Some how great ideas come across as crazy when you first hear them. I thought that Jim Holm's idea of recycling coal fired power plants by converting them into nuclear power plants was crazy the first time I encountered it. I now think it is a terrific idea. I wrote about the idea in May and it recently bubbled up on the "Energy from Thorium" discussion form. I usually don't openly discuss ideas that come up on the discussion form, because I think what is said in the discussion form is a private conversation. But in the case of converting coal fired power plants into LFTR plants, this is an idea that has been floated by Holm, and which I seconded in May.In addition to Jim I owe a good deal to Dr. Robert Hargraves. Several months ago, in an unposted note I wrote:
Dr. Robert Hargraves is a very bright fellow. He thought of some of my best ideas before I did. I did not steal Dr. Hargraves ideas, but I may have borrowed a few. I think that I actually developed my ideas for a factory build, small LFTR before I read Dr. Hargraves Blog. There are actually a few variations between Dr. Hargraves visions and mine, but that is beside the point. Both of us think along similar lines about the advantages of small reactors and how to build them quickly, in expensively and in large numbers. Our thinking is directed to slightly different technologies. Dr. Harvraves offers us some interesting insights into technological advances since the 1970's that can contribute of PBR and for that matter LFTR technology. Anyone who is interested in Reactor safety, ought to read Dr. Hargraves discussion of PBR passive safetyIn addition, Kirk Sorensen, David Walters, David LeBlanc, Axil, DV82XL, Lars Jorgensen, the Sovietologist, Alex P, Dr. Buzz0, Jaro, and numerous others have deeply influenced my thinking. Lets face it, if there is a nuclear Renaissance these guys are in its intellectual forefront. it is a whole lot easier to have have good ideas if there are a lot of bright people around to steal your ideas from.
One idea that I quickly latched on to was the idea of the small reactor as the key to the rapid deployment of the enormous amount of nuclear power we need to deploy between now and 2050. I first thought of small reactors in 207, when I asked myself a simple question: How can we deploy enough rectors by 2050 to replace at least 80% of the fossil fuels we currently use. My answer was to do what you always do when you want to make a large number of modular objects. You build them in factories. But a Westinghouse AP-1100 is a little big to transport from a factory to its final destination. Westinghouse decided that if it got a large number of AP-1100 orders, it could factory build kits, and assemble the kits on site. This is going to take maybe 16 million hours of on site labor, so the AP-1100 is not a a factory built reactor.
What you need to increase the speed reactor deployment, is a factory constructed reactor that is small enough to transport by truck, railroad or barge, from he reactor factory, to its final set up site. Kitk Sorensen and a couple of his fellow UTK nuclear engineering graduate students had designed a transportable 100 MWe reactor, and so 100 kWe was the placeholder size. In fact, David LeBlanc designed a 400 MWe reactor, the core of which would be ridiculously easy to build in a factory, and be transported to its final set up site by truck. So I regard the final choice of reactor size as a matter to be decided by the people who are going to build the thing.
I picked out the Molten Salt Reactor as the best technology for the project, because of its simplicity, small size per unit of power output, and because the MSR offered solutions to virtually every problem of nuclear power. It is very safe, produces as little as 0.1% of the waste produced by conventional reactors, is up to 300 times more efficient than conventional reactors, and will never run out of fuel. A variant of the MSR, the Liquid Fluoride Thorium Reactor is a thorium fuel cycle reactor. Thorium is a very abundant mineral, so abundant that we will never run out of it no matter how much energy we extract from thorium. I was familiar with the MSR because my father had spent nearly 20 years of his Oak Ridge National Laboratory career involved in various research projects related to the concept. One is always fortunate or unfortunate in ones choice of parents, and I was very fortunate to get a leg up on understanding this very important nuclear technology because of my father.
At any rate by the time I launched my blog I already had developed the model which I call the Aim High Plan after Dr. Rober Hargraves' Aim High presentation which offers the important points of my model. I believe that the Aim High Plan not only should be adopted, but inevitably will be adopted. Indeed there is little choice if we are to have a high energy future for all of the people on earth.
