The Rosy-fingered Dawn of the Second Nuclear Era

Our Day Will Come
Ruby & The Romantics

Our day will come
And we’ll have everything.
We’ll share the joy
Falling in love can bring.

No one can tell me
That I’m too young to know (young to know)
I love you so (love you so)
And you love me.

Our day will come
If we just wait a while.
No tears for us -
Think love and wear a smile.

Our dreams have magic
Because we’ll always stay
In love this way
Our day will come.
(Our day will come; our day will come.)

Our dreams have magic
Because we’ll always stay
In love this way.
Our day will come.
Our day will come

From the Amidah (Shemoneh Esreh)
Return in mercy to thy city Jerusalem and dwell in it, as you have promised; rebuild it quickly, in our days, as an enduring structure, . . .
Some time ago I told Kirk Sorensen to get ready because his time was coming. His time has now arrived, and far more quickly than I had anticipated.

Kirk Sorensen is a visionary. His vision recaptures the vision of Alvin Weinberg. Since last spring there has been a growing Internet buzz about the Liquid Fluoride Thorium Reactor. There can be little doubt of the central role of Kirk Sorensen in creating this buzz. Kirk, after all rebranded the generation old Oak Ridge National Laboratory idea of a molten salt thorium breeder reactor, the LFTR. But he did more than that, he created a forum on which people would be free to think about the vision. Unlike many visions, Kirk’s vision had taken real tangible form. I know, because my father had been there, had helped to shape those tangible forms, and he was still alive. I could talk to him, ask him questions, get his recollections of the tangible form of Kirk’s vision.

“Energy from Thorium” has three parts. The Blog, the Discussion Form, and the document repository. Through the Document Repository, I was able to put together my childhood and youthful experiences of my father, with his own documentation of his research. Although largely unseen, the LFTR had been a part of my life for almost two decades. Much of my father’s early work was covered in secrecy. When I asked him what he did at work, he would reply that his work was a government secret. By the time the work ceased to be secret, the habit of compartmentalization of work and home had set in. Every now and then, my father might say a few words about stories that appeared in the Oak Ridge newspaper. Later he was to complain about a peer review of a paper he had written. “They complain,” my father said, “that I refer too much to research that has been done at ORNL. What they don’t realize that the research we do here is the best in the world”. My father was and is a truly modest man, and a master of the literature review. If my father said that ORNL research was the best in the world, it was because he had good reason to think so.

There is no question that when my father started researching molten salt chemistry in July 1950 that ORNL thinking on reactor design was far in advance of of the rest of the world including Chicago. In fact ORNL thinking about reactor design in 1950 was two generations ahead of the rest of the world. They would began to catch up, when NASA asked Kirk Sorensen to look at the idea of putting a reactor into space. As he sought a viable design, Kirk discovered the MSR, but more than that, he rediscovered Alvin Weinberg’s vision. Alvin Weinberg had published a visionary essay, “Energy as an Ultimate Raw Material, or Burning the Rocks and Burning the Sea,” during 1959 in Physics Today (vol. 12, no. 11, p. 18).

Weinberg’s vision was huge is scope as he later explained:

In this essay I speculated on the very long-range future-hundreds, even thousands, of years in the future. Where will our energy come from at that distant time when coal, oil, and natural gas have been used up? Solar energy is one obvious inexhaustible source. Another, if it works, could be controlled thermonuclear energy based on deuterium from the sea (thus “Burning the Sea”). My main point, however, was to stress what Phil Morrison and then Harrison Brown had already noticed: that the residual and all but infinite uranium and thorium in granite rocks could be burned with an energy yield larger than the energy required to mine and refine the ore—but only if breeders, which could burn nearly all the fertile material, are used. I spoke of “Burning the Rocks”: the breeder, no less than controlled fusion, is an inexhaustible energy system. Up till then we had thought that breeders, burning 50% instead of 2% of the uranium, extended the energy derivable from fission “only” 25-fold. But, because the breeder uses its raw material so efficiently, one can afford to utilize much more expensive—that is, dilute—ores, and these are practically inexhaustible. The breeder indeed will allow humankind to “Burn the Rocks” to achieve inexhaustible energy!

In his autobiography Weinberg confessed:

“I became obsessed with the Idea that humankind’s whole future depended on the breeder. For Society generally to achieve and maintain a standard of living of today’s developed countries, depends on the availability of relatively cheap, inexhaustible sources of energy.”

