Pages

August 02, 2011

Kirk Sorensen has a Forbes Blog - The Future of Energy

Kirk Sorensen now has a regular Forbes Blog - The Future of Energy

Kirk Sorensen has been running the Energy from Thorium site and discussion forum on thorium

Kirk has started a thorium power company Flibe Energy.

Here are several of his first articles -

Fissile Material has the Midas Touch

The energy content in fissile material means that it is worth six times its weight in gold.

So unlike gold that can only be sold for money once, fissile material if properly used has the Midas touch–it can keep turning worthless uranium-238 or thorium into fissile material indefinitely.

The bad news is that we are not using fissile material properly in today’s nuclear reactors. We’re wasting its Midas touch. The good news is that we can build new reactors that will be able to exercise this amazing ability. They will change the world. They will be the future of energy.



Is Fissile Material Worth its Weight in Gold?

One megawatt-hour has a wholesale cost in the US of about $40, so 7600 MW*hr would be worth about $300,000. If we had a hypothetical nuclear reactor that could turn fissile material to gold, it would make about $50,000 for each kilogram it transmuted. But in the real world where real reactors release energy from the fission of fissile material, that’s worth $300,000 per kilogram fissioned. That’s a six-to-one difference.

A Simplified Nuclear “Waste” Digester

A recently released report titled “Fast Spectrum Molten Salt Reactor Options“.

We only consume a small fraction of the energy content in the uranium (less than 1%) before we remove it and throw it away. We don’t do this because we’re stupid or evil, we do it because it’s very difficult to get the vast majority of the energy out of the uranium.

Building nuclear reactors that “burn” the rest of the uranium is hard, because we have to build a totally different kind of reactor from the kinds we have today. These reactors use “fast” neutrons instead of “slow” neutrons in the reactor. All of our reactors today use “slow” neutrons, and again, there’s some very good reasons for that. We’re not using “slow” neutrons because it’s a bad idea–in fact, using “slow” neutrons solves a lot of problems.

The Oak Ridge paper suggests using liquid nuclear fuels instead of solid nuclear fuels. That solves a lot of problems right from the outset. Liquid fuels are mixed up in big batches, by remote control, with very simple procedures. Solid fuels also have to be mixed up in big batches by remote control but then have to be fabricated into shapes, typically pellets or spheres. Getting the fabrication just right is a major cost and technical challenge. That’s just not a problem for liquid fuels.

The material used for the fuel in the Oak Ridge report is different. It’s a salt, which means it’s in a class of materials that are the most stable and non-reactive known to man. And since the fuel is a liquid, it is its own vehicle for moving that heat from the inside of the core to the outside. It doesn’t react with air and water. These salts aren’t as good as sodium at moving heat (thermal conductivity) but they hold a lot more heat than sodium (thermal capacity). This means that they have the potential to be more compact and less expensive.

A Simplified Nuclear “Waste” Digester, Part 2

The salt-based fast reactor can fix a lot of problems that the sodium-cooled, solid-fueled fast reactor faces.

The biggest one is safety. I’ve already mentioned how the salts are stable and unreactive and the sodium is dangerous and explosive. But another reason is that things get, shall we say, “twitchy” in a fast reactor versus a reactor that uses slowed-down neutrons. Twitchy is NOT a good quality to have in a nuclear reactor, and it’s one of the bigger reasons we use slowed-down neutrons in all our reactors. Fast reactors based on salt can remove most of the “twitchiness” from fast reactors compared to the ones built around sodium.

Meltdown is another big issue when you’re dealing with a solid-fueled reactor, because the structures of the reactor aren’t designed to hold melted solid fuel. It’s too hot. So it can potentially melt through the big steel vessel that holds the fuel and the sodium if there is a meltdown.



If you liked this article, please give it a quick review on ycombinator or StumbleUpon. Thanks
blog comments powered by Disqus