Tuesday, December 2, 2008

Long Green

The primary goal of Nuclear Green, and for that matter of Energy from Thorium is and has been the relaunching of the development of the Liquid Fluoride Thorium Reactor/Molten Salt Reactor approach to reactor design. I believe that the LFTR represents the best long term energy option for human society, and its eventual adoption is inevitable. The success of the LFTR is not a matter of if but when.

The LFTR is clearly the best of reactor options. It has inherent safety features, which when coupled with a defense in depth safety system, will make serious accidents very, very unlikely, and will always protect the public from the consequences of any serious accident. It is more likely that the human race will die off as a result of an extinction event, than there would be a LFTR accident that would produce a single casualty among the general public.

The LFTR destroys nuclear waste rather than produces them. In fact Molten Salt Reactors have been repeatedly proposed as the solution to the nuclear waste problem. Because the fuel of the LFTR can be continuously reprocessed, Molten Salt Reactor offer a good environment for the fission of transuranium elements. While ideally the LFTR would always operate with U-233 as its nuclear fuel, and would produce more U-233 through the thorium breeding cycle, it has been proposed to start LFTR operations by initially fueling it with plutonium from nuclear waste. That would kill two birds with one stone, booth initiating LFTR operations and destroying the most dangerous element in nuclear waste. Thus the LFTR, far from being a tool for nuclear proliferation, is a singular tool for nuclear deproliferation, for destroying nuclear weapons building materials.

Finally because of the absolute abundance of Thorium in the earths crust, and the prodigious amount of energy that LFTRs can release by the LFTR, that the human population of the earth will never use up all of the available thorium. Thorium this prodigious gift to human energy needs is now waisted. It is quite literally thrown away. More energy could be extracted from thorium in the coal ash piles of power plants, than from burning the original coal. Thorium can be extracted from mine tailings, enough to power the United States for hundreds and perhaps thousands of years without ever turning a shovel of earth to mine more thorium.

The abundance of thorium, its energy potential, and the benefits of the thorium fuel cycle all point to thorium as the major source of future energy. The most significant competitor to thorium will be not the sun or the wind but uranium. Yet the uranium fuel cycle will be more expensive to operate because of the cost advantages of liquid salt reactors. Only liquid salt uranium fueled reactors could compete with the LFTR on costs, and fuel efficiency.

Why then don't we have the LFTR now? It all boils down to a question of money and politics. In his autobiography Alvin Weinberg wrote:
In 1962, the AEC issued a report to the president on civilian nuclear power. Lee Haworth, a superbly responsible physicist-administrator, was in charge of drafting the report. He projected a nuclear deployment by 2000 of about 700 gigawatts (compared with the actual deployment in 1993 of 102 gigawatts), which seemed at the time quite reasonable. Both the fast breeder based on the 239Pu-238U cycle and the thermal breeder based on the 233U-232Th cycle figured prominently in the report. Indeed, the report implied that both systems should be pursued seriously, including large-scale reactor experimentation. It particularly favored molten uranium salts for the thermal breeder. But the molten-salt system was never given a real chance. Although the AEC established an office labeled "Fast Breeder," no corresponding office labeled "Thermal Breeder" was established. As a result, the center of gravity of breeder development moved strongly to the fast breeder; the thermal breeder, as represented by the molten-salt project, was left to dwindle and eventually to die.

The fast-breeder project in the United States centered around the Clinch River Breeder, a 250-megawatt sodium-cooled breeder to be built in Oak Ridge by Westinghouse. But, by this time, objections to the breeder were being voiced, ostensibly because the breeder, with its coupled chemical reprocessing system, lent itself to the clandestine diversion of plutonium for nuclear weapons. But in my view the real aim of some of the more dedicated opponents of Clinch River was the extirpation of nuclear energy. The Clinch River Breeder was a handy and vulnerable target, particularly since it could not produce power at a competitive cost. And the opponents eventually won—Clinch River was killed in 1975.

