Development of Experimental and Modelling Capabilities and Tools at Canadian Nuclear Laboratories for Investigations on Inherent and Passive Safety Designs of Advanced Reactor Concepts

A robust technical programme that supports the research, development, and licensing activities underpins Canada's plans for deployment of small modular reactors (SMR) and support of Generation-IV reactors. Canada aims to achieve SMR deployment through the technical, environmental, economic, and policy landscapes outlined in the Canadian SMR Roadmap and Canadian SMR Action Plan. CNL has proactively pursued research activities to support a broad technical programme. One research focus is the development of experimental and modelling capabilities to enable the assessment of passive and inherent safety systems for decay heat removal in postulated accident scenarios. The capabilities developed are pertinent to reactor cavity cooling systems, reactor vessel auxiliary cooling systems, direct reactor auxiliary cooling systems, and heat pipes, which are featured in various SMR designs. Particular capabilities being developed pertain to natural convection heat removal with molten salts as the working fluid, including investigations with self-heating fluids that simulate fuel salts. Likewise, heat removal with heat pipes, interactions and inherent instabilities of coupled natural circulation loops, and the effectiveness of radiation heat transfer from graphite samples are technical areas of interest. In addition, the instrumentation technologies investigated for such systems often involve novel challenges due to chemical, thermal, or flow environments. The effect of intrusive instrumentation on low-flow measurements is explored via combinations of intrusive and non-intrusive measurement techniques. The progress and outcomes to date of several capabilities being pursued are described in the paper.