Under the Microscope: Civil nuclear power was introduced in the 1950s with great fanfare. In future, we were told, electricity would be generated in limitless supply and at a cost that would be "too cheap to meter".
Unfortunately this dream was not realised and, from the beginning, the nuclear industry was plagued with problems.
These problems peaked in 1986 when the Russian power station at Chernobyl exploded with tragic loss of life locally and widespread radioactive contamination of Europe. Chernobyl seemed to toll the death knell of the nuclear industry, but, in the meantime we have become conscious that generating power by the conventional burning of fossil fuels poses perhaps greater problems for the environment than does nuclear power. I refer to the enhanced greenhouse effect which is gradually warming the world. At the end of the day, the answer may well be a cleaned-up nuclear troupe.
Nuclear power as we know it now is based on nuclear fission. In nuclear fission, enormous energy is released when the uranium atom splits into two roughly equal fragments. Enormous energy is also released in another nuclear process called nuclear fusion, which is the opposite of nuclear fission. In nuclear fusion, atoms combine to form heavier atoms. The enormous energy generated in stars comes from nuclear fusion, when hydrogen atoms fuse to form helium.
Efforts are ongoing worldwide to design a nuclear industry based on nuclear fusion, which, in principle, would not have many of the problems associated with nuclear fission. It is hoped that a nuclear fusion industry will be up and running by the middle of the 21st century, but we may have to wait much longer. In the meantime, if we are to get help from the nuclear industry, it will have to come from nuclear fission.
I am not in favour of the current nuclear fission industry for the following reasons: (a) the possibility of disastrous accidents; (b) the long-lived radioactive waste; (c) the connection with nuclear weapons; (d) vulnerability to easy attack in the event of war and consequent explosive release of huge amounts of radioactivity. It may well be possible to redesign nuclear fission plants so that each of these problems is either eliminated or drastically minimised.
There are two fission reactor designs that eliminate or greatly reduce the possibility of a disastrous accident. During the 1950s, American scientists designed a "fail-safe" nuclear fission reactor. It uses the laws of physics to shut down the reactor in an emergency rather than relying on complex safety systems.
The design, called Triga, uses a special form of uranium fuel mixed with hydrogen-rich zirconium hydride. Any sudden surge of heat automatically causes the hydrogen to kill the chain reaction that powers the reactor within milliseconds. Many small Triga research reactors have been built around the world and not one has failed in 40 years experience.
Another possible solution to the safety problem is to replace the current generation of reactors with high temperature gas-cooled reactors (HTGR). For various reasons, such reactors are far less prone to catastrophic accident than the current generation and, in any event, HTGR reactors would be built underground. A further advantage of the HTGR reactor is that it can run on a mixture of uranium and thorium. Extracting weapons-grade plutonium from such a reactor is extremely difficult and this would greatly help to stop the spread of nuclear weapons around the world.
So, it may be possible to prevent catastrophic accidents, but what about the high-level and long-lived waste that is generated by nuclear fission.
This waste must be stored under secure conditions for upwards of 100,000 years before it can be released into the environment. The most popular current idea for storage is in stable geological repositories deep in the earth. However, there is something deeply disturbing and unreasonable about generating waste so toxic that it must be closely guarded and segregated for 100,000 years.
Last year, a research group at Strathclyde University made a breakthrough that might possibly be developed to deal with the high-level waste problem.
An intense burst of laser light was used to turn a radioactive isotope with a half-life of 16 million years into another isotope with a half-life of only 25 minutes. The possibility, therefore, arises of transforming long-lived high-level nuclear waste into a form that quickly decays and can be easily handled and stored.
My fourth objection to current nuclear fission stations, their vulnerability in the event of war, is much more easily dealt with than the other objections. The solution would simply be to build future nuclear power stations below ground and sufficiently protected to ensure that surface bombing would not affect them.
It is forecast that, by 2020, worldwide demand for electricity will soar by 75 per cent. If this demand is met by fossil-fuel power stations, greenhouse gas emissions will increase massively. Although wind energy, solar power and other renewable energy sources are helping to reduce our reliance on fossil fuels, few believe that renewable sources can contribute more than a small fraction of the projected shortfall. A redesigned nuclear fission programme may yet prove to be the only solution.
• William Reville is associate professor of biochemistry and director of microscopy at UCC