[ARTICLE]New age nuclear

What if we could build a nuclear reactor that offered no possibility of a meltdown, generated its power inexpensively, created no weapons-grade by-products, and burnt up existing high-level waste as well as old nuclear weapon stockpiles? And what if the waste produced by such a reactor was radioactive for a mere few hundred years rather than tens of thousands? It may sound too good to be true, but such a reactor is indeed possible, and a number of teams around the world are now working to make it a reality. What makes this incredible reactor so different is its fuel source: thorium.

Named after Thor, the warlike Norse god of thunder, thorium could ironically prove a potent instrument of peace as well as a tool to soothe the world's changing climate. With the demand for energy on the increase around the world, and the implications of climate change beginning to strike home, governments are increasingly considering nuclear power as a possible alternative to burning fossil fuels.

But nuclear power comes with its own challenges. Public concerns over the risk of meltdown, disposal of long-lived and highly toxic radioactive waste, the generation of weapons grade by-products, and their corresponding proliferation risks, all can make nuclear power a big vote-loser.

A thorium reactor is different. And, on paper at least, this radical new technology could be the key to unlocking a new generation of clean and safe nuclear power. It could prove the circuit-breaker to the two most intractable problems of the 21st century: our insatiable thirst for energy, and the warming of the world's climate.

BY THE END OF this century, the average surface temperature across the globe will have risen by at least 1.4˚C, and perhaps as much as 5.8˚C, according to the United Nations Intergovernmental Panel on Climate Change.

That may not sound like much, but small changes in the global average can mask more dramatic localised disruptions in climate.

Some changes will be global: we can expect sea levels to rise by as much as 0.9 metres, effectively rendering a huge proportion of what is now fertile coastal land uninhabitable, flooding low-lying cities and wiping out a swathe of shallow islands worldwide.

The principal culprit is carbon dioxide, a gas that even in quite small quantities can have a dramatic impact on climate, and has historically been present in the Earth's atmosphere at relatively low concentrations.

That was until human activity, including burning fossil fuels, began raising background levels substantially.

Yet while we're bracing ourselves to deal with climate change, we also face soaring demand for more energy - which means burning more fossil fuels and generating more greenhouse gases.

That demand is forecast to boom this century. Energy consumption worldwide is rising fast, partly because we're using much more of it - for air conditioning and computers, for example. In Australia alone, energy consumption jumped by 46 per cent between the mid-1970s and the mid- 1990s where our population grew by just 30 per cent. And energy use is expected to increase another 14 per cent by the end of this decade, according to the Australian Bureau of Statistics. Then there's China, which, along with other fast-growing nations, is developing a rapacious appetite for power to feed its booming economy.

And fossil fuels won't last forever. Current predictions are that we may reach the point of peak production for oil and natural gas within the next decade - after which production levels will continually decline worldwide.

That's if we haven't hit the 'peak oil' mark already. That means prices will rise, as they have already started to do: cheap oil has become as much a part of history as bell-bottomed trousers and the Concorde.

Even coal, currently the world's favourite source of electricity generation, is in limited supply. The U.S. Department of Energy suggests that at current levels of consumption, the world's coal reserves could last around 285 years. That sounds like breathing room: but it doesn't take into account increased usage resulting from the lack of other fossil fuels, or from an increase in population and energy consumption worldwide.

According to the U.S. Energy Information Administration, as of 2003, coal provided about 40 per cent of the world's electricity - compared to about 20 per cent for natural gas, nuclear power and renewable sources respectively. In Australia, coal contributes even more: around 83 per cent of electricity.

This is because coal is abundant and cheap, especially in Australia. And although a coal-fired power plant can cost as much as A$1 billion (US$744 million) to build, coal has a long history of use in Australia. Coal is also readily portable, much more so than natural gas, for example - which makes it an excellent export product for countries rich in coal, and an economical import for coal-barren lands.

But the official figures on the cost of coal don't tell the whole story. Coal is a killer: a more profligate one than you would expect.

And it maintains a lethal efficacy across its entire lifecycle.

One of the main objections held against nuclear power is its potential to take lives in the event of a reactor meltdown, such as occurred at Chernobyl in 1986. While such threats are real for conventional reactors, the fact remains that nuclear power - over the 55 years since it first generated electricity in 1951 - has caused only a fraction of the deaths coal causes every week.

Take coal mining, which kills more than 10,000 people a year. Admittedly, a startling proportion of these deaths occur in mines in China and the developing world, where safety conditions are reminiscent of the preunionised days of the early 20th century in the United States. But it still kills in wealthy countries; witness the death of 18 miners in West Virginia, USA, earlier this year.

But coal deaths don't just come from mining; they come from burning it. The Earth Policy Institute in Washington DC - a nonprofit research group founded by influential environmental analyst Lester R. Brown - estimates that air pollution from coal-fired power plants causes 23,600 U.S. deaths per year. It's also responsible for 554,000 asthma attacks, 16,200 cases of chronic bronchitis, and 38,200 non-fatal heart attacks annually.

The U.S. health bill from coal use could be up to US$160 billion annually, says the institute.

