Effect of different cross-section data sets on reflectors of a typical material test research reactor

Studies were carried out to investigate the effects of various neutron cross-section data sets on the effectiveness of different reflector materials used in a typical MTR type research reactor by three-dimensional modeling of the reactor core using reactor simulation codes WIMS-D4 and CITATION. The use of old and newly released WIMSD libraries based on different cross-section data sets resulted in almost same effective reflector thicknesses for the same reflector materials, however, significant differences were observed in reactivity worths of some reflectors.