VVER1000/320 operational transient simulation with the CATHARE computer program

A simulation of VVER1000/320 operational transients was performed with the CATHARE2 V1.3L computer program. These transients consisted of consecutive shutdowns of two primary side pumps, prior to which, the reactor was under nominal operational condition with 72 and 52% power levels, respectively. T he comparison between calculated and measured data indicated that the progr am was able to qualitatively predict the main phenomena taking place in bot h the primary and the secondary sides of the plant. The role of pump inerti a was studied It was found that implementation of inertial pump shutdown le d to a better agreement with experiment. There was a lack of detailed infor mation on the secondary-side geometry. Thus, it was difficult to conclude w hether the quantitative discrepancy between experiment and calculation was due to the physical model or the geometric uncertainty.