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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Mar-10-10 11:33 PM
Original message
Thorium Fuel: No Panacea for Nuclear Power
Edited on Wed Mar-10-10 11:34 PM by kristopher
(Open Access Document)

Thorium Fuel: No Panacea for Nuclear Power
By Arjun Makhijani and Michele Boyd

A Fact Sheet Produced by the Institute for Energy and Environmental Research and Physicians for Social Responsibility

Thorium fuel has been proposed as an alternative to uranium fuel in nuclear reactors. There are not thorium reactors, but rather proposals to use thorium as a fuel in different types of reactors, including existing light‐water reactors and various fast breeder reactor designs.

Thorium, which refers to thorium‐232, is a radioactive metal that is about three times more
abundant than uranium in the natural environment. Large known deposits are in Australia, India, and Norway. Some of the largest reserves are found in Idaho in the U.S. The primary U.S. company advocating for thorium fuel is Thorium Power (www.thoriumpower.com ). Contrary to the claims made or implied by thorium proponents, however, thorium doesnt solve the proliferation, waste, safety, or cost problems of nuclear power, and it still faces major technical hurdles for commercialization.


Not a Proliferation Solution

Thorium is not actually a fuel because it is not fissile and therefore cannot be used to start or sustain a nuclear chain reaction. A fissile material, such as uranium‐235 (U‐235) or plutonium‐239 (which is made in reactors from uranium‐238), is required to kick‐start the reaction. The enriched uranium fuel or plutonium fuel also maintains the chain reaction until enough of the thorium target material has been converted into fissile uranium‐233 (U‐233) to take over much or most of the job. An advantage of thorium is that it absorbs slow neutrons relatively efficiently (compared to uranium‐238) to produce fissile uranium‐233.

The use of enriched uranium or plutonium in thorium fuel has proliferation implications. Although U‐235 is found in nature, it is only 0.7 percent of natural uranium, so the proportion of U‐235 must be industrially increased to make enriched uranium for use in reactors. Highly enriched uranium and separated plutonium are nuclear weapons materials.

In addition, U‐233 is as effective as plutonium‐239 for making nuclear bombs. In most proposed thorium fuel cycles, reprocessing is required to separate out the U‐233 for use in fresh fuel. This means that, like uranium fuel with reprocessing, bomb‐making material is separated out, making it vulnerable to theft or diversion. Some proposed thorium fuel cycles even require 20% enriched uranium in order to get the chain reaction started in existing reactors using thorium fuel. It takes 90% enrichment to make weapons‐usable uranium, but very little additional work is needed to move from 20% enrichment to 90% enrichment. Most of the separative work is needed to go from natural uranium, which has 0.7% uranium‐235 to 20% U‐235.

It has been claimed that thorium fuel cycles with reprocessing would be much less of a proliferation risk because the thorium can be mixed with uranium‐238. In this case, fissile uranium‐233 is also mixed with non‐fissile uranium‐238. The claim is that if the uranium‐238 content is high enough, the mixture cannot be used to make bombs without a complex uranium enrichment plant. This is misleading. More uranium‐238 does dilute the uranium‐233, but it also results in the production of more plutonium‐239 as the reactor operates. So the proliferation problem remains either bomb‐usable uranium‐233 or bomb‐usable plutonium is created and can be separated out by reprocessing.

Further, while an enrichment plant is needed to separate U‐233 from U‐238, it would take less separative work to do so than enriching natural uranium. This is because U‐233 is five atomic weight units lighter than U‐238, compared to only three for U‐235. It is true that such enrichment would not be a straightforward matter because the U‐233 is contaminated with U‐232, which is highly radioactive and has very radioactive radionuclides in its decay chain. The radiation‐dose‐related problems associated with separating U‐233 from U‐238 and then handling the U‐233 would be considerable and more complex than enriching natural uranium for the purpose of bomb making. But in principle, the separation can be done, especially if worker safety is not a primary concern; the resulting U‐233 can be used to make bombs. There is just no way to avoid proliferation problems associated with thorium fuel cycles that involve reprocessing. Thorium fuel cycles without reprocessing would offer the same temptation to reprocess as todays once‐through uranium fuel cycles.


Not a Waste Solution

Proponents claim that thorium fuel significantly reduces the volume, weight and long‐term radiotoxicity of spent fuel. Using thorium in a nuclear reactor creates radioactive waste that proponents claim would only have to be isolated from the environment for 500 years, as opposed to the irradiated uranium‐only fuel that remains dangerous for hundreds of thousands of years. This claim is wrong. The fission of thorium creates long‐lived fission products like technetium‐99 (half‐life over 200,000 years). While the mix of fission products is somewhat different than with uranium fuel, the same range of fission products is created. With or without reprocessing, these fission products have to be disposed of in a geologic repository.