Coal is also radioactive: most coal is laced with traces of a wide range of other elements, including radioactive isotopes such as uranium and thorium, and their decay products, radium and radon. Some of the lighter radioactive particles, such as radon gas, are shed into the atmosphere during combustion, but the majority remain in the waste product - coal ash.

People can be exposed to its radiation when coal ash is stored or transported from the power plant or used in manufacture of concrete. And there are far less precautions taken to prevent radiation escaping from coal ash than from even low-level nuclear waste. In fact, the Oak Ridge National Laboratory in the U.S. estimates the amount of exposure to radiation from living near a coal-fired power plant could be several times higher than living a comparable distance from a nuclear reactor.

Then there are the deaths that are likely to occur from falling crop yields, more intense flooding and the displacement of coastal communities which are all predicted to ensue from global warming and rising oceans.

There's so much heat already trapped in the atmosphere from a century of greenhouse gases that some of these effects are likely to occur even if all coal-fired power plants were closed tomorrow. Whichever way you look at it, coal is not the smartest form of energy.

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[Article]Nuclear power: Energy solution or evil curse?

Explosions and meltdown fears at Japan's damaged nuclear plants have renewed debate about the safety of atomic energy and cast doubts over its future as a clean energy source.

Environmental groups and others have been quick to point out that this is a total vindication of their stance against any form of nuclear-sourced energy.

Walt Patterson at the London-based foreign affairs think-tank Chatham House, questions why any government would build nuclear plants when there are so many others sources of energy generation.

"Why turn to the slowest, the most expensive, the narrowest, the most inflexible, and the riskiest in financial terms?" he asks.

But proponents of the nuclear option insist nuclear power has the lowest carbon footprint, the latest reactors are perfectly safe, and it produces sustainable energy at a cost that is competitive with other methods.

Safety addressed

The facilities north of Tokyo were damaged after an 8.9-magnitude earthquake and tsunami left more than 1,000 dead and at least 10,000 missing.

"Putting things into perspective, when the loss of life in Japan is probably going to be much higher than presently recorded, the problems with the nuclear reactors are a high-profile side-line," says Ian Hore-Lacy at the World Nuclear Association (WNA).

He points out that although the facilities were built in the 1960s, there have only been minor radiation releases.

A disaster on the scale of the Chernobyl nuclear accident in the former Soviet Union is highly unlikely, according to experts, because Japan's reactors are built to a much higher standard and have much more rigorous safety measures.

"New reactors are much more sophisticated," Mr Hore-Lacy says. "They are one or two orders of magnitude safer than older models."

He insists the very latest nuclear reactor models have passive cooling systems, so if they were to experience any disaster such as those currently being experienced in Japan, it would not present any danger whatsoever to the public.

Public perceptions

An incident at Three Mile Island in the US in 1979 and the Chernobyl accident in 1986, raised concerns about the safety of the nuclear power industry as well as nuclear power in general, slowing its expansion for a number of years.

But the public perception of the nuclear industry has to be balanced with the compelling need to reduce dependence on oil, gas and coal, along with the climate-warming carbon dioxide emissions they produce, proponents insist.

Mr Hore-Lacy is adamant that the only way enough energy can be sustainably produced to cater for the increasing global demand is with nuclear power.

"Nuclear power has two distinct advantages over coal and gas," he says.

"First there is the question of energy security."

He explains that uranium, used in the production of nuclear power, has the advantage of being a highly concentrated source of energy, which is easily and cheaply transportable, and that the quantities needed are very much less than for coal or oil.

"One kilogram of natural uranium will yield about 20,000 times as much energy as the same amount of coal," he says.

The second issue is that of the carbon footprint.

Nuclear energy is considered by proponents to be a clean alternative to the expensive exploration of oil and gas - both of which are faced with dwindling reserves.

However, that is not a view shared by everyone.

"Nuclear power needs climate change more than climate change needs nuclear power," says Mr Patterson of Chatham House.

Alternative methods

Anti-nuclear campaigners say the crisis in Japan is a timely reminder of the dangers of atomic energy, particularly in a region known for its seismic activity.

They advocate the use of alternative systems to meet the global demand for energy - the most popular being solar energy, biomass energy, hydropower and wind turbines.

All systems have their drawbacks, however, whether it is the cost of installation, the transformation of farming land, or the site of large structures on the landscape.

The European Gas Advocacy Forum has issued a report saying that natural gas should play a key role in reaching Europe's 2050 climate targets in the most cost-efficient manner.

Rune Bjornson, at the Norwegian energy company Statoil, says natural gas is cost competitive, with CO2 emissions being 70% lower than those of coal.

Meanwhile, the WNA's Mr Hore-Lacy says that once a nuclear reactor is up and running, the operators are "laughing all the way to the bank".

He maintains that the biggest disincentive to building more nuclear power plants is raising the capital for the initial start-up cost - some 80% of the required amount.

"Once it is running, the actual price per kilowatt of energy produced is cheaper than other methods, and running costs are minimal," he says.

But everything comes at a cost.

Governments, companies and individuals have to decide upon a balance between environmental concerns, and the price they are willing to pay, or can afford, for their energy.

And the crisis in Japan has upset that balance for many.

