TRISOUtils

Overview

TRISOUtils houses functions for calculations required for various UCO related materials.

Molar Mass

TRISOUtils calculates the molar mass of the kernel, which is used in UCOThermal and TRISOBurnup.

where (wt.%) is the initial U-235 enrichment, (dimensionless) and (dimensionless) are the initial oxygen to uranium and carbon to uranium stoichiometries of UCO, (dimensionless) is the atomic fraction, (kg/mol) is the atomic weight and (kg/mol) is the molar mass of the kernel.

UCO is assumed to be formed of UO, UC, and UC.

UC and UC are known to mix during heat treatment and form a UC phase, where x<2.

The atomic weights of the UCO constituents are:

Theoretical Density

TRISOUtils calculates the theoretical density of the kernel, which is used in UCOElasticityTensor.

where (kg/m) is the theoretical density and (dimensionless) is the weight fraction. The quantities and come from the calculations described in the kernel molar mass section.

The theoretical densities of the UCO mixture components are:

Fission Products

TRISOUtils calculates the kernel solid fission product yields for silver (Ag), cesium (Cs), strontium (Sr) and the gaseous products krypton (Kr) and xenon (Xe) together, through the correlations below.

Validity Range

Burnup: assumed valid at all burnups.

U enrichment: assumed valid at all enrichments.

Silver

Cesium

Strontium

Krypton and Xenon

where (atoms/fission) is the fission yield, (%FIMA) is the burnup, and (%) is the U enrichment. Miller et al. (2018).

The krypton and xenon yield is used in UCOFGR.

References

  1. G.K. Miller, D.A. Petti, J.T. Maki, D.L. Knudson, and W.F. Skerjanc. PARFUME Theory and Model Basis Report. Report INL/EXT-08-14497 (Rev.1), Idaho National Laboratory, September 2018.[BibTeX]