French researchers of the Reactor Physics Group of the Laboratoire de Physique Subatomique et de Cosmologie Roepot very Promising results from their TMSR research. They are building a strong case for large non-Moderated Thorium Molten Salt Breeders. Such reactors would be very useful for Baseload power generators. The main draw back for a no moderator reactor would be the much larger starting charge required if TMSR/LFTR type reactors were expected to generate most electrical energy or to provide most energy for the national economy. A World Wide deployment by 2050 would creat a very large shortage of fissionable materials for start up charges even with graphite core reactors.
E. MERLE-LUCOTTE, D. HEUER, M. ALLIBERT, V. GHETTA,
C. LE BRUN, R. BRISSOT, E. LIATARD, L. MATHIEU
LPSC, Université Joseph Fourier, IN2P3-CNRS, INPG
LPSC, 53, avenue des Martyrs, F-38026 Grenoble Cedex – France
Molten salt reactors, in the configuration presented here and called Thorium Molten Salt Reactor
(TMSR), are particularly well suited to fulfil the criteria defined by the Generation IV forum, and
may be operated in simplified and safe conditions in the Th/233U fuel cycle with fluoride salts. The
characteristics of TMSRs based on a fast neutron spectrum are detailed in this paper, focusing on
their excellent level of deterministic safety. We aimed at designing a critical TMSR able to burn
the Plutonium and the Minor Actinides produced in the currently operating reactors, and
consequently to convert this Plutonium into 233U. This leads to closing the current fuel cycle
thanks to TMSRs started with transuranic elements on a Thorium base, i.e. started in the Th/Pu
fuel cycle. We study the transition between the reactors of second and third generations to the
Thorium cycle in a European frame. -
The Thorium Molten Salt reactor (TMSR) presented here with no moderator in the core appears as a
very promising, simple and suitable concept of molten salt reactor. The non-moderated TMSR
configurations considered in this paper, based on a fast neutron spectrum, present particularly
interesting characteristics. Their deterministic safety level is excellent. They can be started with a fuel
made from the TRU wastes produced in current LWRs. Their rather large initial fissile inventory does
not prevent fast deployment thanks to their good 233U breeding. The technology which in principle
does not involve the transportation of radioactive materials outside the reactor site as well as the
presence of 232U within the fuel can be considered as restricting proliferation risks.
The concept itself has some appealing aspects compared to earlier versions of MSRs. The reactor core
is extremely simple. Simulation calculations do not point to major reprocessing constraints. In
particular the fluxes considered should allow the batch mode reprocessing to be installed in the
vicinity of the reactor. Initial studies of the scientific feasibility of the on-line control of the salt
composition and of its chemical and physical properties have not unearthed a showstopper.
When it comes to Generation-4, it appears that the major nuclear energy powers have given a higher
priority to the SFR concept. This mostly reflects a justified confidence in a technology which,
although it has not yet reached all the performances expected for a GEN-4 reactor, has already been
successfully tested in numerous projects. But all the properties detailed in this paper, especially its
deterministic safety performances and its ability to reduce the radio-toxicity of wastes currently
produced, put the TMSR in a very favoura
ble position to fulfil the conditions defined by the GEN IV
International Forum. Moreover this TMSR concept may be very appealing to countries which hold
important thorium resources and have some remaining adjustment margins in the definition of their
nuclear energy policy. The TMSR is thus an excellent candidate to produce the large amounts of
nuclear energy that the world will need in the near future.
I’ve converted the MSBR design section of ORNL-4449 to HTML. It’s got lots of good stuff in it about reactor siting, building design, afterheat removal, etc, from back in 1969.
I’ve been drawing the reactor cores from the ORNL MSRP reports lately.
I hope you like them.
Here’s the one from ORNL-4119:
Here’s the picture from ORNL-4528 that I used for reference.
Doing these has helped me learn a lot about fluoride reactor core design.