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[Article]Nuclear energy: assessing the emissions

For decades nuclear power has been slated as being environmentally harmful. But with climate change emerging as the world's top environmental problem, the nuclear industry is now starting to enjoy a reputation as a green power provider, capable of producing huge amounts of energy with little or no carbon emissions¹. As a result, the industry is gaining renewed support. In the United States, both presidential candidates view nuclear power as part of the future energy mix. The US government isn't alone in its support for an expansion of nuclear facilities. Japan announced in August that it would spend $4 billion on green technology, including nuclear plants.

But despite the enthusiasm for nuclear energy's status as a low-carbon technology, the greenhouse gas emissions of nuclear power are still being debated. While it's understood that an operating nuclear power plant has near-zero carbon emissions (the only outputs are heat and radioactive waste), it's the other steps involved in the provision of nuclear energy that can increase its carbon footprint. Nuclear plants have to be constructed, uranium has to be mined, processed and transported, waste has to be stored, and eventually the plant has to be decommissioned. All these actions produce carbon emissions.

Critics claim that other technologies would reduce anthropogenic carbon emissions more drastically, and more cost effectively. "The fact is, there's no such thing as a carbon-free lunch for any energy source," says Jim Riccio, a nuclear policy analyst for Greenpeace in Washington DC. "You're better off pursuing renewables like wind and solar if you want to get more bang for your buck." The nuclear industry and many independent analysts respond that the numbers show otherwise. Even taking the entire lifecycle of the plant into account nuclear energy still ranks with other green technologies, like solar panels and wind turbines, they say.

Life studies

Evaluating the total carbon output of the nuclear industry involves calculating those emissions and dividing them by the electricity produced over the entire lifetime of the plant. Benjamin K. Sovacool, a research fellow at the National University of Singapore, recently analyzed more than one hundred lifecycle studies of nuclear plants around the world, his results published in August in Energy Policy². From the 19 most reliable assessments, Sovacool found that estimates of total lifecycle carbon emissions ranged from 1.4 grammes of carbon dioxide equivalent per kilowatt-hour (gCO₂e/kWh) of electricity produced up to 288 gCO₂e/kWh. Sovacool believes the mean of 66 gCO₂e/kWh to be a reasonable approximation.

The large variation in emissions estimated from the collection of studies arises from the different methodologies used - those on the low end, says Sovacool, tended to leave parts of the lifecycle out of their analyses, while those on the high end often made unrealistic assumptions about the amount of energy used in some parts of the lifecycle. The largest source of carbon emissions, accounting for 38 per cent of the average total, is the "frontend" of the fuel cycle, which includes mining and milling uranium ore, and the relatively energy-intensive conversion and enrichment process, which boosts the level of uranium-235 in the fuel to useable levels. Construction (12 per cent), operation (17 per cent largely because of backup generators using fossil fuels during downtime), fuel processing and waste disposal (14 per cent) and decommissioning (18 per cent) make up the total mean emissions.

According to Sovacool's analysis, nuclear power, at 66 gCO₂e/kWh emissions is well below scrubbed coal-fired plants, which emit 960 gCO₂e/kWh, and natural gas-fired plants, at 443 gCO₂e/kWh. However, nuclear emits twice as much carbon as solar photovoltaic, at 32 gCO₂e/kWh, and six times as much as onshore wind farms, at 10 gCO₂e/kWh. "A number in the 60s puts it well below natural gas, oil, coal and even clean-coal technologies. On the other hand, things like energy efficiency, and some of the cheaper renewables are a factor of six better. So for every dollar you spend on nuclear, you could have saved five or six times as much carbon with efficiency, or wind farms," Sovacool says. Add to that the high costs and long lead times for building a nuclear plant about $3 billion for a 1,000 megawatt plant, with planning, licensing and construction times of about 10 years and nuclear power is even less appealing.

Power games

But, says Paul Genoa, director of policy development for the Nuclear Energy Institute (NEI), a nuclear industry association based in Washington DC, "it's a fallacy to say one energy source is better, and that we should use it everywhere. The reality is that we need a portfolio solution that will include nuclear."

"If you look at lifecycle emissions from renewable technologies, typically they are on the order of only 1 to 5 per cent of a coal plant," says Paul Meier, director of the Energy Institute at the University of Wisconsin-Madison. Looked at as a replacement for fossil fuels, existing nuclear plants prevent 681 million tonnes of carbon from being emitted every year in the United States alone, according to the NEI.

Meier also points out that nuclear energy is capable of providing baseload power - that is, large amounts of power that can run consistently and reliably. Nuclear plants run 90 per cent of the time, while wind and solar power provide electricity only intermittently and have to be backed up, often by fossil fuel plants. "The modern electric grid relies on baseload power," says Genoa. "That's power that's running 24 hours a day, 365 days a year. It's only shut down for maintenance." Money spent on energy efficiency, however, is equivalent to increasing baseload power, since it reduces the overall power that needs to be generated, says Sovacool. And innovative energy-storage solutions, such as compressed air storage, could provide ways for renewables to provide baseload power.

