Energy From Thorium Discussion Forum

Here's a recent paper from Dr. Kazuo Furukawa and his colleagues:

A Road Map for the Realization of Global-scale Thorium Breeding Fuel Cycle by Single Molten Fluoride Flow (PDF, 3.0 MB)

Excellent paper. Great to see Dr. Furukawa is still active in the field. I highly recommend people reading his comments on the advantages of molten salt reactors and why the acceptance of these designs has had such a hard time, very insightful. This is in section 3 of the paper.

I wonder about the "and his colleagues" bit.

The linked document says that its a DRAFT for the June 2007 ICENES conference in Turkey.

While there are some good things in this draft, there are also some very debatable ones, and some that are just plain wrong.

The author list includes seventeen names -- which makes it hard to believe that all these people would sign on to everything that's in this draft.

If indeed the current draft is only the product of one person, as I suspect, then I think its unethical to post it publicly before all the other people named as authors have had a chance to review/ edit it.

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They may be in the middle of that review cycle right now...let's give him the benefit of the doubt.

Hi Jaro,

What were the things you had the most problems with? I know they stretch things a bit in their promotion of molten salt and the complaints against industry (quite political in places instead of technical). Overall though I thought it a good presentation.

One interesting bit of information that I think we`ve been looking for in other post threads was how low plutonium production actually is compared to LWR.

For Molten Salt Reactors

Pu production =0.5 Kg per year per 1000MWe

For LWR

Pu = 250 Kg per year per 1000 MWe

As Kirk has previously mentioned, you can even cut off that small amount of Pu production by removing Np when you fluorinate the fuel salt.

Jaro mentioned problems he had with the paper. One thing I did forget to mention in my last post was a big problem I had with their statement about negative temperature coefficient being large. Now that I reread it though, they are not really saying anything untrue. Let me quote from page 15 of the report:

"The MSR has a large negative temperature coefficient of the fuel salt and can supress an abnormal change of reactor power. Because the heat capacity of the graphite is large, resulting in only a slow temperature increase, it is possible to control the reactivity although the temperature coefficient of the graphite is positive."

When I first read that I had a problem with it as I thought they were claiming a strong overall negative temp coefficient. When you examine that statement closely though, it does make sense. The problem I had with it is that early ORNL work calculated a very slight overall negative temperature coefficient (at least with the MSBR). That has since been shown to be not true and that overall it was slightly positive because of effects from the graphite (but can be fixed relatively easily).

However, it is true that the salt itself has a healthy negative coefficient. It is the effect of graphite that brings in the unhealthy positive term. This undesired effect is slow acting though as the graphite has to heat up secondarily. ORNL work quoted a time constant of 140 seconds which sounds like a quite a lot of time to react to any sort of power increase. Thus this Furukawa statement is accurate if perhaps slightly misleading.

David,

Political is right.

On the technical side, I guess that my biggest beef is with the paper's promotion of accelerator driven breeders, while deriding FBRs.
This is absurd, as has already been pointed out on this forum previously:



I think the point is that either type of facility for producing fissile material is, at least under the GNEP scenario, intended to be built & operated only in countries that are signatory to the NPT.
As regards possible proliferation to non-NPT countries, one could probably argue that ADS are a bigger risk than FBRs, as they don't require the construction of an entire thermal power plant.

But I'll give them credit for at least recognizing that the highest possible breeding ratio is desirable, if we want rapid growth in nuke power in the future.

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Dr. Furukawa has sent me the final version of his paper, and here is the link:

A Road Map for the Realization of Global-scale Thorium Breeding Fuel Cycle by Single Molten Fluoride Flow (PDF, 3.0 MB)

I am also disabling the link in the original post and removing the previous version of the paper from the server.