Onset of boiling of chemically reacting nitrogen dioxide in a vessel volume under the vessel emergency depressurization conditions

The results of an experimental study of nitrogen dioxide at the onset of boiling during blowdown from depressurized vessel at P0 ranged from 0.4 to 8.0 MPa are presented. An experimental set-up and procedure are described. The effect of overheating in the vessel vapour plenum under the onset of nitrogen dioxide boiling during as well as the effect of flow blockage under the coolant blowdown through the break opening of 4x10-3 m diameter are considered. The unsteady heat transfer between a vessel wall and coolant has been investigated. The findings obtained are generalized and the approximation functions are given to calculate a non-stationary flow rate, the residual mass of fluid in the vessel and wall-to-medium heat fluxes under blowdown. The data obtained can be used to calculate emergency conditions and safety systems for plants using chemically reacting nitrogen dioxide