Effectiveness of radial flow on rewetting of AHWR fuel cluster

Rewetting of a hot surface is the process of establishing direct liquid contact with a large portion of the surface whose initial temperature exceeds that required to maintain film boiling for prescribed surface and flow conditions. The Advanced Heavy water Reactor (AHWR) is a natural circulation vertical pressure tube type boiling light water cooled and heavy water moderated reactor. In case of a loss of coolant accident, the clad surface temperature goes up very high and comes down due to coolant injection from the Emergency Core Coolant System (ECCS). The rewetting takes place in Boiling Water Reactors (BWR) due to top flooding and Pressurised Water Reactors (PWR) due to bottom flooding. But in AHWR, the emergency coolant enters into the reactor core in radial direction and after this, cross flow phenomenon takes place from one fuel pin ring to next. The study is being carried out on the effect of cross flow on rewetting of AHWR fuel bundle. This paper will discuss the modeling of the experimental setup having pressure tube, fuel cluster, steam generator, accumulator etc and study the effect of radial flow on rewetting of fuel pins. An analysis of the model, considering with and without cross flow, has been carried out and shows that the pick fuel temperature is sensitive to cross flow. The thermal hydraulic safety analysis code Relap5/3.2 is being used for modeling of experimental setup for rewetting study.