The nuclear power plant of the future – a hybrid?
A combination of fusion and fission may be the future of the nuclear power industry. The idea has been put forward by Professor Olov Ågren as an alternative to the fusion reactor Iter being built in France and to the new fast reactors that use nuclear waste as fuel.
The hybrid reactor is still in the concept phase, but researchers at the Division of Electricity have created a model and carefully calculated how it would work. There are several advantages, according to Olov Ågren.
‘Above all, it enhances safety. If we shut down, the supply of neutrons is stopped in a millisecond, and since the 25-meter high reactor is built vertically, cooling can be done with self-circulating molten lead.’
Another advantage is that nuclear waste from today’s nuclear power plants can be used as fuel for the fusion process. And the waste that is formed breaks down faster.
‘Today’s nuclear power plants produce waste that is radioactive for 100 000 years, but we can get this down to 500 years. The dilemma is that if fissile substances are not burned off, the waste can be used for nuclear weapons.’
Researchers have long tried to get fusion to work, first in the Jet reactor in England and now in Iter, which is being built in France. But this places high technological demands, and this research is expensive. Iter will cost an estimated SEK 160 billion to construct.
The hybrid reactor also uses fusion, but just as a spark plug that starts the fission. You can control the supply of neutrons, unlike today’s light water reactors and tomorrow’s fast reactors, where the nuclear fuel burns all by itself. Olov Ågren shows a model of a hybrid reactor that is envisioned to be 25 metres high and six metres in diameter.
‘It’s extremely compact. It involves only small volumes that can yield 500 megawatts of electricity. That corresponds to half of a standard power plant.’
To build the reactor would cost many billions of crowns, but Olov Ågren believes that this is the technology of the future.
‘Today there is great interest in fusiondriven reactions, and that’s due to difficulties in succeeding with fusion alone. This is a simpler alternative.’
To solve tomorrow’s energy problems, safer reactors have to be developed. On the one hand, it’s a matter of preventing the risk of meltdowns, and, on the other hand, preventing fuel from being used in nuclear weapons. Because nuclear power will be needed in the future as well, maintains Olov Ågren.
‘Renewable energy will not be sufficient to replace fossil fuels like oil and coal. Nuclear power plants have the advantage of being compact: they’re small in relation to how much energy they produce. But more research is needed.’
Annica Hulth