ML24130A251

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Modification No. P00015 to Task Order No. 31310020F0101 Under Contract No. 31310020D0003
ML24130A251
Person / Time
Issue date: 05/06/2024
From: Rachel Glaros
Acquisition Management Division
To: Stein G
Engineering Mechanics Corp of Columbus
References
31310020D003
Download: ML24130A251 (1)
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Text

31310020D0003/31310020F0101

Summary of Clause Changes:

Clause titled STATEMENT OF WORK is incorporated as follows:

STATEMENT OF WORK

TASK ORDER STATEMENT OF WORK (SOW) REVISION NO. 4

1. EWC TASK ORDER TITLE

Technical Support for Component Integrity Assessments

2. BACKGROUND

The NRCs Office of Nuclear Regulatory Research (RES) provides data, standards, tools, and methods to the NRCs regulatory offices to support their reviews of material performance-related licensing submittals and safety issues. The confirmatory research on materials performance focuses on both the development of methodologies needed to support regulatory actions and the work supporting the technical bases for codes and standards development. A common theme in this work is a proactive approach to the management of age-related degradation due to mechanisms such as fatigue and stress-corrosion cracking. For example, to better understand how nuclear power plant components are influenced by the phenomenon of primary water stress-corrosion cracking (PWSCC), the NRC is focusing research efforts on continued development of analysis methods and computational tools. The NRC also is assessing the impacts of PWSCC on the leak-before-break behavior of nuclear power plant piping systems.

Criterion 4, "Environmental and Dynamic Effects Design Bases," of Appendix A, "General Design Criteria for Nuclear Power Plants," to Title 10 of the Code of Federal Regulations (10 CFR), Part 50, "Domestic Licensing of Production and Utilization Facilities," states, in part, that the dynamic effects associated with postulated reactor coolant system pipe ruptures may be excluded from the design basis when analyses that the NRC has reviewed and approved demonstrate that the probability of fluid system piping rupture is extremely low under conditions consistent with the design basis for the piping. Licensees typically have demonstrated compliance with this probabilistic criterion through deterministic and highly conservative leak-before-break analyses.

NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition," Section 3.6.3 [1] provides guidance for the NRC staff's review of licensee analyses submitted in accordance with 10 CFR Part 50, Appendix A, Criterion 4.

NUREG-0800 Section 3.6.3 precludes the assessment of piping systems with active degradation mechanisms. However, it is known that PWSCC is occurring in systems that have been granted prior NRC approval under 10 CFR Part 50, Appendix A, Criterion 4 to exclude dynamic effects associated with postulated reactor coolant system pipe ruptures from the design basis. Given advances in probabilistic methodologies, the NRC staff and industry concluded that it was more appropriate to perform probabilistic analyses of postulated reactor coolant system pipe ruptures to fully address and quantify uncertainties and directly demonstrate compliance with the

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probabilistic requirements of 10 CFR Part 50, Appendix A, Criterion 4.

To develop the capability to perform the necessary probabilistic analyses, RES worked in collaboration with the Electric Power Research Institute to develop a new computer code called Extremely Low Probability of Rupture (xLPR). xLPR is a state-of-the-art probabilistic fracture mechanics code for piping applications. Code development was a multi-year effort that built on the results of a successful pilot study. The code was designed, built, and tested under a rigorous software quality assurance program and provides regulators, industry, researchers, and the public with new quantitative capabilities to analyze the risks associated with nuclear power plant piping systems subject to degradation mechanisms. Core capabilities of the code include modeling fatigue, stress-corrosion cracking, inservice inspection, chemical and mechanical mitigation, leak rates, and seismic effects.

As the initial regulatory application of xLPR Version 2.0 (V2.0), RES has used the code to study the impacts of PWSCC in systems that have been granted prior NRC leak-before-break approval under 10 CFR Part 50, Appendix A, Criterion 4. These activities included sensitivity studies to identify which models, sub-models, and types of input variables contribute most significantly to uncertainty in the results from the code. RES also used xLPR V2.0 to re-evaluate previous leak-before-break analyses for a subset of the current fleet of plants. The re-evaluations considered the impacts of PWSCC, fatigue, inservice inspection, and mitigation to determine the trend in rupture frequencies and other metrics. With the completion of these activities, RES needs to complete re-evaluations of previous of leak-before-break analyses for the remaining plants in the fleet. In addition, RES needs to consider the results and assess current leak-before-break regulations and guidance and, if applicable, make recommendations for enhancement.

Beyond leak-before-break studies, the xLPR code supports broader NRC efforts to further the use of probabilistic fracture mechanics analyses using state-of-the-art computational tools. To this end, RES has begun publicly distributing the xLPR code with the goal of establishing a user group. Public availability of xLPR V2.1 was announced in [2] and details about the code have been presented in various NRC public meetings [3] and [4]. Public distribution and user group participation benefits the NRC in several respects. For example, the broader user base: (a) exercises the code more thoroughly than would be possible if use were limited to only NRC applications, (b) increases confidence in the codes capability to accurately model individual phenomena and system behavior over the required range of conditions, (c) reduces the level of effort required by RES to ensure the validity of the codes results, and (d) leverages expertise of the users as they identify code deficiencies and errors and propose fixes. Public distribution is further expected to increase use of the xLPR code to support licensing actions and codes and standards development, and RES needs to maintain the necessary capabilities to support the related regulatory reviews. In concert with these activities, support for continued maintenance and development of the xLPR code is necessary to ensure its long-term usability.

