Reply dgharris
Hello!
I hope you will take the time to visit Kirk Sorenson's Energy from Thorium site.
But to quickly offer comment on your assertions:
Thorium MSRs (often liquid fluoride thorium rx, LFTR) are proposed to use LiF and BeF mixed salt. These have low neutron cross sections and are essentially inert in the rx. Since the coolant loops are only under atmospheric pressure plus pumping pressure, leaks very quickly congeal. There is no steam explosion as found with high pressure superheated water.
Emergency shutdown is done through a system drain, merely a section of frozen salt that is kept below freezing point by a refrigeration or cooling system. In an emergency the coolant is removed, the frozen salt plug melts, and the system drains to a tank. At Oak Ridge, an MSR ran with this system, draining the salt into a tank each weekend and restarting on Monday, for several years.
FYI, Li an Be F salts are not very toxic. Even so they are not sprayed about in case of an emergency.
By contrast, proposed breeders want to use liquid sodium as a primary coolant and water as a heat transfer fluid. Care to speculate what a heat exchanger failure might look like in this device?
LFTR is proposed to use a core and blanket. The core is where most of the fission occurs, and the neutrons travel into the blanket where they transmute thorium to protactinium, thence U. U233 is the gamma emitter of concern. But all the U is removed...by bubbling Fgas through a side stream, then the U is reduced which changes it from gas to solid, and it is fed to the core where it fissions. Also, this sidestream is available for replenishing Th as it is utilize, just dump it in...no fuel rods.
Continuous processing is a huge advance, as is doing all this work in the gas phase.
LFTR is a mighty clever system!
You might ask, can it process radioactive wastes or surplus atomic weapons. Yes, but there are technical differences in the reactor.
Theoretically it can be done...the option has been well considered and to me it appears to be practical.
Tusky