Journal of Nuclear Science and Technology · 1989 · 10 citations · 2 references
EngineeringNuclear EngineeringPhysicsNuclear ChemistryNuclear MaterialsNuclear PhysicsDelayed Neutron BehaviorNeutron TransportNeutron Transport TheoryNuclear Fuel MaterialsNuclear Waste FormsSpent Fuel BehaviorDelayed Neutron KineticsDelayed Neutron Precursor DynamicsDelayed Neutron Precursor KineticsDelayed Neutron PrecursorsDiffusional EffectsPellet FuelingPrecursor TransportRelease Kinetics Characterization
The release behavior of delayed neutron (DN) precursors from the breached fuel was analyzed, based on the diffusional release model. In this analysis, spherical co-ordinate simple approach as well as two-dimensional finite element method were used for the predomiant DN precursor 137I. It was shown that the fuel sodium reaction product (FSRP) layer at the pellet outer surface provided a predominant role for the accelerated release of DN precursors. The macroscopic diffusion coefficient for DN precursors in the FSRP layer was estimated to be 10−9 to 10−10 m2/s, which is greater than that in unreacted fuel by more than about 106. It was demonstrated that the DN signal response correlated to the growth of the FSRP layer, and did not depend on temperature change of interior fuel itself.
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