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DOE OSTI2015

Summary of Investigations on Technical Feasibility of Direct Disposal of Dual-Purpose Canisters

This study has evaluated the technical feasibility of direct disposal in a geologic repository, of commercial spent nuclear fuel (SNF) in dual-purpose canisters (DPCs) of existing designs. The authors, representing several national laboratories, considered waste isolation safety, engineering feasibility, thermal management, and postclosure criticality control. The 3-year study concludes that direct disposal is technically feasible for most DPCs, depending on the repository host geology. Postclosure criticality control, and thermal management strategies that allow permanent disposal within 150 years, are two of the most challenging aspects. This document summarizes technical results from a series of previous reports, and describes additional studies that can be done especially if site-specific information becomes available from one or more prospective repository sites.

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DOE OSTI2018

Sustainable Data Evolution Technology (SDET) for Power Grid Optimization (Final Report)

This project develops an innovative sustainable data evolution technology (SDET) to create open-access power grid datasets and facilitate updates to these datasets by the power grid community. The lack of open-access, realistic large-scale datasets significantly limits the ability of researchers, developers and ultimately end users to develop, benchmark and compare new methods and tools for optimizing the operation and planning of the grid, which leads to slow adoption by end users. Available open datasets include the IEEE sponsored 14-300 bus transmission test cases and distribution test feeders, the Edinburgh Power Systems Test Case Archive (39-2224 buses), and the Polish cases (2383-3375 buses) available with MATPOWER. These datasets serve certain purposes, but for power grid optimization, they are insufficient in one or more of these aspects: 1) they are too small; 2) they are incomplete in both models and scenarios for optimization purposes; and 3) they are static and are not keeping up with grid needs. The SDET technology delivers large-scale realistic datasets and data-creation tools capable of generating new datasets. We work closely with the Category-2 data repository project awarded by the same GRID DATA program. The generated datasets and data creation tools are compatible with and available through the data repository. The objective is to make this a sustained effort within and beyond the ARPA-E GRID DATA program so that the datasets can evolve over time and meet the current and future needs for power grid optimization and potentially other applications in power grid operation and planning. The novel and disruptive features of SDET differentiate itself from prior work in the following aspects: 1) SDET derives features and metrics for both transmission and distribution (T&D) systems by analyzing many public and private datasets provided by our industry partners National Rural Electric Cooperative Association (NRECA) and PJM Interconnection (PJM). 2) SDET develops data-creation tools and use these tools to generate large-scale open-access realistic datasets that comply with the metrics for both T&D systems. 3) SDET validates the created datasets using industry tools provided by our vendor partner GE Energy Solution. The data creation tools, as well as the created datasets, are integrated into the data repository (DR. POWER) funded by ARPA-E GRID DATA program in Category 2. Users can use the datasets and access these data creation tools to create and update datasets, thus datasets can evolve per user requirements and power grid development. The SDET is a novel and disruptive technology compared to current ad hoc and static dataset generation. It is expected the SDET technology will fundamentally enhance the development, assessment, and adoption of new methods and tools for power grid optimization and other applications, which in turn would significantly improve the reliability, resiliency, and efficiency of the power grid – a major ARPA-E mission objective.

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DOE OSTI2019

DOE SFWST Campaign R&D Roadmap Update Rev.1.

The Spent Fuel and Waste Science and Technology (SFWST) Campaign of the U.S. Departmentof Energy (DOE) Office of Nuclear Energy (NE), Office of Spent Fuel and Waste Disposition(SFWD) is conducting research and development (R&D) on deep geologic disposal of spentnuclear fuel (SNF) and high-level nuclear waste (HLW). R&D addressing the disposal ofSNF/HLW in the U.S. is currently generic (i.e., "non-site-specific") in scope, following thesuspension of the Yucca Mountain Repository Project in 2010. However, to prepare for theeventuality of a repository siting process, the former Used Fuel Disposition Campaign (UFDC) ofDOE-NE, which was succeeded by the SFWST Campaign, formulated an R&D Roadmap in 2012outlining generic R&D activities and their priorities appropriate for developing safety cases andassociated performance assessment (PA) models for generic deep geologic repositories in severalpotential host-rock environments in the contiguous United States. This 2012 UFDC Roadmap alsoidentified the importance of re-evaluating priorities in future years as knowledge is gained fromthe DOE's ongoing R&D activities.

