Researchers suggest a new type of safety barrier for nuclear reactors, which could have prevented the disasters at Chernobyl and Fukushima, could reduce the probability of core melt to that of a large meteorite hitting the site.
Following the most notorious accidents in the history of nuclear energy at Three Mile Island (1979), Chernobyl (1986) and Fukushima (2011), which all turned into devastating disasters due to meltdown in the core of a reactor and in turn leading to the release of radiation into the environment, many countries around the world pledged to a nuclear power phase-out.
However, many of the alternative energy sources currently in operation, such as oil and coal plants, have major drawbacks. They rely mainly on non-renewable resources and produce significantly less energy than nuclear power plants. Furthermore, they are considered to be amongst the main contributors of carbon emissions and, thereby, the climate crisis which humanity aims to battle.
Now researchers Francesco D’Auria (University of Pisa, Italy), Nenad Debrecin (University of Zagreb, Croatia) and Horst Glaeser (Global Research for Safety, Germany) have argued that a future powered by nuclear energy might be neither a lost cause nor a game of ‘Russian roulette’.
In a recent paper, published in the journal Nuclear Energy and Technology and the result of 30-40 years of collaboration, the researchers have proposed a new safety barrier to be implemented in large Light Water Reactors around the world.
Coming at a fraction of the cost of the already obsolete one that it would replace, this barrier is expected to reduce the probability of a core melt to that of a large meteorite hitting the site, the researchers say.
In December 2017, the ‘Chernobyl liquidators’ monument by Andrei Kovalchuk was ceremonially unveiled on Poklonnaya Hill in Moscow’s Victory Park to pay tribute to the people who took part in the clean-up operations after the explosion at the Chernobyl nuclear power plant on April 26, 1986.
With their new technological solution, these scientists aim to bring together research findings from the last few decades, mostly in relation to accident analysis capabilities and nuclear fuel material performance, as well as the concepts of the very pioneers who developed the nuclear technology in the past century.
Furthermore, the team hope to restore public confidence in nuclear power – an efficient and sustainable source of renewable energy, they say – as well as bridging the gaping chasm between what society has learned about nuclear energy over the years, the technology, and what is being implemented in practice.
Among the up-to-date research findings and knowledge to be implemented in the novel technological solution are the recently discovered nuclear fuel structural weakness, as well as a more elaborate Extended Safety Margin Detection (E-SMD), which allows for an emergency shutdown of a reactor, following even low and very low probability events. It also provides advance information to the operators about the actions needed to prevent or mitigate possible damage.
The recruitment of an Emergency Rescue Team (ERT) has also been proposed in the paper, which will consist of a group of highly trained and specialised rescuers who will be in possession of suitable machinery and equipment. Each ERT individual will also have access to each nuclear reactor installed within an assigned geographic region and who will be able to reach any of the sites within an hour or execute a remote shutdown of the reactor.
In the study, the researchers go on to explain how and why these exact features would have prevented core melt and the eventual nuclear disasters at each of the three notorious nuclear power stations.
The Three Mile Island accident – the most devastating accident in US commercial nuclear power plant history – was considered to be the result of a rather typical combined failure. The team suggested than an alarm from E-SMD detectors would have triggered the emergency shutdown of the unit well before the event.
In the case of Chernobyl, where critical human errors are found to have led to the accident, the team said an intervention from the ERT, a remotely controlled shutdown and perhaps the deployment of the military would have prevented the consequent catastrophe.
Finally, at Fukushima, the extended core damage at the plant’s units 1 to 3 would have also been prevented thanks to the combination of emergency alerts and prompt action by the ERT, the scientists explained.
The researchers also note that, in spite of the notoriety of the three nuclear disasters, there have been approximately 500 safely operated nuclear power plant units since the demonstration of the capability to control the fission reaction in 1942 and the connection of a nuclear fission-driven electricity generator to the electrical grid in 1954.
Furthermore, the researchers point out that there have been a few thousand accident-free reactors used for purposes different from electricity production, including research, production, and marine propulsion.
“The industry and/or the Government of responsible countries where applicable, become the main players for the possible implementation of the ideas in this paper,” the scientists write in conclusion. “A strategy is needed in this connection: academia and research institutes willing to be engaged in practical applications of nuclear technology should become actors.”
Regarding the Fukushima disaster of 2011, it was reported in September 2019 that Japan will be ramping up its nuclear-decommissioning programme following this event, with its Government calling on plants to plan ahead in order to lower costs and reduce safety risks.
Source: E&T Magazine