In 1969 as ORNL was, under orders from the USAEC, winding down its brilliantly successful Molten Salt Reactor Experiment, Alvin Weinberg wrote,

The achievement of a cheap, reliable, and safe breeder remains the primary task of the nuclear energy community. (In expressing this view, I suppose I betray a continuing frustration at the slow progress of fusion research, even though the Russian success with the tokamak has quickened the pace.) Actually not much has changed in this regard in 25 years. Even during World War II, many people realized that the breeder was central. It is only now, with burner reactors doing so well, that the world generally has mobilized around the great aim of the breeder.

As all readers of Nuclear Applications & Technology know, the prevailing view holds that the LMFBR (Liquid sodium cooled fast breeder) is the proper path to ubiquitous, permanent energy. It is no secret that I, as well as many of my colleagues at ORNL, have always felt differently. When the idea of the breeder was first suggested in 1943, the rapid and efficient recycle of the partially spent core was regarded as the main problem. Nothing that has happened in the ensuing quarter-century has fundamentally changed this. The successful breeder will be the one that can deal with the spent core most rationally—either by achieving extremely long burnup, or by greatly simplifying the entire recycle step. We at Oak Ridge have always been intrigued by this latter possibility. It explains our long commitment to liquid-fueled reactors-first, the aqueous homogeneous and now, the molten salt. groups working vigorously on molten salts outside Oak Ridge. . . .

. . . indeed, the enthusiasm displayed here is no longer confined to Oak Ridge. There are now several groups wor
king vigorously on molten salts outside Oak Ridge. The enthusiasm of these groups is not confined to MSRE, nor even to the molten-salt breeder. For we now realize that molten-salt reactors comprise an entire spectrum of embodiments that parallels the more conventional solid-fueled systems. Thus molten-salt reactors can be converters as well as breeders; and they can be fueled with either 239Pu or 233U or 235U.

However, we are aware that many difficulties remain, especially before the most advanced embodiment, the Molten-Salt Breeder, becomes a reality. Not all of these difficulties are technical. I have faith that with continued enlightened support of the US Atomic Energy Commission, and with the open-minded, sympathetic attention of the nuclear community . . . the molten-salt reactors will find an important niche in the unfolding nuclear energy enterprise.

Alvin Weinberg’s 40 year old expression of faith now seems at last to be on the verge of fulfillment, thanks to Kirk’s vision and hard work. I once told Kirk that he needed to get ready because his day would come. I now believe that that day is upon us.

The first thing that Kirk did was to give the Thorium fuel cycle Molten Salt Reactor a new name, The Liquid Fluoride Thorium Reactor (LFTR). The reason was simple, liquid fluoride sounded far more benign than dangerous sounding term “molten salt”. Aside from connotation, LFTR overtly tied the reactor concept to the use of the thorium fuel cycle. We hope the curious will ask, “what is that?” The term LFTR is an opening to tell the story of the Molten Salt Reactor, its safety, its potential to “eat” nuclear waste, to lower reactor costs, and the endless abundance of unused Thorium in the crust of the earth.

Kirk was invited to Washington on November 3 to give a presentation at a workshop on Post-carbon energy issues, sponsored by the renowned Dr. Jim Hansen. Kirk must have made an impression. In his latest briefing paper Tell Barack Obama the Truth – The Whole Truth
Hansen makes the following statement:

Nuclear Power. Some discussion about nuclear power is needed. Fourth generation nuclear power has the potential to provide safe base-load electric power with negligible CO2 emissions.

There is about a million times more energy available in the nucleus, compared with the chemical energy of molecules exploited in fossil fuel burning. In today’s nuclear (fission) reactors neutrons cause a nucleus to fission, releasing energy as well as additional neutrons that sustain the reaction. The additional neutrons are ‘born’ with a great deal of energy and are called ‘fast’ neutrons. Further reactions are more likely if these neutrons are slowed by collisions with non-absorbing materials, thus becoming ‘thermal’ or slow neutrons.

All nuclear plants in the United States today are Light Water Reactors (LWRs), using ordinary water (as opposed to ‘heavy water’) to slow the neutrons and cool the reactor. Uranium is the fuel in all of these power plants. One basic problem with this approach is that more than 99% of the uranium fuel ends up ‘unburned’ (not fissioned). In addition to ‘throwing away’ most of the potential energy, the long-lived nuclear wastes (plutonium, americium, curium, etc.) require geologic isolation in repositories such as Yucca Mountain.

There are two compelling alternatives to address these issues, both of which will be needed in the future. The first is to build reactors that keep the neutrons ‘fast’ during the fission reactions. These fast reactors can completely burn the uranium. Moreover, they can burn existing long-lived nuclear waste, producing a small volume of waste with half-life of only sever decades, thus largely solving the nuclear waste problem.

