From: Energy Conservation and Management (In Press)
Recommendations for a restart of molten salt reactor development
By R.W. Moir
The concept of the molten salt reactor (MSR) refuses to go away. The Generation-IV process lists the MSR as one of the six concepts to be considered for extending fuel resources. Good fuel utilization and good economics are required to meet the often-cited goal of 10 TWe globally and 1 TWe for the US by non-carbon energy sources in this century by nuclear ﬁssion. Strong incentives for the molten salt reactor design are its good fuel utilization, good economics, amazing fuel ﬂexibility and promised large beneﬁts. It can:
* use thorium or uranium;
* be designed with lots of graphite to have a fairly thermal neutron spectrum or without graphite moderator to have an epithermal neutron spectrum;
* ﬁssion uranium isotopes and plutonium isotopes;
* produces less long-lived wastes than today’s reactors by a factor of 10–100;
* operate with non-weapon grade ﬁssile fuel, or in suitable sites it can operate with enrichment between reactor-grade and weapon grade ﬁssile fuel;
* be a breeder or near breeder;
* operate at temperature >1100 °C if carbon composites are successfully developed.
Enhancing 232U content in the uranium to over 500 ppm makes the fuel undesirable for weapons, but it should not detract from its economic use in liquid fuel reactors: a big advantage in nonproliferation.
Economics of the MSR are enhanced by operating at low pressure and high temperature and may even lead to the preferred route to hydrogen production. The cost of the electricity produced from low enriched fuel averaged over the life of the entire process, has been
predicted to be about 10% lower than that from LWRs, and 20% lower for high-enriched fuel, with uncertainties of about 10%. The development cost has been estimated at about 1 B$ (e.g., a 100 M$/year base program for 10 years) not including construction of a series of reactors leading up to the deployment of multiple commercial units at an assumed cost of 9 B$ (450 M$/year over 20 years). A beneﬁt of liquid fuel is that smaller power reactors can faithfull test features of larger reactors, thereby reducing the number of steps to commercial deployment. Assuming electricity is worth $ 50 per MWe h, then 50 years of 10 TWe power level would be worth 200 trillion dollars. If the MSR could be developed and proven for 10 B$ and would save 10% over its alternative, the total savings over 50 years 31 would be 20 trillion dollars: a good return on investment even considering discounted future savings.
The incentives for the molten salt reactor are so strong and its relevance to our energy policy and national security are so compelling that one asks, ‘‘Why has the reactor not already been developed?”
(Copyright) 2008 Published by Elsevier Ltd.
Comment: In my estimation Moir is very conservative in his estimate of the savings that can be accomplished through the use of molten salt reactor technology. His estimates are based on studies conducted at ORNL in the 1970's. They assume a large reactor (1 GW) in a conventional setting. At the same time he is advocating using radical new technologies such as the use of carbon-carbon composites, closed cycle gas turbines, and underground siting. These would radically alter the cost estimates for MSR construction and set up. Small reactor would also enable the mass production of reactors, which has the potential to produce great manufacturing savings.
Moir is also assumes that a scaling up of reactor size would be desirable, but this is very conservative. In fact small MSRs can produce electrical power very efficiently. Moir believes that it would be possible to have a 100 MW MSR operating by 2023, but Moir is thinking in terms of business as usual. He is thinking of the normal course of research and development. The era of business as usual is about to end. The crisis is upon us. It will transform the way we see our problems, and our commitment to seeking solutions. A World War II style creash program could shrink R&D timeframes drastically.
Since I grew up in Oak Ridge, I have the Manhattan project as a frame of reference. I once heard my uncle tell the story of how one day in 1942 he drove from a coal mining camp in the Cumberland Mountains to Knoxville, Tennessee. He drove through communities like Elza, and Scarborough on to Knoxville. When he drove back home late in the day, the road had been blocked by the Army, and the communities were gone. That was the beginning of Oak Ridge. That is what it is like when you give up business as usual in the face of a crisis.
The task that scientists and engineers faced in 1942 when they began to develop the technology required to produce atomic bombs was much more daunting that those that would be faced by the developers of the MSR. The world's first reactor began opperating at the university of Chicago first went critical on Dec. 2, 1942. The X-10 Graphite Reactor, located at Oak Ridge was designed and built in ten months. The Graphite reactor went critical on November 4, 1943.
At the same time, a huge plant, K-25, was being built. Construction went forward despite the fact that scientist were far from sure that they could get the gaseous diffusion process to work.
That was not business as usual!