 ML24011A272
References
EPID L-2022-NTR-0002, NEI 16-03, Rev. 1
Download: ML24011A002 (1)

Text

FINAL SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR THE NUCLEAR ENERGY INSTITUTE TOPICAL REPORT NEI 16-03, REVISION 1, GUIDANCE FOR MONITORING OF FIXED NEUTRON ABSORBERS IN SPENT FUEL POOLS PROJECT NO. 689; DOCKET NO. 99902028; EPID L-2022-NTR-0002

Table of Contents

1.0 INTRODUCTION

2.0 REGULATORY EVALUTION........................................................................................

2.1 Applicability of NRC Regulatory Requirements and Guidance.....................................

2.1.1 NRC Regulations.........................................................................................................

2.1.2 General Design Criteria................................................................................................

2.1.3 NRC Guidance Documents..........................................................................................

3.0 TECHNICAL EVALUATION

3.1 Guidance for Developing a Neutron Absorbing Monitoring Program...........................

3.2 Coupon Testing Program.............................................................................................

3.2.1 Overview of NEI 16-03, Revision 1..............................................................................

3.2.2 NRC Staffs Evaluation of the Coupon Testing Program..............................................

3.3 Industrywide Learning Aging Management Program...................................................

3.3.1 Overview of NEI 16-03, Revision 1..............................................................................

3.3.2. NRC Staffs Evaluation of the Industrywide Learning Aging Management Program....

3.4.

In-Situ Measurement Program.....................................................................................

3.4.1. Overview of NEI 16-03, Revision 1..............................................................................

3.4.2. NRC Staffs Evaluation of In-Situ Measurement Program..........................................

3.5.

Evaluating Neutron Absorber Test Results................................................................

3.5.1. Overview of NEI 16-03, Revision 1............................................................................

4.0 CONDITIONS, LIMITATIONS, AND/OR ACTION ITEMS...........................................

5.0 CONCLUSION

S..........................................................................................................

1.0 INTRODUCTION

By letter dated August 19, 2022 (Ref. 1), as supplemented by letters (Ref. 4) dated October 12, 2022, December 15, 2022, May 23, 2023, and August 24, 2023, the Nuclear Energy Institute (NEI) submitted proposed methodology document NEI 16-03, Revision (Rev.) 1, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools (Ref. 2), on behalf of its members for U.S. Nuclear Regulatory Commission (NRC) review and endorsement. NEI 16-03, Rev. 1 includes Electric Power Research Institutes (EPRIs) Technical Report 3002018497, Industrywide Learning Aging Management Program (i-LAMP): Global Neutron Absorber Material Monitoring Program for Spent Fuel Pools (Ref. 3) dated August 2022, as an alternative monitoring approach.

The purpose of NEIs document is to provide guidance for licensees to develop an acceptable fixed neutron absorber monitoring program in spent fuel pools (SFPs) as a means to demonstrate compliance with applicable regulations in Section 50.68 of Title 10 of the Code of Federal Regulations (10 CFR), Criticality Accident Requirements, Appendix A to 10 CFR Part 50, General Design Criterion (GDC) 61, Fuel Storage and Handling and Radioactivity Control, and Appendix A to 10 CFR Part 50, GDC 62,Prevention of Criticality in Fuel Storage and Handling, with respect to neutron absorbing materials (NAMs). Although NEI requested the NRC staff to endorse NEI 16-03, Rev. 1, the NRC staff is not proposing to issue a regulatory guide to endorse NEI 16-03. Instead, as stated in this Safety Evaluation (SE), the NRC staff is treating NEI 16-03, Rev. 1, as a topical report, and as described below, the NRC staff has determined that NEI 16-03, Rev. 1 is acceptable, with the limitation described below, for referencing in a licensing action that includes the information described below in Section 4.0 of this SE.

2.0 REGULATORY EVALUTION The effectiveness of the NAM installed in SFP storage racks ensures that the effective neutron multiplication factor (keff) does not exceed the maximum value derived from the criticality analysis of record (AOR) and other licensing basis documents. The AOR is the basis, in part, for demonstrating compliance with plant technical specifications and with applicable NRC regulations. Degradation or deformation of the credited NAM may reduce safety margin and potentially challenge the subcriticality requirement. NAMs utilized in SFP racks exposed to treated water or treated borated water may be susceptible to reduction of neutron absorbing capacity, changes in dimension, and/or loss of material that increases keff. A licensee implements a monitoring program to ensure that degradation of the NAM used in SFPs, which could compromise the ability of the NAM to perform its safety function as assumed in the AOR, will be detected.

2.1 Applicability of NRC Regulatory Requirements and Guidance NRCs regulatory requirements and the corresponding staff review criteria and guidance for NAM monitoring programs are identified in the following subsections.

2.1.1 NRC Regulations The regulations in 10 CFR 50.68(b)(4), Criticality accident requirements, indicates that if the licensee does not credit soluble boron in the SFP criticality AOR, the keff of the SFP storage

racks must not exceed 0.95 at a 95 percent probability, 95 percent confidence level, if flooded with unborated water. If the licensee does take credit for soluble boron, the keff of the SFP storage racks must not exceed 0.95 at a 95 percent probability, 95 percent confidence level, if flooded with borated water; and if flooded with unborated water, the keff must remain below 1.0 at a 95 percent probability, 95 percent confidence level.