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DOE OSTI2019

Innovative Linear and Nonlinear Solvers for Simulating Multiphase Flow within Large-Scale Engineered Subsurface Systems

Numerical simulation of non-isothermal multiphase porous flow combined with reactive transport is used in a wide range of applications, which include nuclear waste repositories, enhanced recovery of petroleum reservoirs, contaminant remediation, geothermal engineering, and carbon sequestration. Understanding and predicting underground phenomena can have enormous impact on how to deal with world issues like climate change, clean water, and renewable energy. The main motivation for this proposal arises from safety assessment of future nuclear waste repositories using the U.S. Department of Energy (DOE) Geologic Disposal Safety Assessment (GDSA) Framework, and performance assessment (PA) for Waste Isolation Pilot Plant (WIPP), the nation's only active nuclear waste repository in Carlsbad, New Mexico. I am a technical staff member at Sandia National Laboratories involved in both projects.

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DOE OSTI2015

Cost Estimation Inputs for Spent Nuclear Fuel Geologic Disposal Concepts

A set of 16 geologic disposal concepts is described in sufficient detail for rough-order-of-magnitude repository cost estimates, for disposal of spent nuclear reactor fuel in generic crystalline, argillaceous, and salt host geologic media. The description includes total length, diameter, and volume for all underground shafts, ramps, drifts and large-diameter borings. Basic types of ground support are specified. Total repository capacity is assumed to be approximately 140,000 MT of spent fuel, but concepts are described in terms of modular panels each containing 10,000 MT. Waste packaging is described, and the materials and outer dimensions for disposal overpacks are given. The manner of emplacement is specified, with any additional fixturing, lining, buffer materials, and backfill needed. Thermal limits for waste package emplacement or repository closure are given, as appropriate for enclosed and open emplacement modes, respectively. The 16 disposal concepts are based on disposal concept studies performed for the Used Fuel Disposition R&D program between 2011 and 2014, and the accompanying engineering analyses.

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DOE OSTI2020

Benched: Upgrading and Updating the Los Alamos Benchmark Suite for the 21st Century [Slides]

The presentation begins by stating that most organizations make choices to handle specific things when preparing input files for validation, such as which elemental abundance data to use, how to decompose specific elements, and setting calculation precision. It also discusses the consequences, which include differing calculation results between different organizations for the same case, even when using the same code. This is illustrated by the intercomparison exercise and input files that are prepared by one organization and are not necessarily correct for another. The presentation explains that the Los Alamos Benchmark Suite is a centralized repository of high-quality benchmark models currently under development at LANL. The objectives of the new repository are to remain up to date with the latest ICSBEP revision, to have a formal review and revision process, to (eventually) be an open-source repository, and to provide new tools for improved input and output file generation and review.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2018

International Collaboration Activities on Engineered Barrier Systems

International collaborations on nuclear waste disposal is an integral part of the Spent Fuel Waste Science and Technology (SFWST) campaign within the DOE Fuel Cycle and Technology (FCT) program. These engagements with international repository R&D programs provide key opportunities to participate in experiments with international partners on research investigations developing laboratory/field (underground research laboratories (URL) experiments) data of engineered barrier system (EBS) components (e.g., near-field) and characterization of transport phenomena in the host rock (e.g., far-field). The results of these field and laboratory experiments are used in the evaluation of coupled processes and the development of state-of-the-art simulation approaches to evaluate repository performance. Thermal heating from radionuclide decay in the waste canisters will increase temperature in the surrounding EBS driving chemical and transport processes in the near- and far-field domains of the repository. URL heater-tests for extended periods of times (e.g., years) provide key information and data of thermal effects on barrier responses to temperature and water saturation levels.

