Deproliferation, India and the Thorium Fuel Cycle

In the first part of this essay, I reviewed the almost inevitable rise of China and India to great power status. I pointed out that by 2050, current expectations are that by 2050, China and India will be ranked along with the United States as great powers of the first order. I noted that both China and India are committed to the development of Thorium fuel cycle nuclear technology, and the possibility that those commitments could chalenge the current course of American nonproliferation policy.

It is possible to produce fissionable U-233 from thorium from the same sort of reactors used to produce weapons grade plutonium, yet during the cold war, no one thought to do so. Frank von Hippel is a self-styled non-proliferation expert who has greatly influenced American, and even global non-proliferation policy. Other self-styled non=proliferation experts tend to advocates arms control policies suggested by von Hippel. Together with Jungmin Kanga and von Hippel, actually attempted to explore this seemingly rational step was not taken during and after the cold war in a paper titled U-232 and the Proliferation- Resistance of U-233 in Spent Fuel.

They write,

Uranium-233 is, like plutonium-239, a long-lived fissile isotope produced in reactors by single-neutron capture in a naturally-occurring abundant fertile isotope (see Figure 1). The fast critical mass of U-233 is almost identical to that for Pu-239 and the spontaneous fission rate is much lower, reducing to negligible levels the problem of a spontaneous fission neutron prematurely initiating the chain reaction -- even in a "gun-type" design such as used for the U-235 Hiroshima bomb (see Table 1). Why then has plutonium been used as the standard fissile material in the "pits" of modern nuclear weapons while U- 233 has not? This question is not just of historical interest, since there is increasing interest in U-233-thorium fuel cycles.

Kanga and von Hippel note

One of the most important reasons why plutonium was chosen over U-233 as a weapons material is that first-generation plutonium-production reactors were fueled by natural uranium, which contains almost as large a fraction of neutron-absorbing fertile material (U-238) as is possible consistent with a reactor achieving criticality. In a natural-uranium fueled reactor, such as the Canadian heavy-water-moderated (HWR) reactor type, Pu-239 is produced by neutron absorption in U-238 at a rate of about one gram of plutonium per thermal megawatt-day (MWd) of fission energy release at low U-235 "burn ups," (see Figure 2).1 Approximately one MWd is released by the fission of one gram of fissile material. After taking into account the neutron requirements for maintaining a steady chain reaction, there is about one excess neutron available per fission and virtually all of these neutrons are absorbed by U-238. Production of U-233 requires the addition of the fertile material Th-232. If the fuel is natural uranium, only a relatively small percentage of thorium can be added before it becomes impossible to sustain a chain reaction. We"estimate that about 7 percent thorium oxide can be added to HWR fuel achievable burnup is reduced from 7000 to 1000 MWd/t (thermal megawatt- days per ton-heavy metal). Because the thermal-neutron absorption cross-section of Th-232 is almost 3 times larger than that of U-238, this concentration of thorium would yield about 0.2 grams of U-233 per MWd at burnups lower than 1000 MWd/t (see Figure 3). Thus most of the fissile material produced in the core would still be plutonium.

Kanga and von Hippel also state,

For a country with uranium-enrichment capabilities, the balance between plutonium and U-233 production could be shifted almost all the way toward U-233 by fueling production reactors with highly-enriched uranium. Indeed the U.S. produced much of its weapons plutonium in the Savannah River heavy-water-moderated production reactors, using highly-enriched uranium fuel and depleted uranium targets in mixed-lattice arrangements.

But Kanga and von Hippel also noted a second problem for weaponizing U-233,

But at this point it should be noted that countries with uranium enrichment capacities to the level of highly-enriched uranium already possess the capacity to produce nuclear weapons. And the process of producing U-233 using HEU-235 to in production reactors, destroys more weapons grade fissionable material than it produces. The use of U-235 at Savannah River to produce Pu-239 was motivated by the fact that Pu-239 had useful military qualities that U-235 lacked. The military qualities of U-233 are inferior too the military qualities of U-235. Thus the choice to produce Pu-239 but not U-233 at Savannah River was rational. Kanga and von Hippel acknowledge the problem,

A second problem with U-233 as a fissile material for either weapons or reactor fuel is that it contains an admixture of U-232, whose decay chain produces penetrating gamma rays. The decay chain of U-232 is shown in Figure 4. The most important gamma emitter, accounting for about 85 percent of the total dose from U-232 after 2 years, is Tl-208, which emits a 2.6-MeV gamma ray when it decays (see Appendix C). For plutonium containing a significant admixture of 14.4-year half-life Pu-241, the most important source of gamma-ray irradiation from is its 433-year half-life decay product, Am-241, which emits low-energy (< 0.1 MeV) gamma rays. These gamma rays do not represent a significant occupational hazard for weapon-grade plutonium (0.36% Pu-241) but their dose becomes more significant for "reactor-grade" plutonium, which contains on the order of 10 percent Pu-241. Thus both U- 233 contaminated with U-232 and reactor-grade plutonium are made less desirable as weapons materials by virtue of the fact that their gamma emissions bring with them the potential for significant radiation doses or shielding requirements for workers involved in nuclear weapons production and for military personnel handling nuclear weapons.

How much less desirable? Kanga and von Hippel report that at a 1% U-232 contamination level a worker would begin to accumulate a cancer risk after working with U-233 for less than three minuits. But 1% U-232 is unusual to say the least. The problem is simple, U-233 poses problems for workers and military personel by exposure to radiation from a U-232 daughter product, while the same radiation poses problems for weapons electronics in storage.

Kanga and von Hippel report that India is researching laser isotope separation of U-233 from U-232. But does this represent a proliferation challenge? First if Indian researchers can separate U-233 from U-232 using lasers, they can also separate U-235 from U-238, and U-235 from U-238 separation is one of the two classic route to nuclear weapons. U-235 based weapons are reliable enough that they do not require tests to identify their military effect. This is not the case for U-233 based weapons. The only known test of a U-233 based weapon failed to accomplish test objectives, although it did explode with a respectable if not as large as expected bang, Thus it would appear that given routs to U-233 and U-235 based weapons, given equivalent costs and technical obstacles, but without tests, military planners will prefer the U-235 based weapons.

Now it can be argued that India should not develop laser uranium enrichment technology because such technology poses proliferation risks, but Burma, a rogue state, is also developing Laser enrichment technology, although it is very unlikely that the Burmese will master it. Burma is also attempting to master centrifuge technology, and given the track records of Pakistan and Iran, that appears to more likely.

