Molten Salt Reactor

Ed Cone linked to a great article this morning concerning the fate of nuclear energy:

a growing body of evidence suggests that new nuclear construction projects are prone to the same setbacks as those undertaken a generation ago, when lengthy delays and multibillion-dollar cost overruns were commonplace. This raises serious questions about the potential of nuclear power as a front-line solution in the battle against climate change.

Or, the bankers are sissies, we can’t pour concrete or place re-bar and the engineers are dolts.

RBM showed up with another great article:

Molten-salt reactors have a number of advantages over today’s water-cooled technology:

1. They cannot suffer a meltdown, because the fuel is already molten. If the cooling systems are shut off, the reactors shut down through their essential physics; they are inherently safe.

2. They cannot explode, because they run well below the boiling point of the salts and require no pressure vessels. This also makes their components relatively lightweight and easy to manufacture.

3. They can run at relatively high temperatures, which increases their efficiency and makes the heat usable for many industrial purposes.

4. They can remove fission wastes continuously, so there is never a danger from “afterheat” when a reactor is shut down.

5. The extracted wastes are relatively pure rather than containing large amounts of unused fuel, so their bulk is comparatively tiny. The wastes can be made ready for permanent disposal right at the reactor site. Fuel cannot be diverted for weapons because it never leaves the reactor building.

6. They can be started up with plutonium from spent nuclear fuel or reclaimed weapons material, and can destroy this fuel while breeding new fuel from thorium.

7. The physics of breeding thorium to uranium creates uranium-232 as well as uranium-233, which is not a difficulty for power production but makes the material unsuitable for use in weapons. Even more so than light-water reactors, molten-salt thorium breeders do not pose a risk of nuclear weapons proliferation.

According to recent news, the USA has approximately 900,000 tons of high-grade thorium reserves. This is approximately 2000 years of supplies at current rates of electric consumption, or hundreds of years if thorium was substituted for all fossil fuel. Lower-grade thorium resources include coal ash.

And I stole one from RBM in my comments.

With visions of nuclear electricity “too cheap to meter” long gone, the case for breeder reactors has shifted from creation of new fuels to management of spent fuels. Without breeder reactors, the case for reprocessing is less than compelling. Considered in isolation, the economic arguments for and against reprocessing are a wash. Most of the arguments concerning security and terrorism, too, seem moot. But until or unless breeder reactors are commercialized that can truly burn up all the residual fissile material found in spent fuels, reprocessing will simply concentrate high-level waste in a form that’s hotter and harder to handle, exchanging one nuclear waste headache for another.

Now that I’ve completely ripped them off, let’s go fishing.

From Wikipedia:

The low pressure makes the entire reactor core much simpler and lighter, while the high temperatures makes the turbines that extract energy much more efficient, allowing them to be smaller as well. Another advantage of a small core is better neutron economy, which makes the molten salt design particularly suitable for use with non-uranium fuel cycles…

The salts do not burn in air or water, and the fluoride salts of the actinides and radioactive fission products are generally not soluble in water…

Salts of long-lived transuranic metals go back into the reactor as fuel…

Control of the salt’s corrosivity is easy. In the MSRE, a beryllium rod was inserted into the salt until the UF3 was the correct concentration.

OTOH:

The high neutron density in the core rapidly transmutes lithium-6 to tritium, a radioactive isotope of hydrogen. In an MSR, the tritium forms hydrogen fluoride (HF). Tritium fluoride is a corrosive, chemically poisonous, radiotoxic gas. All MSR designs used very expensive isotopically purified lithium-7 for their carrier salts in order to reduce tritium formation as far as possible. The MSRE proved that this worked…

Since it uses unfabricated fuel, basically just a mixture of chemicals, current reactor vendors don’t want to develop it. They derive their long-term profits from sales of fabricated fuel assemblies.

This is almost too good to be true:

A safe thorium breeder reactor using slow thermal-energy neutrons also has a low breeding rate. Each year it can only breed thorium into about 109% of the U233 fuel it consumes. This means that obtaining enough U233 for a new reactor can take eight years or more, which would slow deployment of this type of reactor. Most practical, fast deployment plans would start the new thorium reactors with plutonium from existing light-water reactor wastes or decommissioned nuclear weapons. This scheme also decreases society’s stock of high-level wastes…

Thorium is more abundant than uranium. The Earth’s crust has about three times as much.

I’m having Deja Vu all over again:

The business model for molten-salt fueled reactors would not involve fabricating fuel assemblies, and therefore seems risky to many nuclear vendors.

Oh, look who we just ran into:

One of the main disadvantages of solar – and most renewables – is that it is difficult to guarantee regular supply to the grid. Supply drops off at night and at times of cloud cover, meaning that even in the sunniest desert there are no 100 per cent guarantees of regular supply.

Solar thermal technologies can increasingly get round this problem by either using molten salt to store the sun’s heat overnight, using it to create the steam and power the turbines long after the sun has set, or by integrating a biomass or even fossil fuel generator to power the turbines when weather conditions mean the the solar panels fail to generate enough energy.

They’re testing in Seville:

So far the company has demonstrated that it is possible to store up to eight hours of solar energy by heating tanks containing 28,000 tonnes of salt to more than 220C.

The sites seem related:

Torresol Energy is an alliance between Spanish engineering group SENER and Abu Dhabi-based renewable energy initiative Masdar. Masdar is headed by Abu Dhabi Future Energy Company, which is owned by the government of Abu Dhabi through the Mubadala Development Company.

By God, there’s responsible use of our petro-dollars:

Saudi per capita oil consumption is now the highest (32.88 bbl in 2006), followed by US (25.64); and India at #20 (0.87.) New, sustainable energy (and water) sources are needed as much in oil rich Gulf states as anywhere else.