Ricerc@Sapienza

In the framework of the Horizon 2020 SESAME project (thermal hydraulics Simulations and Experiments for the Safety Assessment of MEtal cooled reactors), the CIRCE pool facility has been refurbished by ENEA to host HERO test section (Heavy liquid mEtal pRessurized water cOoled tubes) with the aim to test an innovative concept of the steam generator bayonet tubes proposed for ALFRED (Advanced Lead Fast Reactor European Demonstrator) and to provide experimental data for code validation.

A numerical activity, aimed to evaluate the capability of RELAP5-3D© to reproduce the main thermal-hydraulic phenomena in an HLM pool-type facility, in different operative conditions, is presented. For this purpose, the experimental campaign performed in CIRCE-ICE test facility has been selected for the code assessment.

The best estimate plus uncertainty (BEPU) method plays a key role in the development of the innovative Generation IV nuclear reactors, for the improvement of knowledge and the good evaluation of the safety margins for new phenomena. The aim of this paper is to validate an uncertainty quantification (UQ) approach using RAVEN code. RAVEN, developed at the Idaho National Laboratory, is a multipurpose probabilistic and uncertainty quantification framework, capable to communicate with any system code, implemented with an integrated validation methodology involving several different metrics.

Transient analyses in a water-cooled fusion DEMO (Demonstration Power Plant) reactor have been performed to support the WCLL (Water-Cooled Lithium Lead) breeding blanket design. In this framework, the Design Basis Accident (DBA) analysis of an in-box LOCA has been carried out. The WCLL breeding blanket concept relies on Lithium Lead (LiPb) as breeder, neutron multiplier and tritium carrier, which is cooled by water at 15.5 MPa with an inlet temperature of 295 °C and an outlet temperature of 328 °C.

Some considerations to preliminarily design the size of the Expansion Volume (EV) and the relief pipes for a Vacuum Vessel Pressure Suppression System, to be adopted in a fusion reactor based on a helium cooled blanket, are presented. The volume of the EV depends on the total energy of the cooling system and it can be sized based on a required final pressure at equilibrium, by a simple energy balance. Two different EV solutions have been analysed: a “dry” EV and a “wet” EV.