Every reference this guy uses has been debunked five ways from Sunday:

http://pche-sts.blogspot.com/2012/05/disinformation-and-anti-propaganda....

Bottom line: Let's build some and see.

Mike, thanks a lot! Great blog post. I agree!

Please give us a link!

Thanks a lot. Super.

Clearly, the author of this article doesn't understand the myths behind his own "myths".

The issue of 232U is irrelevant to a system in which all the fissiles and all the fertiles, and all the rest remain inside the reactor salt forever, unless we want them out -- Xenon out for efficiency, Molybdenum out for sale, etc.

The Thorium breeder is, in fact, not even the necessary first step, since we need fissile to start any reactor, whether it later becomes a breeder or not.

The DMSR (denatured) is what can consume any fissile waste from solid fuels, and even breed Pu from the vast amount of solid 238U lying around. If we do the latter, we likely have a faster neutron spectrum (epithermal-fast) and a secured system. We've over 100 years worth of all U isotopes sitting around, including 'depleted' U as UF6 canisters -- tens of thousands of them just in Kentucky.

But in any case, MSR or LFTR, let's get some reality. The power out put of a 3GW thermal (1GWe) liquid-salt fission plant arises from less than 1kg of fissioned material per hour. That's for over a million people.

That amount of 233U, 235U, 239Pu... is an English golfball in size. As fluoride/chloride salt, it's much larger, but, in order to steal a bomb's worth of fissile, someone would have to sit beside a reactor, running at 700C and radiating profusely, all while dripping out several net kilos of fissile -- that's a lot of salt and a lot of hours for the siphoning.

Even if the thief had worked on building the plant and installed a secret drain pipe to the outside perimeter, the fact that a liquid salt reactor consumes just what it needs each second to run the turbine (or other) thermal load, means that any diversion of fissile will be obvious - city lights will dim, operator instruments will fade, and turbines will sound sad.

A thief will maintain a 700C, highly-radioactive liquid path to his catch pail for hours?

Many easier, survivable ways to get or make bomb materials.

The folks in the media who write oddly ignorant pieces really need to follow Tom Lehrer's advice to those who feel they "can't communicate",

;]

Hah, that thief scenario is pretty improbable! :D

Thanks Alex for the enlightening comment.

Yes, here it is: http://thoriumforum.com/reply-mr-makhijani

I posted a comment on Meyerson's blog:

http://kevinmeyerson.wordpress.com/2012/05/06/thorium-nuclear-bombs/#com...

I think it's not stupidity, just ignorance. And we thank you for explaining it to us!

I'm just guessing here, but the only scenarios I can think of would be to burn spent fuel - which isn't bomb-grade - in a two-fluid LFTR's core to act as a neutron source, which would convert U-238 in the blanket into Pu-239, or convert Th-232 in the blanket into Pa-233.

In either scenario, the substance created would need to be continuously extracted from the blanket salt. The Pa, once sequestered, would soon become pure U-233.

The LFTR wouldn't be an iso-burner if used in this manner, so it would have to be continuously fed spent fuel, which would have to be processed to some degree beforehand and converted to fluoride form. The core would essentially serve as a spent fuel stove, used to cook up bomb material in the blanket.

This may or may not be as difficult as directly processing bomb-grade material out of spent fuel. Can anyone put this into perspective for me?

The issue of using spent fuel comes down to secure processing and secure use, since Plutonium & Neptunium have fissile isotopes and thus can constitute weapons.

Chemistry of processing spent fuel also enters, since acid reduction and fluorination work somewhat differently for Pu (and perhaps Np). from how they work with U isotopes.

The key question for using spent fuel is thus security. In the denatured MSR, any fissile/fertile can be used and retained in a single-fluid system, if desired. The addition of fissile would occur on a yearly basis, and the transuranics could be fissioned away, if the neutron spectrum were so designed.

The DMSR is the likely candidate for getting rid of wastes efficiently...

http://tinyurl.com/8xmso5v

I guess large Th plants will have to be extremely secure anyway, right?

I see Totterdell making one error -- Thorium233 decays into Pa233, it needs no neutron. Only 2 neutrons are needed for breakeven breeding & fissioning.

Not particularly. Thorium fluoride isn't a weapon. What's fissionable 233U, only exists inside the core fluid. Read what I wrote on the Kevin Myerson myths page.

1kg of U or Th is consumed per hour for a city. How long do you think one could sit by a reactor siphoning out fluoride salt before getting enough 233U to make a bomb? Rmember, there's about 30 tons of slat in there and at most a ton of fissile.

Plus, the siphoning rate would have to be very slow to avoid dimming the lights! Talk about frying terrorists!

True, and that's the point -- we're not making extra fissile to have to take out and transport to another reactor. The iso-breeder makes just what it needs and no more. The neutron budget is tight, but manageable. The MSR is a broad family of systems, with many opportunities to use architecture & materials to not only exploit those 2.3 neutrons, but to manage longevity of the structures.

That's exactly my point - that using a 2-fluid LFTR to make weapons-grade material would be turning it into a Rube Goldberg device. Whatever chemistry you have to do to prepare spent fuel to serve as LFTR fuel to breed weapons-grade material in the blanket, you could do the same or similar chemistry to isolate weapon-grade material from the same spent fuel. Thus I refute Meyerson's contention that LFTRs would be used to make weapons. And in any case, you're right - this is all academic until the first wall material for 2-fluid LFTRs has been developed.