Cooldown Study of TVS-2M Model FA with Reflooding

An experimental study was performed of the influence of mixing intensifier-grids on the cooling of a 37-rod electrically heated TVS-2M model with top and bottom reflooding. It is shown that the mixing grids bring about a very small reduction of the maximum temperature of the rods and longer cooling time of the assembly. To cool the TVS-2M model, the starting temperature of the fuel-rod simulators and the power input can be significantly lower in top reflooding than in bottom reflooding. The effect of the flooding rate is similar to that observed in bottom flooding – as the flooding rate increases, the maximum temperature of the rods and the cooling time of the assembly decrease. The experiments showed that with reflooding the mixing grids do not greatly affect the cooling efficiency of TVS-2M.