List of

References:

[1] NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition, Section 3.6.3, Leak-Before-Break Evaluation

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Procedures, Revision 1, March 2007, NRC Agency wide Documents Access and Management System (ADAMS) Accession No. ML063600396

[2] Extremely Low Probability of Rupture (xLPR) Probabilistic Fracture Mechanics Code Version 2.1 Public Release Announcement, NRC ADAMS Accession No. ML20157A120

[3] Summary of the April 23, 2020, RES Category 3 Public Meeting with EPRI and Stakeholders to Discuss Public Release of the xLPR Probabilistic Fracture Mechanics Code, NRC ADAMS Accession No. ML20142A303

[4] Summary of the June 3, 2020, RES Category 3 Public Meeting with EPRI and Stakeholders to Discuss Models in the xLPR Probabilistic Fracture Mechanics Code, NRC ADAMS Accession No. ML20182A086

3. OBJECTIVE(S)

The objective of this task order is to obtain expert technical assistance services from the Contractor to support component integrity assessments. Support is needed in areas such as the application, maintenance, and development of computational tools and methodologies for performing component integrity assessments. Support is also needed to analyze emerging issues and evaluate and develop codes and standards and other aspects of NRCs regulatory framework related to component integrity.

This requirement falls under Technical Support Service Area (TSSA) 3.4, entitled Component Integrity and Materials Performance.

4. STATEMENT OF WORK TASKS

Task 1: Generalization Study

The Contractor shall use the xLPR code to study the impacts of PWSCC for the entire fleet of U.S. pressurized-water reactors (PWRs) to determine whether any changes are needed to current regulatory requirements and guidance related to leak-before-break. The use of other computational tools may be needed to develop inputs for or otherwise support the analyses performed using the xLPR code. Specific activities include, but are not limited to, the following:

A. The Contractor shall review and categorize all PWR piping systems previously approved for leak-before break. The goal of this review and categorization is to reduce, to the extent practical, the number of analyses that will need to be performed.

B. The Contractor shall define the specific analyses necessary to bound each category of piping system. Factors present in the PWR fleet, such as PWSCC mitigation techniques and inservice inspection, shall be considered. Definition of the analyses may be an iterative process, and the results from prior studies should be used to inform this effort.

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C. The Contractor shall determine and develop the inputs necessary to perform each of the analyses. Sources for inputs could include the open literature, xLPR-related documentation, prior studies and analyses, and docketed correspondence available from both internal and external NRC ADAMS. The Contractor may also need to perform finite element analyses to develop weld residual stress profile inputs. The Contractor shall promptly communicate any input gaps that it cannot fill to the COR.

D. The Contractor shall execute the analyses using the xLPR code. The Contractor shall compare the results of these analyses against acceptance criteria identified by the COR.

E. Based on the results of the analyses, the Contractor shall prepare an assessment of current regulatory requirements and guidance related to leak-before-break. Recommendations for enhancing these regulations and guidance shall be provided as appropriate.

Task 1 Completion Date: The task shall be completed by September 10, 2021.

Task 1 Anticipated Travel: One trip for up to 3 Contactor personnel of up to 3 days duration to NRC Headquarters from the Contractors office(s). (Total of 1 Trip)

Task 1 Deliverables: The Contractor shall prepare an Analysis Plan for completion of this task.

The Analysis Plan shall, at minimum, include the categories of piping systems, analyses that will be performed to bound each category, completion schedule and status of each analysis, and any potential input gaps. The Contractor shall submit the Initial Analysis Plan to the COR no later than 30 days after award of the task order. Thereafter, the Contractor shall maintain and update the Analysis Plan as needed until the task is complete. The Analysis Plan Updates shall be provided to the COR biweekly until the analyses are complete and incorporate any comments provided by the COR.

The Contractor shall submit information (e.g., code input and output files) from the analyses executed per the Analysis Plan (as updated) as they are completed.

In addition, the Contractor shall prepare a Technical Letter Report (TLR) covering all work performed under this task. The Contractor shall prepare the TLR in parallel with performing the analyses executed per the Analysis Plan (as updated). In-progress drafts of the TLR shall be submitted to the COR monthly. The in-progress TLR drafts shall incorporate any comments provided by the COR on the previous submission. The Contractor shall complete the TLR after executing all the analyses in the Analysis Plan (as updated). The Contractors completed TLR shall be submitted by March 01, 2021.

Thereafter, the Contractor shall support the NRC staffs review of the TLR. The review will be completed in several stages and may take up 5 months to complete. The COR will communicate comments generated as a result of this review process to the Contractor. The Contractor shall address all comments and prepare interim updates to the TLR as necessary. Some comments may require the Contractor to perform additional analyses to address. Interim updates to the TLR shall be provided to the COR weekly during the review process through September 10,

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2021. The Contractor shall finalize and submit the TLR in a form ready for NRC publication by September 10, 2021.

Task 2: xLPR Code Maintenance, Development, and Technical Support

Task 2a - xLPR Code Maintenance and Development

As directed by the COR, the Contractor shall provide technical assistance to support xLPR code maintenance and development needs. Maintenance activities include, but are not limited to:

developing modifications to code-related products, such as the source and executable code, user manual, data libraries, configuration control documents, and other reference files and documents, to correct identified problems, improve performance or maintainability, keep the products usable in a changed or changing environment, and detect and correct latent faults. Maintenance activities also include, but are not limited to: (a) configuration management, (b) documenting, tracking, and processing maintenance requests, (d) performing testing necessary to ensure proper functionality of the code following maintenance-related changes, and (e) electronic storage of files. Development activities include modifications that significantly expand the functional capabilities of the xLPR code.

