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TIRICE and TIMaSC

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Purpose

The Technology Inclusive, Risk-Informed Change Evaluation (TIRICE) process provides an alternative change evaluation process for determining if NRC approval is required before implementing certain facility changes to reactors that were licensed using the methodologies in NEI 18-04, Revision 1, "Risk-Informed Performance-Based Technology-Inclusive Guidance for Non-Light Water Reactor Licensing Basis Development," as endorsed by Regulatory Guide 1.233, "Guidance for a Technology-Inclusive, Risk-Informed, and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light Water Reactors." The NRC endorses, subject to clarifications, the methodology described in NEI 22-05, “Technology Inclusive Risk Informed Change Evaluation (TIRICE): Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07” in Regulatory Guide 1.261, “Guidance for Technology Inclusive Risk-Informed Change Evaluation.”

The Technology Inclusive Management of Safety Case (TIMaSC) process provides a process for the management of a licensing modernization project-based safety case. Examples of TIMaSC guidance includes how to manage the safety case in the event operating experience indicates reliability or capability targets for safety significant structures, systems, and components (SSCs) are not met or operating experience indicates reliability or capability targets for safety significant SSCs have more than anticipated margin.

Public Meetings/Documents

Date Meetings/Document
06/11/2026 Issuance of RG 1.261, “Guidance for Technology-Inclusive Risk-Informed Change Evaluation”
01/29/2026

TIMaSC Public Meeting to discuss White Paper

08/22/2025 Submittal of SC-21256-100, “Technology Inclusive Management of Safety Case (TIMaSC) White Paper,” Rev 0
08/08/2025

Issuance of DG-1439, “Guidance for Technology-Inclusive Risk-Informed Change Evaluation” for public comment

05/08/2025

TIMaSC presentation at the Periodic Advanced Reactor Stakeholder Meeting

06/18/2024

Technology Inclusive Management of Safety Case Technical Contents

01/31/2024 Submittal of NEI 22-05, “Technology Inclusive Risk Informed Change Evaluation (TIRICE) Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07”, Revision 0
05/11/2023

Technology Inclusive Management of Safety Case Process

05/09/2023

Technology Inclusive Risk-Informed Change Evaluation Process

09/13/2022

Technology Inclusive Risk-Informed Change Evaluation Process

06/09/2022

Technology Inclusive Risk-Informed Change Evaluation Process

Page Last Reviewed/Updated Thursday, July 23, 2026

Page Last Reviewed/Updated Thursday, July 23, 2026