Thomas Cochran, a nuclear physicist and senior scientist at the Natural Resources Defense Council (NRDC), an environmental group in Washington DC, says that although nuclear power has relatively low carbon emissions, it should not be subsidized by governments in the name of combating global warming. He argues that the expense and risk of building nuclear plants makes them uneconomic without large government subsidies, and that similar investment in wind and solar photovoltaic power would pay off sooner. "There are appropriate roles for federal subsidies in energy technologies," he says. "We subsidized heavily nuclear power when it was an emerging technology 30, 40, 50 years ago. Now it's a mature technology."

Nevertheless, the Energy Policy Act of 2005 saw the US Congress offer billions of dollars in tax breaks and loan guarantees in an attempt to kickstart construction. Although a number of utilities are pursuing licences for a total of 30 new nuclear plants in the United States, none have been approved yet. Even assuming that new subsidies were to increase US nuclear power by 1.5 times the current capacity, the result would be only an additional 510 megawatts per year from now until the year 2021. Wind power, the NRDC estimates, provides more than 1,000 megawatts a year, and that figure is likely to increase.

Another question has to do with the sustainability of the uranium supply itself. According to researchers in Australia at Monash University, Melbourne, and the University of New South Wales, Sydney, good-quality uranium ore is hard to come by. The deposits of rich ores with the highest uranium content are depleting leaving only lower-quality deposits to be exploited.³ As ore quality degrades, more energy is required to mine and mill it, and greenhouse gas emissions rise. "It is clear that there is a strong sensitivity of ... greenhouse gas emissions to ore grade, and that ore grades are likely to continue to decline gradually in the medium- to long-term," conclude the researchers.

But the nuclear industry points to technological advances of its own that are likely to make nuclear power less expensive and less carbon intensive. Genoa says that new methods of mining uranium and building reactors designed to run on less uranium-rich fuel could make nuclear power even more attractive. "If we're using the same reactors in two centuries, then we've missed the boat. There are going to be other technologies," Genoa says.

References

1. Solomon, S. et al. (eds.) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge and New York, 2007); http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf
2. Sovacool, B. Energy Policy 36, 2950–2963 (2008).
3. Mudd, G. M. & Diesendorf, M. Environ. Sci. Technol. 42, 2624–2630 (2008).

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Chernobyl

Chernobyl accident in 1986.

This accident dated 24 years back is still a nightmare in most people's heart and is one of the contributing factor why nuclear technology is heavily opposed or go against.

It is one of the most advanced nuclear powerplant of its time, operated by a group of most brilliant scientists and engineers; however, the disaster still happened because of their pride and ego.

Basically, what happened was, they were trying to run an experiment to prove the plant's capability or performance, hence all the safety systems were bypassed, and accident occured! Without containment building, the radiation spreaded throughout Europe reaching as far as Sweden.

Another thing that makes Chernobyl as the last is that the nuclear reactor out there currently are all "negative void temp coefficient" type of reactor eversince Chernobyl occured. Chernobyl was using the "positive void temp coefficient" concept which makes it not so safe.

The below pictures will explain why.

For Chernobyl type of reactor, as the coolant heats up and vaporize, the reaction in the reactor will increase due to the absence of the coolant that acts as moderator and to capture some of the neutrons. Hence, the increase in reaction will further increase the temperature, more and more coolant will heats up and vaporize, allowing the reactor to reach a certain temperature where the core will melt down. This is called "positive void temp coefficient".

Meanwhile, for modern reactors, that mostly use water as moderator or coolant, this problem is no longer a worry. As the moderator(water) heats up and vaporize, the neutrons are not moderated and hence fission with the fuel will not present as they are still fast neutrons. As this happens, the reaction rate will slow down and the temperature of the reactor will accordingly decrease, allowing the moderator/coolant(water) to condense and fill back the void. When the void is filled, the reaction rate will rises and it keeps on repeating. In a way, such design is self-regulating and self-sustaining. This is known as the "negative void temp coefficient".

As a nutshell, Chernobyl accident is once and for all. The chances that accident of such magnitude will happen again is almost zero, as the world now is alert and cautious when dealing in nuclear. As long as we do the following, we will be on the safe side, preventing history from being repeated:

• DO NOT bypass safety systems - what is going to protect us, when safety systems are bypassed?
• DO NOT let pride take over - when pride is there, we tend to miss plenty of details.
• DO NOT neglect designed procedures - no one knows better than the designers about their systems, they experimented!
• DO NOT run dangerous experiments on any operating nuclear reactor - do it on experimental nuclear reactor!
• DO make sure containment building is there!

Once bitten, twice shy. We are in the shy state now, another accident, and nuclear will no longer be in talk. Hence, it is of utmost importance, that safety should always be the number 1 priority or concern in nuclear! 

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What is Nuclear Waste? Most people have no idea.

When asked "What is nuclear waste?", most people might answer "garbage from nuclear plants" or perhaps "the stuff that comes from reactors". As it turns out, both answers are superficially correct, but entirely miss the point. All human endeavors produce garbage. We know what we have in our household garbage, but precious few people know what constitutes nuclear waste. There are actually two classifications of the stuff; low-level and high-level radioactive wastes. Low-level nuclear waste is essentially the trash produced from cleaning materials and plant maintenance, similar to most industrial garbage with one difference; it's detectably radioactive. Low-level waste from nuclear plants is about equal in volume and radioactivity to the combined radioactive trash from hospitals, colleges, and research laboratories. And, it's usually less radioactive than the huge, un-monitored volumes of fly ash dumped daily from coal-burning power plants. (see reference 2, below) Regardless, low-level nuclear waste really isn't the issue. High level nuclear waste is the core of the issue; specifically the fuel cells that come from the power plant reactor after they can no longer maintain an efficient chain reaction.  The nuclear waste issue boils down to this high-level stuff, and misconceptions abound.

