Blowdown into full-pressure containment

Experimental results are presented of the blowdown of a 14 litre pressure vessel containing saturated steam/water at 10.4 and at 7 MPa into a 1.8 m3 vessel. Various condensation heat transfer schemes are used in a simple theoretical model to estimate the containment pressure transient and these estimates are then compared with experimental results. The pressure rise is generally overestimated, sometimes by very large amounts, and none of the schemes normally used in reactor safety calculations take into account all the effects likely to arise from differing initial conditions. A simple modification to an existing scheme gives a better estimate under the experimental conditions so far investigated. (author)