PHASE II – FINAL TECHNICAL REPORT – DEVELOPMENT OF CAN2 (CANISTER CORROSION ANALYSIS, ASSESSMENT AND ACTION PLANS): A PREDICTIVE DETECTION AND INTERPRETATION SOFTWARE PLATFORM FOR LIFE-CYCLE MANAGEMENT OF SPENT FUEL CANISTERS
Research Purpose: With 1000’s of dry storage canisters (DSCs) presently loaded with spent nuclear fuel (SNF) and more loaded each year, utilities must properly address aging effects to ensure canister longevity. The primary objective of this work was to develop and deliver a web-based machine learning software tool that addresses aging effects for optimizing life-cycle decisions and ensuring long-term performance of welded stainless-steel DSCs for the storage of SNF. Incorporating this tool into daily operations will promote pro-active decision-making and improved risk management to minimize the likelihood of a potentially catastrophic, failure event (i.e., loss of the canister’s containment boundary). Description of Research Completed During Phase II: During Phase II the following R&D was completed to accomplish the abovementioned objectives: (1) an improved physics-based chloride induced stress corrosion cracking (CISCC) model was developed to quantify the time evolution of damage, (2) a supplemental experimental program was completed for model calibration and verification, (3) the Phase I literature review was extended to better quantify pit and crack initiation thresholds, and compile experimental/field data for verification of initiation and growth statistics, (4) a probabilistic decision network was developed for determining financially optimal lifecycle strategies given the plethora of uncertainties in the CISCC model, (5) a cloud-based software platform, leveraging artificial intelligence (AI) with online database capabilities, was developed for implement aging management programs (AMPs) and ensuring safe long-term performance of the DSCs, (6) the CISCC model and decision network were integrated into the software platform for evaluating the nation’s fleet of DSCs, (7) an interactive and configurable dashboard was incorporated into the software to summarize pertinent results in an easy-to-understand and intuitive manner, and (8) an extensive market research study was completed, working closely with the commercialization assistance provider, Larta, which resulted in a thorough Go-To-Market strategy. Phase II Research Findings: Some key findings from the completed Phase II research include: (1) the time evolution of CISCC is sensitive to the dynamic nature of the input weather data including ambient temperature, site absolute humidity, and site aerosol concentration (i.e., average annual conditions can result in either conservative or non-conservative initiation and failure time predictions), (2) the resulting failure time distribution is sensitive to input data uncertainty, thus, a probabilistic approach is required, (3) when determining financially optimal lifecycle decision strategies, model prediction uncertainties must be accounted for, (4) while significant experimental data was gathered throughout this effort, various research laboratories, universities, and investigators should share existing data and plan future efforts to ultimately reduce input data uncertainty and improve verification and validation, (5) analyzing the currently available data for all US ISFSIs it was determined that even the most susceptible ISFSIs are not highly susceptible to CISCC, and that once CISCC initiates and presents itself, there should be significant time to detect it and remediate it prior to failure, (6) inspections are completely ineffective if they are not properly timed, i.e., after damage has initiated and it can be detected with the limited coverage area of the currently available inspection techniques, and (7) using the newly developed model, the financially optimal lifecycle strategy was determined to be any strategy that results in indefinite remediation of CISCC, as any strategy that requires future periodic maintenance activities accumulates excessive costs over the canister’s lifecycle (identified effective strategies include cleaning the canister and then sealing off the vents after the decay heat is low enough such that maximum canister surface design temperatures are no longer a concern, placing the susceptible canister into a larger canister that is not susceptible to CISCC once passive cooling is no longer required, and relocating the canister to a storage facility that is not susceptible to CISCC). Potential Application of the Phase II Research: The software platform developed has many potential uses including: (1) implementation of AMPs and day-to-day engineering support for ISFSIs, (2) engineering analysis support and identifying improved designs and technology for cask vendors and service providers, (3) justify the need and focus areas of future research, and (4) monitoring the status of SNF and integrity of DSCs. The improved CISCC model can also be used for alternate applications throughout the nuclear industry and other aging energy industries, as well as the individual components of the model, on their own. Additionally, the financial-based lifecycle decision network was implemented generically such that it can be tailored to alternate lifecycle strategies throughout the aging energy industries.
- Research Organization:
- The Equity Engineering Group, Inc.
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE), Office of Spent Fuel and Waste Disposition. Office of Spent Fuel and Waste Science and Technology
- DOE Contract Number:
- SC0019932
- OSTI ID:
- 1899549
- Type / Phase:
- SBIR (Phase II)
- Report Number(s):
- DOE-E2G-0019932
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
97 MATHEMATICS AND COMPUTING
Life-Cycle Management
Decision Making
Aging Management
Machine Learning
Artificial Intelligence
Pitting Corrosion
Stress Corrosion Cracking
Web Tool
Online Databases
Spent Nuclear Fuel
Dry Storage Canisters.