The Indian three stage nuclear Research and Development program is well known, and despite setbacks, it has made steady progress over the last 50 years. During much of that time, the global anti-proliferation community sought to punish India for its pursuit of nuclear weapons. India, which shares common borders with two nuclear armed hostile states that are allied against it, believed that a small nuclear arms program was prudent, given the likelihood that at least one of its enemies might use nuclear weapons against it. India maintained its nuclear weapons program despite a 34 year embargo on uranium and other nuclear related trade items. The embargo somewhat handicapped the development of the Indian nuclear industry, and limited the production of nuclear power in India.

It should be pointed out that in 1974, at the beginnings of the international nuclear trade sanctions against India, that nation lacked many of the characteristics of a great power. Never the less it refused to back down on its nuclear weapons program. Today, India is rapidly becoming a great power. It is conceivable that by 2050 India will have the largest economy of any nation. At worst India will have by most estimates the second or third largest economy. India, like China is developing aircraft carriers, a standard military technology for projecting power.

If in 1974, a relatively weak India refused to subordinate itself to the nuclear policies dictated by the United States, by 2050 a very powerful Indian State will certainly not place itself under American Nuclear hegemony. The 123 agreement between India and the United States offered India recognition of its great power status.

The Indian three stage Indian Nuclear development plan directly contradicts the non-proliferation policy advocated by Frank von Hippel who opposes nuclear waste reprocessing and the use of fast reactors. Von Hipple states,

Reprocessing is enormously dangerous. The amount of radioactivity in the liquid waste stored at France's plant is more than 100 times that released by the Chernobyl accident. That is why France's government set up antiaircraft missile batteries around its reprocessing plant after the 9/11 attacks.

Even more dangerous, however, is the fact that reprocessing provides access to plutonium, a nuclear weapon material. That is why the U.S. turned against it after 1974, the year India used the first plutonium separated with U.S.-provided reprocessing for a nuclear explosion. President Gerald Ford and Henry Kissinger, his secretary of State, managed to intervene before France and Germany sold reprocessing plants to South Korea, Pakistan and Brazil, all of which had secret weapons programs at the time.

The heart of the Indian long range three stage nuclear program involves recycling spent fuel from conventional power reactors. Plutonium in that spent fuel becomes the the Fissile start charge for for fast breeder reactors, which produce plutonium and U-233 from thorium. That fuel is recycled and the the Plutonium is returned to the fast breeder while the thorium is used to power thorium fuel cycle thermal breeder reactors.

Von Hippel apparently has not produced a comprehensive case study of nuclear disarmament issues from the Indian perspective, but he thinks he knows what the Indians should be doing. In 2006 he co-authored a paper which offered prescriptions for demands which the United States should seek to include in any nuclear trade agreement with India. In particular von Hippel demanded that any nuclear trade agreement with India should require that before trade can begin

that India has stopped the production of fissile material (plutonium and highly enriched uranium) for weapons or else joined a multilateral fissile production cutoff agreement;

Von Hippel also called for

A determination and annual certification that U.S. civil nuclear trade does not in any way assist or encourage India's nuclear weapons program.

The Conditions which von Hippel sought to impose on India might be described as humiliating for a great power, even a great power which was content to hold a small number of nuclear weapons. India faces a possible military alliance between China and Pakistan which together hold far more nuclear weapons than India does. Thus India's nuclear arsenal may not offer India sufficient for conceivable national defense needs.

In addition von Hippel has taken a stance that nuclear fuel reprocessing is conducive to weapons use of fissile materials. Von Hippel also objects to fast reactors because a fast reactor fleet will inevitably be dependent on fuel reprocessing, and theoretically fast reactors could produce fissionable materials that could be used in nuclear weapons. Later in this essay, I will examine problems with von Hippel's belief that reprocessing and fast reactors increase the likelihood of nuclear proliferation. In Fast Breeder Reactor Programs: History and Status, a study coauthored by von Hippel, he remarks

India’s Prototype Fast Breeder Reactor (PFBR), expected to be completed in 2010, will have the capacity to make 90 kg of weapon-grade plutonium per year, if only the radial blanket is reprocessed separately and 140 kg per year if both radial and axial blankets are reprocessed.15 The Nagasaki bomb contained 6 kg of weapon-grade plutonium and modern weapons designs contain less. At 5 kg per warhead, the PFBR would produce enough weapon-grade plutonium for 20–30 nuclear weapons a year, a huge increase in production capacity in the context of the South Asian nuclear arms race. were left mixed with the plutonium, however — a project that the U.S. Department of Energy abandoned when it learned that the technology was not in hand — the gamma radiation field surrounding the mix would still be less than one-hundredth the level the IAEA considers self-protecting against theft and thousands of times less than the radiation field surrounding plutonium when it is in spent fuel (figure 1.4).

It is doubtful that von Hippel favors Indian reprocessing of Thorium cycle nuclear fuel. Thus to the extent that American nonproliferation policy is influenced by von Hippel and his followers, American nonproliferation policy, it is likely to conflict with Indian nuclear policy. The Indian nuclear policy had from its inception of using nuclear power to turn India into a rich and powerful nation. Not just militarily and politically powerful, but economically powerful as well. It is unlikely that the Indian political leadership will abandone their goal of achieving great power political and economic status for India, and the prevailing view that nuclear power will play a key roal in accomplishing that goal. To understand Indian national goals is to begin to understand the realpolitik of Indian objections to American nonproliferation as interpreted by Frank von Hippel.

Much 20th century thinking about nuclear nonproliferation, sprang from ethical goals. Nuclear war, is a moral wrong, and the use of nuclear weapons is evil. These assumptions cannot be dispited. But nuclear weapons and their use exist in a morally imperfect world, where people believe that they are sometimes are forced to commit acts that are morally wrong, and even to do things which in absolute moral terms are evil. It is not necessicary to justify such behavior in order to acknowledge that it exists, and to regard the necessity of responding to the real acts of people, as imposing on us constraints on the moral aspects of our life and thought. It is desirable to bring together the real world of human thought and action, with the more lofty goals offered by moral thought. Such is the case if we wish to control the production and use of nuclear weapons.

Thus future American policy towards India nuclear developments ought to focuse on a conversion of the ethical with the realpolitik goals. American policy has no choice but to accept that India has chosen a path that will lead to a thorium based economy. as well as the Indian need for a limited stock of nuclear weapons, at least in the short run.. Once Indian goals accepted, India will willingly participate in the creation on an international order directed towards arms control.

The NNL doesn't like Thorium

I look at criticism as something that is positive. If you are on the right track. It may signify that you are getting some where and for that reason people who don't like your purposes may be getting concerned. This I would argue might be the case with thorium. If you are the wrong track, careful attention to he criticism may tell you that you are wasting your time. But critics can also be wrong.

