Material Property Correlations: Comparisons between FRAPCON-3.4, FRAPTRAN 1.4, and MATPRO

Abstract

The U.S. Nuclear Regulatory Commission uses the computer codes FRAPCON-3 and FRAPTRAN to model steady-state and transient fuel behavior, respectively, in regulatory analysis. In this document, material property correlations for oxide fuels and cladding materials are presented and discussed. Comparisons are made between the material property correlations used in the most recent versions of the codes, Comparisons are also made with MATPRO, which is a compilation of material property correlations with an extensive history of use with various fuel performance and severe accident codes. In addition to model-to-model comparisons, model-to-data comparisons and source codes for the FRAPCON-3.4 and FRAPTRAN 1.4 correlations are provided.iii iv ForewordThe U.S. Nuclear Regulatory Commission uses the computer codes FRAPCON and FRAPTRAN to model steady-state and transient fuel behavior, respectively, in regulatory analysis. To effectively model fuel behavior, material property correlations must be used for a wide range of operating conditions (e.g., temperature and burnup). In this sense, a "material property" is a physical characteristic of the material whose quantitative value is necessary in the analysis process.The consolidated resource for "material properties" cited most often in the literature is MATPRO (as documented in Volume 4 of NUREG/CR-6150). MATPRO is a compilation of fuel and cladding material property correlations with an extensive history of use with fuel performance and severe accident codes. However, consistency among the material property correlations in FRAPCON-3, FRAPTRAN, and MATPRO has never been complete, as the material property correlations in the fuel performance codes have evolved to accommodate recent fuel design changes.

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“…The conductivity of M5 ® was taken from [12] and set to the value of k c = 18 W/(m K). The internal cladding temperature was found to be T wi = 344°C.…”

“…Therefore, to apply this model to a PWR, a correction was introduced to take into account the difference in coolant pressure and its effect on elastic deformations of the cladding material. The correction was calculated using, for the calculation of the Young modulus of Zircaloy, the MATPRO formula [12]:…”

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“…These codes permit to evaluate the variation as function of time of all significant fuel rod variables, including fuel and cladding temperatures, cladding stress and strain, cladding oxidation, fuel irradiation swelling, fission gas release, and rod internal gas pressure. FRAPCON-3.4 uses fuel, cladding, and gas material properties from MATPRO [4] that was updated to include burnup-dependent properties and properties for advanced zirconium-based alloys. In conventional power reactors, the fuel rod consists of UO 2 pellets inside a zirconium-based alloy cladding called Zircaloy-2 (Zr-98%; Sn-1.5%; Fe-0.15%; Cr-0.1%; Ni-0.05%) used in BWR (boiling water reactors) and Zircaloy-4 (with removal of Ni), where the Ni is removed, used in pressurized water reactors (PWR and CANDU (Canada Deuterium Uranium)).…”

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“…In addition, FRAPCON-3.4a and FRAPTRAN 1.4 share a common material properties library for fuel properties, cladding properties, and gas properties. These properties are described in a material properties document [3].…”