Adjoint-weighting for critical systems with continuous energy Monte Carlo

Traditionally, Monte Carlo radiation transport codes have been unable to tally adjoint-weighted quantities in a robust and consistent way. A new framework based on the iterated fission probability interpretation of the adjoint flux is developed that solves this problem at minimal increase in CPU time. A derivation of adjoint-weighted tallies is presented along with a methodology for computing adjoint-weighted reactor kinetics parameters and first-order reactivity perturbations. Details are given for the implementation in the production MCNP code. The calculations are benchmarked to both experimental measurements and calculations with the discrete ordinates code, Partisn. (authors)