In this work, we describe a new method for parallelizing the source iterations in a Monte Carlo criticality calculation. Instead of having one global fission bank that needs to be synchronized as is traditionally done, our method has each processor keep track of a local fission bank while still preserving reproducibility. In doing so, it is required to send only a limited set of fission bank si...

Nuclear transmutation has been reported by lots of experiments. The features of this phenomenon are the production of elements which shows fission-like distribution and their anomalous isotopic ratios or the selective Z and mass changes [1]. To analyze this phenomenon, the selective channel scission (SCS) model has been proposed and improved [2]. The SCS model is powerful and can predict the fi...

Based on general arguments presented in this report, nuclear criticality was eliminated from performance assessment calculations for the Waste Isolation Pilot Plant (WIPP), a repository for waste contaminated with transuranic (TRU) radioisotopes, located in southeastern New Mexico. At the WIPP, the probability of criticality within the repository is low because mechanisms to concentrate the fis...

The interest in interplanetary space travel has stimulated much discussion on the desirability of using nuclear, rather than chemical, energy for the spacecraft propulsion. Comparisons of the relative merits of various propulsion systems have been extensively discussed in the literature. The results of such studies yield a diversity of conclusions, depending on the assumptions which are made in...

We present a summary of the actinide-plus-fission-product burnup credit criticality safety licensing analysis for Expansion Stage 2 (ES2) external spent fuel pool at Gösgen nuclear power plant. In ES2, nine 1 storage racks currently installed in are going to be supplemented by ES2 with significantly reduced assembly pitch. They designed loadings assemblies above well-defined minimum required bu...

Six advanced reactor concepts have been selected for Generation-IV reactors and are being investigated worldwide to meet the challenging goals of effective resource utilization and waste minimization (sustainability), improved safety, enhanced proliferation resistance, and reduced system cost. [1] The six systems are very high temperature reactor (VHTR), sodium-cooled fast reactor (SFR), superc...

In reactor calculations, a detailed 3-D power density distribution is required for core optimization studies and safety analyses. The general Monte Carlo based neutral particle transport tool, MCNP [1], has the capability to obtain detailed power density distribution in a reactor through its criticality calculation mode (KCODE mode). However, there is no standard tally type in MCNP that is able...