Although the molten-salt system was never allowed to show its full capability as a breeder, a 233U-232Th thermal breeder was demonstrated in Admiral Rickover's Shippingport reactor. Operating with 233U fuel and a thorium blanket, this reactor actually demonstrated a breeding ratio of 1.03—i.e., for every 233U burned, 1.03 new 233U was produced. This accomplishment has gone unnoticed since the cost of power from Shippingport is much higher than from other sources. Whether, as cheap uranium becomes scarce, other reactors will be fueled with 233U and thorium remains to be seen. Thus, as Wigner once said, breeders may emerge from incremental improvements of existing light-water or heavy-water reactors, or may spring from entirely new technologies specifically designed for the breeder. As for fast uranium breeders, the latter path is being followed in France, Japan, India, and Russia. (The French fast breeder PHENIX has demonstrated a breeding ratio of 1.13.) But as for thermal thorium breeders, it seems that these will emerge from the existing nonbreeder LWR or CANDU rather than from molten-salt technology.

Why didn't the molten-salt system, so elegant and so well thought-out, prevail? I've already given the political reason: that the fast breeder arrived first and was therefore able to consolidate its political position within the AEC. But there was another, more technical reason. The molten-salt technology is entirely different from the technology of any other reactor. To the inexperienced, molten-salt technology is daunting. This certainly seemed to be Milton Shaw's attitude toward molten salts—and he after all was director of reactor development at the AEC during the molten-salt development. Perhaps the moral to be drawn is that a technology that differs too much from an existing technology has not one hurdle to overcome—to demonstrate its feasibility—but another even greater one—to convince influential individuals and organizations who are intellectually and emotionally attached to a different technology that they should adopt the new path. This, the molten-salt system could not do. It was a successful technology that was dropped because it was too different from the main lines of reactor development. But if weaknesses in other systems are eventually revealed, I hope that in a second nuclear era, the molten-salt technology will be resurrected.

Weinberg thus points to the AEC role of Molten Salt Reactor foe Milton Shaw during the 1960's and early 1970's. Beyond Milton Shaw was the politics of nuclear power, with coal interests and anti nuclear activists forming a tacit alliance against nuclear power. From the beginning of the Nixon administration onward the fortunes of nuclear research declined in the United States. Jimmy Carter maded the disasterous decision to turn to coal for electrical generation at the very time scientists led by Alvin Weinbery were warning off the dangers of CO2 triggered global warming. Oponants of nuclear power, lead by psudo-physicist Amory Lovins, were perfectly willing to go on burning fossil fuels, as long as it was burned in small, allededly more efficient generators. Lovins, Ralph Nader, and Helen Caldicott, willingly served as fronts for the coal barons, and seldom even mentioned CO2 or global warming. In fact, in 1989 Amory Lovins blamed part of the CO2 problem on Nature, and argued that energy efficiency was cheap and indeed the only needed solution to the CO2/Global Warming problem. In the mean time the coal fired power plants dumped billions of tons of CO2 into the atmosphere every year, and the coal barons banked their money. Amory Lovins banked his money too.

Coal now is in decline, and Amory Lovins is fighting a rearguard action against nuclear power. The story is now being told that energy will be very expensive in the post-carbon age. As I argued yesterday, there are potentially innovative ways to lower LFTR cost to a fraction of the cost of conventional nuclear technology. The potential of cheap power through LFTR technology needs to be explored in ways that only money can bring about. The route to green power begins with long green.

1 comment:

Jason Ribeiro said...

Charles, the arguments against the cost of nuclear don't take into consideration the hidden costs of energy choices. For example, while Lovins loves to point out how wonderfully efficient a combined cycle gas plant is, he completely ignores that it still emits CO2 - the hidden cost. He doesn't seem to consider at all the horrendous unreliability and capacity factor problems of wind and solar either - another hidden cost. It's sad to see a charlatan like this dupe so many people.


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