Sensors & transducers


Nuclear applications


Safety is a top priority for nuclear applications in power plants. CO2-cooled reactors are inherently safer than water-cooled reactors, but it is essential


to prevent, detect, and repair CO2 leaks to maintain safe operation. Infrared sensors from Edinburgh Sensors provide the ideal leak detection


solution for nuclear research and nuclear power plants N


uclear power stations convert energy stored in nuclear fuels such as uranium or plutonium into electricity. Energy is


released using nuclear fission reactions; neutrons are fired at nuclear fuel rods to form excited nuclei that split into smaller nuclei, free neutrons, heat, and radiation. The heat is then moved away from the nuclear reaction core to generators, producing electricity. Nuclear power plants provide several advantages compared to fossil fuel plants including low carbon electricity generation. Small amounts of nuclear fuel provide large amounts of electricity, so nuclear power generation is often more cost effective and reduces fuel mining impacts compared with fossil fuels.


SafEty Of nuClEar pOwEr IS a majOr COnCErn Catastrophic large-scale nuclear applications accidents in Chernobyl and Fukushima have resulted in widespread public fear of nuclear power generation. However, modern plant design processes emphasise safety; as a result, the overall risk of accidents at nuclear power


30


plants is low and continues to decline. Major nuclear accidents, like those at


Chernobyl in 1986 and Fukushima in 2011, are typically the result of a series of events involving overheating, fuel meltdowns, and explosions, resulting in the release of large amounts of radioactive material into the environment. Neutrons released during nuclear fission initiate a chain reaction that generates a large amount of heat and controlling the chain reaction is vital. There are many different nuclear power plant designs currently in operation, with varying ways to control nuclear fission chain reactions. Some reactors rely on water as the primary coolant,


while others use gases such as CO2 or helium, molten metals or molten salts.


watEr COOlIng InCrEaSES thE rISk Of ExplOSIOnS While water cooling provides high power density and therefore excellent thermal efficiency, systems that use water as the primary coolant have several drawbacks, including the risk of explosions during meltdown events. If there is a power cut and the system’s water


pumps fail, the fuel rods can reach very high temperatures, at which point water splits, producing explosive hydrogen and oxygen gas. This possibility was demonstrated in 2011 when an earthquake and tsunami in Japan led to a power outage at the Fukushima nuclear plant, removing power from the cooling systems, resulting in overheating of the fuel reactors, which were flooded with water and led to explosions that released large amounts of radioactive material into the environment.


CO2 prOvIdES SafEr COOlIng than watEr


Using CO2 as the primary coolant in a nuclear reactor is inherently safer than using water, as


CO2 is less reactive and does not pose a risk of exploding. CO2 is also more flexible in terms of operating temperatures and pressures, resulting


in a more stable system that responds more slowly to catastrophic faults than water-cooled


reactors. However, reactors that use CO2 coolants have lower power densities than water- cooled reactors, resulting in larger reactors and reduced efficiencies.


February 2019 Instrumentation Monthly


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