Kirk and I have been separately looking at ORNL-4528, a document that sets out ORNL thinking about a modular two fluid, graphite moderated MSR project. This concept was developed at ORNL between 1966 and 1967 and ORNL-4528 documents thinking about the concept during that brief period. This design work is of current interest because of interest in small factory build LFTRs in the Energy from Thorium community. ORNL’s interest in modular MSRs was motivated by somewhat different concerns. For ORNL scientists, the lifespan of a MSR Graphite core was am issue of major concern. The limited lifespan of the graphite core necessitated periodic reactor shutdown for core replacement. The use of small modular reactors allowed a generation plant to continue operating at 75% of capacity while one core was being replaced. The replacement of the smaller chore of the modular reactor would also have been a somewhat easier task.
The basic purpose of ORNL-4528 differed from other MSR designs between 1962 and 72. Unlike other reactor system design projects ORNL-4528 was not written to as a part of an ongoing development program. Rather it was written after the two fluid line of development it represented had been dropped in favor of a single fluid design. ORNL-4528 was one of five 1 GWe MSR designs developed between 1961 and 1971 by ORNL or by associated engineering firms. The purpose of the other 4 designs was explained by ORNL-5018:
The objectives of this activity are: (I) to develop the conceptual design for a commercial 1000 MW(e) MSBR in sufficient detail to identify the major areas im which additional technology development is required and to produce meaningful estimates of the nuclear and economic performances of this reactor type, (2) to develop the design criteria and conceptual design for a molten-salt demonstration reactor that will provide the information necessary for construction of commercial MSBRs in sufficient detail to identify additional technology development which is required for construction of the demonstration reactor and to provide improved estimates of the capital and operating costs for the demonstration reactor, (3) to develop the design criteria and conceptual design for a molten-salt test reactor in sufficient detail to identify additional technology development which is required for construction of the test reactor and to provide improved estimates of the capital and operating costa for the test reactor, and (4) to develop the design criteria and conceptual design for a molten-salt teat reactor mockup in sufficient detail to identify additional technology development which is required for construction of the test reactor mockup and to provide improved estimates of the capital and operating costs for the mckup.
An additional important objective of this activity is the examination of alternate reactor types such as molten-salt converter reactors using uranium or plutonium fuel makeup as well as uses for molten-salt reactors other than large central station electric power generation in sufficient detail to assess the likely economic importance of alternate molten-salt reactor types. Limited conceptual design work would be carried out on alternate reactor types which show promise.
Because the line of research document led by ORNL-4528, its intent was not to offer clues for future development, but to document a terminated line of research. Many ORNL scientists, including my father, were not in agreement with the decision to abandon the two fluid approach, their continued believe in the soundness of their views, may have motivated the desire to document the modular two fluid design.
At any rate the design documented by ORNL-4528 is far from mature and contains flaws. I would encourage our readers to find flaws and comment on them.
ORNL-4528 is a great document that both Charles and I have been looking at a lot lately. In the interest of making it easier to read through ORNL-4528, I’m in the process of converting the sections of the document into webpages. I’ve got the first 4 out of 7 ready, and here they are:
In some respects the LFTR does not qualify as a black swan. Certainly not by Nassim Nicholas Taleb’s standards. Its emergence was far from random. There could scarcely be a better provenance for a reactor idea than to have been first proposed by Eugene Wigner, Alvin Weinberg and Gale Young in 1945. To this we have to add the contributions of Harold Urey. Raymond C. Briant, Ed Bettis, and many others. I would also add my father, C.J. Barton, Sr., to the list. An idea whose fathers included to Nobel-prize winning scientists and the patent holder for the light-water Reactor can hardly be considered highly improbable. It was however, daring, and once Alvin Weinberg’s other invention, the light-water reactor, entered popular culture, along with the reactor dome and cooling tower, the liquid core reactor concept became something of an aberration in the folk concept. After all the worse thing could happen to a reactor was a core melt down, and now those crazy Oak Ridge scientists were trying to melt the reactor’s core deliberately.
The Molten Salt reactor was a black swan in the since that it violated a common public perception of what constituted order. A liquid core reactor is inherently disorderly concept in a folk universe that desperately wants reactor core’s to be solid and not melt.
