Published on Saturday December 28 2013 (AEST)
Today, power production cannot do without nuclear power plants, which account for 10% of the electrical power generated.
According to experts, nuclear power production will remain viable for several decades to come, more specifically until we've mined all uranium ore and have none left.
All nuclear power plants operate on the same principle, specifically on the use of heat that's released during the fission of uranium in a sustained chain reaction. Heat makes water boil, with the steam causing the turbine to rotate and generate electricity. To regulate the emission of heat, special-purpose substances are introduced into the active area of the reactor to slow down the ongoing nuclear reaction.
The first experimental reactor started operation in Chicago in 1942. Its output was negligible, barely sufficient to sustain the chain reaction. It was all top secret, so no photographers were ever let in and no photos of the reactor were therefore made.
1946 saw research reactors start operation in Canada and at Moscow's Kurchatov Institute research centre. Now, electricity began to be generated on industrial scale for the first time in 1954, at the Obninsk nuclear power plant near Moscow. A nuclear physicist and an expert on nuclear power production, Igor Ostretsov, says that graphite was used at Obninsk to slow down the nuclear reaction.
"Graphite-moderated reactors emerged from so-called industrial reactors that were used to obtain plutonium for nuclear bombs. This gave rise to the making of high-power channel-type reactors, of which Russia has built 14, including the four that were used at the Chernobyl nuclear power plant. One of the four is known to have exploded. It was good as a plutonium-breeding reactor, but bad as a power producer. As they became bigger in size, these reactors revealed a lot of problems that eventually resulted in a disaster".
The advantage of graphite reactors is that they run on low-enriched or even natural uranium, and boast low construction costs.
Russia is the only country to operate these kinds of graphite reactors today. Moscow has made a decision not to prolong their service life. Differently built graphite reactors are also operational in the UK. The high-power channel-type reactors will be replaced by safer boiling water reactors, says a senior expert with the Institute for Energy and Finance, Sergei Kondratyev, and elaborates.
"The basic difference is that the new reactors have a stable negative feedback, in other words, if the chain reaction grows too fast, the reactor will shut itself down. That was not often the case with the high-power channel-type reactors. This is very important in terms of safety, for another Chernobyl plant-type accident is just ruled out. The new reactors have several coolant circuits, which makes radioactive contamination of the coolant or scatter radiation quite unlikely".
A number of boiling-water reactor modifications have been used extensively across the world recently. But let's not forget about yet another type of reactors, namely fast-neutron reactors. Here's more from Sergei Kondratyev.
"Russia has currently only one fast-neutron reactor operational, at the Beloyarsk nuclear power plant, in the Sverdlovsk Region. Russia is the leader in building such reactors and has recently helped build one in China. But the developed countries, such as Japan and France, have frozen programmes involving the fast-neutron reactor technology, which is quite expensive. But these reactors could help settle the problem of reprocessing and regenerating nuclear fuel, since we realize that uranium is a non-renewable fuel".
Today Russia and other countries build generation III+ nuclear reactors, which by far surpass the IAEA safety requirements. The reactors have by far higher temperature of the nuclear reaction, which boosts energy efficiency. Designers have been thinking of ways to produce generation IV reactors. Surprisingly, one of the six types of future reactors will use graphite. The first generation IV nuclear power plant will hardly be built before 2030, and this is what Sergei Kondratyev says about the output of this kind of reactor.
"Two trends are likely to emerge in building generation IV reactors. The first one is that the new reactors will boast an increasingly great energy output, which is understandable. A power plant area matters, because areas are mostly densely-populated and land is expensive. On the other hand, we've seen a keen interest in building small compact nuclear power plants, because power-consuming industries have recently been located in remote areas. I believe we will live to see both mini-nuclear power plants and extra-power reactors".
World nations can go on developing ways to produce nuclear power for the next 60 years or so, when we run out of all proved uranium reserves, Igor Ostretsov says. According to the expert, scientists should learn to use accelerators to ensure direct uranium-238 and thorium combustion. And then we'll take all nuclear power production from the Earth to the Moon, sometime in the late 21st century.