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DOE OSTI2019

Preliminary Engineering and Cost Analysis for DPC Disposal Solutions. Final Draft

There are currently (as of January, 2019) more than 2,700 dual-purpose canisters (DPCs) loaded with spent nuclear fuel (SNF) across the United States. DPCs continue to be loaded at a rate of more than 200 per year by mid-century there are likely to be more than 8,160 DPCs in service. Options for disposing of SNF loaded in DPCs include repackaging into specialized disposal canisters, directly disposing of the loaded DPCs (with or without modification), or some combination of the two. The main technical challenges for direct disposal of loaded DPCs are thermal management, handling and emplacement operations for the large, heavy packages, and postclosure criticality control. This report focuses on postclosure criticality control which is the most challenging. The challenge lies in determining how to modify DPCs so as to minimize the probability that a criticality event might occur in a repository, or if the DPCs are not modified, to understand the nature and consequences of postclosure criticality events. There are several approaches that could facilitate direct disposal of loaded DPCs with acceptable repository performance. This report describes these approaches and presents comparative analysis of the rough-order-of-magnitude (ROM) costs. Repackaging SNF in DPCs into specialized disposal canisters could be financially and operationally costly with additional radiological, operational safety, and management risks. A disposition approach that would not involve repackaging or modifications to DPCs (future or already loaded) is development of a new licensing strategy that addresses the risk (probability and consequence) from criticality events. A different approach would modify existing loaded DPCs (some or all of them), and change the loading or design of future DPCs, to decrease the probability of a criticality event in a repository below levels of concern. This report investigates the cost to modify existing loaded DPCs, and the cost to modify the loading or design of future DPCs to facilitate direct disposal. It establishes the ROM cost for repackaging SNF that has been loaded into DPCs, into specialized canisters for disposal. It also identifies technical and regulatory challenges associated with the potential design modifications and loading considerations. It is left to future analyses to compare radiological, operational safety, and management risks associated with the available approaches.

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DOE OSTI2019

DOE SFWST Campaign R&D Roadmap Update

The Spent Fuel and Waste Science and Technology (SFWST) Campaign of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Spent Fuel and Waste Disposition (SFWD) is conducting research and development (R&D) on deep geologic disposal of spent nuclear fuel (SNF) and high-level nuclear waste (HLW). R&D addressing the disposal of SNF/HLW in the U.S. is currently generic (i.e., "non-site-specific") in scope, following the suspension of the Yucca Mountain Repository Project in 2010. However, to prepare for the eventuality of a repository siting process, the former Used Fuel Disposition Campaign (UFDC) of DOE-NE, which was succeeded by the SFWST Campaign, formulated an R&D Roadmap in 2012 outlining generic R&D activities and their priorities appropriate for developing safety cases and associated performance assessment (PA) models for generic deep geologic repositories in several potential host-rock environments in the contiguous United States. This 2012 UFDC Roadmap also identified the importance of re-evaluating priorities in future years as knowledge is gained from the DOE's ongoing R&D activities.

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DOE OSTI2020

Dual Purpose Canister Reactivity and Groundwater Absorption Analyses

The current spent nuclear fuel (SNF) management strategy includes reliance on dry storage. Utilities are meeting their interim storage needs on an individual basis with use of large-capacity dry storage casks, with a current focus on meeting existing storage and transportation requirements, as disposal requirements are not currently available. These casks are commonly known as dual-purpose (i.e., storage and transportation) canisters (DPCs). However, a small percentage of single-purpose (storage only) systems is also being used to meet storage needs. These are included under the “DPC” heading. This report investigates the postclosure criticality safety aspects of DPCs. Placing large, heavy waste packages containing DPCs into a repository for direct disposal has not yet been implemented domestically or internationally. Therefore, direct disposal of DPCs represents new engineering and scientific challenges. Some of the engineering challenges that have already been addressed include handling and placement, use of ramps vs. shafts, use of hoists, use of transport equipment, and thermal management. Additionally, some studies have been conducted in the past regarding the feasibility of direct disposal from a criticality analysis perspective and have concluded that while possible, demonstrating subcriticality over the disposal time period is a challenge. The alternative to direct disposal of DPCs into a repository is to repackage the SNF into different canisters. The direct disposal of DPCs without cutting them open and repackaging is appealing because it could be more cost-effective, reduce the complexity of fuel management operations both in and outside reactor facilities, and result in less cumulative worker dose during interim storage and handling before eventual disposal in a deep geologic repository.

