Practice of Reactivity Measurement at Central Research Institute for Physics, Budapest

At the Central Research Institute for Physics, Budapest /CRIP/ a series of critical assemblies has been built and investigated since 1960, namely: - ZR-1 and ZR-2 critical assemblies fueled by 10% enriched fuel pins /EK-lo type/ moderated and reflected by light water. Both assemblies had a highly variable lattice pitch. - ZE-3 system fueled by 36% enriched hexagonal-tubular fuel-assemblies /WWR-M type/ moderated by light water and reflected by Be. - ZR-4 solid homogeneous zero-power reactor fueled by 20 % enriched U₃O₈ dispersed in polyethylene/ and reflected by graphite. When investigating these systems the following methods have been chosen and applied routine for reactivity measurements