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The busyness of the nuclear fuel supply chain
Ken Petersenpresident@ans.org
With all that is happening in the industry these days, the nuclear fuel supply chain is still a hot topic. The Russian assault in Ukraine continues to upend the “where” and “how” of attaining nuclear fuel—and it has also motivated U.S. legislators to act.
Two years into the Russian war with Ukraine, things are different. The Inflation Reduction Act was passed in 2022, authorizing $700 million in funding to support production of high-assay low-enriched uranium in the United States. Meanwhile, the Department of Energy this January issued a $500 million request for proposals to stimulate new HALEU production. The Emergency National Security Supplemental Appropriations Act of 2024 includes $2.7 billion in funding for new uranium enrichment production. This funding was diverted from the Civil Nuclear Credits program and will only be released if there is a ban on importing Russian uranium into the United States—which could happen by the time this column is published, as legislation that bans Russian uranium has passed the House as of this writing and is headed for the Senate. Also being considered is legislation that would sanction Russian uranium. Alternatively, the Biden-Harris administration may choose to ban Russian uranium without legislation in order to obtain access to the $2.7 billion in funding.
Konor Frick, Shannon Bragg-Sitton
Nuclear Technology | Volume 207 | Number 4 | April 2021 | Pages 521-542
Technical Paper | doi.org/10.1080/00295450.2020.1781497
Articles are hosted by Taylor and Francis Online.
This paper provides a comprehensive overview of the development of a NuScale power module in the Modelica process model ecosystem at Idaho National Laboratory (INL) as part of the U.S. Department of Energy’s Office of Nuclear Energy Integrated Energy Systems (IES) program.
Model development has led to the creation of a dynamic NuScale module in the Modelica language that operates under natural circulation and is consistent with design parameters set forth in the design certification documentation for the Nuclear Regulatory Commission (NRC). Controllers have been developed that are consistent with controllers mentioned by NuScale design certification documents. While characteristic time constants may differ due to controller gains, the actual control actions of the system are consistent with NuScale prescribed actions. In addition to natural circulation and controllers, the NuScale power module includes hot channel calculations, reactivity control, and a pressurizer. Hot channel calculations include bulk fluid temperature, outer clad temperature, fuel centerline temperature, and departure from nuclear boiling ratios. Reactivity control incorporates moderator and fuel temperature feedback mechanisms, boron concentration, and control bank positions. A pressurizer with sprays and heaters was developed to maintain primary system pressure within bounds. Further, the model has been developed to allow the user to input beginning-, middle-, or end-of-cycle reactivity conditions.
Three simulations were run that demonstrate the capability of the model controllers to meet target parameters while preserving system values within reasonable bounds. The first simulation is an initialization study at 160 MW(thermal)/50 MW(electric) that compares the model steady-state values with the design certification values. This simulation demonstrates the capability of the model to operate in natural circulation mode and closely matches operating values set forth in the NRC design certification documents. The second simulation is a power uprate from 160 MW(thermal)/50 MW(electric) to 200 MW(thermal)/60 MW(electric), and the final simulation is of a typical summer day where the turbine demand oscillates throughout the day. These illustrate the capabilities of the system to operate under natural circulation while maintaining system parameters within controller bounds and to match turbine output with turbine demand.
This work adds a systems-level model of the NuScale power module with associated control systems, reactivity coefficients, control banks, coolant through fuel temperature profiles, and associated mass flow rates throughout the system that have been added to the Modelica ecosystem. This model will be the basis of work that is utilized in the Joint Use Modular Plant program at INL, which proposes to utilize a single power module to support research, development, and demonstration activities, with a specific aim to demonstrate various IES configurations. As part of the ecosystem, the NuScale module can be quickly integrated with existing Modelica modules (e.g., thermal energy storage, reverse osmosis, high-temperature steam electrolysis, gas turbines) to model energy grids in different geographical locations.