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A semianalytical nonlinear model is described for the calculation of the burst release and release rate of volatile fission product (VFP) from a fuel pellet under steady-state and transient reactor conditions as well as the radial density distribution in the open porosity. The density of the VFP in the porosity channels is assumed to depend on three functions, one of which is an analytical function of parameters characterising the physics and the geometry of the pellet, another rigorously satisfies the required boundary conditions, and the last is the solution of a highly nonlinear differential equation for a time function ("kinetic time") that represents the evolution of the density profile. The constant multiplier for the latter function is suitably calculated with the zeros of the Bessel function J(0)(x). The density c(r,t) of the VFP in the open porosity of the pellet is used to find the pressure p(r,t) in the open pores. The integration procedure of the transport equation for different initial and boundary conditions is described. Calculation experiments are presented and discussed.

Additional information

Authors: SYROS C, University of Patras, Laboratory of Nuclear Technology, Patras (GR);RONCHI C, JRC Karlsruhe (DE);SPANO C, JRC Karlsruhe (DE)
Bibliographic Reference: Article: Nuclear Technology, Vol. 94 (1991) pp. 213-227
Record Number: 199111427 / Last updated on: 1994-12-02
Original language: en
Available languages: en