If the spent fuel is not reprocessed, thorium‐232 is very‐long lived (half‐life:14 billion years) and its decay products will build up over time in the spent fuel. This will make the spent fuel quite radiotoxic, in addition to all the fission products in it. It should also be noted that inhalation of a unit of radioactivity of thorium‐232 or thorium‐228 (which is also present as a decay product of thorium‐232) produces a far higher dose, especially to certain organs, than the inhalation of uranium containing the same amount of radioactivity. For instance, the bone surface dose from breathing the an amount (mass) of insoluble thorium is about 200 times that of breathing the same mass of uranium.

Finally, the use of thorium also creates waste at the front end of the fuel cycle. The radioactivity associated with these is expected to be considerably less than that associated with a comparable amount of uranium milling. However, mine wastes will pose long‐term hazards, as in the case of uranium mining. There are also often hazardous non‐radioactive metals in both thorium and uranium mill tailings.


Ongoing Technical Problems

Research and development of thorium fuel has been undertaken in Germany, India, Japan, Russia, the UK and the U.S. for more than half a century. Besi des remote fuel fabrication and issues at the front end of the fuel cycle, thorium‐U‐233 breeder reactors produce fuel (breed) much more slowly than uranium‐plutonium‐239 breeders. This leads to technical complications. India is sometimes cited as the country that has successfully developed thorium fuel. In fact, India has been trying to develop a thorium breeder fuel cycle for decades but has not yet done so commercially.

One reason reprocessing thorium fuel cycles havent been successful is that uranium‐232 (U‐232) is created along with uranium‐233. U‐232, which has a half‐life of about 70 years, is extremely radioactive and is therefore very dangerous in small quantities: a single small particle in a lung would exceed legal radiation standards for the general public. U‐232 also has highly radioactive decay products. Therefore, fabricating fuel with U‐233 is very expensive and difficult.


Not an Economic Solution

Thorium may be abundant and possess certain technical advantages, but it does not mean that it is economical. Compared to uranium, thorium fuel cycle is likely to be even more costly. In a once‐through mode, it will need both uranium enrichment (or plutonium separation) and thorium target rod production. In a breeder configuration, it will need reprocessing, which is costly. In addition, as noted, inhalati on of thorium‐232 produces a higher dose than the same amount of uranium‐238 (either by radioactivity or by weight).

Reprocessed thorium creates even more risks due to the highly radioactive U‐232 created in the reactor. This makes worker protection more difficult and expensive for a given level of annual dose. Finally, the use of thorium also creates waste at the front end of the fuel cycle. The radioactivity associated with these is expected to be considerably less than that associated with a comparable amount of uranium milling. However, mine wastes will pose long‐term hazards, as in the case of uranium mining. There are also often hazardous non‐radioactive metals in both thorium and uranium mill tailings.

Fact sheet completed in January 2009
Updated July 2009
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NNadir Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Mar-10-10 11:57 PM
Response to Original message
1. Your unreferenced "fact sheet" is happily devoid of a single fact.
Edited on Thu Mar-11-10 12:28 AM by NNadir
India, I note, couldn't give a rat's ass what a bunch of self referntial uneducated anti-nukes think.

I would like to compare the technical quality of this drivel with a technical paper by someone who actually understands reactor physics, thus proving that the anti-science brats who most vociferously oppose nuclear energy are precisely those who are incompetent to understand it.

This quote is from the paper Usha Pal, V. Jagannathan at the Bhabha Atomic Research Centre (where they don't hire glib hand wavers who know zero physics) Annals of Nuclear Energy 35 (2008) 12321245 in an article entitled "Physics design of initial and approach to equilibrium cores of a reactor concept for thorium utilization."

India, for the record, which doesn't give a fuck about the consumerist car CULTist opinion of bourgeois brats living oblivious lives in the West, has huge thorium reserves which it plans to utilize in spite of international stupidity.

A unique feature of ATBR concept is the judicious arrangement of fissile seed and fertile zones to achieve a flat and low excess reactivity for a two year fuel cycle duration and a low power peaking factor at all times. Unlike conventional LWRs, there is no requirement of mechanical control absorbers or burnable poison for 3D power shaping and reactivity control at nominal power. This paper elucidates the physics design principles in designing the initial core of ATBR and its ensuing fuel cycles till the equilibrium core is reached. A discussion on the refueling principles of ATBR and its contrast with refueling methods practiced elsewhere is presented below...

...The first is a transitional period, i.e. pre-equilibrium phase while the second is the equilibrium phase. In equilibrium the refueling scheme can be frozen for a given fuel assembly design and cycle energy requirement and this phase constitutes more than 90% of the lifetime of the reactor...

