Nuclear Fission
As soon as the U-235 nucleus captures a neutron, it splits into two lighter atoms and throws off two or three new neutrons. The two new atoms emit gamma radiation as they settle into their new states. Three things about this induced fission process that make is especially interesting. The probability of a U-235 atom capturing a neutron as it passes by is fairly high. In a reactor working properly, one neutron ejected from each fission causes another to occur. This process of capturing said neutron and splitting happens extremely quickly and an incredible amount of energy is released in the form of heat and gamma radiation when a single atom splits. The two resulting atoms from the fission later release beta radiation and the neutrons, together, weigh less than the original U-235 atom. One pound of highly enriched uranium, such as the uranium to power nuclear submarines / nuclear aircraft carriers, is equal to around a million gallons of petrol. A pound of uranium is smaller than a baseball while a million gallons of petrol would fill 50ft per side (~ same size as a five story building).
For these properties of U-235 to work a sample of uranium must be enriched so that it contains 2-3% more uranium-235. 3% enrichment is used in civilian nuclear reactors which are used to generate power and electricity.1 3
This diagram shows how a pressurised water reactor works which uses nuclear fuel rods to power the turbines and this occurs by the heat produced from nuclear fission turning water into steam which then turns the turbines, cools and is recycled to be used again.
Nuclear Waste
There are three types of nuclear waste: High, Intermediate and Low level waste. High Level Waste (HLW) is ‘spent’ fuel rods. HLW gets hot because it is still very radioactive. It has to be stored carefully, but it doesn’t last long and there isn’t very much of it. All of the UK’s HLW is stored in a pool of water at Sellafield. Intermediate Level Waste (ILW) is less radioactive than HLW but the amount of ILW is increasing as HLW decays into ILW. Low Level Waste (LLW) is there protective clothing and medical equipment the can be slightly radioactive. It is pack in drums and dumped in a landfill site that has been lined to prevent leakages.
In 2004, the government set up the Nuclear Decommissioning Authority (NDA) to clean up hazardous nuclear waste at sites around the UK. More than95% of the radioactive waste comes from nuclear power stations, while the rest comes from medical use, industry and scientific research. They call it the UK’s ‘nuclear legacy’
The NDA will spend around £1,000 million each year, for approximately 50 years; however, before it can start work the government needs to find a method of disposing nuclear waste that is acceptable to the public.
Nuclear waste has minimal effect of the UK’s average background radiation but it is still harmful due to contamination. Imagine some waste leaks into a water supply; this could be taken up by a vegetable / animal which you eat. Now the radioactive material is in your stomach where it can irradiate your organs. It is dangerous and similar to radon gas poisoning.
Some radioactive materials last more thousands of years or more, the NDA must dispose of it in ways that are safe and secure for many generations.2
4
This flow diagram shows how nuclear waste is stored, primarily it is cooled for several years in a tank, then it is mixed with glass, it is then poured into a container while molten. The waste then cools to a solid state in the steel container. The steel containers are the stored above ground in channels surrounded by a concrete shield and a concrete store. They are cooled by air circulation. A possible means of disposing of nuclear waste in the future would be depositing it about 300-2000m under ground with the rocks acting as a natural protective chamber.
Building, Maintaining and Decommissioning a Nuclear Power Plant.
The estimates for the cost of nuclear power varies considerably, several organisations have tried putting a price on a kilowatt hour (kWh) of electricity produced by nuclear power, taking into account the cost of building, maintaining and decommissioning power stations. 5
The Royal Academy of Engineers’ figures shown above are some of the most optimistic, and are similar to quotes by the nuclear industry for a new generation of reactors. A 2002 UK government report said the power from Sizewell B, the most recently built reactor, costs 6p/kWh.
By 2020 it is estimated that the cost would have dropped to 3-4p/kWh, although the anti-nuclear New Economics Foundation said that such costs are dramatically underestimated and could cost twice as much.
British Energy estimated that overall the cost of operating its power stations from April-September 2007 was 2.6p/kWh.
Behind these variations lies a series of costs which are difficult to quantify. Nuclear construction costs have a history of exploding over budget and past decommissioning bills have been large, although, proponents say better technology will bring financial improvements to both areas.