The emergence of thorium cycle criticism is good news, because it signals that Thorium/MSR advocates have accomplished their first goal, which is to make thorium nuclear technology widely known.

A paper titled The Thorium Fuel Cycle offers its readers

an independent review of the thorium fuel cycle by the UK National Nuclear Laboratory (NNL), highlighting the strengths and weaknesses not just in the UK context but globally.

First it should be asked how did the staff of the NNL come to its conclusions. Scientists normally would begin an assessment of the potential of a technology with a literature review. In 2005 the International Energy agency published Thorium Fuel Cycle - Potential Benefits and Challenges *IAEA TECDOC-1450). That review tells us how information was collected for its composition

The information on thorium and thorium fuel cycles has been well covered in the IAEA- TECDOC-1155 (May 2000) and IAEA-TECDOC-1319 (November 2002). The objective of the present TECDOC is to make a critical review of recent knowledge on thorium fuel cycle and its potential benefits and challenges, in particular, front end, applying thorium fuel cycle options and back end of thorium fuel cycles. The review has been prepared based on three consultancy meetings held at IAEA, Vienna 1–3 July 2002, 14–16 April 2003 and 15–16 September 2003, where experts from Canada, France, India, Israel, Japan, the Russian Federation, USA and IAEA had participated and supported by information and published papers from specialists on thorium fuels and fuel cycles.

In contrast the NNL review states,

NNL has many years experience of the nuclear fuel cycle and associated science and technology, including fuels, reactors and reprocessing. We are therefore in an ideal position to be able to independently assess and advise decision makers on both current and future fuel cycles such as thorium. The statements in this note are backed up by extensive experience of nuclear R&D and the nuclear industry worldwide, including thorium assessments and programs in which the NNL was involved.

Thus the NNL was relying on its in house expertise on the thorium fuel cycle, but how competent were its researchers to make this judgement? First it would seem that NNL researchers had not participated in the Thorium fuel cycle assessment process conducted by the IAEA. We know that IAEA tells us the countries from which participants in its thorium cycle assessment process had come, and those nations did not include the UK. That

A second difference between the IAEA TECDOC-1450 and the NNL paper is the documentation of the former and the complete lack of documentation in the latter.

Other comparisons between the TECDOC-1450 and the NNL paper are also instructive. TECDOC-1450 states,

In recent years, there has been renewed and additional interest in thorium because of the intrinsic proliferation resistance of thorium fuel cycle due to the presence of 232U and its strong gamma emitting daughter products,

In contrast the NNL states

Contrary to that which many proponents of thorium claim, U-233
should be regarded as posing a definite proliferation risk. For a thorium fuel cycle which falls short of a breeding cycle, uranium fuel would always be needed to supplement the fissile material and there will always be significant (though reduced) plutonium production.

The NNL does not state the reason for its disagreement with the NAEA, nor does it state why it

rejects the widely heald beliefe that the thorium cycle offers more proliferation resistance than the Uranium fuel cycle.

TECDOC-1450 notes

Closed’ 232Th–233U/238U denatured breeder cycle designed to maximize proliferation- resistance by minimal processing of the fuel salt and by addition of 238U to isotopically dilute and denature fissile 233U isotope. Though this lowers the breeding ratio marginally (slightly above 1.0) as compared to 232Th–233U ‘closed’ cycle, it ensures intrinsic proliferation resistance of the fuel cycle.

In other words in a denatured fuel cycle, the breeding ratio would be so close to unity, that the would be weapons builder would be forced to sacrifice his reactor load of fissionable material in order to produce weapons. In addition by diluting U-233 with U-238, Weapons grade U-233 would be difficult to extract.

The NNL claims,

Attempts to lower the fissile content of uranium by adding U-238 are considered to offer only weak protection, as the U-233 could be separated in a centrifuge cascade in the same way that U-235 is separated from U-238 in the standard uranium fuel cycle.

But first most would be proliferators do not possess centrifuge cascade and as Iran has discovered centrifuge technology is not easy to develop, and centrifuges are not available on the open market. Once a would be proliferator who is considering use of U-233 from a denatured thorium reactor faces a choice: Either to pull uranium out of the reactor and process it through centrifuge cascades to obtain weapons grade U-233, or to process ordinary uranium through the centrifuge cascades in order to obtain weapons grade u-235. The benefits of the two processes are the same. The cost of the U-235 path is the problems posed by obtaining the uranium. The would be proliferator may not possess a Uranium mine, or uranium bating resources. Uranium is difficult to obtain on the open market. In contrast obtaining U-233 from the reactor fuel of a unity breeder, would mean that fissionable U-233 that can only be replaced in the reactor by breeding is being withdrawn from the reactor, and will be impossible to replace by breeding. In effect in the long run the denatured U-233-thorium reactor will have to be sacrificed if U-233 is withdrawn for weapons purposes. Secondly U233 is adulterated by U-232 which decays into a extremely dangerous radioactive daughter product. This makes the handling and storage of weapons containing U-233 a far larger problem than the handling and storage of a U-235 based weapon. Centrifuges can be used to separate U-233 and u232, but this would involve more centrifuge cascade than would be required to separate U-235 and U-238, and would be more costly and time consuming. Clearly then the problems posed by attempting to weaponize denatured U-233 from a thorium cycle reactor would be greater than the problems posed by separating U-235 from U-238. Those problems are what is referred to by the term proliferation resistant.

It should be added that proliferation resistance in any reactor does not offer strong proliferation protection. Nuclear weapons proliferation is quite easy and and cheap, and nations do not need or even desire thorium reactors in order to obtain the capacity to build nuclear weapons. Proliferation resistance is about preferred paths to nuclear weapons, not prevention. Proliferation control depends on a strong international order that is capable of keeping weapons technology out of unacceptable hands. To date that international order has had mixed success at best.

A proliferation resistant technology is one which a would be proliferator would prefer to not use because it costs more, presents greater technical difficulties or poses other disadvantages. If a nation already has access to centrifuges capable of separating U-233 from U-238, it already possesses the means to separate weapons grade U-235 from U-238. The IAEA acknowledges that there are greater challenges involved in the weaponization of U-233 than in the weaponization of U-235. Thus contrary to the NNL the weaponization of U-233 produced by thorium breeding is very unlikely.