2.1.2 General Design Criteria GDC 61, Fuel storage and handling and radioactivity control, states, in part, that The fuel storage and handling, radioactive waste, and other systems which may contain radioactivity shall be designed to assure adequate safety under normal and postulated accident conditions. These systems shall be designed (1) with a capability to permit appropriate periodic inspection and testing of components important to safety[.]

GDC 62, Prevention of Criticality in Fuel Storage and Handling, states that Criticality in the fuel storage and handling system shall be prevented by physical systems or processes, preferably by use of geometrically safe configurations.

2.1.3 NRC Guidance Documents NUREG-0800, Standard Review Plan [(SRP)], Section 9.1.1, Rev. 3, Criticality Safety of Fresh and Spent Fuel Storage and Handling (Ref. 7) provides guidance regarding the acceptance criteria and review procedures to ensure that the proposed changes satisfy the requirements in 10 CFR 50.68.

NUREG-0800, Standard Review Plan, Section 9.1.2, Rev. 4, New and Spent Fuel Storage (Ref. 8) provides guidance regarding the acceptance criteria and review procedures to ensure that the proposed changes satisfy the requirements in 10 CFR 50.68.

NUREG-1801, Generic Aging Lessons Learned (GALL) Report, Rev. 2 (Ref. 9) provides guidance on what constitutes an acceptable monitoring program for NAMs providing criticality control in the SFP.

3.0 TECHNICAL EVALUATION

This technical evaluation section documents the NRC staff's evaluation of the NEI 16-03, Rev. 1 against the relevant criteria identified in Section 2.0 of this SE.

3.1 Guidance for Developing a Neutron Absorbing Monitoring Program NEI 16-03, Rev. 1 provides guidance for developing a NAM monitoring program for NAM in the SFP. The purpose of a NAM monitoring program is to verify that the NAM installed in SFPs continues to provide the criticality control relied upon in the AOR and help to maintain the subcriticality margin in accordance with 10 CFR 50.68 requirements. NEI 16-03, Rev. 1 provides an approach for developing a NAM monitoring program that relies on periodic inspection, testing, monitoring, and analysis of the NAM. To accomplish this purpose, the NEI 16-03, Rev. 1

states that a monitoring program must be capable of identifying unanticipated changes in the absorber material and determining whether anticipated changes can be verified. NEI 16-03, Rev. 1 describes a method that uses coupon testing, in-situ measurement, and/or an i-LAMP as a means to monitor potential changes in characteristics of the NAM.

The NRC staff reviewed NEI 16-03, Rev. 1 to determine whether the approach it describes will result in an acceptable monitoring program, i.e., one that has the ability to ensure that potential degradation of SFP NAM will be detected, monitored, and mitigated. As set forth below, the NRC staff determined that an appropriate combination of the three methods listed above (coupon testing, in-situ measurement, and/or i-LAMP) can comprise an effective NAM monitoring program. During the course of NRC staffs review, several topics were identified that warranted clarification. The NRC staff issued a request for additional information (Ref. 10) and NEI provided clarifying responses and modified NEI 16-03, Rev. 1 as appropriate.

3.2 Coupon Testing Program 3.2.1 Overview of NEI 16-03, Revision 1 NEI 16-03, Rev. 1 describes the use of a coupon testing program as the preferred method for a NAM monitoring program. This method employs small sections (coupons) of the same NAM installed in the SFP, which are attached to a structure (coupon tree) in the SFP. The coupon tree is placed near freshly discharged fuel assemblies in an attempt to accelerate potential degradation mechanisms.

NEI 16-03, Rev. 1 provides the following criteria for an acceptable coupon program:

The number of coupons needs to be adequate to allow for sampling at intervals for the intended life of the absorbers.

The sampling intervals are based on the expected rate of material change.

Performance of coupon testing includes:

Basic testing defined as visual observations, dimensional measurements, and weight analysis, and Full testing defined as density measurements, Boron-10 (10B) areal density (AD) measurements, microscopic analysis, and characterization of changes, in addition to the basic testing parameters.

NEI 16-03, Rev. 1 states that the coupons will be located in the SFP such that their exposure to parameters controlling change mechanisms is conservative or similar to the in-service neutron absorbers. For neutron attenuation testing, NEI 16-03, Rev. 1 provides acceptance criteria for the NAM depending on if there is, or is not, an anticipated loss of 10B AD. The acceptable result for NAMs with expected 10B AD loss is the 10B AD of the test coupon is greater than the 10B AD assumed in the licensees SFP criticality AOR. For NAM without an expected loss of 10B AD, the acceptable result is the 10B AD of the test coupon is equal to the original 10B AD of the coupon (within measurement uncertainty).