All maintenance and development activities shall be performed in accordance with the xLPR Software Maintenance Plan, as may be revised from time-to-time, and any implementing procedures as directed by the COR. In addition, all Contractor personnel involved in maintaining or developing the xLPR code shall receive training as specified in the xLPR Software Maintenance Plan and participate in any other supplemental training as directed by the COR. The Contractor shall coordinate its maintenance and development activities with other code maintainers as directed by the COR. It also may be necessary or advantageous for the Contractor to prepare, deliver, and maintain electronic systems to support the effective and efficient performance of the maintenance and development activities. Such systems shall be implemented as approved by the COR.

Task 2b - xLPR Code Technical Support

Under this task, the Contractor shall provide a broad range of technical assistance support related to the xLPR code and its various applications. It includes support for the NRC staff, general analysis and technical support, and support to build the community of public xLPR code users.

Upon request, the Contractor shall assist users from the NRC staff with proper use of the code.

Support may include, but is not limited to, areas such as:

  • assisting with code installation
  • preparing, optimizing, and troubleshooting issues with inputs
  • investigating, interpreting, and resolving code errors and warnings
  • extracting, aggregating, and interpreting results
  • responding to questions about operation of the code and the models contained therein

The Contractor shall respond to all NRC staff user support requests within 2 business days.

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Support shall be provided via phone, email, or both as appropriate to facilitate the most expeditious resolution. When the total time required to respond to a request is anticipated to or exceeds 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />, the Contractor shall notify the COR. Thereafter, any further technical assistance related to the request shall be limited to the time authorized by the COR.

In addition, as directed by the COR, the contractor shall provide general analysis and technical support, including but not limited to:

  • developing inputs
  • performing analyses using the code and analyzing and interpreting the results
  • conducting sensitivity studies and other statistical analyses
  • investigating and implementing custom changes to the code to accommodate analysis needs
  • assisting with resolution of technical review comments on documents
  • developing and delivering training
  • providing support for resolution of emergent issues

The Contractor shall also assist with activities to support and build the community of public users of the code. This will primarily include support for holding up to 3 meetings or workshops per year. These events will generally serve as a venue for sharing information about the code and to provide a means for code users to interface with each other. Contractor support could include, but is not limited to, preparing and delivering guidance and training, conducting studies pertaining to the code and presenting the results, and other engagement activities, The events may be held either in-person or virtually; however, only one event per year may be held in-person.

Task 2 Completion Date: Expiration date of the Task Order.

Task 2 Anticipated Travel: One trip per year for up to 2 Contactor personnel of up to 3 days duration to locations at distances similar to NRC Headquarters from the Contractors office(s)

(Total of 4 Trips)

Task 2 Deliverables: Task 2a deliverables are as required by the xLPR Software Maintenance Plan depending on the scope of the particular maintenance activities assigned by the COR.

Task 2b deliverables are the draft materials presented at the user group meetings, which shall be submitted no later than 15 days before the meeting is scheduled to be held. The Contractor shall incorporate any comments on the draft presentation materials from the COR. The contractor shall provide the final presentation materials no later than 5 days before the meeting is scheduled to be held.

Task 3: Codes and Standards Technical Support

This task requires the contractor to participate in American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code committees within Section XI,Section III, and other appropriate code groups, as instructed by the COR. Some of the issues of importance

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presented at the committee meetings pertain to aging effects and component integrity issues. In addition, it is anticipated that new developments and results obtained using the xLPR code (e.g.,

new code cases) will be introduced to the ASME B&PV committees. Technical support is needed so that the NRC staff may adequately understand the technical and regulatory issues associated with related code actions so that it may vote appropriately. Accordingly, the Contractor shall prepare for, attend, and prepare a summary of the topics, discussions, and any presentations given at the regular ASME B&PV code meetings. As directed by the COR, the Contractor shall also provide support outside of the regular code meetings. This may include assisting the NRC staff with preparing its own code actions or with reviewing code cases or other proposed code actions.

Task 3 Completion Date: Expiration date of the Task Order.

Task 3 Anticipated Travel: Four trips per year for up to 2 Contactor personnel of up to 3 days duration to locations at distances similar to NRC Headquarters from the Contractors office(s)

(Total of 4 Trips)

Task 3 Deliverables: For any Contractor presentations given at the ASME B&PV Code meetings, the draft presentation materials shall be submitted no later than 2 weeks before each meeting. The final presentation materials incorporating any comments from the COR shall be submitted no later than 1 week before each meeting. The Contractor shall prepare and submit a letter report summarizing the meeting minutes and the presentations made at the ASME meetings no later than 2 weeks after each meeting.

Task 4: Ad-Hoc Technical Support The Contractor shall provide ad-hoc technical assistance to the NRC as directed by the COR.

This technical assistance may include, but is not limited to, the following topics:

I. Benchmarking studies.

II. Providing training to NRC staff on component integrity topics.

III. Support for emerging needs on component integrity issues.

IV. Severe accident considerations on piping issues. Severe accidents, such as seismic damage or high temperature faulted conditions may occur that require help from the contractor to investigate.