Basically, while the initial costs are high, the cost of nuclear power doesn’t fluctuate and spiral with uranium prices in the way that electricity from fossil fuels do.5
A “brief” summary of the argument for and against nuclear power stations being built in the UK.
Nuclear power generation emits low amounts of “carbon dioxide and the emissions of green house gasses”; therefore the contribution of nuclear power plants to global warming is relatively small. Also the technology is ready and available, meaning it does not have to be developed first and it is possible to generate a high amount of electricity from a single plant.6
Also, although Chernobyl was the worst nuclear accident in history it is still not a convincing argument as, technically, more people have died in a single coal mining accident than nuclear accidents in history put together (Although the life span of nuclear power has been nowhere as near that of coal mining) and nothing can be made failsafe so there is no point in criticising a particular system for not being what is impossible. Chernobyl happened because of a flawed design in a reactor operated by poorly trained personnel. The nuclear reactors in Britain today and the rest of the world have little or nothing in common with the design of the Chernobyl reactor. Yet is it always worth listening to people against nuclear power, yet without a renewed nuclear programme, Britain may face a future where 70% of its energy needs may come from gas and people have seen the instability of the suppliers of gas which is imported to this country.7
However the problem of radioactive waste is still an unsolved one and the waste from nuclear energy is extremely dangerous and it has to be looked after carefully for thousands of years. There are high risks despite a general high security standard; accidents will happen as it is almost impossible to build a 100% secure nuclear power plant and the small probability of failure will always stay. Consequences of an accident would be devastating for the Earth as well as life living on it (e.g. Chernobyl) and the more nuclear power plants that are built, as well as nuclear waste storage; the higher it is for the probability of said disastrous failure somewhere in the world. Nuclear power plants as well as nuclear waste could also be preferred targets for terrorist stacks as no nuclear power plant in the world could withstand an attack similar to 9/11 in New York. Such a terrorist act would be catastrophic for everyone. Also the waste created by nuclear power plants could be used to build nuclear weapons, so the knowledge of how nuclear power stations work could also be used to build nuclear weapons (which in turn is called nuclear proliferation).
Also, the energy source for nuclear power is uranium, which is a scarce resource and its supply is estimated to only last for the next 30 to 60 years depending on the demand and the time scale for formalities, plans and building a nuclear power station would take around 20 to 30 years in the West, so it is very unlikely to build new nuclear power stations in a short period of time.6
Greenpeace UK believe the government is the wrong solution to climate change, saying that the reality is a new generation of nuclear reactors simply won’t deliver the urgent emissions cuts needed to tackle climate change, with even the most optimistic estimates suggest that a new generation of nuclear power stations will only reduce our emissions by 4% by 2024, which is far too little and far too late to stop global warming or even address the predicted energy gap.
Instead, a new generation of reactors will “create tens of thousands of tonnes of the most hazardous radioactive waste, which remains dangerous for up to a million years. It will establish new targets for terrorists, including nuclear waste trains carrying deadly cargoes along our public rail network for decades to come. It will keep the threat of a nuclear reactor accident hanging over us and risk the proliferation of weapons-grade plutonium. And it will render the public liable for the enormous cleaning up costs.”
While New Scientist said:
“At last, a study which would appear to prove conclusively that living near nuclear power plants is a hazard to human health, particularly where children are concerned .
For over 20 years government scientists have led the public to believe that clusters of leukaemia around power stations were inexplicable, just coincidence, or perhaps a virus. Anything but radiation, as the levels of radionuclides emitted were declared "too small".
Nuclear power, nuclear weapons and, more recently, the use of depleted uranium have all been so important to multinational corporations and the military that their real impact has been constantly shrouded in deceit and half-truths.
The German government deserves congratulations for its acceptance of the findings of the new "KiKK" studies of childhood cancer near nuclear power plants that Ian Fairlie reports.
In the regions most contaminated by the 1986 accident at Chernobyl in the Ukraine, thyroid cancer has risen a hundredfold, a statistic which could not be ignored.
But there are rises in many other cancers, immune system diseases and in the numbers of children born with genetic disorders, which are long overdue for more research.
The widespread use of depleted uranium in the Iraq wars of 1990 and 2003 has left a deadly legacy of disease which is damaging and killing children today and will continue to afflict the Iraqi people for many generations to come.