What is it?

The so-called waste atoms in the spent, exhausted fuel cells after they come out of the reactor, are the remains of the fuel's Uranium (U-235) and Plutonium (Pu-239) nuclei after they split (fission). These pieces are known as "fission fragments" in nuclear jargon. In everyday language, they are nuclear waste atoms.

The resulting atomic fission products are newly-formed elements which are no longer U-235 or Pu-239. They have become a large number of common elements including all rare earths, a number of active metals, semi-precious metals and even a trace of Silver. Neutrons seldom spilt nuclei right down the middle. On uncommon occasions the U-235 and Pu-239 do split in half, but most of the time they don't. One thing that always happens; if you take the atomic number of one of the new atoms, let's say Cesium (atomic no. 55), and subtract it from Uranium's atomic number (92), we get the atomic number of the other new atom, which is 37. This turns out to be Rubidium. Quite simply, the atomic numbers of the two new atoms, freshly made by splitting Uranium, always equal 92. When Pu-239 fissions, the atomic numbers of the two new atoms add up to Plutonium's atomic number of 94. 

As it turns out, The Cesium-Rubidium pair is the most probable result of U-235 fission, at a little less than 10% of all possible pairings. Other pairs in the 2% to 9% range include Barium-Krypton, Strontium-Xenon, and Yttrium-Iodine. The vast majority of pairings (always adding up to atomic number 92 or 94) are progressively less probable, all the way down to a tiny probability with the Iron-Dysprosium pair, at much less than .001 %. In total, a spectrum of 42 possible elements from U-235 fissions. With Plutonium, the pairings are slightly different because Pu-239 has a higher atomic number, which is two more than U-235. This adds four more possible elements, including Manganese, Chromium, Holmium and Erbium, all of which will have a fuel cell abundance of less than .01 %. In all cases, these freshly made elements are all immediately radioactive. 

The most intensely radioactive waste elements are those with the shortest half-lives. The least radioactive waste elements are those with the long half lives. The ones we really need to concern ourselves with are those with half-lives between one day and five billion years. All radioactive materials will lose their easily detectable radioactivity after about nine half-lives. To be conservative, let's say the radioactive lifetime of a radioactive element is ten half-lives. Any isotope with a half life less than a day is essentially non-radioactive after 10 days, and is of no long-term consequence. It takes longer than 10 days after reactor shutdown to begin moving the used fuel out of the reactor for long-term storage, so the very short half-life isotopes are not an issue. At the converse extreme, all isotopes with a half life greater than 5 billion years are so low in actual radioactivity that it becomes difficult to distinguish them from totally stable, non-radioactive elements. Because of their minuscule radioactivity, they are also of no long-term consequence. Interestingly, some naturally-occurring elements are so subtly radioactive that their unstable nature was not understood until about 35 years after Hiroshima, when detectors of ultra-high sensitivity first became available. These subtly radioactive natural elements include (but are not limited to) Indium-115, Tellurium-130, and Lanthanum-138, all with half-lives of 10 billion years or more, and none of which are considered radioactively significant. All three are also to be found in the nuclear waste matrix.

Numerically, about 5% of the waste elements made from splitting U-235 and Pu-239 have half lives less than one day. Another 75% of the radioactive elements we find in high level nuclear waste have half lives between one day and five years. We thus find the majority of the waste elements are non-radioactive after about 50 years. This includes many valuable rare earths such as Neodymium, (welders goggles, light-spectrum calibration equipment in astronomy, and laser technology) and Ruthenium (low cost solar cells). Other modern uses of these Rare Earths include magnets in hybrid cars, wind turbines, computer hard drives and cell phones. There are also many active, semi-precious metals in the waste atom matrix such as Cadmium, which is used in making batteries and electroplating. Recycling exhausted power plant reactor fuel after 50 years of closely-monitored storage would make these resources available to the world. Burying un-recycled fuel cells would be throwing these valuable materials away, which would be a true waste. 

In fact, only 8 of the nuclear waste elements have isotopes which are of radioactive concern after 50 years. Only 3 of the 15 Rare Earths in nuclear waste are detectably radioactive after 50 years (Promethium, Gadolinium, and Terbium).  Recycling could remove these long-lived radioactive elements from the non-radioactive matrix and placed back into storage. But, should we not just throw these remaining radioactive residuals away? Of course not, because of the 3 valuable Rare Earths and a bit of Silver in there (which has the longest isotopic half life of about 100 years), plus four other valuable active and semi-precious metals. Eventually, these precious materials can be recovered and become a valuable resource to our future descendants. Patience is, after all, a virtue.