V. Confirmatory analyses on an as-needed basis.

VI. Emergency needs for rapid assistance on piping related technical issues as they arise.

VII. Testing to enhance computational tool models and databases. This may include:

a. material testing, such as fracture testing, cyclic testing for mixed hardening WRS fields, creep test update for post-weld heat treatment improvements
b. leakage rate testing VIII. Review the NRC staffs use of the deliverables from this effort in assessing aspects of NRCs regulatory framework related to component integrity.

Task 4 Completion Date: Expiration date of the Task Order.

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Task 4 Anticipated Travel: None.

Task 4 Deliverables:

The specific deliverables and schedule for ad-hoc technical support activities shall be determined by the COR in writing commensurate with the level of effort. The deliverables may include presentations and presentation slides, comments on NRC staff technical documents, technical papers, or TLRs.

For TLRs, the Contractor shall prepare and submit a Draft TLR covering all work performed no later than 30 days of completion of the work. Each Draft TLR shall summarize the efforts completed, propose conclusions, and identify recommendations for any issues identified. If the contractor performs material testing, the Draft TLR shall also include thorough descriptions of any material testing performed under this task, including test procedures and matrices, and all test results. The contractor shall also provide any test results in their raw data form and in Excel. The contractor shall prepare a Final TLR incorporating any comments on the Draft TLR from the COR. The contractor shall provide the Final TLR no later than 30 days after the receipt of comments from the COR.

Task 5: Preliminary Evaluation of Industry Loss-of-Coolant Accident (LOCA) Frequency Estimates Developed Using the xLPR Code

LOCA frequency estimates (i.e., pipe ruptures as a function of break size) are used in a variety of regulatory applications, including probabilistic risk assessment of nuclear power plants. Component integrity assessment is thus an important aspect in developing robust LOCA frequency estimates. As discussed with the Electric Power Research Institute (EPRI) in a public meeting on June 14, 2022 (ML22173A222), the industry is conducting studies using the xLPR code to evaluate the LOCA frequency estimates in NUREG-1829, Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process, Volumes 1 and 2, issued April 2008 (ML082250436 and ML081060300). The results of the EPRI studies may be used to support the technical basis for future regulatory applications, including licensing of accident-tolerant fuels. Given the potentially broad implications of the results, the NRC staff desires to closely follow EPRIs efforts.

The Contractor shall follow and assess EPRIs technical approach for informing LOCA frequency estimates by:

  • reviewing in-progress EPRI results as may be presented at meetings, in technical papers or reports, and as otherwise made available to the NRC/RES staff
  • participating in periodic meetings between the NRC/RES staff and EPRI
  • performing confirmatory analyses using the xLPR code and other software tools as appropriate

The final deliverable of this task is a technical letter report (TLR) summarizing the Contractors assessment of EPRIs approach. The assessment shall address the following areas at a minimum:

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  • use of the xLPR code and related models within their known capabilities and limitations
  • appropriate use of prior NRC analysis results generated using the xLPR code
  • adherence to NRC guidance for probabilistic fracture mechanics analyses (e.g., Regulatory Guide 1.245, Preparing Probabilistic Fracture Mechanics (PFM) Submittals, issued January 2022 (ML21334A158), and NUREG/CR-7278, Technical Basis for the use of Probabilistic Fracture Mechanics in Regulatory Applications, issued January 2022 (ML22014A406)
  • rigor of statistical analyses used to develop input data and results
  • breadth and depth of sensitivity studies and analyses
  • treatment of uncertainties
  • methodology for aggregating component-level results into system-and plant-level estimates

Based on this assessment, the Contractor shall make a recommendation as to whether the LOCA frequency estimates in NUREG-1829 should be updated based on the latest EPRI data or if further studies should be performed. The Contractor shall develop the TLR in stages as outlined in the deliverables below. The COR may revise the due dates based on the availability of EPRI data or for other reasons.

Task 5 Completion Date: The task shall be completed by January 31, 2023.

Task 5 Anticipated Travel: None.

Task 5 Deliverables: The contractor shall prepare and submit Draft input to the TLR assessing available EPRI results through June 14, 2022, by September 30, 2022. The contractor shall prepare and submit Draft input to the TLR assessing available EPRI results after June 14, 2022, by November 30, 2022. The contractor shall prepare and submit a Final TLR by December 15, 2022. The contractor shall provide the Final TLR incorporating any comments from the COR by January 31, 2023.

Task 6: Formal Evaluation of LOCA Frequencies Using the xLPR Code

The industry is interested in increased enrichment for power reactor fuels because it has the potential for increased operational flexibility, fewer fuel assembles to purchase, and ability to achieve higher burnup. However, to receive approval for the increased enrichment levels, vendors and licensees may need to request exemptions form appropriate NRC regulations and license amendments to change their allowed enrichment levels. The NRC is currently pursuing rulemaking that would amend its regulations to increase flexibility and reduce such exemption requests. This rulemaking would affect nuclear reactor licensees seeking to use fuel designs that make use of enrichments greater than the current limit (e.g., accident tolerant fuel).

As part of this rulemaking, the Commission directed the NRC staff to address fuel fragmentation, release, and dispersal, for which the NRC staff proposed five possible alternatives. Development of the technical basis for several of these alternatives will rely on loss-of-coolant (LOCA) frequency estimates, which can be generated with the xLPR code. In parallel, the industry has been developing its own alternative licensing strategy (ALS) for increased enrichment. The technical basis for the ALS is also based, in part, on calculations from the xLPR code, and the

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results are planned to be submitted in March 2024 for NRC staff review in a topical report. The focus of this task is to assist the NRC staff with (a) developing the technical basis for the increased enrichment rulemaking leveraging the results from Task 1, and (b) reviewing the ALS topical report submission leveraging results from Task 5.

