Research in boiling crisis in WWER-1000 fuel assemblies

The measurement of critical heat flows on models of fuel assemblies of WWER-1000 reactors was made on the ZES SKODA large water loop. Maximum parameters of the loop are given and the technological part of the loop is described. The experiments were made on two types of bundles. Bundle A consisted of 7 rods with even heat generation and bundle B of 7 rods with cosine heat generation. The critical heat flows were measured in the pressure range 16 - 18 MPa and at mass flow rates of 2400 - 3800 kg/m2.s. Inlet temperatures were 300 - 310 degC. All measurements were performed in the saturated nucleate boiling range. The measured values were compared with the OKB GIDROPRESS correlation for calculating WWER-1000 reactor cores. (E.S.)