Epithermal neutron spectrum filtering experiment design at the VENUS-F zero power fast reactor

VENUS-F is the fast spectrum zero power research reactor operated at SCK CEN. It serves the purpose of code and nuclear data validation in support of fast reactor design. It is therefore crucial to have a well understood and as validated as possible model, capable of reproducing the experimental results as much as possible. In the past decade, several experimental campaigns were performed to measure integral reactor parameters at VENUS-F, showing several disagreements of the model results with the experiments due to insufficient knowledge of nuclear data or inadequate modelling of either the materials or the interfaces. The CoRREx experiment is proposed to relate those discrepancies to a number of energy ranges via boron filtering of the neutron spectrum. This work shows the preliminary design of the CoRREx experiment and the rationale guiding the choice of the filtering material and of the filter thickness. The results of the study were also fitted based on a relation derived on a simplified model to ease the filter thickness adjustment.