Results of a Neutronic Simulation of HTR-Proteus Core 4.2 using PEBBED and other INL Reactor Physics Tools: FY-09 Report

Abstract

The Idaho National Laboratory's deterministic neutronics analysis codes and methods were applied to the computation of the core multiplication factor of the HTR-Proteus pebble bed reactor critical facility. A combination of unit cell calculations (COMBINE-PEBDAN), 1-D discrete ordinates transport (SCAMP), and nodal diffusion calculations (PEBBED) were employed to yield k eff and flux profiles. Preliminary results indicate that these tools, as currently configured and used, do not yield satisfactory estimates of k eff . If control rods are not modeled, these methods can deliver much better agreement with experimental core eigenvalues, which suggests that development efforts should focus on modeling control rod and other absorber regions. Under some assumptions and in 1-D subcore analyses, diffusion theory agrees well with transport. This suggests that developments in specific areas can produce a viable core simulation approach.