Solution of PHWR 3D kinetics benchmark using TRIKIN code

Highlights: •This paper describes space-time kinetics formulation for transient analysis of Pressurized Heavy Water Reactors. •Improved Quasistatic (IQS) approximation has been used for factorization of neutron fluxes. •3D kinetics Benchmark problem (AECL-7236) of PHWR has been analyzed. •Obtained TRIKIN results are in good agreement with benchmark solution, demonstrating space-time capability of code for PHWRs. -- Abstract: Scaling up of core sizes beyond present generation has rendered renewed topicality to space-time kinetics and relevant safety research. Detailed computational codes to solve transient neutron diffusion equation for the highest level of approximation including core thermal as well as system feedbacks are being established worldwide. Consistent with this objective a general purpose 3D kinetics code 'TRIKIN' has been developed in the Atomic Energy Regulatory Board (AERB) and the Indian Institute of Technology Bombay, India to carry out transient analysis for a variety of power reactors. Code has been validated against a series of international benchmark problems for light water reactors. This paper presents an extension of the validation array of the TRIKIN code by solving a 3D kinetics PHWR benchmark problem (AECL-7236). A brief overview of space time kinetics methods is presented. Detailed numerical scheme of improved quasistatic (IQS) method to solve transient neutron diffusion equations, adopted in TRIKIN code has been described. Description of 3D kinetics PHWR benchmark problem and its solution using TRIKIN code has been presented. TRIKIN results have shown good agreement with benchmarks results, demonstrating excellent space-time kinetics capability of the code for PHWR type reactors.