The Big Picture: It's nearly impossible to imagine making meaningful carbon dioxide reductions without designing safer, cleaner reactors and rolling them out immediately — because no one wants to build more of the reactors we have today.
Where We Are Now: 372 GW
What We Need by 2050: 700 GW
Tech to Watch: Next-generation Nuclear
Of all carbon-free energy sources, nuclear power is the only one that's already working on a large scale, generating 21 percent of America's electricity. It's also the one that freaks people out the most. Memories of Chernobyl, fears of terrorists getting nuclear material, and unease over waste that stays radioactive for tens of thousands of years all mean that before nuclear power can be expanded on an order needed to meet greenhouse-gas-reduction targets, engineers will need to build new reactors that help mitigate the unique dangers of nuclear fission.
In the short term, we'll have to settle for so-called Generation III+ reactors — simpler, safer and cheaper versions of the water-cooled behemoths that dot the landscape today. But 20 to 30 years down the line, things start to get much more interesting. Here's a look at the next few decades of nuclear power.
Design: Pressurized water
How it Works: Like today's reactors, these bathe enriched uranium fuel in water that absorbs heat to make steam.
Promise: Gen III+ pressurized-water reactors add "passive" safety mechanisms that cool the reactor if the plant loses power. For example, in an emergency, water flows from an extra tank above the reactor, driven by gravity.
Problems: Radioactive waste takes years to cool before it can be stored in underground repositories, which still don't exist.
Status: Mitsubishi-Westinghouse, which developed the design, has received approval from the U.S. Nuclear Regulatory Commission and has signed contracts to build six reactors in the U.S. and four in China.
Design: Pebble bed
How it Works: Tennis-ball-size graphite spheres (pebbles) filled with uranium dioxide fuel capsules are stacked in the reactor like gumballs, where they start a nuclear reaction. A pump sends helium into the reactor, where it flows around the pebbles, absorbs heat, and then drives a turbine.
Promise: If the coolant is lost, the graphite pebbles absorb enough heat to prevent the fuel from melting down.
Problems: A single reactor requires billions of perfectly manufactured fuel capsules. If oxygen seeps in, the fuel can catch fire. The reactor uses enriched uranium (also good for making bombs) and produces radioactive waste.
Status: Researchers have built and run small test reactors, but the design hasn't been commercialized.
Design: Traveling wave
How it Works: Enriched uranium starts the process, releasing neutrons that help convert scrap depleted uranium (left over from enrichment plants) into plutonium. The plutonium releases yet more neutrons that convert more depleted uranium into usable fuel [see illustration above].
Promise: Very little enriched uranium is required, and there is already enough to last for centuries using this technology.
Problems: Cooling the reactor could require molten sodium, which catches fire if it comes into contact with oxygen or water. No one has built even an experimental traveling-wave reactor.
Status: A think tank called Intellectual Ventures wants to build a plant by 2020, but outside experts are skeptical, saying it could take decades.
Interesting that all the work put into writing this broad ranging piece to look at solutions to the huge energy problem we all now face manages somehow completely to ignore fusion energy.
Fusion is nature's way of expressing energy release on the large scale. Just look up into the sky any time, day or night. All that light, from the sun and all other stars, comes from fusion... nature's energy engine.
Scientists have been working to harness fusion for something like 50 years, and the old joke that "it's 50 years in the future and always will be" no longer stands.
In fact scientists "cracked" fusion crudely when the first hydrogen bomb exploded, because that was a crude manifestation of the fusion process. What they have been doing ever since is to work out how to do the same thing (releasing energy locked inside atoms when the big bang created them) in a controlled way and on a small scale, producing a steady energy output.
Despite years of half-hearted funding, they are now on the threshold of achieving this.
There are still huge technical challenges to face, but (as pointed out in an earlier comment) Moore's Law applies... these problems are being overcome one by one, and the clock is ticking.