For developing the technical basis for the increased enrichment rulemaking, as directed by the COR, the Contractor shall use the xLPR code to reanalyze LOCA frequency estimates from NUREG-1829, Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process, Volumes 1 and 2, issued April 2008 (ML082250436 and ML081060300).

The scope shall include, but not be limited to, reanalysis of all the piping base cases, which are summarized in NUREG-1829 Table 3.7 as follows:

boiling water reactor (BWR) recirculation system weld BWR feedwater system weld pressurized water reactor (PWR) hot leg weld PWR surge line weld PWR high-pressure injection make-up system weld

The Contractor shall supplement the base case analyses with sensitivity studies or other analyses as requested by the COR. The Contractor shall use existing input data and results from Task 1 to the maximum extent practicable. The Contractor may need to develop custom analysis inputs from the open literature, docketed correspondence, or by conducting finite element analyses (e.g., for weld residual stress profile development). The interim deliverable is a comparison of the reanalyzed results against the original results from NUREG-1829.

For assistance reviewing the ALS topical report submission, the Contractor shall review the topical reports and conduct confirmatory analyses using the xLPR code or other means as approved by the COR. The results from Task 5 may be used to inform the review. The Contractor shall also assist with developing requests for additional information, reviewing responses to those requests, and supporting meetings with the NRC staff review team and the applicant, as necessary. The specific areas of review shall be determined by the COR but may include the following:

selection of appropriate analysis inputs appropriateness of selected quantities of interest use of the xLPR code and related models within their known capabilities and limitations appropriate use of prior NRC analysis results generated using the xLPR code adherence to NRC guidance for probabilistic fracture mechanics analyses (e.g., Regulatory Guide 1.245, Preparing Probabilistic Fracture Mechanics (PFM) Submittals, issued January 2022 (ML21334A158), and NUREG/CR-7278, Technical Basis for the use of Probabilistic Fracture Mechanics in Regulatory Applications, issued January 2022 (ML22014A406) rigor of statistical analyses used to develop input data and results breadth and depth of sensitivity studies and analyses treatment of uncertainties

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methods for aggregating component-level results into system-and plant-level estimates

The final deliverable for this task is a TLR that fully documents the NUREG-1829 piping base case analyses and any supporting studies and analyses along with any confirmatory analyses performed to support the review of the industry topical reports.

Task 6 Completion Date: Task 6 shall be completed by December 31, 2024.

Task 6 Anticipated Travel: None.

Task 6 Deliverables: The contractor shall prepare and submit NUREG-1829 piping base case reanalysis results by May 31, 2024. The Contractor shall prepare and submit a single Draft TLR for Tasks 6 and 7 for NRC staff review by October 15, 2024. The contractor shall provide a Final TLR incorporating any comments from the COR by December 13, 2024.

Task 7: Formal Evaluation of LOCA Frequencies Using Operating Experience Data Analysis and Expert Elicitation

Activities under this task will be used to provide component failure frequency estimates and associated engineering analysis that will be used, in part, to benchmark the xLPR analyses performed under Task 6. This task will further assess the NUREG-1829 technical basis to determine if it should be updated based on knowledge gained since its issuance.

The Contractor shall estimate separate BWR and PWR piping failure frequency estimates based on operating experience data. The Contractor shall use an operating experience database to develop these frequencies. The database shall contain all reported U.S. operating experience related to passive system failures and should identify affected systems, the attributes of the failure, and identify the likely causal factors. The Contractor shall also identify any known database gaps. The failure frequency estimates generated from the operating experience data shall cover distinct time-periods from 1985 to 2004 and from 2005 to the present day. The estimates shall differentiate between failures in PWR hot, cold, and cross-over legs and BWR main recirculation loop piping and failures in greater than 6 inches nominal pipe size (NPS)

PWR and BWR branch connection piping. As directed by the COR, information on relevant population attributes shall also be provided. The results will be used to benchmark the xLPR LOCA frequency estimates from Task 6.

The Contractor shall also estimate separate BWR and PWR non-piping failure frequencies based on operating experience data. The Contractor shall use an operating experience database to develop these frequencies. The database shall contain all identified U.S. operating experience related to non-piping passive system failures and should identify affected systems, the attributes of the failure, and identify the likely causal factors. The Contractor shall also identify any known database gaps. The failure frequency estimates generated from the operating experience data shall cover distinct time-periods from 1985 to 2004 and from 2005 to the present day. The estimates shall differentiate between non-piping failures leading to a break size greater than a complete failure of PWR and BWR branch connection piping that is greater than 6 inches NPS

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and those that with a greater than 6 inches NPS. As directed by the COR, information on relevant population attributes shall also be provided.

Additionally, the Contractor shall participate in focused elicitation. As directed by the COR, the Contractor shall identify other component failure scenarios that may not be present in the operating experience database(s) with consideration given to knowledge gained since the publication of NUREG-1829. The goal of this activity is to determine if updates to select operating experience based expert testimony documented in NUREG-1829 are needed. The Contractor shall perform this updated elicitation using at least two of the experts from the original NUREG-1829 elicitation. Both separate operating-experience-based and engineering-based assessments will be needed to execute this task. The Contractor shall work with the COR to develop questions to guide the elicitation.