“It came from Oak Ridge” could have been the title of a 1950′s horror movie, in which a humble beast is accidentally radiated in Oak Ridge, and is transformed into a giant mutant monster that has it in for a large city. Late in my father’s scientific career, he was asked to write a report for the National Academy of Science. Reviewers complained that my father had referenced too many ORNL researchers. My father’s response was that the best research in the world for his topic – the environmental transport of radioisotopes – was being done in Oak Ridge. When I was a quasi intern at ORNL in 1971, the Laboratory was buzzing about CO2 and anthropogenic global warming. ORNL was the first scientific institution in the world to take the danger of AGW seriously. In the 1970′s ORNL researchers were warning of about the environmental dangers of burning coal. So called “environmental experts” like Amory Lovins decided that they knew better than Oak Ridge Scientists who were in their estimation “shills for the nuclear industry.” Thus, so called environmentalists ignored the problem of CO2 emissions and Anthropogenic Global Warming. After all, “it came from Oak Ridge.”
The Molten Salt Reactor was brilliantly conceived by Oak Ridge scientists and engineers in the 1940′s and 50′s. By the end of the 1950′s the AEC was beginning to recognize that the Oak Ridgers were on to something. But ORNL’s MSR had a rival, the fair-haired boy from Chicago, favored by the Atomic Energy Commission, the Liquid Metal Fast Breeder Reactor. With its promise of almost unlimited Plutonium, the LMFBR was not the best candidate to provide American power reactors with a sustainable fuel supply, but it did assure the Atomic Energy Commission of a steady stream of nuclear weapons stretching into the distant future. That Plutonium was not a good nuclear fuel for Light Water Reactors was never a matter of concern.
The LMFBR had the potential to breed more fissionable material than the MSR, but plutonium could never break even as a nuclear fuel in a light water reactor. Thorium could, if the reactor used U-233 it could produce as much U-233 from thorium as it burned. But the Atomic Energy Commission did not think that U-233 was good for making bombs, so the LMFBR got most of the money. Argonne knew that no matter how dangerous sodium was, the Atomic Energy Commission wanted plutonium, and so its LMFBR always had the inside track. inevitably as the Vietnam war ate into the capacity of the the United States Government to to finance science research. Alvin Weinberg had made himself to a target of AEC wrath by being too out spoken about nuclear safety. So Weinberg had to go, and it was easy to get rid of the MSR at the same time. With Weinberg out of the way, the MSR became an impossible sell. It came from Oak Ridge, and was not useful in making nuclear weapons.
It is of course an improbable story that the solution to the global energy crisis was identified by Eugene Wigner and his associates during World War 2, and that the plans or solving the problem have existed in government archives since the 1970′s and continues to be ignored. This is a far more bizarre story than Nassim Taleb’s account of problems being solved by unexpected random mutations of ideas, Yet when I looked at the question of how much it would cost a few days ago, the answer that i found was perhaps as little as a dollar a watt. That was less than I had expected, a lot less. It was a exciting, but frightening too. None of us wants to look like a fool. The answer that it would cost as little as $1 a watt seemed almost too good to be true.
The idea of a fluid fueled thorium breeder was first proposed by Nobel Laureate Eugene Wigner, together with Wigner’s protégé Alvin Weinberg, and highly regarded engineer Gale Young in 1945. Between 1945 and 1958 Wigner and Weinberg who rose to be director of Oak Ridge National Laboratory had focused on a heavy water fluid fuel reactor the aqueous homogeneous reactor. But in 1948, an young Oak Ridge engineer, Ed Bettis, invented a second type of fluid fueled reactor, the Molten Salt Reactor, which was to demonstrate far greater potential as a thorium breeder and power production reactor.
Between 1950 and 1976 Oak Ridge National Laboratory developed the revolutionary Molten Salt Reactor concept. R. C. Briant and Alvin Weinberg explained in 1958 that there were
Two very different schools of reactor design have emerged since the first reactors were built. One approach, exemplified by solid fuel reactors, holds that a reactor is basically a mechanical plant; the ultimate rationalization is to be sought in simplifying the heat transfer machinery. The other approach, exemplified by liquid fuel reactors, holds that a reactor is basically a chemical plant; the ultimate rationalization is to be sought in simplifying the handling and reprocessing of fuel.