Thus it would appear that some NNL pronouncements on thorium are in significant conflict with the IAEA assessment. In addition other NNL pronouncements are unrealistically pessimistic. For example the NNL states,

In the foreseeable future (up to the next 20 years), the only realistic prospect for deploying thorium fuels on a commercial basis would be in existing and new build LWRs (e.g., AP1000 and EPR or PHWRs, [e.g. Candu reactors]. Thorium fuel concepts which require first the construction of new reactor types (such as High Temperature Reactor (HTR), fast reactors and Accelerator Driven Systems (ADS)) are regarded as viable only in the much longer term (of the order of 40+ years minimum) as this is the length of time before these reactors are expected to be designed, built and reach commercial maturity.

In fact a prototype Indian commercial fast reactor is expected to be online before the end of 2012, while Indian thorium breeding fast breeders are expected to come on line in a little more than a dozen years later. By 2025 India plans to have growing fleets of Thorium Fast Breeder Reactors, and Advanced Heavy Water Reactor unity thorium converters. Thus the NNL estimate appears of the development time for thorium cycle fast breeders may be off by as much as a generation.

It would appear then that the NNL's report on thorium was prepared with less than rigorous preparation. The report includes a number of assertions which are questionable. We now have to ask why did the NNL UK publish this report? The answer can be found in Laboratory Director Paul Howath's statement of purpose at he the beginning of the report,

and advise decision makers on both current and future fuel cycles such as thorium.

It is plausible, given the content of the NNL report, that the NNL has little expertise in the thorium fuel cycle and limited resources. The leadership of the NNL prefers to focus on technology they understands, rather than technology they does not fully understand. The NNL has by now either receive enquiries about thorium cycle nuclear technology from national leaders, or has reason to believe that it will. It thus has a need to offer excuses for a lack of interest in thorium cycle research and development. No one likes to admit that we don't know how, and have our hands full with what we are doing now. The result is a bad report.

Small Reactors, Mass Reactor Deployment, and the LFTR

There is at present no end of projects to build small and mini reactors. Most of these projects will not get beyond the concept stage, but a few probably will. I distinguish between mini and small reactors by power output. I would class reactors that generate less than 100 MWe as mini reactors, and reactors that generate from 100 MWe to 400 MWe as small reactors.

Mini reactors are primary useful in situations in which you need small stand alone energy producing units. Think of cities like Juneau, Alaska, where about 30,000 people live. Juneau is too small to rate a big power plant, and too remote to rate an electrical grid hookup. Juneau thus needs a very reliable and low cost, 24 hours a day, 365 days a year electrical technology, to keep all of its dishwashers, and hair blowers running. The 25 MWe Hyperion reactor would appear to offer everything Juneau needs, and at a cost Juneau can afford. Of course. the prototype Hyperion mini-reactor has not been built yet, so estimates of cost and claims about practicality might be subject to revision.

In addition to providing electricity, mini reactors could provide district heat for cities like Juneau. If Juneau had a water shortage, electricity from the reactor could be used to desalinate sea water through reverse osmosis. Local industries could use the Hyperion's heat as input into chemical and manufacturing processes. Clearly then mini-reactors are potentially useful then, but perhaps most useful to smaller communities that are off the grid.

Small reactors are large enough to be useful on a grid, but small enough to be partially or completely factory produced. The proposed Babcock & Wilcox 125 MWe mPower reactor is an ideal example of the small reactor. While engineers will argue in theory that small reactors will be more expensive than large reactors, factory production can change that. Babcock & Wilcox appear to be planning to build their small reactor as a lit in a factory, and then assemble the kit on site. Westinghouse is planning to build the much larger AP-1000 using the same kit system, so Babcock & Wilcox does not seem likely to save a great deal of money with its small reactors, and indeed the amount of on site labor Babcock & Wilcox appears to believe it will need to manufacture the mPower will not lead to a major cost breakthrough.

The Tennessee Valley Authority (TVA) is planning to buy the first mPower, and to set it up in East Tennessee. Was planning to build as many as 4 big reactors, and still might build them, but the mPower means that TVA can buy reactors in smaller chunks and thus encounter lower financial risk. A large reactor could cost the TVA as much as $7 billion and possibly more. The mPower would be expected to cost under $1 billion, and begin producing power more quickly than a large reactor. Producing power means you don't have to carry interest.

Thus the advantage of a small conventional reactor like the B&W mPower, is that it lowers risks. The mPower has some slight advantages in deployability, but apparently very little advantage in price over larger reactors.

One way to get costs down is to to get better control of labor costs. One good way to do that is to build your reactors in India. Indian built reactors are, even by Chinese standards, inexpensive, and as I have frequently argued the Indians may be about to eat everyone's lunch through low energy prices. The Indians have been building small reactors for years, perfecting their design, and trying out cost savings tricks. What they have learned is impressive, and if they start manufacturing reactor kits in factories as the Chinese are doing, they will stand on

the edge of an energy revolution.

So one way to lower nuclear costs would be to employ Indian labor in reactor construction. But that would not work in the United States or other advanced societies. We have to bring labor costs down by increasing labor productivity. In addition we face a time limit. Climate scientists say we need to bring CO2 emissions under control by 2050. Under control means something like an 80% reduction in CO2 emissions, so that means replacing most of the world's current sources of energy. Thus energy replacements need to be hugely scalable, and they need to be cheap. Conventional reactors are neither scalable enough nor cheap enough, The mPower example demonstrates that small conventional reactors are not going to do the trick. In order to meet our need for low cost and high deployment, we need a compact reactor that is small enough to be transported by rail, truck or barge, easily and quickly assembled on site, and online within a few months. The whole energy generation system has to be low price, and its nuclear fuel will have to be both low cost and abundant.

When I figured this out, the answer to how to do this became amazingly clear. My father had done research on just such a reactor over a 20 year period of time at Oak Ridge National Laboratory. That reactor, the Molten Salt Reactor, was known to be capable of operating on the thorium fuel cycle. Researchers believed it to be extremely safe. It was so good at destroying nuclear waste that it had been actually proposed for use in a nuclear waste destroying system. The MSR was both simple and compact, ideal for factory production, and transportation. The MSR was extremely efficient. Thus building a huge reactor was not required in order to efficiently produce electricity. In fact a 100 MWe MSR could produce electricity more efficiently that a 2000 MWe conventional reactor. Nor did the power production system require elaborate housing. You could ship in the turbines and generators by truck, rail or barge, set them up in an old power plant or factory, hook them up to the grid, and to the reactor, and you are ready to produce power.

If you are worried about terrorist attack, you can dig a hole and stick your reactor in it. Kirk Sorensen has produced such designs. Once your reactor is in the hole, it is not going to be damaged by truck bombs, or aircraft attacks. On-site set up and assembly can be facilitated by highly automated machinery.