The final deliverable for this task is a TLR that fully documents the piping and non-piping operating experience evaluations, including benchmarking against the xLPR LOCA frequency estimates from Task 6, and the expert elicitation responses. The report shall include failure frequency estimates summarized by system, degradation mechanism, and normalized by appropriate population attribute for the degradation mechanism. The report should also summarize the following: events with attributes that could lead to break-before-leak in these systems (e.g., water hammer and flow-accelerated corrosion), events causing leakage or loss-of-coolant, any readily apparent qualitative reasons for significant deviations from the baseline event frequencies, and the associated piping and non-piping attributes. The report shall also document the responses to the expert elicitation.

Task 7 Completion Date: Task 7 shall be completed no later than December 31, 2024.

Task 7 Anticipated Travel: None.

Task 7 Deliverables: Within 5 business days of award of modification, the Contractor shall prepare and submit a Draft Analysis and Reporting Plan for COR review and approval. This plan shall detail the specific activities and analyses that the Contractor will perform to meet the requirements of Task 7. The Contractor shall provide Interim and Incremental Reports on the outcome of these activities and analyses, and the Draft Analysis and Reporting plan shall provide a schedule for submitting these reports to the NRC. All the activities and analyses and associated Interim and Incremental Reports shall be submitted by June 28, 2024. With 3 business days of receipt of the CORs comments on the Draft Analysis and Reporting Plan, the Contractor shall address the comments and submit a Final Analysis and Reporting Plan. The Contractor shall follow the Final Analysis and Reporting Plan, and any deviations from the final plan must be approved by the COR in writing.

The Contractor shall prepare a single Draft TLR for Tasks 6 and 7 and submit it to the NRC staff for review by October 15, 2024. The draft TLR shall incorporate content from the Task 7 Interim and Incremental Reports as directed by the COR. The Contractor shall provide a Final TLR incorporating any comments from the COR by December 13, 2024.

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5. APPLICABLE DOCUMENTS AND STANDARDS

The following documents and standards are applicable to the Task Order:

  • xLPR Software Maintenance Plan
6. DELIVERABLES/MILESTONE SCHEDULE AND REPORTING REQUIREMENTS

The contractor shall provide the deliverables stated in the table below in electronic format unless otherwise directed by the COR. The electronic format shall be provided using a Microsoft-based product, (e.g., Outlook, Word, Excel, PowerPoint) unless the COR and the contractor specifically agree on another format. All deliverables, with the exception of the Monthly Letter Status Report (MLSR) shall be in the format of draft version, revision version with redline/strikeout with a change-control appendix, and a revised version which shall become the final version. The contractor shall maintain appropriate version control in an electronic format.

The contractor shall explicitly state in its submittal(s) that the product provided is the deliverable for Task/Subtask XX, as further described below.

The Contractor shall submit the following deliverables to the Task Order COR. Unless otherwise directed by the COR or the Contracting Officer (CO), the Contractor must provide all deliverables except the MLSR as draft products. The COR will review all draft deliverables (and coordinate any internal NRC staff review, if needed) and provide comments back to the contractor. The Contractor shall revise the draft deliverable based on the comments provided by the COR and then deliver a revised version of the deliverable, which will then be considered the Final Version. When mutually-agreed upon between the Contractor and the COR, the Contractor may submit preliminary or partial drafts to help gauge the Contractors understanding of the particular work requirement. More than one round of drafts may be needed if the Contractor does not successfully incorporate the CORs comments on the previous draft.

The Contractor shall develop, maintain, and control data, files, information, and deliverables pursuant to this Task Order.

DELIVERABLE/MILESTONE SCHEDULE

Task No. Description Due Date 1 Initial Analysis Plan 30 days after award of the task order 1 Analysis Plan Updates Biweekly until the Contractor completes all the analyses 1 Analysis information (e.g., Submitted as the analyses are completed code input and output files) 1 In-progress TLR drafts Submitted monthly 1 Completed TLR March 01, 2021 Interim TLR updates in Submitted weekly during the review 1 response to NRC staff process through September 10, 2021 review comments

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1 Final TLR September 10, 2021 Deliverables are as required by the xLPR Software Maintenance Plan 2a depending on the scope of As directed by the COR the particular maintenance activities assigned by the COR.

2b Draft xLPR User Group No later than 15 days before the meeting is presentation materials scheduled to be held Final xLPR User Group 2b presentation materials No later than 5 days before the meeting is incorporating any comments scheduled to be held from the COR Draft ASME B&PV Code 3 meeting presentation No later than 2 weeks before each meeting materials Final ASME B&PV Code 3 meeting presentation No later than 1 week before each meeting materials incorporating any comments from the COR Letter report summarizing the topics, discussions, and No later than 2 weeks after each of the 3 any presentations given at meetings the ASME B&PV code meetings Specific draft deliverable as determined by the COR.

Schedule for draft deliverables as determined by the COR.

Draft TLR covering all work 4 performed in response to Duration for support in response to each technical assistance request technical assistance request is to be from the COR. Each draft agreed-upon with the COR. Draft TLRs are TLR shall summarize the due no later than 30 days after of efforts completed, propose completion of the work.

conclusions, and identify recommendations for any issues identified.

Schedule for final deliverables as determined by the COR.

Final deliverable 4 incorporating any comments Final TLR 30 days after contractor receipt from the COR. of COR comments. If applicable, revisions are due 30 days after COR request for a revision.