The other compelling alternative is to use thorium as the fuel in thermal reactors. Thorium can be used in ways that practically eliminate buildup of long-lived nuclear waste. The United States chose the LWR development path in the 1950s for civilian nuclear power because research and development had already been done by the Navy, and it thus presented the shortest time-to-market of reactor concepts then under consideration. Little emphasis was given to the issues of nuclear waste. The situation today is very different. If nuclear energy is to be used widely to replace coal, in the United States and/or the developing world, issues of waste, safety, and proliferation become paramount.

Nuclear power plants being built today, or in advanced stages of planning, in the United States, Europe, China and other places, are just improved LWRs. They have simplified operations and added safety features, but they are still fundamentally the same type, produce copious nuclear waste, and continue to be costly. It seems likely that they will only permit nuclear power to continue to play a role comparable to that which it plays now.

Both fast and thorium reactors were discussed at our 3 November workshop. The Integral Fast Reactor (IFR) concept was developed at the Argonne National Laboratory and it has been built and tested at the Idaho National Laboratory. IFR keeps neutrons “fast” by using liquid sodium metal as a coolant instead of water. It also makes fuel processing easier by using a metallic solid fuel form. IFR can burn existing nuclear waste, making electrical power in the process. All fuel reprocessing is done within the reactor facility (hence the name “integral”) and many enhanced safety features are included and have been tested, such as the ability to shutdown safely under even severe accident scenarios.

The Liquid-Fluoride Thorium Reactor (LFTR) is a thorium reactor concept that uses a chemically-stable fluoride salt for the medium in which nuclear reactions take place. This fuel form yields flexibility of operation and eliminates the need to fabricate fuel elements. This feature solves most concerns that have prevented thorium from being used in solid-fueled reactors. The fluid fuel in LFTR is also easy to process and to separate useful fission products, both stable and radioactive. LFTR also has the potential to destroy existing nuclear waste, albeit with less efficiency than in a fast reactor such as IFR.

Both IFR and LFTR operate at low pressure and high temperatures, unlike today’s LWR’s. Operation at low pressures alleviates much of the accident risk with LWR. Higher temperatures enable more of the reactor heat to be converted to electricity (40% in IFR, 50% in LFTR vs 35% in LWR). Both IFR and LFTR have the potential to be air-cooled and to use waste heat for desalinating water.

Both IFR and LFTR are 100-300 times more fuel efficient than LWRs. In addition to solving the nuclear waste problem, they can operate for several centuries using only uranium and thorium that has already been mined. Thus they eliminate the criticism that mining for nuclear fuel will use fossil fuels and add to the greenhouse effect.

The Obama campaign, properly in my opinion, opposed the Yucca Mountain nuclear repository. Indeed, there is a far more effective way to use the $25 billion collected from utilities over the past 40 years to deal with waste disposal. This fund should be used to develop fast reactors that eat nuclear waste and thorium reactors to prevent the creation of new long-lived nuclear waste. By law the federal government must take responsibility for existing spent nuclear fuel, so inaction is not an option. Accelerated development of fast and thorium reactors will allow the US to fulfill its obligations to dispose of the nuclear waste, and open up a source of carbon-free energy that can last centuries, even millennia.

The common presumption that 4th generation nuclear power will not be ready until 2030 is
based on assumption of ‘business-as-usual”. Given high priority, this technology could be ready for deployment in the 2015-2020 time frame, thus contributing to the phase-out of coal plants. Even if the United States finds that it can satisfy its electrical energy needs via efficiency and renewable energies, 4th generation nuclear power is probably essential for China and India to achieve clear skies with carbon-free power.

Hansen adds

Prompt development of safe 4th generation nuclear power is needed to allow energy options for countries such as China and India, and for countries in the West in the likely event that energy efficiency and renewable energies cannot satisfy all energy requirements.

Deployment of 4th generation nuclear power can be hastened via cooperation with China, India and other countries. It is essential that hardened ‘environmentalists’ not be allowed to delay the R&D on 4th generation nuclear power. Thus it is desirable to avoid appointing to key energy positions persons with a history of opposition to nuclear power development. Of course, deployment of nuclear power is a local option, and some countries or regions may prefer to rely entirely on other energy sources, but opponents of nuclear power should not be allowed to deny that option to everyone.

I believe that we may be seeing the dawn of Weinberg’s Second Nuclear Era.

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