What about fuel, you ask. It turns out that there is a great deal of thorium just laying around. There is something like 400,000 tons of thorium sitting on beaches in India. As David Walters would say, all you need is 4 Indians with shovels and a pickup truck. In an afternoon, they can dig up enough thorium to produce 1 GWe for a year. Thorium in easily recoverable amounts is found in mine tailings, thus we don't need new thorium mines to produce it, we can simply scoop up thorium that is already on the surface. Even in seemingly small concentrations the energy recovery potential from thorium is such, that the energy investment required to bring about that recovery is worth while.

There would not seem to be any potential impediments to the Liquid Fluoride Thorium Reactor solution to our energy issues. They can be built in large numbers in factories. Small LFTRs are efficient and easily transported. They can be set up anywhere. The do not require water for cooling, they can be cooled with air. They are not good nuclear proliferation tools. They are safe. Their materials output is safe after 300 years, and need not be considered waste.

What is wrong with the LFTR? Some money needs to be spent on their development. A crash development program that cost less than what is spent on the NASA Space program in a year would probable come up with a commercial LFTR model in 5 years or so. Thus considering the enormity of the energy challenges we face, the LFTR provides a doable solution.

So called energy experts claim that there is no such thing as a silver energy bullet, but there is a thorium bullet, and we have every reason for using it. Small Liquid Salt Thorium cycle reactors hold amazing promise for solving the energy problems that confront us during the next 40 years.

Indian Reactor Costs, Further Investigations

I recently received a link to an Indian Government PROJECT IMPLEMENTATION
STATUS REPORT covering central Sector projects for the first three months of 2009. This report is part of an ongoing effort by the Indian government to monitor cost and time performances of construction projects. The Report notes seven Indian reactor projects:
1. The Kaiga Power project Units 3 and 4
Both 220 MWe PHWRs
2. The Kudankulam Power Project units 1 and 2
Both are Russian 1000 MWe VVER-1000 light water reactors
At present Russia and India have an agreement to build four more reactors at the Kudankulam site.
3 The Rajasthan Power Project Units 5 and 6
Both 220 MWe PHWRs
4. The Prototype Fast Breeder Reactor
1 Unit @ 500 MWe
Four other production units are planned for construction during the next decade.

Costs:
The reported cost of the two Units of the Kaiga project is Rs.3282 crores, or about $656 Million. (the crores is a unit of 100,000). Thus their capital cost of the Kaiga reactors is $1.49 per watt. The Rajasthan units have an estimated cost of Rs.3072 crores. with a capital cost of $1.40 per watt. Lets review some other recent Indian PHWR costs:

TAPP-3&4 has an approved cost of Rs. 6525 crores, but it is anticipated that the Project would be completed in about Rs.6000 crores. . .,

Or about $1.11 cents per watt. The lower cost can be attributed to economies of scale for the 540 MWe PHWR units. I previously inferred from statements about TAPP costs that the construction cost for 220 MW PHWRs ran about $1.18 per watt. That not appears to be 20 to 30 cents low per watt. it should be noted that the 700 MWe PHWR uses a slightly upgraded variant of the 540 MW PHWR core. If the upgrade is accomplished without any significant cost increases, then the cost of the 700 MWe PHWRs could run as low as $0.85 per watt. I would like to caution that this estimate is not yet supported by data supplied from Indian sources, thus must be considered both tentative and speculative, but this suggests that very careful attention should be paid to future Indian reactor costs.

it would appear then that the cost of mid size indigenous Indian Reactors is quite competitive with that of the Russian reactors now being built in India. The first two VVER-1000 carry an approved cost of Rs.13171 crore, or about $2.6 billion. This gives us an overnight cost of $1.31 per Watt. the Indians may well be motivated to build the higher cost Russian reactors because they bring with them access to Uranium fuel. The indigenous Uranium supply is the Achilles heel of the Indian nuclear industry.

Indian costs compared to Western costs

Indian reactors are built with appropriated funds rather than borrowed funds. The Indian government doers expect a return on its investment, as it should if it intends t0o continue building reactors. Power from Indian reactors currently costs Indian consumers between Rs. 2 and 2.5 per kWh, about 4 to 5 cents per kWh. Thus the price of power produced by Indian reactors is competitive with the process of electricity produced from coal fired power plants.

Thus the Indian nuclear industry, has the potential to be a world beater in the cost of of post carbon electricity. It should be noted that there are potentials to lower the cost of Indian reactors could be extended even further. Large scale reactor construction can utilize factory production of reactor kits, a system being evolved in China. important reactor parts such as pressure tubes and fuel bundles, can be mass produced. And large scale production of parts such as pumps and steam generators can lower costs. Thus the Indian nuclear industry has the potential to build reactors substantially below $1.00 per watt, and possibly substantially below 85 cents per watt. Thus a very real probability exists that by 2050nIndian electricity could cost half of what Chinese electricity costs, and as little as 20% of the cost of electricity in Europe and the United States. Even lower reactor and electrical costs would be possible if India chose to adopt LFTR type reactors, as a move to achieve maximum efficiency from the thorium fuel cycle.

If this analysis is correct, we might find contrary to our present expectations, that India, and not China will energy as the world's most significant economic power by the end of the 21st century.

Invitation: I invite more information on Indian nuclear technology and costs, in order to extend my analysis.

India Plans Uranium Powered Export Version of AHWR

The AHWR represents the ultimate third phaser of the three phase Indian nuclear plan for a thorium breeder nuclear economy. In the first phase conventional Light and heavy water reactors will burn uranium based fuel. Once the fuel will no longer sustain a chain reaction, it will be removed from the reactor and processed to separate plutonium from other materials. The Plutonium then is rase to fuel fast breeder reactors. The fast breeders produce more plutonium but also breed thorium, producing U-233. The U-233 is then used to fuel the start up AHWRs which are also thorium Breeders. Once Indian AHWRs start operating, they will produce their own fuel. India has very little uranium and a lot of thorium, so the plan to base the Indian nuclear future on the thorium fuel cycle is sound.

The AHWR is a very technologically advanced small (300 MWe) reactor that would not cost a poor country an arm and a leg to buy, and would is designed to operate outside a highly developed grid. There is a market for such reactorsa outside India, and indeed potentially a very large market, provided the reactor uses low enrichment uranium. At present the Indians are beginning to seek customers for their present generation of small PHWRs, that are low enrichment uranium burners. There would undoubtedly be a marker for a AHWR with its sophisticated safety features, were that reactor adapted for uranium fuel. The Indian Atomic Energy Commission, has recently announced that it will be designing and building a low enriched uranium version of the AHWR. Chairman Anil Kakodkar of the IAEC stated,

"A new version of AHWR named Advanced Heavy Water Reactor-Low Enriched Uranium (AHWR-LEU) that uses low enriched uranium along with thorium as fuel has been designed recently."

