Implementing a test facility in reduced scale for analysis of boron dispersion in a pressurizer of an integral compact and modular reactor

Small Modular Reactors, SMRs, are variants of compact modular reactors of generation III+ that present attractive features such as simplicity, enhanced safety and are economically competitive. In an iPWR (integral pressurized water reactor), the pressurizer is located at the top of the reactor vessel; this configuration requires the investigation of the mechanisms adopted for the homogenization of boron. The present work shows the contributions to the design of an experimental installation proposed to provide relevant data to study the boron homogenization phenomena in a pressurizer of an SMR. For this, an experimental installation was built with a test section made of stainless steel with a volumetric scale equal to 1:200, representing one-fourth of the pressurizer of an iPWR. The experimental installation has a test section, a heat exchanger, two pumps, five flow meters and three stainless steel tanks with capacities of 0.143, 0.069 and 0.216 m3. The test facility layout was mounted so that the test section was fed with water or saline solutions with different concentrations, representing scenarios of boration or deboration. To determine the concentration at the inlet and outlet of the test section, samples have been collected every 10 min during the experiments representing some scenarios (boration/deboration). The electrical conductivity of these samples was determined by a conductivity meter and converted to the concentration of the tracer element (NaCl) used. Three representative experiments were conducted and it was possible to prove the viability of using the experimental setup in a reliable form, for the range of values occurring in the boron homogenization phenomenon in a pressurizer of a compact modular reactor.