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DOE OSTI2021

Overview of Advanced Reactor Simulation Capabilities to Support Demonstrations

The Virtual Test Bed (VTB) was established to support the deployment of advanced reactors by facilitating the use of state-of-the-art modeling and simulation capabilities. These tools are able to solve previously prohibitive challenge problems in greater levels of fidelity and in a multi-physics framework. A VTB repository was recently set up to host models for a wide variety of reactor types and using a range of NEAMS-developed software. Table I summarizes the different capabilities already available in the repository and up-and-coming near/long term ones. The repository currently hosts models for a wide variety of reactor types, including High-Temperature Gas Cooled Reactors (HTGR), Sodium Fast Reactors (SFR), Fluoride salt cooled High-temperature Reactors (FHR), Molten Salt Reactors (MSR), and Heat-Pipe Microreactors (HP-MR). It should be noted that work is ongoing for all of the models and each example problem is at a different state of maturity.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2020

Status Update on the High Precision Isotopic Measurements on High Burnup LWR Fuel in 2020

The US Department of Energy (DOE) Office of Nuclear Energy (NE) is currently investigating the feasibility of directly disposing dual-purpose (storage and transportation) canisters (DPCs) in a spent nuclear fuel (SNF) repository. Criticality during the repository performance period (10,000 years or more) is one of the major concerns related to direct disposal of DPCs, specifically as the system undergoes degradation in the repository environment and timeframe. Oak Ridge National Laboratory (ORNL) is developing an as-loaded criticality analysis methodology using full (actinides + fission products) burnup credit that exploits the inherent criticality margin associated with actual canister-specific loading configuration. Burnup credit criticality analysis requires validation of the depletion/decay codes used to generate the burned isotopic inventory of an assembly by comparing the code-predicted inventory with experimentally determined isotopic data. Currently, isotopic measurement data for boiling water reactors (BWR) SNF are limited, and additional measurements will be highly beneficial for BWR burnup credit analysis, which is essential to demonstrate disposability of BWR DPCs. Moreover, new pressurized water reactor (PWR) samples of isotopic measurements will expand the PWR sample population and consequently will greatly improve sample statistics. In turn, this will reduce uncertainty in the computational determination of the isotopic composition of commercial SNF and eliminate additional penalties currently used for lack of data. As part of the isotopic analysis task, eight diverse, high burnup (HBU) samples from several PWR rods are being dissolved and isotopically analyzed to provide high-quality measurement data for PWR SNF to reducing the uncertainties associated with PWR isotopic depletion validation. The isotopics of interest focus on nuclides important to burnup credit, shielding, and decay heat in PWR SNF. Additionally, eight high burnup BWR fuel samples from the Limerick nuclear power plant have been identified for measurement to support reducing uncertainties associated with BWR isotopic depletion validation.

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DOE OSTI2023

Panorama 360 (Final Report)

This is the final technical report for the DOE-funded Panorama 360 project. Panorama 360 provided a resource for the collection, analysis, and sharing of performance data about end-to-end scientific workflows executing on DOE facilities. The work focused on workflows that include experimental data generation at DOE facilities. The main activities of Panorama 360 include the development of: 1. A distributed repository that stores different types of workflow execution data (e.g., point and time series performance traces at fine- and coarse-grained levels); 2. A set of open-source data capture, curation, and publishing tools fully integrated with a state-of-the-art workflow management system that automates data ingestion to the repository and enables users to discover, query, and process data from the repository; 3. A set of analysis algorithms and machine learning based tools to perform analysis and characterization of the gathered data, which can be used to detect anomalous performance or system faults; and 4. Best practices and recommendations for workflow evaluation, analysis, execution, and architectures.

