Estimation of measured control rod worths in fast breeder test reactor - Effect of different delayed neutron parameters

Control rod worths have been measured by the inverse kinetics method in the small PuC-UC core of the Fast Breeder Test Reactor at Kalpakkam. Delayed neutron fractional yields based on Tuttle's data, ENDF/B-VI data, and the full summation approach of Brady and England have been used to get measured control rod worths. Unreasonably large reductions in control rod worths are obtained by the ENDF/B-VI data. It is suspected that the procedure, of normalizing fractional yields obtained by the summation approach to earlier evaluated total yields, is inconsistent.