5 Draft input to the TLR 9/30/2022 assessing available EPRI

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results through June 14, 2022 Draft input to the TLR 5 assessing available EPRI 11/30/2022 results after June 14, 2022 5 Final TLR 12/15/2022 5 Final TLR incorporating any 1/31/2023 comments from the COR 6 NUREG-1829 piping base 5/31/2024 case analysis results 6 and 7 Draft TLR 10/15/2024 6 and 7 Final TLR incorporating any 12/13/2024 comments from the COR 7 Draft Analysis and 5 business days from award of Reporting Plan modification Final Analysis and 3 business days from receipt of COR 7 Reporting Plan comments on Draft Analysis and Reporting Plan Interim and Incremental As identified in the Final Analysis and 7 Reports Reporting Plan with all complete by 6/28/2024 MLSRs of the IDIQ contract.

The MLSRs shall include detailed summary of the All work effort carried out and 20th calendar day of the following month the labor hours expended on each labor category for the tasks.

The contractor shall submit the raw and processed data and worksheet and/or input files used in analyses with the Draft TLRs, upon request by the COR and with the Final TLRs, in a tabulated Excel format or other format as directed by the COR.

7. REQUIRED LABOR CATEGORIES

Labor Category Minimum Qualification Requirement

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1)B.S. in Engineering, Science, or similar technical field, And, 2)Minimum 10 years of regulatory research project management and oversight experience

Education and Skillsets that are not Required, but Desired for this Task Order Requirement:

  • M.S. in Engineering, Science, or similar technical field, or equivalent research and/or academic experience
  • Demonstrated experience in working with/ managing with NRC regulatory research projects Project Manager (PM) *Demonstrated experience in materials science research
  • Demonstrated experience managing computer code maintenance and development activities
  • Knowledge of piping fracture issues in light-water reactor nuclear powerplants
  • Knowledge of NRC regulations and guidance as they pertain to leak-before-break
  • Knowledge of nuclear power plant component integrity issues, such as corrosion, fatigue, stress-corrosion cracking, thermal and mechanical loadings and resulting stresses
  • Knowledge of American Society of Mechanical Engineers (ASME) codes and standards pertinent to nuclear powerplant design and inservice inspection

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1.Ph.D. in Engineering, Science, or similar technical field, And, 2.Minimum combined 20 years experience covering all the following key technical areas:

  • Expertise in probabilistic fracture mechanics computer code maintenance, development, and applications
  • Expertise performing sensitivity analyses, sensitivity studies, stability analyses, uncertainty analyses, and other statistical analyses
  • Detailed knowledge of piping fracture issues in light-water reactor nuclear power plants
  • Detailed knowledge of NRC regulations and guidance as they pertain to leak-before-break
  • Detailed knowledge of nuclear power plant component integrity issues, such as corrosion, fatigue, stress-corrosion cracking, thermal and mechanical loadings and resulting stresses Detailed knowledge of ASME codes and standards pertinent to nuclear power plant design and inservice inspection

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1.Ph.D. in Engineering, Science or similar technical field, And, 2.Minimum combined 10 years experience covering all the following key technical areas:

  • Expertise in probabilistic fracture mechanics computer code maintenance, development, and applications
  • Expertise performing sensitivity analyses, sensitivity studies, stability analyses, uncertainty analyses, and other statistical analyses
  • Detailed knowledge of piping fracture issues in light-water reactor nuclear powerplants
  • Detailed knowledge of NRC regulations and guidance as they pertain to leak-before-break
  • Detailed knowledge of nuclear power plant component integrity issues, such as corrosion, fatigue, stress-corrosion cracking, thermal and mechanical loadings and resulting stresses
  • Detailed knowledge of ASME codes and standards pertinent to nuclear power plant design and inservice inspection

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1.M.S. in Engineering, Science or similar technical field, And, 2.Minimum combine 10 years experience covering all of the following key technical areas:

  • Expertise in probabilistic fracture mechanics computer code maintenance, development, and applications
  • Knowledge of piping fracture issues in light-water reactor nuclear power plants
  • Knowledge of NRC regulations and guidance as they pertain to leak-before-break
  • Knowledge of nuclear power plant component integrity issues, such as corrosion, fatigue, stress-corrosion cracking, thermal and mechanical loadings and resulting stresses Knowledge of ASME codes and standards pertinent to nuclear power plant design and inservice inspection
8. GOVERNMENT-FURNISHED PROPERTY

The NRC shall furnish to the following property for the performance of this task order:

  • Access to all results from previous NRC task orders, as needed for this project per the CORs determination, including all past data, analyses, and reports.
  • Access to NRCs internal ADAMS shall be provided to the Contractors personnel for the search and retrieval of proprietary information.
  • Access to EPRI technical reports and data obtained through applicable NRC-EPRI Memoranda of Understanding, as needed for this project per the CORs determination.
  • Access to xLPR source and executable code, user manual, data libraries, configuration control documents, and other reference files and documents pertinent to development and maintenance of the xLPR code, as needed for this project per the CORs determination.

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9. PERIOD OF PERFORMANCE

Refer to Section F.2 TASK/DELIVERY ORDER PERIOD OF PERFORMANCE

10. PLACE OF PERFORMANCE

The work to be performed under this task order shall be performed at the Contractors facility except for the travel described in Section 11.1 of this statement of work.

11. SPECIAL CONSIDERATIONS

11.1 TRAVEL/MEETINGS

The following travel* may occur under this Task Order:

  • Attendance at meeting may be in person or virtually, as approved by the COR.