Although almost never mentioned, some of the radioactive elements in exhausted fuel cells with half lives a bit greater than a few weeks are very useful in medical healing practices. These include specific isotopes (atomic varieties) of Cesium, Strontium, Yttrium, Iodine, and Xenon. By recycling exhausted fuel within a few months after removal from a reactor, these valuable medical tools could be available. This does not mean exhausted reactor fuel ought to be recycled such a short time after reactor removal. However, even calling freshly made exhausted fuel a "waste" is far from correct.

In actuality, by making "nuclear waste atoms" we're literally realizing the old alchemist's dream of turning crude base metal into something precious. Split U-235 and Pu-239, recycle the spent fuel after 50 years, and we get lots of valuable stuff.  As it turns out, by removing all of the so-called waste atoms from the exhausted fuel, and we do nothing other than bury the stripped fuel cells, the remaining fuel cells becomes less toxic than natural Uranium in less than 500 years! That's a long time, to be sure, but not the thousands-upon-thousands of years routinely expounded on through the news media and preached about by many governmental bodies. By not recycling the fuel, it remains more toxic than natural uranium for about 100,000 years. That's a very, very long time, but it need not be the case!

"It'll be radioactive forever!"

Another myth has to do with the radioactive toxic lifetime of high level nuclear waste. It won't be forever. The entire universe will be radioactive forever due to the perpetual production of radioactive isotopes by stars. But, not high level nuclear power plant waste. Here's the cold, technical facts.

Brand new Uranium fuel cells are made up of naturally-occurring U-238 and U-235 atoms, with 97-99% of the matrix U-238 and 1-3% U-235. Exhausted reactor fuel, after about three years in the reactor, is about 5% waste atoms, 1% Plutonium isotopes, and 94% U-238, when it is removed. The natural Uranium-238, which the waste atoms and Plutonium are encased in, has a half-life of 4.5 billion years. The "it'll be radioactive forever" notion comes from the natural U-238 making up the large majority of the exhausted fuel with an effective lifetime of 45 billion years. The reactor fuel had essentially a 45 billion year radioactive lifetime when it came from the Earth, thus it was "radioactive forever" before it was ever installed in the reactor. Un-recycled spent fuel cells will actually be less radioactive than natural Uranium after roughly 500 years because more than 99%  of the "waste" atoms will have completely lost their radioactivity, and the half life of the Plutonium atoms is considerably less than U-235 so it diminishes total radioactivity much faster than naturally-occurring Uranium. Since the waste atoms and the exhausted fuel itself is not actually a "radioactive forever" issue, what's the problem?

The BIG Problem...or is it?

Plutonium is most often perceived to be the problem. For the first 5 decades of the post-Hiroshima era, Plutonium was believed to be only a man-made element with but one use…making bombs. All Plutonium was assumed to be "weapon's grade" simply because it could hypothetically be used to make bombs, thus the best thing to do would be to bury the exhausted fuel cells from power plants a mile or two deep in the Earth, in solid rock or salt deposits, and leave it there. The technical realities with power plant Plutonium are very different from these essentially fictitious beliefs.

In the late 1990's, Plutonium was discovered to exist in trace quantities of a few unusual natural Uranium deposits around the world. U-238 may not fission in a reactor environment, but it does have a very small probability of spontaneous fission. That is, on rare occasion, an atom of U-238 will split apart all by itself. Each spontaneous U-238 fission releases three neutrons into the surrounding Uranium deposit. The surrounding U-238 atoms absorb many of these fresh neutrons and become U-239. U-239 radioactively decays rather quickly. This is because one of the neutrons in it's nucleus will literally spit out an electron (Beta radiation) and become a proton, making it a new atom of Neptunium-239. Np-239 also radioactively decays in the same way U-239 does, releasing an electron out of its nucleus and it becomes Pu-239. This only seems to happen in unusually pure natural uranium deposits. The discovery of trace amounts of naturally-occurring Pu-239 in these unusual Uranium deposits made essentially no impact on the news media, public, or the scientific community at large. But, it did make an impact on atomic scientists, and served to answer a troublesome atomic question that had plagued nuclear scientists for decades.

Where did naturally-occurring U-235 come from, anyway?

It doesn't seem to be found anywhere but in a Uranium deposits here on Earth. U-238 is sometimes found in cosmic rays but no U-235, and, many non-Uranium ores (such as coal) have trace amounts of U-238 but no U-235, indicating there is something strange about U-235 being found on Earth at all. Then the (above) discovery of natural Plutonium was made. Also, another remarkable discovery occurred. During nearly a half-century of military breeder reactors producing a significant stockpile of Plutonium, some of the stored Plutonium literally sat around for decades awaiting its use in weapons. During that time, something weird happened. The expected concentrations of Pu-239 and U-235 in the "old" stockpiles were off a tiny bit. There was a bit too much U-235, and a bit too little Pu-239. As it turns out, Pu-239 radioactively decays by releasing the nucleus of a helium atom (Alpha radiation) out of its nucleus, and becomes U-235! These two discoveries gave atomic scientists a possible reason for the existence of U-235 in nature. 

