NERTHUS thermal spectrum molten salt reactor neutronics and dynamic model

Dunkle, Nicholas; Richardson, Jarod; Pathirana, Visura; Wheeler, Anne; Chvála, O.; Skutnik, Steven E.

doi:10.1016/j.nucengdes.2023.112390

Cited by 3 publications

(6 citation statements)

References 15 publications

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“…The results completed in this paper were performed by running a depletion simulation of a generic molten-salt reactor in Serpent 2.1.32 [4]. The MSR model, named NERTHUS, is open-source and freely available on GitHub.…”

Section: Methodsmentioning

confidence: 99%

“…The model used in this work is the NERTHUS neutronics model. A detailed discussion of the development, methodology and the benchmarks of the model are explained in a previous paper [4]. For reader convenience, the most relevant information about the model is included here.…”

Section: Nerthus Neutronics Modelmentioning

confidence: 99%

“…The MSRE had a loop transit time of 25.2 s [20] (p. 102). In the generic MSR model used in this paper, the loop transit time is 30.6 s [4]. In both of these cases, the loop transit time is the time in which a unit of fuel salt takes to complete a journey through the primary loop back to its starting point.…”

Section: Isotopes Of Interestmentioning

confidence: 99%

“…An analysis on the connected relationship between off-gas and plutonium buildup was performed with simulations in Serpent [2]. The work included in this paper is an expansion of previous work on safeguards considerations for MSRs [1], plutonium signatures in MSRs [3], and also utilizes the NERTHUS neutronics model [4]. These techniques are potentially valuable safeguards and process monitoring tools for MSRs, and thus, deserve further investigation.…”

Section: Introductionmentioning

confidence: 99%

“…Multi-physics modeling methods have recently been used to simulate MSRs [13]. The MSR model used in this work is the NERTHUS neutronic model made in Serpent [4].…”

Section: Introductionmentioning

confidence: 99%

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Plutonium Signatures in Molten-Salt Reactor Off-Gas Tank and Safeguards Considerations

Dunkle

Wheeler

Richardson

et al. 2023

JNE

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Fluid-fueled molten-salt reactors (MSRs) are actively being developed by several companies, with plans to deploy them internationally. The current IAEA inspection tools are largely incompatible with the unique design features of liquid fuel MSRs (e.g., the complex fuel chemistry, circulating fuel inventory, bulk accountancy, and high radiation environment). For these reasons, safeguards for MSRs are seen as challenging and require the development of new techniques. This paper proposes one such technique through the observation of the reactor’s off-gas. Any reactor design using low-enriched uranium will build up plutonium as the fuel undergoes burnup. Plutonium has different fission product yields than uranium. Therefore, a shift in fission product production is expected with fuel evolution. The passive removal of certain gaseous fission products to the off-gas tank of an MSR provides a valuable opportunity for analysis without significant modifications to the design of the system. Uniquely, due to the gaseous nature of the isotopes, beta particle emissions are available for observation. The ratios of these fission product isotopes can, thus, be traced back to the relative amount and types of fissile isotopes in the core. This proposed technique represents an effective safeguards tool for bulk accountancy which, while avoiding being onerous, could be used in concert with other techniques to meet the IAEA’s timeliness goals for the detection of a diversion.

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Section: Methodsmentioning

confidence: 99%

Section: Nerthus Neutronics Modelmentioning

confidence: 99%

Section: Isotopes Of Interestmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Multi-physics modeling methods have recently been used to simulate MSRs [13]. The MSR model used in this work is the NERTHUS neutronic model made in Serpent [4].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Plutonium Signatures in Molten-Salt Reactor Off-Gas Tank and Safeguards Considerations

Dunkle

Wheeler

Richardson

et al. 2023

JNE

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Molten salt reactor system dynamics in simulink and modelica, a code to code comparison

Pathirana

Creasman

Chvála

et al. 2023

Nuclear Engineering and Design

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Molten Salt Reactor Loss of Flow Accident Analysis using the NERTHUS Dynamic Model

Dunkle,

Bogetic

2023

nuclscitechnolopenres

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Background Molten salt reactors (MSRs) can have different behavior to various types of accidents compared to conventional reactors. MSRs also have different safety limitations that many are unfamiliar with. With limited operating time, simulations with a dynamic model are a valuable method of analyzing the effects of potential accidents scenarios. Methods The model used in this work is the NERTHUS Dynamic Model in MATLAB-Simulink, which is a generic MSR design agnostic to any specific reactor design. The type of accident investigated in this work are pump failures in each of the fluid loops (i.e., primary, secondary, and tertiary) with no control rod movement and the only response being a trip to the once-through steam generator feedwater at different delay times. Pump failure was modeled as an exponential decay curve to represent the effects momentum would have on the resulting flow coastdown. Results The results of these simulations show that an MSR could be safely powered down in the event of a pump failure by decreasing the feedwater flow rate to the steam generator in a timely manner. A delayed response leads to fluid temperatures in the loops rapidly decreasing to the point where freezing of the coolant salts can become a concern. Conclusions The trending behavior across the simulations is that the temperatures between the reactor core outlet and the location of the pump failure increase compared to pre-transient conditions. The temperatures of the loops further downstream than the pump failure will decrease unless action is taken.

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NERTHUS thermal spectrum molten salt reactor neutronics and dynamic model

Cited by 3 publications

References 15 publications

Plutonium Signatures in Molten-Salt Reactor Off-Gas Tank and Safeguards Considerations

Plutonium Signatures in Molten-Salt Reactor Off-Gas Tank and Safeguards Considerations

Molten salt reactor system dynamics in simulink and modelica, a code to code comparison

Molten Salt Reactor Loss of Flow Accident Analysis using the NERTHUS Dynamic Model

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