Detailed multi-physics modelling of nuclear power plants has become a necessity in the era of best-estimate analysis. For a number of transients with strong coupling between the neutronics in the reactor core and the fluid-dynamics in the primary circuit and overall heat transfer, it is required to carry out coupled system thermal hydraulics and core 3D neutronics analysis. Point kinetics approach in the system thermal-hydraulics code RELAP5 limits its use for many reactivity-induced transients, which involve asymmetric core behavior. In a recent development, a simplified multipoint kinetics model has been coupled with system thermal-hydraulics code RELAP5 to circumvent its inadequacy for the analysis of reactivity-induced transients involving asymmetric core behaviour. The objective of the present paper is to validate the simplified multi-point kinetics model against an asymmetric fast transient benchmark problem in a large power reactor. Time step and nodalization sensitivity studies have been performed. It is demonstrated that the multipoint kinetics model results are in good agreement with the benchmark, advocating its applicability.