Development of the Assembly-Level Monte Carlo Neutron Transport Code M3C for Reactor Physics Calculations

The general geometry continuous-energy Monte Carlo code M3C is currently under development at the Bhabha Atomic Research Centre for reactor physics calculations. The development of the Monte Carlo code M3C for reactor design entails the use of continuous-energy nuclear data and Monte Carlo simulations for each of the neutron interaction processes. This paper describes the current status of the development of the code. The performance and accuracy of the code in application to a variety of problems have been investigated. The important features of this code are treatment of heterogeneous lattices by general geometry, use of point cross sections along with unionized energy grid approach, thermal scattering model for low-energy treatment, probability table treatment in unresolved resonance range, and capability of handling the microscopic fuel particles (TRISO) dispersed randomly, which is very useful in modeling high temperature gas-cooled reactor fuels. Apart from all of the important features in any Monte Carlo code available worldwide, the M3C code has an advanced capability to handle the geometry, which is not described by mathematical equations but only represented by the geometrical points. The code has been validated for its accuracy against a large number of sample problems covering a wide range from simple (like spherical) to complex geometry (like pressurized heavy water reactor lattice) and including randomly dispersed TRISO fuel particle systems. The code is presently restricted to assembly-level calculations.