In regard to sampling frequency, NEI 16-03, Rev. 1 states that the acceptable initial sampling interval for testing of new material (i.e., with a limited, or no, operating history) is up to 5 years, with subsequent intervals up to 10 years. For those materials that have well-documented

operating experience, they do not have a history of degradation or degradation mechanisms, and information on stability of the material condition is well developed. NEI 16-03, Rev. 1 states that initial and subsequent test intervals up to 10 years are acceptable. NEI 16-03, Rev. 1 states that for materials with known degradation mechanisms, or a history of known degradation (e.g.,

Boraflex, Carborundum, Tetrabor, etc.), the acceptable interval for neutron attenuation testing is at least once every five years. In addition, NEI 16-03, Rev. 1 includes neutron attenuation testing in the full testing approach for any NAMs used, as a component of a satisfactory NAM monitoring program.

3.2.2 NRC Staffs Evaluation of the Coupon Testing Program The NRC staff has evaluated NEI 16-03, Rev. 1 for the basic and full portions of a coupon testing program. The basic portion of the testing includes methods to monitor the physical condition of the NAM so that signs of potential degradation may be observed. The full portion of the testing includes neutron attenuation testing for all NAMs that are credited in the SFP criticality analysis, which will allow the licensee to detect a potential loss in 10B AD. The staff finds the coupon testing program to be acceptable because it includes measurements of 10B AD and of dimensional changes in the material that can impact the ability of the NAM to perform its function as assumed in the licensees SFP criticality AOR.

The NRC staff also determined the acceptance criteria for the coupon testing program provided in NEI 16-03, Rev.1 is acceptable, as follows. The acceptance criteria are adequate to establish that the assumptions regarding the AD of the NAM in the licensees SFP criticality AOR will be maintained, because the acceptance criteria show that the material is either not losing 10B AD (for materials not expected to lose 10B AD), or the 10B AD is still above the 10B AD assumed in the licensees SFP criticality AOR (for NAM anticipated to lose 10B AD). In addition, the NRC staff recognizes that if a coupon being tested approaches the 10B AD value used in the licensees SFP criticality AOR, the licensee would likely need to perform further evaluations and/or take additional corrective actions to conclude that the in-service NAM will not degrade below the 10B AD assumed in the licensees SFP criticality AOR. Provisions for additional corrective actions that may be necessary are discussed in Section 2.4, Evaluating Neutron Absorber Test Results, of NEI 16-03, Rev. 1, and NRC staffs evaluation is discussed in Section 3.5 of this SE.

NEI 16-03, Rev. 1 also states that coupons may be re-inserted into the SFP after non-destructive examination and analysis as long as the coupons are not subjected to heat drying which may cause mechanical damage. The NRC staff understands that the re-installation of coupons may be valuable for licensees that have a limited number of coupons remaining. As stated previously, coupon testing is the preferred method for NAM monitoring and efforts to maintain the coupon inventory are acceptable if the reinserted coupons will continue to yield valid data.

3.3 Industrywide Learning Aging Management Program 3.3.1 Overview of NEI 16-03, Revision 1 The primary difference between NEI 16-03, Rev. 0 and NEI 16-03 Rev. 1 is the addition of i-LAMP as an alternative monitoring option for BORAL plants that do not have surveillance coupons in their SFP. The objective of i-LAMP is to provide access to surrogate or sibling pool data for plants that do not have a coupon monitoring program. The i-LAMP approach is not intended to serve as a replacement for a coupon monitoring program for SFPs with coupons.

The key components of i-Lamp are the SFP coupon database, water chemistry database, analysis of these databases, and analysis of their potential impact on reactivity. The core of i-LAMP is an SFP coupon database. EPRI compiled data from existing coupon test reports and continues to add data as new test results become available.

NEI 16-03, Rev. 1 states that the following data is being collected from plants with BORAL coupon monitoring programs:

Pool name Rack installation year Rack type (egg crate versus flux trap)

Stainless steel encapsulation or not Coupon unique identification (ID) number Coupon analysis year(s), if the same coupon is analyzed multiple times Dimension data (pre-characterization and post-irradiation)

- Height, width, thickness

- Weight

- Areal density values (pre-characterization and post-irradiation)

- Pit and blister data To participate in i-LAMP and leverage surrogate test results for an SFP, a facility that does not have a BORAL coupon monitoring program identifies a sibling plant or plants in the existing database.

The essential parameters needed to identify an appropriate sibling plant are listed below:

Similarity of BORAL characteristics

- Areal density values

- Manufacturing and installation years

- Thickness Similarity of water chemistry data between SFPs

- Boron levels

- Chlorine, Fluorine, Sulfate levels

- Other chemistry parameters NEI 16-03 Rev. 1 calls for licensees to review i-LAMP data at least every 5 years to confirm the continued acceptable performance of sibling pool BORAL.

Acceptance Criteria are described as follows:

The sibling pool BORAL material is represented in the i-LAMP database.

Representation is determined using the parameters described above including material age, areal density, and SFP water chemistry.

Applicable surrogate data has been updated with new operating experience within the last 10 years, unless older data remains bounding for the sibling pool.

Applicable surrogate data does not indicate unanticipated changes are occurring.

Applicable surrogate data confirms that there is no loss of 10B within the measurement uncertainty.

NEI 16-03 Rev. 1 states that based on major research projects conducted by EPRI and data collected from the industry, there are no known degradation mechanisms that have resulted in loss of 10B in BORAL. Because of this, NEI 16-03, Rev. 1 proposes a 2 bin approach which separates plants into those with coupons and those without coupons. NEI 16-03, Rev. 1 proposes that plants without coupons are bounded by the collective database of plants with coupons and therefore do not need to perform a detailed analysis to confirm that they are bounded by a sibling plant or plants. The NRC staffs evaluation of this concept is provided below.