Kakodkar added,

"This version can also meet the requirement of medium sized reactors in countries with small grids while meeting the requirements of next generation systems,"

This announcement is another step indicating that Indian plans for atomic energy are now becoming very ambitious. This week Indian Prime Minister, Manmohan Singh, announced at a conference of devoted to nuclear energy, that the Indian state was setting a goal of a generating capacity of 470,000 MWs of nuclear generating capacity by 2050. This very ambitious goal represents a hundred fold expansion of nuclear generating capacity over the next 40 years.

The ambitious Indian plan would require factory manufacture of reactor modules if not entire reactors. Automated factory production would lower nuclear costs, allowing India to become a low cost nuclear supplier to under developed countries. The quality of Indian AHWR technology is good enough to find AHWR customers world wide including in Europe and North America.

Confusion about Generation 4 Reactors

There is at present a great deal of confusion about Generation 4 reactors at the moment. In particular a cheer leading section for the Integral Fast Reactor (IFR) has emerged during the past few months. The IFR is a sodium cooled fast breeder reactor reactor that includes passive safety features. Like the LFTR the IFR features a negative coefficient of reactivity. As the reactors core temperature rises, reactivity drops and then stops completely. Thus a IFR would not experience core melt down due to a run away chain reaction. The core sits in a large pool of liquid sodium that serves as a heat sink that provides passive cooling to the reactor in the event of a shut down of the reactor cooling system.

The IFR's most significant draw back is the use of sodium as a coolant. The IFR probably will likely be less expensive than LWRs to build. It is unlikely that the the IFR can be manufactured at a cost that is competative with the LFTR. The LFTR core will be relative small. This greatly eases the problem transporting a LFTR from a factory to the power generation site. In contrast the large containment vessel for the IFR's passive safety system is probably too large for truck or rail transportation. Either the IFR containment structure must be transported by barge or it must be manufactured on site, adding to construction costs.

The community of interest in the IFR has not reached the point where details of IFR construction are examined carefully, and potential limitations noted. The IFR appears to be less aware of cost issues as an important factor in determining the future of their favorite technology. This is most decidedly not the case for Indian fast breeder reactors which will start being completed late in the next decade. The Indian anticipate that their fast breeder reactors can be built for as little as $1.20 per kW of generating capacity and that electricity from them can be marketed at four cents a kWh. At that point the Indian FBR will emerge as a major factor in the future of energy. It would be hard to imagine the Chinese ignoring the advantages of the Indian Fast Breeder Reactors. The Indians could very go into business building FBRs all over Southeast Asia, the Middle East and possibly Africa.

Indian reactor design undergoes constant modification as Indian nuclear Engineers continuously improve reactor designs. The Indians are now developing revolutionary 3 reactor designs. The FBR, that uses Plutonium oxide fuel and operates both as a uranium and a plutonium fule cycle breeder, A second fast breeder which will use metal rather than oxide fuel and will probably include IFR type features, and an Advanced Heavy Water Reactor which will be capable of breeding thorium fuel cycle fuel. Indian Labor costs will mean that all three reactors potentially will find a very wide spread market.

American built IFR will have a difficult time competing with Indian Fast Breeder Reactors. I have previously demonstrated that the bottom end of the factory built LFTR cost range would coincide with projected cost range for Indian Fast Breeders during the next decade. Since it is difficult to imagine a nation maintaining great economic power status with high cost energy/electricity, economic competition with India and China would probably impose on the United States and other advanced economies the lowest cost post-carbon energy solutions. Unless there is a major advance in IFR cost control, that solution will most likely be the factory built LFTR. The Asian solution may well involve the use of Fast Breeder Reactors, but that choice will impose some costs and other disadvantages.

Nuclear proliferation constitutes a second issue concerning Generation 4 nuclear reactors. I would again like to point out the thinking errors that presume that the development and deployment of nuclear technologies in the United States will lead play a causal role in the development of nuclear weapons technologies by rogue states and terrorists. In the case of rogue states low cost routes to obtaining nuclear technology already exist, and use of Generation 4 technology as part of a nuclear weapons program would confer penalties and disadvantages on the would be proliferator. In fact it might be seen as preferable that the would be proliferator choose to develop nuclear weapons through use of proliferation resistant and costly generation 4 technology, rather than low cost and technically unsophisticated graphite pile reactors, or uranium centrifuges. The use of the lower cost technology would more likely lead to success, while the choice of generation 4 technology as a proliferation tool, is very unlikely to increase proliferation risks, along with every other nuclear evil imaginable.

The word proliferation appears 9 times in Amory Lovins litle essay:"New" Nuclear Reactors, Same Old Story . According to Lovins as soon as an Integral Fast Reactors is turned on in the United States, nuclear weapons start rolling out of the back end and streight into the hands of insame, pro-terrorist rogue dictators. The moment the first IFR starts opperating in the United States, according to Lovins, Chavez gets atom bombs.

IFRs are often claimed to “burn up nuclear waste” and make its “time of concern . . . less than 500 years” rather than 10,000–100,000 years or more. That’s wrong: most of the radioactivity comes from fission products, including very-long-lived isotopes like iodine-129 and technicium-99, and their mix is broadly similar in any nuclear fuel cycle. IFRs’ wastes may contain less transuranics, but at prohibitive cost and with worse occupational exposures, routine releases, accident and terrorism risks, proliferation, and disposal needs for intermediate- and low-level wastes. It’s simply a dishonest fantasy to claim, as a Wall Street Journal op-ed just did,8 that such hypothe¬tical and uneconomic ways to recover energy or other value from spent LWR fuel mean “There is no such thing as nuclear waste.” Of course, the nuclear industry wishes this were true.

Needless to say, Lovins does not bother with fairness or truth. That is not the Lovins way.

Lovins is the soul of subtlety compared to Australian "Green" Jim Green. Pronuclear bloggers in Australia have taken a shine to the IFR, and Green is going to set everyone straight. Green spends a little time discussing thorium, but it is clear he knows nothing about the LFTR and next to nothing about Thorium. Ignorance never stopped the Friends of the Earth from opposing nuclear power before. Why should it now:

The use of thorium, instead of plutonium, as a nuclear fuel doesn’t solve the weapons proliferation problem. Irradiation of thorium (indirectly) produces uranium-233, a fissile material that can be used in nuclear weapons.

