[ahaefner]

Commercial power reactors are very expensive initially (multiple billions). This is a huge barrier to entry for most power plants. So the thinking is if the size can be reduced so can the cost.

The military is interesting because they already have small reactors in submarines and ships. And they have access to the highest grade fuel because they don't have to follow power plant regulations. So it seems like if these modular reactors would be useful to them, they could easily adapt these reactors for land use.

This startup is hard to gauge because there's so few actual details about their design. For example, how are they going to use thorium as a fuel? You can't just use thorium without a strong neutron starter source or some other fuel engineering.

[beefman]

'It can burn any fuel' is just code for 'we have no real core design yet'. But it doesn't matter, because no nuclear fuel is significantly better than any other, and they're all thousands of times better than alternatives.

Thorium is always used in mixed cores. An accelerator-driven thorium reactor will contain uranium from breeding even if no uranium is ever loaded into it.

[jddw]

There are core designs for low enriched uranium loading, mixed thorium loading, and spent fuel loadings. Have to make sure a fuel design works before it's claimed to work.

[beefman]

With 12 years of burnup? I've been having trouble getting burnup codes to handle thorium. What are you using? Apparently I should be using Serpent.

But anyway, 12 years is too long, even if it's feasible. Something like 4 years should be better, due to the learning curve on these. For instance, think of a reactor in the field as a ship on a long trip while technology at home continues to improve

http://en.wikipedia.org/wiki/Wait_Calculation

Edit: The lower the enrichment, and the lower the excess reactivity, the better.

[jddw]

The concept is to start small to overcome cost and regulatory barriers more quickly and for less.

And yes, we kick start using thorium with low enriched uranium or spent fuel to build up U233. Then we just keep reusing the thorium fuel over multiple refueling periods without reprocessing or separations until it is depleted.