It is time for the insidious effects of long-term low-level radiation to be properly examined and acknowledged as one of the major drawbacks to the expansion of nuclear power.
Add in the problems of high cost, waste disposal, vulnerability to terrorist attack or accident caused by human error, and its close links with nuclear weapons proliferation, and the risk which nuclear energy production poses daily to children living nearby is simply unacceptable”
Conclusion
I believe the UK should try to build nuclear power stations, as the future of energy from fossil fuels is dying and the world would be unable to run without energy. However, I believe that nuclear power stations shouldn’t be the only form of energy source we will try to tap as other sources of energy, which are renewable such as wind, solar and tidal, could prove to be substantial, with more research and extra funding, in Britain’s quest for new energy sources as nuclear power isn’t totally renewable, has a bad reputation and produces toxic waste which will take many millennia to be totally disposed of. However, wind could also be a good combination along with nuclear power as wind farms are quick and cheap to build, but cost a lot in maintenance and could possibly be an eyesore (OH NO) while nuclear power stations take a long time to build and are expensive, yet maintenance is relatively easy and cheap, although decommissioning nuclear power stations can take a long time and cost a lot, as well as contaminating the ground on which it has been built.
Whereas Greenpeace disagree, saying “Nuclear power is a dangerous distraction from the real solutions to tackling . It is a relic of an out of date, centralised and wasteful energy system and will leave a lethal legacy of radioactive contamination for many thousands of years.
Currently two thirds of our energy from power stations in the UK is lost through wasted heat - up the chimneys and down the power lines - because it's produced a long way from where it's needed. We need to generate power closer to where it is required, allowing us to use both the heat for central heating and hot water, and the electricity for our other needs. This is known as a system. If we combined decentralised energy generation with renewable energy and energy efficiency it could deliver 30 per cent larger carbon dioxide savings than building new nuclear power stations.
If we truly want to tackle climate change, now is the time to look forward, not back. We urgently need to embrace a cleaner, cheaper and more efficient energy solution to our problems and leave the outdated, unreliable and dangerous nuclear technology back in the last century, where it belongs.”
Bibliography
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This is a website or newsletter of a private individual or a fringe group and is based on little or no data, with no support within the science community as this source is likely to be someone who knows little or no science or someone known to have a particular point of view and is affiliated with a non-science institute.
2: GCSE, Science Higher, Oxford university press, page 250-251
This source is a school textbook and has a valid and reliable method of data gathering. E.g. health studies with a large sample size, carried out over many years. The explanation is agreed by most, but not all, within the science community. The author is a professional scientist working in the area, though not regarded as a top expert by their peers and the author’s institution is a recognised university or scientific institute
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All 3 of these are ‘quality’ media, with data based on just one study (or several small studies). Little information about sample, or procedures followed. The science explanation is one among several explanations discussed with the science community. The author is a professional scientist whose expertise is in a different field, while the author’s institute is a scientific one but with a doubtful reputation.
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24/6/08
This is a website or newsletter of a private individual or a fringe group and is based on little or no data, with no support within the science community as this source is likely to be someone who knows little or no science or someone known to have a particular point of view and is affiliated with a non-science institute.
7: (Best answer) kinning_park (user name) “About me: I have extensive experience in the telecommunications and information technology industry, and also have experience in the field of medical research” 24/6/08
This is a website or newsletter of a private individual or a fringe group and is based on little or no data, with no support within the science community as this source is likely to be someone who knows little or no science or someone known to have a particular point of view and is affiliated with a non-science institute.
8:
This is a respectable pressure group website, who’s opinion is based on some data, but with questionable validity or reliability. It has a new explanation but with a basis in accepted scientific ideas. The author is an inexperienced scientist or science student, who is affiliated with a scientific institute or company that represents particular views only (May be bias).
9:
This is a science magazine, which uses a valid and reliable method to obtain its data, which is agreed by most but not all within the science community. The author is a professional scientist working in the area – though not regarded as a top expert by their peers, while the author’s affiliation is a recognised university or scientific institute.
10:
This is a respectable pressure group website, who’s opinion is based on some data, but with questionable validity or reliability. It has a new explanation but with a basis in accepted scientific ideas. The author is an inexperienced scientist or science student, who is affiliated with a scientific institute or company that represents particular views only (May be bias).