When Earth formed, around 4.5 billion years ago, there must have been a primordial matrix of about 50% U-238 and 50% Pu-239 occurring, all uniformly mixed together. Pu-239 has a half-life of ~24,000 years. After about a quarter of a million years, all the Pu-239 had become U-235. U-235 has a half-life of ~700 million years. In the 4.5 billion years since the Earth was formed, the U-235 has undergone about 6.5 half-lives, resulting in the 0.7% abundance we find today. Thus, when we realized the existence of trace amounts of Pu-239 found in a few natural Uranium deposits, and the existence of Plutonium's daughter element U-235 in Plutonium stockpiles, we found that Plutonium is, was, and always will be a naturally-occurring element.

The "weapon's grade" myth

Yet, there is the stigma of the term "weapon's grade" that is routinely attached to power plant reactor-made Plutonium, which must be addressed. Let's ask a strange-sounding question. Is it really weapon's grade? Can power plant Plutonium actually be used to make a nuclear weapon?

When a new fuel cell goes into a large, relatively modern reactor (those built between 1975 and 1987), it is about 1% U-235. When a fuel cell leaves the reactor after it's 3-year "lifetime", there are almost no U-235 atoms left in it, but there is the 5% "waste" atoms and about 1% Plutonium found in its place. The 5% "waste" atoms tell an interesting story. Only about 20% of them could have possibly come from U-235 fissioning. 1% Uranium cannot make 5% waste atoms. The numbers just don't add up. Where did the other 80% of the waste atoms come from? Plutonium fissioning! While the initial loading of U-235 fissions, the U-238 is making Plutonium about as fast as the U-235 is being split. As it turns out, some 80% of the energy each fuel cell makes during it's lifetime comes from the splitting of Plutonium. Further, the 1% Plutonium in the spent fuel coming out of power plant reactors is no more "weapon's grade" than the 1% U-235 encased in fuel that originally went into the reactor. Spent fuel containing Plutonium is no more "weapon's grade" than a brand new fuel cell before it goes into a reactor.

But, there's yet another problem with calling power plant Plutonium "weapon's grade". About a third of the Plutonium made in power plant reactors is not the Pu-239 used to make bombs! A third of the Plutonium won't work in bombs.

Two isotopes of Plutonium are being formed in power plant reactors, Pu-239 and Pu-240. Pu-240 atoms naturally experience two additional neutron absorbtions and become Pu-242, which radioactively decays by Alpha emission and becomes U-238. Back to square one, if you will. The production of Pu-240 eventually plateaus at 0.32% abundance, and the Pu-239 at 0.68% abundance in the exhausted fuel cell. It's all good for reactor fuel. But, it's junk for bombs. A mixture of a 100% pure matrix of power plant Plutonium, at 68% Pu-239 and 32% Pu-240, can never explode because Pu-240 doesn't fission. Further, Pu-240 absorbs neutrons better than Pu-239. As a result, Pu-240 is what might be correctly termed a "bomb poison", because it absorbs neutrons sufficiently to keep the chain reaction from becoming extreme enough for an explosion. All by themselves, these two reasons are why power plant reactor Plutonium can not be correctly termed "weapon's grade". Together, they make the term "weapon's grade" grossly inappropriate for power plant Plutonium.

Thousands of years, and no carbon footprint

Uranium is mostly useless other than in reactors, armor for mechanized military vehicles, and bombs. Plutonium is only useful for reactor fuel and bombs. Every nucleus of U-235 and Pu-239 split in a reactor is one less atom potentially used in a bomb. Let's get rid of these bomb-possible isotopes and turn them into valuable resources (the "waste" atoms) that cannot be made into bombs. Let's utilize a paradigm of appropriate environmentalism and recycle (reprocess) exhausted power plant fuel cells. 94% of each exhausted fuel cell from a power plant reactor is still good fuel. By doing the environmentally appropriate thing, and recycling (reprocessing) the spent fuel from power plant reactors (after ~50 years?), we not only reclaim the valuable non-radioactive resources from the waste atom matrix, but we have a useful Uranium-Plutonium matrix for the making of new reactor fuel cells. Without recycling spent fuel, and only using each fuel cell once before discarding it forever as trash, we might have ~150 years of U-235 before we run out. Remember, U-235 is a trace isotope found in nature. However, by recycling the exhausted fuel, that useful lifetime stretches out to thousands of years…with no carbon footprint from the making of our electricity! 

Think about it…

Think GREEN, Think Nuclear.

References :