3.3.2. NRC Staffs Evaluation of the Industrywide Learning Aging Management Program The NRC staff has evaluated the proposal in NEI 16-03, Rev. 1, for the implementation of i-LAMP surrogate test data for BORAL plants without a coupon monitoring program. The staff finds that the guidance provides adequate detail with respect to the essential parameters needed to identify a sibling plant. Specifically, the manufacture date, areal density, service life, physical thickness of the BORAL, and its SFP environment including chemistry should be consistent with or bounded by the characteristics of the BORAL and the service environment in a sibling plant in the existing database.

In addition, the staff finds that the acceptance criteria and surveillance intervals described in NEI 16-03 Rev. 1 conform to the NRC guidance in the GALL Report, Rev. 2. The acceptance criteria provide reasonable assurance that the assumptions regarding the AD of the NAM in the licensees SFP criticality AOR will be maintained, because the acceptance criteria show that the material not losing 10B AD and is still above the 10B AD assumed in the licensees SFP criticality AOR.

With respect to the concept of a 2 bin approach, the staff finds that NEI 16-03 Rev. 1 represents an overly simplistic approach. While it may be true that the data collected in i-LAMP to date is representative of all operating SFPs in the United States, the NRC staff is approving use of the i-LAMP approach only for a SFP for which the i-LAMP data bounds the physical characteristics of the BORAL and environmental conditions in the specific SFP. A licensee seeking to reference NEI 16-03, Rev. 1 in an application will need to verify in its application that such is the case. Any licensee that intends to employ i-LAMP as an alternative monitoring strategy should perform a detailed analysis of their SFP and BORAL material considering the parameters described in NEI 16-03 Rev 1. Failure to perform plant-specific analysis to verify that parameters are consistent with a sibling SFP, or bounded by another SFPs BORAL,

constitutes inappropriate application of i-LAMP as an alternative monitoring strategy. This will be addressed in Section 4.0, Limitations and Conditions of this safety evaluation.

Should a new or different degradation mechanism that causes a loss of 10B in BORAL be discovered, NEI 16-03, Rev. 1, calls for that information to be entered into each affected sites corrective action program. This may include development a coupon monitoring program, or use of in-situ monitoring. If the sibling plant data shows a loss of 10B, then the licensee needs to assume that its plant is also losing 10B and develop another means to monitor its NAM.

3.4.

In-Situ Measurement Program 3.4.1. Overview of NEI 16-03, Revision 1 NEI 16-03, Rev. 1 states that in-situ measurement is another method that can be used to confirm 10B AD of NAM. It further states that this method can be used to supplement coupon monitoring to extend the coupon testing interval, permit greater reliance on basic testing, or in lieu of coupon testing for plants that may no longer have coupons in the SFP. It also states that in-situ measurement can be used if surrogate data in i-LAMP may not be bounding of a plants SFP and NAM parameters.

The NEI 16-03, Rev. 1 states that all in-situ measurement campaigns are to be performed at an acceptable interval and on an adequate number of panels. NEI 16-03, Rev. 1 gives two options for determining what constitutes an adequate number of panels. The first option uses the methodology of NUREG-6698, Guide for Validation of Nuclear Criticality Safety Calculational Methodology (Ref. 10), to measure a minimum of 59 panels to provide 95/95 confidence limits.

The second option selects the panels with the greatest exposure (top 5%) to parameters that influence degradation (e.g., neutron fluence, temperature, time). The number of panels selected from those with the greatest exposure for testing will be no less than one percent of the total panels in the SFP, although more panels can be tested from other areas of the SFP to gain a more representative sampling. NEI 16-03, Rev. 1 also states sources of uncertainty in the in-situ measurement will be identified and quantified.

The sampling interval will be based upon the NAM credited in the SFP. New materials with minimal operating experience will have an initial test interval that does not exceed 5 years, with subsequent intervals up to 10 years (with appropriate operating experience). For materials with known histories of degradation and known degradation mechanisms, test intervals do not exceed 5 years. For other materials that do not have known histories of degradation or known degradation mechanisms test intervals will not exceed 10 years. NEI 16-03, Rev. 1 also states that if used in conjunction with a coupon monitoring program, the in-situ sampling interval can be longer.

NEI 16-03, Rev. 1 also provides acceptance criteria for in-situ measurements. It states that for NAMs that do not have potential degradation mechanisms for loss of 10B AD, results of the in-situ measurements are acceptable if the nominal measured 10B AD is greater than or equal to the value assumed in the licensees criticality AOR (within measurement uncertainties). For materials that have potential degradation mechanisms that result in loss of 10B AD, results are

considered acceptable if the nominal measured 10B AD minus measurement uncertainty is greater than the 10B AD used in the licensees criticality AOR.