The US has successfully tested weapons using uranium-233 (and France may have too). India’s thorium program must have a nuclear weapons component — as evidenced by India’s refusal to allow IAEA safeguards to apply to its thorium program.

Thorium-fuelled reactors could also be used to irradiate uranium to produce weapons grade plutonium.

Some proponents of nuclear fusion power falsely claim that it would pose no risk of contributing to weapons proliferation.

In fact, there are several risks. These include the use of tritium, a radioactive form of hydrogen, as a fusion power fuel. This raises the risk of its diversion for use in boosted nuclear weapons, or, more importantly, the use of fusion reactors to irradiate uranium to produce plutonium or to irradiate thorium-232 to produce uranium-233.

Fusion power has yet to generate a single Watt of useful electricity but it has already contributed to proliferation problems.

Whooo! Green goes well beyond ignorance. Mr. Green appears to have never encountered the concept of neutron economy. If you are running a thorium cycle reactor and you borrow your neutrons to radiate U-238 to make plutonium, where is your new U-233 going to come from? Can you imagine running a thorium cycle LFTR and using it to produce Plutonium-239? Green also has a novel take on the LFTR Tritium problem. Tritium can be diverted for use as a nuclear weapons booster! Then tritium becomes an excuse for a few remarks about fusion. Well tritium and thorium do have something in common. The two words both start with "t". Give Mr. Green am I for imagination. Give him an F for knowledge of nuclear technology.

Revisiting the thorium-uranium nuclear fuel cycle

From: Revisiting the thorium-uranium nuclear fuel cycle
by Elisabeth Huffer, Hervé Nifenecker, Sylvain David
Europhysics News 38 2 (2007) 24-27

Today’s MOX fuels are comprised of approximately 5% pluto-Thorium-uranium breeder reactors with slow neutrons need only a small uranium 233 inventory, on the order of 1 metric ton. Their theoretical doubling time is similar to that of uranium-plutonium fast neutron breeder reactors. However, fission products are much more efficient in poisoning slow neutron reactors than fast neutron reactors. Thus, to maintain a low doubling time, neutron capture in the fission products and other elements of the structure and coolant have to be minimized. An elegant theoretical solution to this problem was proposed in the 1960’s, namely, a reactor in which the fuel is a molten salt which also ser ves as the coolant. Neutron capture on the fission products would be limited thanks to on-line salt recycling, at the cost of additional complexity since the reactor becomes also a chemistry factory. Giving up the low doubling time objective opens the way to molten salt
reactors with drastically simplified on-line fuel processing or to other reactor types, such as those with in-operation fuel loading/unloading such as heavy water reactors (CANDU) or gas-cooled pebble-bed reactors. A particularly interesting scheme would consist in complementing a thorium-uranium reactor f leet with fast neutron reactors with a uranium- plutonium core surrounded with a thorium blanket that could produce the uranium 233 needed in excess to extend an
existing thorium-based reactor fleet.
________________________


Conclusion
It would be unfortunate if orientations were to be decided on the basis of fast decisions made without true scientific and technological debates concerning future reactors and fuel cycles,
using the argument that different orientations would break away too radically from currently accepted procedures. There is no real hurry for the definition of the systems of the future and the
times lend themselves to open and thorough reflection. Granting, however, that pencil and paper designs are not sufficient, small scale prototypes of the more promising reactors will have
to be built within the frame of international collaborations.

It would thus be worthwhile to resume the molten salt reactor program that was started in the 1960s at the Oak Ridge National Laboratory in the US, with the construction of a reactor prototype with a power capacity of a few ten MW.

A Hat Tip to Robert Hargraves and Bill from "Energy from Thorium"

Thorium Fuel Cycle Development in India

Homi Jehangir Bhabha, an Indian physicist, who had, during a pre-World War II stay in Europe, made important discoveries about cosmic rays. Upon his returned to India at the start of the war, he began to campaign for Indian research institutions deveoted to physics and nuclear energy. He quickly established himself as a scientist politician who had the ear of Pandit Nerhu, the first Indian Prime Minister. Shortly after Indian independence in 1948, Bhabha was assigned the task of establishing the Indian Atomic Energy Commission, and developing a nuclear research program.

During the first UN Conference on the Peaceful Uses of Atomic Energy (1955), Bhabha, who was the Conference President, presented a paper on Indian Atomic development. He argued that India lacked energy resources, and in order for the Indian people to have a Western standard of living, Indian electricity must be generated by nuclear means. He noted, "the necessity of obtaining enriched or pure nuclear fuel (plutonium- or uranium-233) for use in future atomic power stations of a more advanced design required the setting up during the next decade of a few atomic power stations designed to produce these materials as well as electric power.”

Bhabha once remarked that "No energy is costlier than no energy". He was what Texans use to call a wheeler-dealer. He used his position at the The First Conference to obtain British, Canadian and American assistance for the Indian nuclear program. Soon Indian Scientists were showing up at Chalk River, Harwell, and Oak Ridge for on the job training.

In addition to training, during the 1950’s, with American support and Canadian help, India began to construct its first reactor, the heavy water Cirus. What the Americans and Canadians did not notice was that the Cirus was capable of producing weapons grade plutonium.

In early 1957, Bhabha summarized his plan for the Indian nuclear energy future,

“It is likely that in the future more advanced and efficient types of atomic power stations will use concentrated atomic fuel, such as uranium-235, uranium-233, or plutonium, rather than the naturally occurring uranium. If we are not to depend on the import of such fuel from abroad, and not to build a gaseous diffusion plant involving an enormous expenditure and technical effort, it is necessary for us to start producing this fuel now by converting natural uranium into plutonium, and thorium into uranium-233 in atomic reactors. If we are therefore, not to lose further ground in the modern world, it is necessary for us to set up some atomic power stations within the coming five years, which will produce plutonium for our future power reactors, in addition to producing electricity now."

Bhabha believed that nuclear generated electricity would play an important future role in the Indian economy, and that India possessed only limited Uranium resources. However, India possessed large thorium reserves. Thus Bhabha believed that the Indian nuclear research must be directed toward the development of the thorium fuel cycle. During the 1950’s Bhabha set out a three stage development program for Indian Nuclear technology.

In the first stage, Heavy water reactors using unenriched uranium derived from India’s limited uranium reserve, would be constructed and begin operating. The use of heavy water reactors meant that India did not need to to develop expensive and power demanding uranium enrichment facilities.

During the second stage, India was to construct Fast Breeder Reactors, which burned plutonium reprocessed from the spent fuel of the heavy water reactors as well as their depleted uranium. India needed to develop breeder technology quickly, because it had limited uranium resources. Breeders allowed India’s uranium supply to be used much more efficiently.

