Grant: NSERC/NRCan/AECL Generation IV Energy Technologies Program

Nuclear power is an attractive energy source in today's society where concern for control of environmental emissions and greenhouse gases is increasing and the expected taxes to be levied on carbon emissions are becoming a reality. The possibility of making our nuclear power plants more efficient and multipurpose to help alleviate these environmental concerns has been gaining much attention and is the focus of the Generation IV International Forum (GIF), an international treaty signed by 13 countries, including Canada, to investigate future nuclear reactor designs. One of the reactor technologies of interest to the GIF is the supercritical water reactor (SCWR). This reactor would use supercritical water (water whose temperature and pressure are above its critical point, 371 degC and 22.1 MPa respectively) to remove the heat from the reactor core and is a logical evolution of current reactor designs. Canada is particularly interested in this design since the pressure-tube configuration of the CANDU reactor is well suited for operation in supercritical conditions. The use of supercritical water to cool the reactor has many benefits including no phase separation (boiling will not occur above the critical point) and higher thermodynamic efficiency of the power cycle due to the much higher temperatures employed (up to 625 degC). For the same net power output as current reactors, the higher efficiencies in a SCWR would result in a smaller reactor that is less costly to build and consumes less fuel thereby reducing used fuel production. The selection of materials that can be used to construct a SCWR is one of the key research areas required before a design can be implemented. This research program will investigate the corrosion and stress-corrosion cracking of alloys that may be considered for use in a SCWR and the subsequent transport and deposition of their corrosion products. A test loop has been built at UNB to simulate the expected operating conditions in a SCWR and will be used to expose candidate materials, coatings or new alloys to a supercritical water environment and evaluate their suitability for use in a SCWR.