Briant and Weinberg added:
At the Oak Ridge National Laboratory we have chosen to explore the second approach to reactor development. . . . it has long been recognized that a liquid fuel which did not require high pressure, in which thorium or its compounds could dissolve, and which did not decompose under radiation would indeed be a major invention for the reactor art. . . .
we have been investigating another class of fluids which satisfies all three of the requirements for a desirable fluid fuel: large range of uranium and thorium solubility, low pressure, and no radiolytic gas production. These fluids, first suggested by R. C. Briant, are molten mixtures of UF4 and ThF4 with fluorides of the alkali metals, . . .
Thus in 2009 the 1970′s to 1980′s 1 GWe MSR would have cost about half the current cost of LWRs, while offering superior technology, and decreased operating expenses. The MSR would have cost less, because it was simpler, required less materials and fewer labor hours to build. The MSR had many inherent safety features that were absent from LWRs. Thus money does not have to be spent compensating for inherent safety defects in MSR design.
In addition to the savings from shifting from LWRs to MSRs, shifting from large reactors, to small, modular, factory built reactors offered an opportunity for significant construction savings. Researchers found that work disorganization was a significant cause of conventional reactor costs. Over 25 percent of workers time in reactor construction projects was wasted by work disorganization. Shifting labor from a construction site to a factory would help to solve the work flow problem. in addition building a large numbers of of small reactors in a factory, increases the rational for the use of labor savings devices on assembly lines. A rapid construction cycle, means less money would be spent on accrued interest. The small rapidly manufactured, low cost MSR is called a LFTR, Liquid Fluoride Thorium Reactor, In addition to the cost saving options already mentioned, other options are possible. It is at least conceivable that LFTR costs as low as 1 Billion Dollars per GW are possible. This is a very preliminary conclusion, but I believe that much more research should be undertaken. However, It is safe to say that some tentative evidence suggests that LFTR capital costs may run as low as $1 billion per GW, and that is a fair likelihood that LFTR costs will run below $2 Billion per GWe. Furthermore, LFTR research that would be preliminary to building pre-production prototype could run as low as $2.4 billion, and we could say that $5 billion is a not unreasonable estimate of the required research investment. Again further research would be desirable and would probably add to our certainty about cost estimates.
When I first began to write Nuclear Green, I did not realize that I would be engaged in revising the history of the nuclear era. Indeed I was unaware that the very possibility of such a revision could be possible. But there were always questions that had first arisen from my fathers choice in 1964 to leave the field of nuclear safety where he was happy and enjoyed very considerable success, in order to return to the field of Molten Salt Chemistry, a field where he had once covered himself with glory, but where he had never known happiness and where he had been for half a decade worn a crown of thorns.
WASH-1222 argued, quite mistakenly, that the Light Water Reactor and the Liquid Metal Fast Breeder Reactor were technologically mature, while the Molten Salt Reactor was not. In fact the AEC, American Reactor manufacturers, and utility companies were losing their illusory control over a vary immature light water reactor technology at the very moment WASH-1222 was written, while the Federal Government was fated to spend over 20 Billion 2009 dollars in a vain attempt to master LMFBR technology. In ORNL-TM-7207, a 1980 Oak Ridge document, ORNL staff members reported that a commercial proliferation-proof MSR could be manufactured for the equivalent of a 2.37 billion 2009 US dollar investment in research and development. A flawed computer model for assessing the capital costs of conventional LWRs failed to alert the Oak Ridge scientists to the fact that the DMSR could be manufactured for 43% of the cost of the Light Water Reactor. Given the superiority of the MSR over the LWR in safety, nuclear waste handling, and power production efficiency, and its ability to manufacture its own fuel on a sustained basis, there is little doubt that the MSR offered a far superior option for American energy future. The failure to recognize that option, and the consequences of that failure is part of my historic revision.