3.4.2. NRC Staffs Evaluation of In-Situ Measurement Program The NRC staff has reviewed the NEI 16-03, Rev. 1 method for performing in-situ measurement testing and finds it to be acceptable, because it allows for detection of degradation mechanisms, potential loss of neutron absorption capacity (e.g., loss of 10B), and ensures the NAM will continue to provide the criticality control relied upon in the AOR. The NRC staff reviewed the methodology recommended for determining the number of panels that may be selected for in-situ inspection and finds it to be acceptable because it is based in part on guidance provided in NUREG-6698, or on selecting panels that have experienced the greatest exposure to the SFP environment. The NRC staff also finds that depending on the population of NAM panels in the SFP, a licensee may need to measure more than the minimum of 59 panels to produce 95/95 confidence limits. The method used for selecting the panels for in-situ testing will be used to obtain data that is bounding or representative of the entire NAM in the SFP.

In addition, the NRC staff has determined that the proposed testing intervals (intervals not to exceed 10 years for materials with no known history of degradation/degradation mechanisms, and 5 years for materials with a known history of degradation/degradation mechanisms or for new materials (i.e., no operating history)) are acceptable and consistent with NRC guidance in the GALL Report, Rev. 2. Regardless of how the licensee uses the in-situ monitoring program (e.g., in conjunction with coupons, without a coupon program, or other reasons as described in NEI 16-03, Rev. 1), NEI 16-03, Rev. 1 is acceptable only if neutron attenuation is performed on the intervals as described in the in-situ methodology. The statement in NEI 16-03, Rev. 1 that the in-situ sampling interval can be longer if used in conjunction with a coupon program does not obviate the need to perform neutron attenuation testing on intervals not to exceed 5 or 10 years (depending on the NAM used and associated operating experience).

In addition, sources of uncertainty can greatly impact results and confidence in the data collected, especially as it relates to the subcriticality margin. Accordingly, the NRC staff finds the program to be acceptable if it includes provisions to identify and evaluate sources of uncertainty in order to assess the reliability of the instruments and methodology used to the collect the data.

3.5.

Evaluating Neutron Absorber Test Results 3.5.1. Overview of NEI 16-03, Revision 1 NEI 16-03, Rev. 1 states that the test results from neutron absorber monitoring may fall within the following categories:

1) Confirmation that no material changes are occurring,

2) Confirmation that anticipated changes are occurring, and/or

3) Identification that unanticipated changes are occurring.

Furthermore, NEI 16-03, Rev. 1 states that the testing results, and/or surrogate i-LAMP data, will be compared to the AOR input (i.e., 10B AD assumed in criticality AOR). If there are no material changes, or if anticipated changes are occurring, then the proposed program indicates that the licensee can conclude that the material continues to be adequately represented in the AOR.

NEI 16-03, Rev. 1 also describes the additional actions that may be necessary when unanticipated changes in the NAM are identified. It states that there are certain technical evaluations that may be necessary in addition to any required regulatory or licensing processes.

The technical evaluations include one to determine if an unanticipated change in NAM may result in a loss of 10B AD. Any potential impacts of a loss of 10B AD on the SFP criticality AOR will be evaluated and addressed through licensee processes. In addition, the results of monitoring and testing are to be evaluated and trended, regardless of potential impact on the SFP criticality AOR. If an unanticipated change does not appear to result in the loss of 10B AD, the change will still be evaluated for impacts on the SFP criticality AOR. The effects on the SFP criticality AOR due to a potential dimensional change of the NAM, or other material in the SFP, are evaluated and addressed in accordance with licensee processes.

3.5.2. NRC Staffs Evaluation of Neutron Absorber Test Results The NRC staff has reviewed the actions described in NEI 16-03 Rev. 1 for when potential degradation is detected in the neutron absorbing material as potential degradation of the NAM may impact 10B AD assumptions in the SFP criticality AOR. The NRC staff finds the actions described in the NEIs document acceptable because they will be able to identify anticipated, and unanticipated changes to provide information that will allow a licensee to determine whether the neutron absorbing material is performing its safety function as credited in the AOR.

The NRC staff has also determined that it is necessary to evaluate and trend the results of 10B AD measurements from neutron attenuation testing in the NAM as described in NEI 16-03, Rev.1. The NRC staff finds the methods to trend data acceptable because they will provide information regarding the potential degradation mechanism(s) and rate for the NAM in the SFP.

This information will also help the licensee determine whether the 10B AD of the NAM will not decrease below the value assumed in the SFP criticality AOR between the specified test intervals for neutron attenuation testing. In addition, these data can identify previously un-evaluated degradation mechanisms that may have an impact on the SFP criticality AOR.

The actions described above ensure, in part, that the ability of the NAM to provide the criticality control relied upon in the AOR, is maintained.

3.6.

NRC Technical Evaluation Conclusion As summarized below, the NRC staff has determined that the NAM monitoring program described in NEI 16-03, Rev. 1 is acceptable because it includes neutron attenuation testing at acceptable intervals or relies on testing from a surrogate i-LAMP plant that is acceptable if the surrogate plant SFP and NAM conditions and parameters are consistent with or bounding of those of the licensees plant. More specifically, the NRC staff finds the interval for inspection and testing acceptable because the frequency is determined to be based on the neutron absorbing material credited and the operational history of that material. Further, depending on

the material used, the interval for neutron attenuation testing will not exceed 5 years (for materials with a history of known degradation or a known degradation mechanism, and new materials), or 10 years (for other materials that do not have a history of degradation, or a known degradation mechanism). Such testing intervals are adequate to detect degradation of NAM before such degradation has the potential to affect criticality safety. Periodic neutron attenuation testing, and the intervals described in NEI 16-03, Rev.1 are consistent with NRC guidance (i.e.,

the GALL Report, Rev. 2). Licensees will likely need to request site-specific NRC review and approval to extend the interval of any neutron attenuation testing past the approved intervals, as described in NEI 16-03, Rev. 1.

