Thermalhydraulic phenomena and code requirements for future reactor safety analysis

An evaluation is made in the present paper of the thermalhydraulic aspects retained of importance for the safety assessment of the new generation of power plants. The Westinghouse AP-600 and the General Electric SBWR concepts are taken as reference. Experimental results obtained in the frame of PIPER-ONE research that are specifically addressed at the simulation of components and systems of the mentioned reactors are summarized together with the results of the application of Relap5/mod2 and mod3 codes to the prediction of accident scenarios in AP-600 and SBWR. On this basis a list of thermalhydraulic phenomena that are peculiar for the new generation reactors is obtained and conclusions are drawn in relation to the acceptability of current codes and to the transient performance of the new reactor concepts. (author)