Simulation of the loss of coolant accidents in PWR by ROSA-2 experiment

The project of ROSA experiments was initiated in 1970 at JAERI to study the behavior of the primary loops of LWRs in the loss of coolant accidents (LOCA). ROSA-2 experiment, which is the second series of the project, is specially designed to simulate the LOCA behavior of a PWR, and is now at the final stage. This report presents the outline of the ROSA-2 experiment placing special emphasis on the results of various experimental observations obtained so far. The first section discusses the implication and the limitations of the ROSA-2 experiment. Verification of the LOCA analysis code is the primary objective. The second section describes the details of the test facility and the key parameters chosen for the series of tests. The third section is devoted to the description of the main results of the tests and to the discussion on the correlation of the analysis with the behavior of real PWR plants. Contents of this section are as follows: (1) reproducibility of the phenomena, (2) physical phenomena associated with LOCA, namely; depressurization effect due to vapor or void condensation; release of accumulated heat from the wall of a pressure vessel and a steam generator; steam-water two-phase counter flow, (3) predictability of LOCA phenomena using the analysis code, such as RELAP-3. Many reference literatures containing more detailed experimental results are also listed. (Aoki, K