Comparison of models for analysis of blowdown tests

A blowdown test facility was established in 1965 to obtain information on the blowdown phenomena associated with a loss-of-coolant accident in water-cooled power reactors. Parametric blowdown tests were performed to evaluate the influence of rupture size, rupture location, initial coolant temperature and system pressure on the rate of change of void fraction in the system following the accident. This paper analyzes results obtained from experiments on ruptures occurring in the steam line and in the recirculation line. A discussion is given on the validity of the proposed models, making use of the BABLO code developed by the author and of the RELAP-2 code by U.S. AEC.The major results obtained are:(1) For the case of the steam-line rupture, substantiation of the validity of the homogeneous model for evaluation of the discharge flow when the mixture level is assumed not to be related to the location of the rupture in the BABLO code.(2) For the case of the recirculation line rupture, proof of the validity of the bubble separation model used in the RELAP-2 code for evaluation of the quality of discharge flow.