Development and validation of a code which couples Monte-Carlo neutron simulations to nuclide transmutation for the computation of irregularly-operated research reactors

Soreq Nuclear Research Center (SNRC) is currently participating in the IAEA CRP T12029 on ''Benchmarks of computational tools against experimental data on fuel burnup and material activation for utilization, operation and safety analysis of research reactors''. Within this framework, a wrapper code was developed in PYTHON to couple MCNP (Monte-Carlo N Particle) and DRAGON's depletion module , using the WLUP (WIMS Library Update Project, 2005) depletion chains with 69 energy-group cross-sections.The development process followed a methodology that was based on validation of results against both numerical simulations as well as experimental data, starting from the IAEA MTR theoretical model (10MW, U-Al HEU MTR) and continuing to actual experimental data and computational simulations of the Ohio-State University Research Reactor (OSURR, 0.5 MW, LEU U3Si2 MTR) . The validation process included the comparison of the multiplication factors, power distribution, the depletion/creation of the main nuclides and the reactivity worth of control and regulating rods. An important feature of the code is the use of several depletion zones in each rod, which is expected to improve the accuracy of the core description and will allow the comparison against gamma spectroscopy experiments of fuel rods in IRR1, which show axial distribution of the fuel depletion