Saturday, April 26, 2008

The benefits of LFTR's

(I posted this as a comment on Energy from Thorium this morning.)

1. The LFTR is an extremely safe reactor design. It is self regulating. Core meltdown is absolutely not a problem. Continuous removal of radioactive gases insure that only small amounts of radioactive gases would be released in a worst case accident. Coolant leaks do not lead to fires or explosions. There would be little or no solid fission product release/radiation problem in the event of a leak. Because of the chemical properties of the liquid salt coolant/fuel attacks by terrorists using explosives or aircraft, would not create a wide dispersal of radioactive materials. The use of liquid salts eliminating a threat to public safety from terrorists attack on LFTRs.

2. The thorium fuel cycle is efficient. Up to 98% of thorium used in a LFTR can be burned. In contrast only about 0.6% of uranium involved in the LWR/uranium fuel cycle is burned.

3. Virtual elimination f the problem of nuclear waste. The LFTR produces 0.1% of the waste that light water reactors produce, per unit of power produced. Instead, the spent fuel of LFTRs contains many useful and some rare and very valuable metals and minerals. LFTR "spent fuel" represents a potential means of providing industry with rare materials in an increasingly resource starved world.

4. Lowest fuel cycle costs coupled with very high fuel safety. A LFTR is more than a reactor. It is a fuel processing/reprocessing system. The liquid salts approach enables fuel and breeding materials to be processed on a continuous basis while the reactor is producing power. This includes continuous removal of gases produced in the nuclear reaction, the processing of newly breed reactor fuel, the removal of fission products. Nuclear fuel (U-233, U-235, and plutonium) can be continuously added to the reactor. Thus the reactor never needs to stop operating for refueling. The nature of the LFTR fuel cycle makes reactor fuel theft by terrorist impossible, while diversion of reactor fuel for weapons purposes a very unlikely approach to nuclear proliferation.

5. Lower manufacturing, construction and siting costs coupled with great manufacturing time efficiencies. The LFTR can be designed in a size that can be mass produced on assembly lines. Many external parts including heat exchanges can be made from low cost carbon-carbon composite materials, dramatically lowering materials, parts, and assembly costs. High reactor operating temperatures mean that electricity can be generated using low cost-highly efficient closed cycle gas turbines. Compact reactor/generation unit means smaller, less expensive reactor/power unit housing is required. The inherently safer design means that less money needs to be spent on reactor safety systems, and on accident containment, while assuring the highest possible public safety. Small reactor/power generator size can simplify siting problems LRTRs can be manufactured and set up in weeks or months, compared years for custom built LWRs.

6. Liquid core reactors can be used to dispose of existing stocks of nuclear waste..

8 comments:

Robert Hargraves said...

Regarding your statements that the LFTR can be mass produced on assembly lines and set up in weeks or months, can you give some evidence for this? Are these, say, 100 MW units? Would this include the onsite chemical reprocessing facilities? I'll use the information in my course, Monday, if any preliminary design work is published and seems reasonable. The course is at
http://rethinkingnuclearpower.googlepages.com

John Tjostem said...

Charles thank your for this concise and well crafted statement about LFTRs. I have been looking for such a statement. On Monday I will give a guest lecture to a college chemistry class. I will much of this information with them.

I am a retired microbiologist. My take on world energy is that fossil fuel can best be replaced with advanced generation nuclear power. Molten salt thorium looks most promising.

John Tjostem

Charles Barton said...

Robert just about any example of complex machinery can be mass produced. The reasons why civilians reactors have not been mass produced has more to do with their limited number, and the size of conventional light water reactors, prohibits the mass production of complete reactors. However I understand that Westinghouse plans to factory produce modular kits for the construction of AP-1000 reactors. AP-1000's are much larger and more complex reactors than proposed designs for LFTR's. Mass production of small Pebble Bed reactors has also been proposed.
http://en.wikipedia.org/wiki/Pebble_bed_reactor

I assume that a LFTR would be less complex than a modern commercial aircraft, which are factory produced over periods of several months. The LFTR production rate would depend on production goals, which would determine factory size. It is probably the case that production would not be as routinized as that of an auto factory, But given a goal to produce a very large number of reactors, highly routinized production is certainly possible.