During the third stage thorium was to be bred, and U-233 would fuel Indian power reactors.

This plan enabled India to boot strap its limited nuclear resources, into a viable nuclear energy program. Of course, along the way, something which Pandit Nehru swore on a stack of Bhagavad Gitas would never happen, did.  India used some of Bhabha plutonium to build nuclear weapons. But remarkably fifty years later, India is still following Bhabha’s three stage plan for nuclear power development. The plan is now at the beginning of the third stage.

India has 13 heavy water reactors with 4 more under construction. These Indian reactors are smaller than western commercial power reactors. India also has fuel reprocessing facilities, and a developmental breeder reactor. A full scale fast breeder (500,000 MW), which will breed both U-238 and Th-232 in a hybrid fuel cycle, is under construction, and is expected to be completed in 2010. A second large thorium fast breeder, the ATGB is already in the planning stage. The KAMINI test reactor is used to test the use of U-233 produced by the Kalpakkam experimental breeder. A Generation 3+ Thorium fuel cycle Advanced Heavy Water Reactor is also in the planning stage. India plans, by 2020, to have reactors capable of generating 20 GWs of power, most of it using thorium fuel cycle nuclear fuel. Bu 2050, India plans to produce 30% of its electricity from thorium fuel cycle nuclear generating facilities.  The Indians believe that their thorium reserve will last them for at least 350 years.

The Indian nuclear program is remarkable in several respects.  First, is the depth of Homi Bhabha's understanding of Indian nuclear resources and the sort of nuclear program that would achieve the maximum benefit from his country. The second, was the reliance on the relatively simple CANDU technology, during the first development stage and its continued development through all three stages. Reactors were kept small, 220 MW's, limiting capitol commitment for each reactor. In addition reactor design was given a chance to develop, successive improvements were made as new reactors were designed. Operational experience gave feedback to reactor designers. During the second stage, the full plutonium - thorium - U233 fuel cycle was tested in two small reactors. 

Finally, believing that they had mastered all of the individual components of their thorium fuel cycle program, the Indians have set about to build prototypes of commercial reactors that are intended to go into serial production. They have been faithful to Bhabha's vision. They have found a way to highly efficient technology, a technology that is far more efficient in its use of nuclear fuel, than the French/American nuclear system by ingeniously mastering and organizing relatively old nuclear technologies, and leveraging them into a fuel efficient system. By doing so they will achieve EROIE's many times that achieved by Western fuel/reactor systems.  They plan to supply electricity to a huge population for at least 350 years from only 500,000 t0ns of nuclear fuel.  Indian scientists and engineers are on the brink of a significant human accomplishment, the realization of Bhabha vision of bringing nuclear generated electricity to India's vast population.

The Thorium Fuel Cycle, Its Neutron Economy

WASH-1097 remains a good source of information on the thorium fuel cycle. In fact, some major recent studies of the thorium fuel cycle rely heavily on WASH-1097.

Sometimes, however, sources on thorium may draw indirectly on WASH-1097, without mentioning it in their bibliography. Although a recent IAEA report on Thorium appears to have been prepared without overt reliance on WASH-1097.

Because it is widely referenced and continues to be an important source of information, I will rely on Wash 1097 for most of the information found is this account.

One of the first things physicists discovered about chain reactions was that slowing the neutrons involved in the process down, promoted the chain reaction. Kirk Sorensen discusses slow or thermal neutrons in one of his early posts.

Under low energy neutron conditions, Th232 can be efficiently converted to U233. The conversion process works like this. Th232 absorbs a neutron and emits a beta ray. A neutron switches to being a protron and the atom is transformed into Protactinium 233. After a period average a little less than a month, Pa 233 emits a second beta ray and is transformed into U233. U233 is fissionable, and is a very good reactor fuel. When a U233 atom encounters a low energy neutron, chances are 9 out of 10 that it will fission.

Since U233 produces an average of 2.4 neutrons every time it fissions, this means that. Each neutron that strikes U233 produces a average of 2.16 new neutrons. If you carefully control those neutrons, one neutron will continue the chain reaction. That leaves an average of 1.16 neutrons to generate new fuel.

Unfortunately the fuel generation process cannot work with 100% efficiency. The left over U234 that was produced when U233 absorbed a neutron and did not fission will sometimes absorb another neutron and become U235. Xenon 135, an isotope that that is often produced when a U233 splits, is more likely to capture neutrons than U233 or Th232. This makes Xenon 135 a fission poison. Because Xenon in a reactor builds up during a chain reaction, it tends to slow a reactor down as the chain reaction continues. The presence of Xenon creates a control problem inside a reactor. Xenon also steals neutrons needed for the generation of new fuel.

In conventional reactors that use solid fuel, Xenon is trapped inside the fuel, but in a fluid fuel Xenon is easy to remove, because it is what is called a noble gas. A noble gas does not bond chemically with other substances, and can be bubbled out of fluids where it has been trapped. Getting Xenon 135 out of a reactor core, makes generating new U233 from Th232 a whole lot easier.

It is possible to bring about 1.08 neutrons into the thorium change process for every U233 atom that splits. This means that reactors that use a thorium fuel cycle, are not going to produce a large excess of U233, but if carefully designed, they can produce enough U233 that burnt U233 can be easily replaced. Thus a well designed thorium cycle reactor will generate its own fuel indefinitely.

Thorium Fuel Cycle Advantages

Introduction: This Russian paper, translated by the IAEA nicely lays out some of the advantages of the thorium fuel cycle.

From: STATUS OF NUCLEAR DATA FOR THE THORIUM FUEL CYCLE
by B.D. Kuz’minov, and V.N. Manokhin Russian Federation State Science Centre, Institute of Physics and Power Engineering, Obninsk

Adoption of the thorium fuel cycle would offer the following advantages:
- Increased nuclear fuel resources thanks to the production of 233U from 232Th;
- Significant reduction in demand for the enriched isotope 235U;
- Very low (compared with the uranium-plutonium fuel cycle) production of long-lived radiotoxic wastes, including transuraniums, plutonium and transplutoniums;
- Possibility of accelerating the burnup of plutonium without the need for recycling, i.e. rapid reduction of existing plutonium stocks;
- Higher fuel burnup than in the uranium-plutonium cycle;
- Low excess reactivity of the core with thorium-based fuel, and more favourable temperature and void reactivity coefficients;
- High radiation and corrosion resistance of thorium-based fuel;
- Considerably higher melting point and the better thermal conductivity of thorium-based fuel;
- Good conditions for ensuring the non-proliferation of nuclear materials.