In addition, the NRC staff finds the proposed program acceptable insofar as it calls for the inclusion of the measurement uncertainty in a determination whether the 10B AD value derived from the program is lower than the assumed value in the SFP criticality AOR. If a given test result shows a 10B AD value lower than the value assumed in the SFP criticality AOR, the program provides for the appropriate corrective actions in accordance with licensee programs and processes.

Based on the foregoing, the NRC staff has determined that NEI 16-03, Rev.1 is acceptable for referencing in a licensing action to implement a NAM monitoring program.

4.0 CONDITIONS, LIMITATIONS, AND/OR ACTION ITEMS Limitations and Conditions are additional restrictions imposed by the NRC staff to further define the scope of applicability of NEI 16-03 Rev. 1 and identify any additional actions that will need to be addressed to support NRC staffs review of a request associated with this NEIs document.

4.1.

Limitations and Conditions Based on the staff review of NEI 16-03, Rev. 1, described above, the NRC staff has identified the following limitation on the use of the methodology shown below:

The NRC staff approves the NEI 16-03, Rev. 1, methodology for employing i-LAMP as an alternative monitoring strategy only if the i-LAMP program provides for the licensee to perform a detailed analysis of its SFP and BORAL material considering the parameters described in NEI 16-03 Rev 1. The i-LAMP alternative strategy is unacceptable unless a plant-specific analysis verifies that SFP conditions and BORAL parameters are consistent with those of a sibling SFP or are bounded by those of another SFPs BORAL. This limitation is imposed to address the discussion in NEI 16-03 Rev.1 of a 2-bin system in which plants without coupons are assumed to be bounded by those with coupons.

5.0 CONCLUSION

S The NRC staff has reviewed NEI 16-03, Rev.1 and the proposed methods for developing a NAM monitoring program. For the reasons discussed in this SE, the staff has determined that a NAM monitoring program implementing the NEI 16-03, Rev. 1 program will be able to detect degradation of neutron absorbing material and provides assurance that the ability of the NAM to provide the criticality control relied upon in the AOR is maintained.

The NRC staff finds that the requirements of 10 CFR 50.68(b)(4), GDC 61, and GDC 62, as well as the guidance provided in SRP 9.1.1, SRP 9.1.2, and the GALL, Rev. 2, would be satisfied with respect to NAMs and the NAM monitoring program if referenced in a licensing action to implement the program, and, for an application requesting use of i-LAMP as an alternative, that meets the limitation stated in this SE. Accordingly, the NRC staff has concluded that NEI 16-03, Rev. 1 is acceptable for referencing in an application requesting approval of a NAM monitoring program.

Each licensee adopting NEI 16-03, Rev. 1 will need to implement it in accordance with its plant-specific processes and licensing basis. This will involve review under the plant commitment control process and 10 CFR 50.59. Either of these processes could result in the need for a plant-specific license amendment request. Each licensee will need to make its own evaluation in this regard under its site-specific change control program.

6.0 REFERENCES

1. Letter from R. McCullum (NEI) to J. Donoghue (NRC), Transmittal of Guidance Document NEI 16-03, Revision 1, "Request for Review and Endorsement of NEI 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, Revision 1 dated August 2022,"

August 19, 2022 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML22231B042).

2. Nuclear Energy Institute Guidance Document NEI 16-03, Revision 1, "Request for Review and Endorsement of NEI 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools," August 2022 (ADAMS Accession No. ML22231B043 (Non-Proprietary).

3. Electric Power Research Institute (EPRI) Technical Report 3002018497, Industrywide Learning Aging Management Program (i-LAMP): Global Neutron Absorber Material Monitoring Program for Spent Fuel Pools, August 2022 (ADAMS Accession No. ML22231B044 (Non-Proprietary).

4. Letters from R. McCullum (NEI) to J. Donoghue (NRC), "Supplement to NEIs Request for Review and Endorsement of NEI 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, Revision 1, dated August 19, 2022", October 12, 2023, (ADAMS Accession No. ML22298A281), and Response to NRC Request for Supplemental Information Supporting the Acceptance review of NEI 16-03, Rev. 1, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, December 15, 2022 (ADAMS Accession Nos. ML22349A656), and Response to NRC Request for Additional Information Supporting the Review of NEI 16-03, Rev. 1, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, May 23, 2023 (ADAMS Accession Nos. ML23143A306),

and Letter from B. Montgomery (NEI) to NRC, NRC Review of NEI 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools August 24, 2023 (ADAMS Accession No. ML23236A503).

5. Nuclear Energy Institute 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, Revision 0-A, May 2017 (ADAMS Accession Nos. ML17263A133 and ML16354A486 (FSE)).