During the 1960's and 70's ORNL reactor engineers designed several small MSRs that could be clustered to equal the power output of a large reactor. In the 1990's Argonne National Laboratory projected building small modular IFRs that could be clustered to provide a power equivalent of a large reactor. So we really are not talking about a newly invented idea. thus it comes as no great surprise that Babcock and Wilcox a long time American reactor manufacture announced plans to build a factory manufactured, transportable reactor. It is a LWR, not a LFTR, but it will offer many features of the AIM high plan. Thus it represents an important transitional step toward realization of the full Aim High Plan.
This now brings me to the old post in which I discussed the issue of economies of scale in nuclear construction, and why small is often better:
David Walters passed on to me a 2004 study, by the University of Chicago," The Economic Future of Nuclear Power." This study looked at both nuclear construction and capital costs, and challenged some frequent assumptions and common beliefs. We should be aware that Rod Adams had already done this. Let us begin with the notion of economies of scale. As Rod Adams explained 12 years ago: "Pick up almost any book about nuclear energy and you will find that the prevailing wisdom is that nuclear plants must be very large in order to be competitive. This notion is widely accepted, but, if its roots are understood, it can be effectively challenged."
In the small world of Nuclear Bloggers, Rod Adams is known as a mighty smart man. Adams argues that the notions about economies of scale in the nuclear power industry was a legacy of the experience reactor manufacturers had had with fossil fuel powered generating facilities. "Experience had taught" Westinghouse, General Electric and their competitors, "that larger power stations could produce cheaper electricity and that electricity from central power stations could be effectively distributed to a large number of customers whose varying needs allowed the capital investment in the power station to be most effectively shared between all customers."
"Their experience was even codified by textbook authors with a rule of thumb that said that the cost of a piece of production machinery would vary by the throughput raised to the 0.6 power. (According to this thumb rule, a pump that could pump 10 times as much fluid as another pump of similar design and function should cost only four times as much as the smaller pump.)"
But in 1996 Adams challenged the idea that economies of scale worked with nuclear power. He asserted, "it is safe to say that there has been no predictable relationship between the size of a nuclear power plant and its cost."
It appeared that large nuclear plant size tended to increase construction time, which in turn increased capitol expenses. Hence, some studies found diseconomies of scale. that outweighed the increased economies related to parts costs.
The University of Chicago's 2004 literature review came to the same conclusion that Adams had. The Chicago study concludes, "It seems reasonable to conclude that few if any scale economies existed in nuclear plant construction in the 1970s and 1980s to confound the identification of learning effects."
Adams advocated small rather than large nuclear power plants. "If a market demand exists for 300 MW of electricity, distributed over a wide geographic area, traditional nuclear plant designers would say that the market is not yet ready for nuclear power, thus they would decide to learn nothing while waiting for the market to expand."
Adams was clearly a head of his time.
Small size, leads for the demand of a larger number of units in order to meet electrical demand. Thus if the standard reactor size produces 100 MWs of electrical power, 10 such units would be required to produce the same amount of electricity as 1000 MW unit. The demand for ten units would lead almost inevitably to serial production. Adams notes, "Though the "economy of scale" did not work for the first nuclear age, there is some evidence that a different economic rule did apply. That rule is what is often referred to as the experience curve. According to several detailed studies, it appears that when similar plants were built by the same organization, the follow-on plants cost less to build. According to a RAND Corporation study, "a doubling in the number of reactors [built by an architect-engineer] results in a 5 percent reduction in both construction time and capital cost."
This in turn lead Adams to point to another factor, that the learning curve, facilitated by serial production, lowers cost through time. It should be noted that the University of Chicago study did not take this line of thinking as far as Adams did, but then Adams thinking about reactor design was far in advance of the thinking found in the august halls of the University of Chicago.
Adams added, "When picking the proper size of a particular product, the experience curve should lead one to understand that high volume products will eventually cost less per unit output than low volume products and that large products inherently will have a lower volume than significantly smaller products."
Adams did not say in 1996, "Mass produce 'em in a factory, but I will wager if I asked him if that was what he was thinking, Adams would have answered, "yes."