1. Blees, Tom; Prescription for The Planet; 2008;
   http://www.prescriptionfortheplanet.com
2. Gabbard, Alex; Coal Combustion : Nuclear Rescource or Danger?: Oak Ridge National Laboratory; Communications and External Relations Group; http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html
3. Backgrounder on Radioactive Waste; United States Nuclear Regulatory Commissionhttp://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste.html; August 18, 2009
4. Whitlock, Dr. Jeremy; Waste Management; Canadian Nuclear FAQ;
   http://www.nuclearfaq.ca/cnf_sectionE.htm; 2009
5. Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management; International Atomic Energy Agency; Vienna, Austria;
   http://www-ns.iaea.org/conventions/waste-jointconvention.htm; 2003-2010
6. Table of Nuclides: Korea Atomic Research Institute;
   http://atom.kaeri.re.kr/; 2000
7. Periodic Table of the Elements; Los Alamos National Laboratory's Chemistry Division;
   http://periodic.lanl.gov/default.htm; updated,12/11/2003
8. Chart of Radionuclides; Columbia University Department of earth and Environmental Sciences;
   http://eesc.columbia.edu/courses/ees/lithosphere/labs/lab12/radionuclides/index.html
9. Interactive Chart of the Nuclides; Brookhaven National Laboratory;http://www.nndc.bnl.gov/chart/reCenter.jsp?z=6&n=8
10. Oklo's Natural Fission Reactor; American Nuclear Society: Public Information;
    http://www.ans.org/pi/np/oklo/          
11. Montgomery, Jerry, Phd and Rondo, Jeffery, PhD; Asymmetrical Fission Products; Unclear 2 Nuclear;
    http://www.unclear2nuclear.com/asymFission.php; 2008
12. Fission Fragments; Georgia State University Department of Physics;
    http://hyperphysics.phy-astr.gsu.edu/Hbase/nucene/fisfrag.html; 2006
13. Boyd, Rex; Radioisotopes in Medicine; World Nuclear Association;
    http://www.world-nuclear.org/info/inf55.html; updated, February, 2010
14. Winter, Mark; Plutonium; Web Elements, Ltd.; University of Sheffield, England;
    http://www.webelements.com/plutonium/isotopes.html; updated, 2009
15. Plutonium; Department of Radiation Protection; U.S. Environmental Protection Agency;
    http://www.epa.gov/radiation/radionuclides/plutonium.html; February, 2009
16. Cohen, Bernard, L.; Plutonium and Bombs: Chapter 13 of The Nuclear Energy Option; Plemum Press Inc.; 1990;
    http://www.phyast.pitt.edu/~blc/book/chapter13.html

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Front-end Nuclear Fuel Cycle

Front end Nuclear Fuel Cycle talks about the process of how uranium is mined from the very ground of the Earth, and then how it is being processes to make into Uranium Oxide or also known as yellow cake. However, today topic is not on the fuel cycle itself, but rather we are focusing much on the aspect of uranium abundances in the Earth.



As we can see in the picture below, we know that the current consumption is much lesser than the current usage of uranium in the world. Bt the question is how can this happen? This in short is because partly:

1) some country has started digging uranium long before NPP is founded.
2) the megatons to megawatts project which converts HEU (highly enriched uranium) into enriched uranium which can be used as fuel for power plant.



However, as we know, the current global power generated by nuclear power plant is roughly 6-7% of the total world power generated. Fossil fuel takes about around 80% of fossiel fuel consumption. So the question here arises is that are there enough uranium to fuel up for few hundred years before it run dry? This is to ensure that given the possibility of NPP to replace all fossil fuel, hence we can estimated the demand of uranium would increase at least 10 fold!!!. This shows that, if the current usage of uranium is 4.5million tonnes, per year by the time NPP take over all the fossil fuel, the demand will become 45 million tonnes per year. This is a huge number to worry about.

However, there are few reason why our group believe that uranium is not going to be depleted.

1) Nuclear price per tonne is still relatively cheap (less than USD80 per tonne).
Cheap price, means less $ goes into the R&D, which leads into less exploration to discover uranium deposits and also less mining of uranium ore. However, should the price rocketed to USD130 or more per tonne, we believe rigorous R&D will be poured into uranium searching, mining techniques and etc. This is because, its much more worth to mine uranium now as the profit margin obtained is so much higher.



2) Megatons to Megawatts Project.
This is a project whereby the US and the Russian has sign a pact to deplete their HEU into NPP fuels. And as we know HEU are at least 90% concentrated with U-235. Hence assuming perfect conversion of 3% enriched uranium-235, we can see that 1 tonne of HEU can produce 30 tonne of fossil fuel. So do imagine the number of enriched uranium we can get from this project.

3) Based on ecolo.org,

PROVEN Uranium reserves worldwide: about 4 million tons (current consumption rate of U worldwide is 60 000 tons per year => proven reserves at 80-130 $/kgU these proven reserves are enough for 65 years of use at the current consumption rate)

ESTIMATED Uranium reserves worldwide: about 16 million tons (current consumption rate of U worldwide is 60 000 tons per year => proven reserves at 80-130 $/kgU these proven reserves are enough for 265 years of use at the current consumption rate)

NON-CONVENTIONAL Uranium reserves worldwide (i.e. uranium contained in phosphates): an ADDITIONAL 22 million tons (representing an additional 365 years of use)

Uranium dissolved in sea water: about 4 billion tons (but more difficult and costly to retrieve)

Therefore, leaving aside the U in sea water, the total ESTIMATED + NON-CONVENTIONAL uranium reserves are enough for more than 600 years of use at current consumption rate using today's reactors and at a cost less than 80-130$/kg U (about twice today's spot price).

This shows that we have a long enough uranium supply for at least 8 generations. It should buy us enough time to discover other possible green fuels to supply our power plant by then.

4) Thorium as nuclear fuel.

Thorium is 3 times more abundant than uranium. However, according to world-nuclear.org, thorium can work pretty well in CANDU reactors ( Canada NPP which operates using normal uranium). Although currently thorium is not able to fissile on its own, if we can convert in into uranium 233 from thorium, we would also obtain a substantial amount of nuclear fuel. Do note that U-233 is as good as U-235 for nuclear power plants fuels.

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