Nuclear Power plant 311 AP.
(photo credit: AP [illustrative])
A team of researchers at Ben-Gurion University of the Negev has discovered ways to increase the safety of next-generation nuclear power plants.
“The Chernobyl and Fukushima Daichii accidents raised awareness and put the issue of severe core accidents – SCA – on the scientific agenda,” said Dr. Gilad Erez from the Unit of Nuclear Engineering in the Faculty of Sciences. “But researching methods to reduce the risk of a nuclear emergency are difficult because neutronic experiments related to SCA would have to involve a critical core undergoing meltdown at 3,000°C, making the experiments impractical to perform.”
Now, with Erez’s research, done in cooperation with Dr. Patrick Blaise of France’s Alternative Energies and Atomic Energy Commission, the nuclear-fission chain reaction in Generation IV – the newest type of nuclear reactor – can be studied. Such a chain reaction during severe accidents and core meltdown in Gen-IV reactors occurs at a temperature of more than 2,500°C.
Erez told The Jerusalem Post that in general, Gen-IV reactors are much safer than the current generation of reactors. However, how they will react in the event of an accident is not yet completely understood.
Inside the reactor core there is a chain reaction of nuclear fissions.
“Neutrons are flying around inside the reactor core, and once they hit a fissionable nuclei, they split it into two,” Erez explained. “The nuclear fission converts to energy, which can be used to generate electricity but also to get additional neutrons. These neutrons are now flying inside the reactor core and they can fission additional nuclei or fissionable material, such as uranium.”
During a severe accident, the core gets too hot, and can undergo a meltdown and convert into a liquid, which is very dangerous.
“If the core melts, the nucleus fission chain reaction can diverge and we can end up in a situation where we lose control over the chain reaction,” said Erez. “It diverges very quickly.
“It is not a bomb, but it is very similar,” he continued. “These are situations we want to avoid.”
Until now, studying such situations was not practical because of their danger. Erez and Blaise have found a way to study the nuclear-fission chain reaction in research reactors, which are smaller and safer than Gen-IV reactors.
This research will grow in importance in the coming years as the current fleet of nuclear reactors ages, eventually failing to meet safety requirements. Furthermore, with worldwide energy consumption expected to continue growing even as the international community attempts to limit carbon emissions, nuclear power is likely to play an increasingly prominent role in the coming decade, as world powers attempt to ensure a reliable supply of energy to a growing population without endangering the environment.
Erez said this research, which was published as the cover story of the International Journal of Energy Research, will allow modern nuclear plants to generate energy but be able to better detect, mitigate and prevent severe accidents in Gen-IV reactors.
Erez added: “That is a big step towards the ultimate goal of studying severe core accidents on a full-core scale.”