There are two realistic approaches to achieving controlled fusion energy... the first is through electro-magnetic confinement (currently the international ITER Project is enduring a period of funding doubt just when the commitment to build a reactor is in its early stages). Then there is Inertial Confinement Fusion, using large lasers to deliver sufficient energy to a small fuel pellet to trigger fusion. This is approaching "Proof of Principle" at the National Ignition Facility (NIF) in Lawrence Livermore, California... a real example of "swords beaten into ploughshares" as a large laser facility originally built for nuclear weapons stockpile stewardship finds a new and far more relevant use in triggering fusion in a fuel pellet for the first time.
Beyond Inertial Confinement there is a variation called "Fast Ignition", using two laser shots in sequence on each fuel pellet, to make it easier to run the process on a fast-repeating basis and thus to produce continuous power. The demonstrator for that will be the UK-led international HiPER Project, now into the planning stage.
And finally, now being planned at Lawrence Livermore, called LIFE, a further step will move forward from inertial confinement to create a hybrid approach in which the fusion process is used to "burn" so-called "spent" nuclear fuel, thus reducing in scale the existing problem of storing large quantities of radioactive waste from fission reactors. It will extract vastly more energy from the fuel than has been possible so far.
Fusion is no easy fix. It will take a long time and cost a lot of money, but really it's peanuts against the money we are wasting on exhausting our supply of fossil fuels right now. There are not many years before the lights will start going out. Essentially we have squandered in a couple of centuries almost all the fossil energy stored by nature on earth over the past 4 billion years. THat really isn't smart !
Fusion will create no CO2, very small amounts of short-lived radioactivity, and the process will depend upon a fuel which is virtually inexhaustible on earth... the hydrogen isotope Deuterium is the prime factor, and that can be found in sea water. No need to point out how much "energy security" for nations around the globe will result from cracking a process which provides a fuel supply to such a large percentage of the planet ! A single cubic kilometre of sea water contains the fusion energy equivalent of the entire world's oil reserves.
The idea of a long term energy roadmap is exactly the kind of thinking we need right now. The challenge for governments across the globe is to engage witrh the heavy responsibilities of such an approach, because clearly the period of time involved significantly exceeds the life of any government. That takes true selfless vison and rules out short term political self-interest. We need leaders around the world capable of rising to that greater challenge... for the sake of our children and generations yet unborn.
Yes, we need to develop renewable energy as much as we can, but equally we must recognise that, on its own, renewable energy won't bridge the huge energy gap we are now facing. Yes, we need a new generation of fission reactors, safer, better built and longer lasting than the earlier attempts... and perhaps most important of all, we absolutely MUST devise ways of weaning mankind from dependence on fossil fuels. That requires not only replacement technologies, but also persuasion... we MUST persuade the developing world (and much of the developed world too), that the only answer is to "bite the bullet" of the energy crisis, and do it now.
Fusion energy is an absolute requirement to handle the serious grid base-load requirement for the long term, and 2050 is a realistic timescale in which to achieve it... but ONLY if we keep on doing the work that has been started, and ONLY if the political vision sustains the necessary funding to get that research and development done. The world needs both magnetic and laser approaches to fusion energy development. We are almost there, with "energy break-even" probably less than 3 years away. Fusion must not be left out of the thinking... even in an article like this. Ideas are the only solution to this problem and the written word is what drives ideas !
James W Makepeace
Fusion's a pipe dream, and a waste of money. How much more money are we going to shovel down that pit when building wind turbines in pastures and putting solar panels on schools works right now?
Wind turbines and Solar panels sound great and may make people feel good, but the truth still stands, they are not commercially viable,hence the reason they haven't been put into practice, even though, in the case of wind turbines especially, the technology has been around for countless years. (medieval windmills anyone?) Both Fission and Fusion power are and should continue to be, an important part of our future energy discussions.
Cool side note on Fission power, if it were so dangerous, would the U.S. have 6+ weapons grade reactors anchored off the coast of Norfolk Virginia, ready to go into battle?
While solar, wind, water, and bio-fuel power generation is possible, it is more expensive than power generated by coal, oil or natural gas. Most people do not want to pay 10% more for their electric power in the summer and pay 60% more to heat their homes in the winter with electricity generated from renewable sources.
