Modeling Molten Salt Reactor Fission Product Removal with SCALE

Technical Report · Sat Feb 01 00:00:00 EST 2020

DOI:https://doi.org/10.2172/1608211· OSTI ID:1608211

Jr. Vicente Valdez, Pedro ^[1]; Betzler, Benjamin R.  ^[2]; Wieselquist, William A.  ^[2]; Fratoni, Massimilliano ^[3]

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1. Univ. of California, Berkeley, CA (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. University of California, Berkeley, CA (United States)

Liquid-fuel Molten Salt Reactors (MSRs) allow for continuous online fuel treatment and processing using a variety of subsystems. Among these subsystems, the off-gas system (OGS) continuously removes fission products from the primary fuel salt through a helium sparging process. Accurately modeling fission product behavior is paramount for the development of MSRs; while there are a variety of depletion modeling and simulation tools that allow for removal of material from a defined system, most of them work in a semicontinuous, batch-wise manner. The new tools implemented into TRITON, in the SCALE suite for reactor analysis and design, aim to address this issue by implementing truly continuous material feeds and removals. In addition, material accountancy is enhanced in these tools, which enable tracking of removed material in user-specified mixtures. These continuous depletion tools provide a way to model material transport throughout systems more efficiently and accurately. This report validates the new SCALE MSR modeling capabilities using data from the Molten Salt Reactor Experiment (MSRE). After a framework was established for deriving realistic removal rates based on design specifications, these rates were used by TRITON to continuously remove specific elements while performing burnup calculations. Results were compared to those obtained in MSRE, with a focus on the ¹³⁵Xe poison fraction. After these capabilities were validated, the learned concepts and best practices were applied to model the Molten Salt Breeder Reactor (MSBR) and the Molten Salt Demonstration Reactor (MSDR) to study the effects of continuous fission product removal in fuel salt reactivity, as well as the lifetime effects.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1608211
• Report Number(s): ORNL/TM-2019/1418; TRN: US2104819
• Country of Publication: United States
• Language: English

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