6. U.S. Nuclear Regulatory Commission, NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants" (SRP), Section 4.2, "Fuel System Design," Revision 3, March 2007 (ADAMS Accession No. ML070740002).

7. U.S. Nuclear Regulatory Commission, Standard Review Plan, Section 9.1.1, Criticality Safety of Fresh and Spent Fuel Storage and Handling, NUREG-0800, Revision 3, March 2007 (ADAMS Accession No. ML070570006).

8. U.S. Nuclear Regulatory Commission, Standard Review Plan, Section 9.1.2, New and Spent Fuel Storage, NUREG-0800, Revision 4, March 2007 (ADAMS Accession No. ML070550057).

9. U.S. Nuclear Regulatory Commission, Generic Aging Lessons Learned (GALL) Report, NUREG-1801, Revision 2, December 2010 (ADAMS Accession No. ML103490041).

10. U. S. Nuclear Regulatory Commission (NRC) E-mail to NEI Final Request for Additional Information - NEI 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, Revision 1 (EPID No. L-2022-NTR-0002) April 24, 2023 (ADAMS Accession No. ML23102A099).

11. U.S. Nuclear Regulatory Commission, Guide for Validation of Nuclear Criticality Safety Calculational Methodology, NUREG/CR-6698, January 2001 (ADAMS Accession No. ML050250061).

Principal Contributor: Matthew Yoder, NRR Date: January 30, 2024 Enclosure NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

1 7

31 Editorial Draft SE text:

The core of i-LAMP is an SFP coupon database.

Suggested edit:

The key components of i-LAMP are the SFP coupon database, water chemistry database, and additional analysis.

Analysis not only includes data analysis for coupons and water chemistry but also impact on reactivity.

The NRC staff finds the comment partially acceptable and revisions have been incorporated.

The NRC staff contends that the coupon database is by far the most important component of i-LAMP. Therefore, the existing language will remain. However, an introductory sentence is added to capture the point that there are other components in the program:

The key components of i-LAMP are the SFP coupon database, water chemistry database, analysis of these databases, and analysis of their potential impact on reactivity.

2 3

13 14 14 20-25 15-16 9-14 17-Editorial/

Clarification Draft SE text:

Section 1.0: the NRC staff has determined that NEI 16-03, Rev. 1 is acceptable, with the limitation described The NRC staff finds the comment partially acceptable and revisions have been incorporated.

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

21 below, for referencing in a license amendment request (LAR) that includes the information described below in Section 4.0 of this SE.

Suggested edit:

the NRC staff has determined that NEI 16-03, Rev. 1 is acceptable, with the limitation described below, for referencing in a licensees regulatory change control process (e.g., 10 CFR 50.59 review, (LAR), etc.) that includes the information described in Section 4.0 of this SE.

Section 3.6:

Based on the foregoing, the NRC staff has determined that NEI 16-03, Rev.1 is acceptable for referencing in a LAR requesting approval of a NAM monitoring program.

Section 5.0 (paragraph 2): The NRC staff finds that the requirements would be satisfied with respect to NAMs and the NAM monitoring program if referenced in an LAR Although the suggested edits are not accepted verbatim, the language will be changed from license amendment request to licensing action.

As described in Section 5.0 of the safety evaluation, the NRC staff does not intend that application of NEI 16-03 Rev 1 is limited to an LAR or that an LAR is required by all licensees implementing the program.

The final comment is not accepted.

Plant procedures are not regulated by the NRC unless they are included in a license commitment. In which case the other processes listed will cover them.

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

requesting use of the program Suggested edit:

The NRC staff finds that the requirements would be satisfied with respect to NAMs and the NAM monitoring program if referenced in a licensees regulatory change control process to implement the program Section 5.0 (paragraph 3): Each licensee adopting NEI 16-03, Rev. 1 will need to implement it in accordance with its plant-specific processes and licensing basis. This will involve review under the plant commitment control process and 10 CFR 50.59. Either of these processes could result in the need for a plant-specific LAR. Each licensee will need to make its own evaluation in this regard under its site-specific change control program.

Suggested edit:

Each licensee adopting NEI 16-03, Rev. 1 will need to implement it in accordance with its plant-

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

specific processes and licensing basis. This will involve review under the plant commitment control process, procedure revision process, and/or 10 CFR 50.59. Either process could result in the need for a plant-specific LAR. Each licensee will need to make its own evaluation in this regard under its site-specific change control program.

Note:

If the suggested edits are untenable, please confirm that the existing SE language does not require licensees to adopt i-LAMP/NEI 16-03 Rev 1 via a LAR, exclusively.

3 9

25-26 Editorial Draft SE text:

With respect to the concept of a 2 bin approach, the NRC staff finds that NEI 16-03 Rev. 1 represents an overly simplistic approach.

Suggested edit:

Suggest deleting the sentence. Licensees will identify sibling(s) for analysis per Limitations and The NRC staff does not find the comment acceptable and the revisions have not been incorporated.

As described in the Limitations and Conditions, the NRC staff does not endorse the 2-bin approach.

Note that the NRC

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

Conditions in the SE.