Most people do not want to pay $10,000 extra for their homes to drill two deep wells, to use a heat pump, that uses water drawn from the ground, to heat and cool their homes. Plus you need a acre of land to drill two wells far apart enough to draw enough water from the ground to heat and cool a home.
Most people do not want to spend $30,000 to put enough solar panels on their roofs to generate enough electric power for their homes.
So far all tests of fusion reactors have failed. Each tests results lead to building larger test fusion reactor in the hope of building a design that produces more energy that it consumes.
I have read that present design of fusion reactors have one major draw back. The magnetic fields we are capable of producing are not powerful enough to contain all the radiation released during fusion. When Deuterium is fused it releases high speed particles that slowly destroy the wall structure of present design of fusion reactors. The projected life span of a deuterium (aka H2) fusion reactor is 5 years, too short of a life span to be cost effective. At this time the cost of solar and wind power is cheaper than the cost of power from a projected functional H2 fusion reactor.
There is a much rarer form of Hydrogen on Earth called H3. Fusion of H3 releases fewer high speed particles to escape the magnetic field generated to hold the plasma. Tests show that the life span of a H3 fueled fusion reactor would be 20 years. A cost of power generated by a H3 fusion reactor is projected to be less than the cost of solar, wind, water, bio-fuel power.
The problem is that H3 is too rare on Earth to be a viable fuel source. There is talk about a possible solution to the shortage of H3 to power fusion reactors on Earth.
The Sun puts out large amounts of H3. Earth's magnetic field prevents H3 from landing upon Earth.
The Earth's Moon has a lot of H3 on it's surface. Why do you think the US is planning upon going back to the Moon? To mine H3 and ship it back to Earth. Or at least that is what some scientists are claiming.
Of course scientists are doing research into building stronger magnetic fields to make fusion with H2 possible and cost effective.
"Mitsubishi-Westinghouse, which developed the design, has received approval from the U.S. Nuclear Regulatory Commission and has signed contracts to build six reactors in the U.S. and four in China."
Just a nit, but I believe it is Toshiba-Westinghouse, not Mitsubishi-Westinghouse :).
Power from fusion is no pipe dream. I'm writing this comment using fusion power right now - by which of course, I mean solar-electic power.
Yeah, solar panels are expensive now, but if they were mass produced in large quantities, the price would drop. Then there's solar thermal, which is very scalable and potentially much cheaper, and further out there's orbiting solar collectors. If we can pipe electricity down from collectors outside the atmosphere, no need to bother with any terrestrial sources.
We need a better power grid, and better storage options to make some of these options (particularly renewable source) workable. A better power grid would also use less energy.
As far as the reactors go...well, whatever brings CO2 down. It's not my favorite option, but anything that displaces coal is automatically a good thing.
Where does Thorium Nuclear fit into the mix. It is my understanding that a thorium reactor can actually "eat" spent uranium fuel, cannot melt down and has a significantly shorter half-life, yet I don't much written about it. I would like to see a future article on the status of this technology
It seems no one is looking into the transfer method.
What I am talking about is the way we convert this energy into usable electricity.
Currently the 'method' is to heat water into steam and drive a turbine that in turn drives a generator.
Seems to me research on the convertion process needs work.
Get more efficient transfer, get more power.
you do know that we dont use fusion reactors, right? we use fission (sp?) reactors, which do the opposite of fusion reactors. they dont put atoms together to create bigger atoms, they split atoms apart and take the energy created. if we had fusion reactors, you realize how much energy could be created from them? instead of having multiple reactors (say 50) to power an equal amount of distance, you could have a single one power that distance (although i am not too sure on the numbers, i do know that fusion produces much much more energy)
There is a more realistic approach to achieving controlled fusion energy. Aneutronic reactor is to be cleaner and safer, neutron-free.
Nuclear fission is safe, the accidents are what make it unsafe D:
We need Robots to control our nuclear facilities! No more human error :)