Verification of adjoint-weighted tally calculation capability in MCS

Abstract

A Monte Carlo method developed by B. C. Kiedrowski, performs adjoint-weighted tallies in continuous energy k-eigenvalue calculations. Each tally contribution, Tp, is weighted by estimating the iterated fission probability, Rp, which is proportional to the adjoint function having the progenitor index, p, in the asymptotic generation at the phase space, r. There is no need for any additional random walk, which means there is only small amount of increase in the computation time. The adjoint weighted tallies are used to calculate adjoint-weighted flux and point reactor kinetics parameters, such as the effective delayed neutron fraction, βeff, and the prompt neutron generation time, A. This Monte Carlo method tallying adjoint-weighted parameters is implemented in MCS which is an in-house Monte Carlo code that has been developed at UNIST. The multi-energy group test problems are used to verify the adjoint-weighted tally calculation capability in MCS, and the results are compared with the result from the Monte Carlo N-Particle (MCNP). The continuous energy test problems are also used to verify the adjoint-weighted tally calculation capability, and the results are compared with the results from the McCARD. The comparison shows good agreement between MCS and the results from the other codes.