Freon 113 Blowdown test results and comparison with FRELAP 113 predictions.

A description of a transparent test rig operation at low pressures with Freon 113 as the working fluid is given. Typical experimental characteristics are presented from blowdown tests carried out on the rig, the depressurisation being effected by a blow-off from the vapour space of a liquid/vapour drum. The full test programme covered a range of blow-off rates, initial circulation rates in the rig, pressures, and heat inputs to an electrical furnace. The experimental characteristics were compared with the predictions of FRELAP 113 (a modification of the RELAP 4 Mod 3 compuer code to operate with FREON 113) but poor agreement was obtained, this being attributed to the deficieincy of the RELAP code in not allowing for thermal non-equilibrium effects. No reverse type flow was experienced in any of the Freon blowdown tests and this fact enabled further comment to be made in respect of a previous comparison between RELAP 4 and the results from a high pressure steam/water test rig of a similar layout. (A)