Nuclear Criticality Safety
The FETCH code allows modelling of the transient behaviour of fissile solutions, with sloshing and pressure feedback. It is therefore of great use in nuclear criticality safety cases, and is here applied to fissile solutions in tanks with both continuous filling and step reactivity insertion.
FETCH is a general geometry finite element transient coupled criticality/multiphase CFD code. It has been benchmarked against CRAC, SILENE and TRACY experiments and has the unique capability (based on detailed gas/bubble modelling) to calculate pressure waves. There is more information available about FETCH...
The radiation transport sub-model treats the whole containment structure (which includes the water jacket in the case of the JCO accident and the dilute Pu simulations), while the multi-phase CFD module treats only the tank contents.
Below are animations of simulations performed using FETCH. These include:
Initial modelling of accident at JCO company
Transient behaviour of fissile Uranium solution in a drum (CRAC, SILENE and TRACY experiments)
Simulation of CRAC 43 experiment
Simulation of SILENE S1-152 experiment
Ejection of control rod with 2.0 dollar step reactivity insertion
Ejection of control rod with 2.8 dollar step reactivity insertion
Transient behaviour of fissile Plutonium solution in a tank