New High Fidelity Multi physics FEM based Code to Simulate the Boron Hide out within CRUD Layer
During the long term high power operation of nuclear power plant, axial offset of power distribution has occurred. CRUD, Chalk River Unidentified Deposit or Corrosion Related Unidentified Deposit, was observed in that situation on the surface of fuel rods, and boron hideout has been suggested as one of the reason for the axial shift [1,2] The lithium history in reactor coolant system during reactor operation is one of the proof for boron hideout [2] However, for the validation of these phenomena, more basic analysis should be conducted, as experimentally and computationally. Experimental validation for the CRUD and boron hideout is extremely hard to conduct because the boron hideout will occur at only high temperature and pressure condition with requirement of real time measurement. Computational validation can easily solve these amount of boron hideout, so modeling approach is necessary. New 2D macro scale model for solving multi physics within the CRUD layer, to predict the amount of boron hideout was developed. Finite element method (FEM) was used by using PETSc and LibMesh libraries. Heat transfer, capillary flow, solute transport and chemistry within the CRUD layer were calculated. Full core simulation system with parallel calculation was constructed with C+ language.