Two bin approach is still discussed elsewhere in NEI 16-03 Rev 1 and this sentence appears to be unnecessary to support the overall regulatory determination made in the SE.

staff expects that any relevant data is shared with i-LAMP participants regardless of their identified sibling plant(s). This is intrinsic to the program and independent of the concept of the 2-bin approach.

4 13 29-36 Clarification Draft SE text:

The NRC staff approves the NEI 16-03, Rev. 1, methodology for employing i-LAMP as an alternative monitoring strategy only if the i-LAMP program provides for the licensee to perform a detailed analysis of its SFP and BORAL material considering the parameters described in NEI 16-03 Rev 1. The i-LAMP alternative strategy is unacceptable unless a plant-specific analysis verifies that SFP conditions and BORAL parameters are consistent with those of a sibling SFP or are bounded by those of an older SFPs BORAL. This limitation is imposed to address the discussion in NEI 16-03 Rev.1 of a 2-The NRC staff does not find the comment acceptable and the revisions have not been incorporated.

As described in response to comment #3 the staff does not endorse the 2-bin approach.

Note that the phrase, or bounded by those of an older SFPs Boral is modified consistent with the response to comment #10.

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

bin system in which plants without coupons are assumed to be bounded by those with coupons.

Suggested edit:

The NRC staff approves the NEI 16-03, Rev. 1, methodology for employing i-LAMP as an alternative monitoring strategy only if the i-LAMP program provides for the licensee to perform a detailed analysis of its SFP and BORAL material considering the parameters described in NEI 16-03 Rev 1. The i-LAMP alternative strategy is unacceptable unless a plant-specific analysis verifies that SFP conditions and BORAL parameters are consistent with those of a sibling SFP.

Note: licensees will identify sibling to perform requisite analysis per the SE, but there is no need to retain language specifically diminishing the 2-bin approach.

Industry understands the 2-bin approach will still effectively be part of the

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

industrywide and learning aspects of i-LAMP after initial implementation of the program.

5 9

27 Clarification Draft SE text:

While it may be true that the data collected in i-LAMP to date anecdotally bounds all operating SFPs in the United States A large body of data has been collected from coupon measurements, actual panels, and EPRI projects such as the Zion comparative analysis project that have shown no parameters with adverse trends in the performance of BORAL.

Suggested edit:

Replace anecdotally bounds with is representative of The NRC staff finds the comment acceptable and the revisions have been incorporated.

6 8

21 Editorial Draft SE text:

The essential parameters needed to identify an appropriate sibling plant is listed below:

Suggested edit:

Replace the word is with the word are in this line.

The NRC staff finds the comment acceptable and the revisions have been incorporated.

7 13 3

Editorial Draft SE text:

described in The NRC staff finds the comment

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

NEI 16-03 are consistent Suggested edit:

Add Rev. 1 after NEI 16-03 acceptable and the revisions have been incorporated.

8 9

12 14-15 39 Editorial/

Clarification Draft SE text:

Section 3.3.2: and its SFP environment including chemistry should be consistent with or bounded by the characteristics of the BORAL Suggested edit:

Remove or bounded by in this sentence.

Section 3.6: SFP and NAM conditions and parameters bound those of the licensees plant.

Suggested edit:

Replace bound with are consistent with The NRC staff does not find the comment acceptable and the revisions have not been incorporated.

Removing the concept of bounding would create a more restrictive situation for licensees. They would be forced to show consistence with another plant.

This leaves the question of whether a parameter is perfectly matched.

That is not the NRC staffs intent. By allowing licensees to be consistent with or bounded by other plants, licensees have more freedom when identifying sibling plants.

Note that are consistent with was added to Section 3.6, but the

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

concept of bounding remains.

9 3

7 7

7 12 13 13 38 3

5 10 17 10 11 Editorial Suggested edit:

Draft SE uses presume/presumption and assume/assumption seemingly interchangeably.

Revise document to be consistent, using assume/assumption throughout, as analyses use assumptions rather than presumptions The NRC staff finds the comment acceptable and the revisions have been incorporated.

10 10 33-36 Clarification Draft SE text:

Failure to perform plant-specific analysis to verify that parameters are consistent with a sibling SFP, or bounded by an older SFPs BORAL, constitutes inappropriate application of i-LAMP as an alternative monitoring strategy. This will be addressed in Section 4.0, Limitations and Conditions of this safety evaluation.

Suggested edit:

Failure to perform plant-specific analysis to verify that parameters are consistent with a sibling SFP, or bounded by an older SFPs BORAL, constitutes inappropriate application of i-LAMP as The NRC staff finds the comment partially acceptable and revisions have been incorporated.

The term bounded by remains but the term older was changed to another.

NUCLEAR ENERGY INSTITUTE TOPICAL REPORT 16-03, REVISION 1 COMMENT/RESOLUTION TABLE FOR NRCs DRAFT SAFETY EVALUATION (DSE)

Comment Number Text Location in the DSE Comment Type (Clarification, Editorial,

Accuracy, Proprietary)

NEI Suggested Revision NRC Response Page Line No.

No.

an alternative monitoring strategy. This will be addressed in Section 4.0, Limitations and Conditions of this safety evaluation.

Note: Age is one of the applicable parameters of interest from NEI 16-03 Rev 1 to be considered in determining a sibling SFP.