Secondly, for reasons I have noted setting up a LFTR site would require less labor, material input, and time than LWRs. Site construction can begin even before the reactor is assembled. The reactor would either show up
completely assembled, or show up in several pre-assembled modules, that could be hooked up to each other in short order.

My model is provided by the Manhattan project. I grew up in Oak Ridge. I know the scale at which things were done. I have no doubt that a reactor construction program on a similar scale is possible, and given significant input of capital, Labor, Knowledge and materials, such a program could succeed.

My assumption is that that we will be at least as motivated to replace fossil fuel energy sources as we we were to win World War II, and that solving the problem would demands similar efforts.

Prove I cannot, the factory notion is a hypothesis based on several hundred years of human experience with factory production. I think that it would be difficult to disprove my assumptions.

Proving my notions about siting could be done by a careful analysis of the siting requirements of one or more small - 100 MW electrical output - LFTRs. As far as I know, no one has gone beyond mr simplistic analysis. It would be, of course highly desirable that this be done. But in the absence of any convincing refutation of my analysis, it is probably as good as any around.

Robert Hargraves said...

Charles,
I also used the Boeing example and MIT's modularization of the pebble bed reactor in the blog
pebblebedreactor.blogspot.com
but more R&D is needed on the LFTR to validate your idea. Are you and Kirk Sorenson able to influence the direction of the Gen IV international effort on molten salt reactors?

Charles Barton said...

Robert, My goal is to influence both the views of the public and the actions of key decision makers. Kirk has similar goals. I accept Alvin Weinberg's view that the deployment of LFTR technology holds the best hope for developing a world wide carbon free energy system. In order for that to be accomplished the LFTR needs to be told in a variety of media arenas. We have started with the Internet because it represents a quick way to develop a community of interest, and a method of getting quick feedback for ideas. By focusing on responses, and by participating in internet debate we get an idea of the issues that we need to focus on. I have decided to launch discussion threads on "Energy from Thorium" that will review questions about LFTR safety, post reactor materials disposal, and costs.

I am not a scientist, but I think that I have a fairly good grasp of some issues, and I can be relentlessly analytic is sorting out issues and problems. I think it is important to identify the issues and have to the extent possible answers in hand, when we address policy makers. To the extent we don't have answers in hand we ought to be able to discuss what would be required to ge the answers.

If we do a good enough jobs of identifying questions, the people who are examining our work will have little choice but to use our own list of questions which we are attempting to answer. It is by such attention to detail that I would hope to gain control of the discussion.

I believe that we have about 4 years to develop out case. In the mean time we can and will be active on the internet. Energy form Thorium is by far the best blog/form on nuclear energy on the Internet. I believe it is also the best site on the Internet to learn about nuclear energy, and reactor technology. I have no doubt that it is widely read, and that what we write catches the eyes of nuclear scientists around the world. I suspect that we may be also beginning to catch the attention of some policy/decision makers, but that has not surfaced yet, and might not for some time.

Robert Hargraves said...

Charles,
One way to influence decision makers is directly. When I became interested in pebble bed reactors went to Rotary Clubs and gave presentations, while inviting political aides to see audience response. I was then able to get one-on-one 30-minute meetings with my NH Congressman and later my Senator. You can do the same.

After I finish giving my Rethinking Nuclear Power course I'll think about LFTR, but the technology is further away than the PBR.

Charles Barton said...

Robert, distance in time is relative. I believe that given sufficient resources, developmental time for either the PBR or the LFTR will not be long. Thank you for your interests and suggestions.

Anonymous said...

A LFTR type reactor was run by the US government in the 1960's for a period of 6 years. Technological advancement in materials construction and handling has advanced considerably since then. Why can't we do again now what we did 50 years ago using more advanced technology? I don't know how the pebble bed can be further ahead in understanding, design, and deployment than the LFTR technology from the 1960's.

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