Travel Description Task(s) Location Date Days Attendees Months 1 -12 Program Review at Various Rockville, TBD 2 Up to 3 NRC MD Task Planning or 1 Rockville, TBD 3 Up to 3 Results Presentation MD xLPR Code Maintenance, 2 TBD TBD 3 Up to 2 Development and Support ASME B&PV Code 3 TBD 11/2020 3 Up to 2 Meeting ASME B&PV Code 3 TBD 02/2021 3 Up to 2 Meeting ASME B&PV Code 3 TBD 05/2021 3 Up to 2 Meeting ASME B&PV Code 3 TBD 08/2021 3 Up to 2 Meeting Months 13-24 Program Review at Various Rockville, TBD 2 Up to 3 NRC MD xLPR Code 2 TBD TBD 3 Up to 2 Maintenance,

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Development and Support ASME B&PV Code 3 TBD 11/2021 3 Up to 2 Meeting ASME B&PV Code 3 TBD 02/2022 3 Up to 2 Meeting ASME B&PV Code 3 TBD 05/2022 3 Up to 2 Meeting ASME B&PV Code 3 TBD 08/2022 3 Up to 2 Meeting Months 25-36 Program Review at Various Rockville, TBD 2 Up to 3 NRC MD xLPR Code Maintenance, 2 TBD TBD 3 Up to 2 Development and Support ASME B&PV Code 3 TBD 11/2022 3 Up to 2 Meeting ASME B&PV Code 3 TBD 02/2023 3 Up to 2 Meeting ASME B&PV Code 3 TBD 05/2023 3 Up to 2 Meeting ASME B&PV Code 3 TBD 08/2023 3 Up to 2 Meeting Months 37-48 Program Review at Various Rockville, TBD 2 Up to 3 NRC MD xLPR Code Maintenance, 2 TBD TBD 3 Up to 2 Development and Support ASME B&PV Code 3 TBD 11/2023 3 Up to 2 Meeting ASME B&PV Code 3 TBD 02/2024 3 Up to 2 Meeting ASME B&PV Code 3 TBD 05/2024 3 Up to 2 Meeting ASME B&PV Code 3 TBD 08/2024 3 Up to 2

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Meeting

Travel Notes-

a. All Contractor travel requires prior written approval from the COR.
b. The number of trips, number of contractor personnel, duration, location, may be modified based on meeting circumstances and COR's need for contractor support. Contractor shall implement travel cost-sharing measures (e.g., sharing rental car) if possible.
c. At the discretion of the COR, meetings may be conducted via telephone, video conference, or at the Contractors office(s).
d. All travel conducted pursuant to this task order is billable at Federal per diem rates, in accordance with Federal Travel Regulations.

11.2 SECURITY

The work will be UNCLASSIFIED; but requires an IT Security Level II Access.

Work on this task order may involve the handling of documents that contain proprietary information. The contractor shall safeguard documents containing proprietary information against unauthorized disclosure. After completion of work, the contractor shall either destroy the documents or return them to the NRC. If they are destroyed, please confirm this in an e-mail to the COR with a copy to the CO and include the date and manner in which the documents were destroyed.

11.3 KEY PERSONNEL

Refer to Section H.5 KEY PERSONNEL for Name and Labor Category/ Position of Key Personnel.

Contractor personnel performing this work shall have experience and/or education -- at a minimum a bachelors degree in engineering/science or equivalent experience and at least 20 years of related experience (combined of all staff) in one or more of the following key technical areas:

  • Expertise in probabilistic fracture mechanics computer code maintenance and development
  • Detailed knowledge of uncertainty characterization methodologies
  • Detailed knowledge of primary system piping fracture issues in light-water reactor nuclear

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power plants

  • Detailed knowledge of NRC regulations and guidance as they pertain to leak-before-break in primary system piping in PWRs
  • Detailed knowledge of corrosion, PWSCC, thermal and mechanical loadings and resulting stresses
  • Detailed knowledge of ASME codes and standards pertinent to nuclear power plant design and inservice inspection

11.4 KEY EQUIPEMENT, CERTIFICATIONS, and ANALYSIS TOOLS

The following analysis tools shall be required to perform the research described in this statement of work:

  • Finite element analysis capabilities with specialized user-defined subroutines using the ABAQUS commercial off-the-shelf software.
  • Commercial off-the-shelf software required in order to run the xLPR code, including, but not limited to, Microsoft Windows, Microsoft Excel, and GoldSim. Specific versions to be identified by the COR.

11.5 SPEECHES, PRESENTATIONS, PAPERS, AND JOURNAL ARTICLES

The Contractors investigator(s) may publish the results of this work in the open literature or may present papers at public or association meetings at interim stages of the work if the article or paper has been reviewed by the COR in draft form and agreement has been reached on the content. Submit the work in final form to the COR, accompanied by NRC Form 390A, Release to Publish Unclassified NRC Contractor Speeches, Presentations, Papers, and Journal Articles.

If agreement on the content has not been reached, NRC may also require that the paper include, in addition to the standard statement Work Supported by the U.S. Nuclear Regulatory Commission, any caveats necessary to cover NRC objections. If NRC objections cannot be covered in this manner, NRC can refuse to authorize publication in the open literature and/or presentation of papers.

The Contractor shall place the following disclaimer on all published papers and articles:

This report was prepared as an account of work sponsored by an agency of the U.S. Government.

Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third partys use, or the results of such use, of any information, apparatus, product, or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this paper are not necessarily those of the U.S. Nuclear Regulatory Commission.

For additional information, see NRC Management Directive 3.9, NRC Staff and Contractor Speeches, Presentations, Papers, and Journal Articles on Regulatory and Technical Subjects.

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