The SAS4A/SASSYS-1 Safety Analysis Code System, Version 5

Fanning, T. H.; Brunett, Acacia J.; Sumner, T.

doi:10.2172/1352187

Cited by 28 publications

(47 citation statements)

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“…The initial radial core expansion model was compared to existing empirical correlations for estimating the reactivity feedback as a function of the normalized power-to-flow ratio (P/F) based on a series of tests from the FFTF reactor. There was good qualitative agreement for P/F <1.25 with discrepancies due to modeling limitations of the core restraint ring [20].…”

Section: Validation and Verificationmentioning

confidence: 84%

“…SAS4A/SASSYS-1 provides a detailed, multiple-channel thermal/hydraulic treatment of the reactor core. A SAS4A/SASSYS-1 [20] calculation is performed to calculate the temperature distribution in the core, and the resulting radial expansion reactivity feedback is computed using either a "simple" or "detailed" model [21].…”

Section: Dif3d/sas4a/sassys-1 Workflowmentioning

confidence: 99%

“…The expansion at the grid plate is assumed to be proportional to the rise in the inlet temperature above the initial steady state-value. The expansion at the ACLP is assumed to be proportional to the change in the average temperature at that location [20]. The reactivity feedback is determined by taking the estimate of the radial expansion of the middle of the active core region and multiplying by the reactivity coefficient obtained from the DIF3D reactor physics code to obtain the reactivity change.…”

Section: Dif3d/sas4a/sassys-1 Workflowmentioning

confidence: 99%

“…In the detailed model, SAS4A/SASSYS-1 calculates a deformed shape for a single representative assembly that is an average assembly in the outer row of the core consistent with the limited free-bow core restraint system. The shape of the assembly is determined by evaluating the deformation of a continuous beam subjected to the thermal gradient across the assembly, considering the restraints due to the grid plate, the load pads, and any restraint rings [20]. Then, the reactivity coefficient for uniform dilation is distributed axially along the assembly according to the normalized power distribution in the active core zone.…”

Section: Dif3d/sas4a/sassys-1 Workflowmentioning

confidence: 99%

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Review of Tools for Modeling Core Radial Expansion in Liquid Metal-Cooled Fast Reactors

Wozniak¹,

Shemon²,

Grudziński³

2020

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Core radial expansion in liquid-metal cooled fast reactor systems is a well-known phenomenon that produces strong reactivity feedback effects. It is crucial from a safety standpoint to design a reactor with the proper core restraint system to guide expansion of the fuel assemblies into a formation that produces negative reactivity feedback in accident conditions. However, the modeling of core radial expansion and its associated reactivity feedback is extremely challenging. Liquid metal-cooled fast reactor designers (both industry and commercial) have pointed to improved modeling of core radial expansion as a key modeling challenge for these types of reactors. The Department of Energy Nuclear Energy Advanced Modeling and Simulation (DOE-NEAMS) program has an important role to play in helping to develop a robust, predictive tool for this phenomenon. A literature review has been performed to identify current simulation capabilities applicable to the prediction of core radial expansion in liquid metal-cooled fast reactors and the resultant reactivity feedback effects. An overview as well as a detailed description of the multi-physics phenomena underlying core radial expansion is given in the first two chapters. The objective of this report is to identify existing software that has been or could be applied to the core radial expansion problem, and then to identify possible paths to develop a robust, coupled multiphysics tool for advanced analysis, in which all three physics (radiation transport, structural mechanics, thermal fluids) are taken into account considering feedback effects from each physics to the other. Several computer codes and workflows have been developed in the United States and abroad to perform individual aspects of radial expansion calculations or to perform loosely coupled analysis. No code system currently exists which tightly and robustly couples the neutronics, thermal hydraulics, and thermal mechanical physics with enough detail to fully resolve the complex core radial expansion reactivity feedback effects. The future availability of such a code system is of vital importance to fully understanding the reactivity feedback effects that occur due to radial expansion, and consequently to optimizing the design of the core restraint system. A potential code development path forward using MOOSE-based tools is suggested in order to leverage the natural tight coupling and robustness of MOOSE-based applications. Additionally, potential gaps for modeling and common assumptions are listed which require further investigation to ensure accuracy for prediction of deformations.

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Section: Validation and Verificationmentioning

confidence: 84%

Section: Dif3d/sas4a/sassys-1 Workflowmentioning

confidence: 99%

Section: Dif3d/sas4a/sassys-1 Workflowmentioning

confidence: 99%

Section: Dif3d/sas4a/sassys-1 Workflowmentioning

confidence: 99%

See 2 more Smart Citations

Review of Tools for Modeling Core Radial Expansion in Liquid Metal-Cooled Fast Reactors

Wozniak¹,

Shemon²,

Grudziński³

2020

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“…The fuel axial expansion model is developed to consider the reactivity feedback in response to the fuel temperature changes during the transient. The fuel reactivity is integrated over the core channels (Equation (4-3)), and the difference between the transient and initial values (Equation (4-4)) is provided to the point-kinetics model for the calculation of fission power (Fanning 2012).…”

Section: Fuel Axial Expansion Reactivity Feedbackmentioning

confidence: 99%

SAM Developments to Support Transient Safety Analysis of Advanced non-LWRs

Hu¹,

Hu²,

Zou³

et al. 2019

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Development of a zero‐dimensional dynamic simulator of a power conversion system with a high‐temperature gas reactor

Juárez‐Martínez

Espinosa-Paredes

2021

Int J Energy Res

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The HTTR-GT/H2 plant is a nuclear power cogeneration plant for hydrogen production. The hydrogen production is based on the thermochemical sulfuriodine cycle able to produce about 30 NM 3 /h of hydrogen and 15 Nm 3 /h of oxygen. The power conversion system consists of a Bryton-cycle helium gas turbine designed to produce 1 MWe electric of power output, and the source of heat is the high temperature engineering test reactor designed by the Japan Atomic Energy Agency. In this work, a preliminary dynamic simulator for the power conversion system was developed. The plant simulator couples the dynamics of the nuclear reactor, the internal heat exchanger, and plant components, such as heat exchangers, coolers, recuperators, compressors, and turbines. Despite the simplicity of modeling, the use of zero-dimensional models showed a good agreement with the reported values, being 0.67% of difference for reactor's power, 0.22% of difference for the coolant outlet temperature, and the differences of the conversion system components compared to the reference ranges between 0.0 and 0.26%.

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The SAS4A/SASSYS-1 Safety Analysis Code System, Version 5

Cited by 28 publications

References 0 publications

Review of Tools for Modeling Core Radial Expansion in Liquid Metal-Cooled Fast Reactors

Review of Tools for Modeling Core Radial Expansion in Liquid Metal-Cooled Fast Reactors

SAM Developments to Support Transient Safety Analysis of Advanced non-LWRs

Development of a zero‐dimensional dynamic simulator of a power conversion system with a high‐temperature gas reactor

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