Evaluation of reactor kinetic parameters without the need for perturbation codes.

The analysis of research reactor transients depends on the effective delayed neutron fraction (k{sub eff}), its family-dependent components ({beta}{sub eff,i}), the prompt neutron lifetime (l{sub p}), and the decay constants ({lambda}{sub i}) for each delayed neutron family. Beginning with ENDF/B-V data, methods are presented for accurately calculating these kinetic parameters within the framework of diffusion theory but without the need for a perturbation code. For heavy water systems these methods can be extended to include the delayed photoneutron component of {beta}{sub eff}. However, a separate calculation is needed to estimate the fractional loss of fission product gamma rays, energetic enough to dissociate the deuteron, from leakage, energy degradation and absorption in fuel and structural materials. These methods are illustrated for a light-water Oak Ridge Research Reactor (ORR) LEU core and for a heavy-water Georgia Tech Research Reactor (GTRR) HEU core where calculated and measured values of the prompt neutron decay constant ({beta}{sub eff}/l{sub p}) are compared