New Transistor Material as Game-Changer for Nuclear Industry
Researchers from the Oak Ridge National Laboratory revealed that gallium nitride semiconductors can successfully withstand severe conditions of nuclear core. This discovery will allow to place electronic components in severe conditions to guarantee more accurate and trustworthy indicators of sensors.
Sensors in the core are used to collect information from the reactor and can reveal potential failures of equipment before their occurrence. The higher the accuracy of a sensor, the more possible it is to envisage failure and prevent unscheduled shut down of a nuclear facility. Complex systems to which sensors are connected shall be placed as far as possible from the core for electronics not to suffer from heat and radiation impact. However, long cables transmitting data from sensors can absorb additional noises and worsen signal introducing an error to data.
Gallium nitride may solve this problem, because it is a wide-bandgap (can work with higher temperatures, stresses and frequencies) semiconductor that is more affordable and resistant to irradiation rates than silicon. Researchers from the Oak Ridge National Laboratory tested its peculiarities and by placing gallium nitride transistors close to the core of the research reactor in the Ohio State University, where elements successfully withstood high temperature and radiation during three days in a row.
Modification of transistors was such an unexpected success, because they were able to handle at least 100 times higher accumulated dose of radiation than a standard silicon device under steady 125 degrees Celsius.
By exposing the transistors to high doses of radiation in the core during several days, the researchers concluded that gallium nitride transistors are capable of surviving at least five and more years.
In the future, the research is also applicable to improve microreactors that because they will be so compact all the operating components, including the sensors, will have to be able to function in unfavorable radiation conditions as compared to those reactors currently in operation. Along with positive aspects, testing in the Ohio University showed that the heat was more harmful for gallium nitride than radiation, so researchers work on further learning of thermal effects.