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DOE OSTI2022

Cladding Degradation Model

This report begins with an evaluation of cladding degradation mechanisms deemed important to assessing barrier capability. Unlike similar efforts done in the past, this evaluation accounts for the hypothetical conditions associated with direct dual-purpose canister (DPC) disposal, including conditions resulting from a postulated, in-package, steady-state criticality event. A total of 16 cladding degradation mechanisms are examined assuming direct disposal of DPCs in two different hypothetical repositories: a saturated repository in shale and an unsaturated repository in alluvium.

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DOE OSTI2022

DECOVALEX-2023, Task F Specification, Revision 8

This report is the revised (Revision 8) Task F specification for DECOVALEX-2023. Task F is a comparison of the models and methods used in deep geologic repository performance assessment. The task proposes to develop a reference case for a mined repository in a fractured crystalline host rock and a reference case for a mined repository in a salt formation. Teams may choose to participate in the comparison for either or both of the reference cases. For each reference case, a common set of conceptual models and parameters describing features, events, and processes that impact performance will be given, and teams will be responsible for determining how best to implement and couple the models. The comparison will be conducted in stages, beginning with a comparison of key outputs of individual process models, followed by a comparison of a single deterministic simulation of the full reference case, and moving on to uncertainty propagation and uncertainty and sensitivity analysis. This report provides background information, a summary of the proposed reference cases, and a staged plan for the analysis.

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DOE OSTI2022

Knowledge Management: FY22 Los Alamos National Laboratory Hydrothermal Lab for Spent Fuel Campaign R&D

The use of Engineered Barrier Systems (EBS) for spent nuclear fuel disposal is being investigated by the U.S. Department of Energy as a part of the Spent Fuel and Waste Disposition (SFWD) Campaign. Such dry spent fuel canisters would be loaded with fuel bundles, and then transported and stored at a nuclear waste repository. Once the canisters are in place underground, the space between the canister and the wall rock will be filled with bentonite clay. Recent research has prioritized high temperature interactions of EBS materials, including phase transitions in bentonite clay, in order to reduce worker dose and repository cost. Higher temperature (i.e., 200ºC) thermal limits are a new area of investigation by the U.S. and international repository science programs. The hydrothermal experimental laboratory at Los Alamos, consisting of rocking autoclaves and cold seal assemblies, is critical to the campaign and presents a significant temperature / pressure safety hazard. Therefore, working competently and safely with these systems is very important to the knowledge management procedures developed at this laboratory. Therefore, the operation of these two systems (rocking autoclaves and cold seal assemblies) will be discussed first.

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DOE OSTI2022

Transient Postclosure Criticality Model Development

A key objective of the United States Department of Energy’s (DOE) Office of Nuclear Energy’s Spent Fuel and Waste Science and Technology (SFWST) Campaign is to better understand the technical basis, risks, and uncertainty associated with the safe and secure disposition of spent nuclear fuel (SNF) and high-level radioactive waste. Commercial nuclear power generation in the United States has resulted in thousands of metric tons of SNF, the disposal of which is the responsibility of the DOE (Nuclear Waste Policy Act of 1982, as amended). Any repository licensed to dispose of SNF must meet requirements regarding the long-term performance of that repository. For an evaluation of the long-term performance of the repository, one of the events that may need to be considered is the SNF achieving a critical configuration during the postclosure period. Of particular interest is the potential behavior of SNF in dualpurpose canisters (DPCs), which are currently licensed and being used to store and transport SNF but were not designed for permanent geologic disposal.

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DOE OSTI2022

Dual Purpose Canister Reactivity and Groundwater Absorption Analyses

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