...The nominal reactor power is 600 MWe or 1875 MWth. The PT is made up of ZrNb (2.5%) with ID/OD of 176/187 mm. Coolant pressure is 70 bar. The ID/OD of Zr-2 calandria tube (CT) is 204/207 mm with an air gap separating the PT and CT. The hexagonal assembly lattice pitch is 300 mm. D2O moderator is filled in the calandria tank of 8400 mm diameter and 4800 mm height at normal pressure and temperature of 80 C at hot operating state. This would provide a radial reflector thickness of 600700 mm. Axial reflector thickness is 600 mm at bottom and top. Active core height is 3600 mm.
Table 2a Description of fuel clusters (seeded + unseeded) in equilibrium core Parameter Fuel type
Seeded fuel cluster (Pu reprocessed from power reactors) Unseeded ThO2 cluster Inner Middle Outer Single ring Fuel clad ID/OD (mm) 10/11.4 9/10.4 12.6/14 12.6/14 Pitch circle diameter (mm) 104130 158 158 No. of fuel rods 24 30 30 30 Seed content (wt. %) 20% PuO2in ThO2 14% PuO2in ThO2 One cycle irradiated ThO2 Fresh unseeded ThO2 rods Fissile fraction in seed 0.745 >0.94 Composition of seed (239Pu:240Pu: 241Pu:242Pu) (69.3:24.1:5.2:1.4) 0.50.7% in situ bred 233U ID/OD of central BeO block (mm) 10/90 (inclusive of Zr-liner) 10/137 Pressure tube ZrN(2.5%) ID/OD (mm) 176/187 176/187 Air gap ID/OD (mm) 187/204 187/204 Calandria tube Zr-2 ID/OD (mm) 204/207 204/207 Hexagonal assembly pitch (mm) 300...

...The present calculations have been performed using the IAEAGX library in 172 energy groups inWIMS/D format. This nuclear data library was obtained as part of IAEA CRP on WIMS library update project (Leszcynski et al., 2001). The lattice calculations of ATBR fuel clusters are done by the CLUB module (Krishnani, 1982) of the PHANTOM code system (Jagannathan et al., 1990). CLUB codesolves the integral transport equation by collision probability method. First flight collision probability method is used within each sub regions of the fuel cluster and three term expansion is used for angular currents at annular region interfaces. The outer hexagonal boundary is circularized. Two group cell homogenized lattice parameters (energy cut off at 0.625 eV) for the seed fuel cluster as a function of burnup, void and fluence of thorium rods in the outermost ring were generated using PHANTOM code. Pure thoria cluster accumulate fissile material at different rates depending on the ambient flux level. A given burnup can be attained by a variety of combinations of flux level and residence times. Hence the lattice parameters of the thoria clusters are parametrically generated for different absolute flux levels as a function of irradiation time in days...



I guess they're not spending a lot of time considering the opinion of light weight bloggers who obviously don't understand a fucking thing about nuclear energy to proceed with their work.

Good for them.

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Mar-11-10 10:57 AM
Response to Reply #1
4. There is nothing in your post to address the information in the OP.
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NNadir Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Mar-13-10 03:24 AM
Response to Reply #4
6. That may be because there is no information in the OP.
Like most of the stuff produced by people who know zero nuclear physics, nuclear chemistry - people who hate nuclear science because it's way over their pathetic little heads, it's just possible that the post consists of rote pablum.

Actually, one would actually need to know some nuclear physics to judge what is and is not in my post, or in the reference to which it refers.

This may explain why you seem to not grasp what my post is about. Here let me help you: People who know nuclear physics - that would be the guys who wrote the paper referenced - couldn't care less what you think about thorium, because, um, they actually know something about thorium and, um, you clearly don't.

It is not my job however to explain my posts to dilettante lightweights, however, so I'll leave it at that.

It doesn't seem to have been a very popular post and I assure you in any case, we saw it the first time, but of course, in case you think we missed it, it's no skin off our backs if you kick it up every few days to see if we've suddenly developed an interest in it.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Mar-13-10 06:27 AM
Response to Reply #6
7. Poor little feller just ain't got a clue...
Arjun Makhijani is an electrical and nuclear engineer with 37 years experience in energy and nuclear issues. He is President of the Institute for Energy and Environmental Research. IEER has been doing nuclear-related studies for twenty years and is an independent non-profit organization located in Takoma Park, Maryland. Makhijani has a Ph.D. (Engineering), from the Department of Electrical Engineering and Computer Sciences of the University of California, Berkeley, where he specialized in the application of plasma physics to controlled nuclear fusion.<1>

Makhijani has extensive professional experience and is qualified in radioactive waste disposal, standards for protection of human health from radiation, and the relative costs and benefits of nuclear energy and other energy sources. He has testified before Congress and has served as a consultant on energy issues to utilities and other organizations, including the Tennessee Valley Authority, the Lower Colorado River Authority, the Edison Electric Institute, the Lawrence Berkeley Laboratory, the Congressional Office of Technology Assessment, and several agencies of the United Nations. He has also served as an expert witness in Nuclear Regulatory Commission proceedings on nuclear facilities and in numerous lawsuits and has testified on a variety of issues including releases of radioactivity from nuclear facilities. He has testified before Congress on several occasions regarding issues related to nuclear waste, reprocessing, environmental releases of radioactivity, and regulation of nuclear weapons plants.

Makhijani has studied the French reprocessing and nuclear energy system and was the director of a team that analyzed ANDRAs plans for a geological repository for high level radioactive waste in France on behalf of a French government-sponsored stakeholder committee (2004).

Publications

Arjun Makhijani has written a number of books and other publications analyzing the safety, economics, and efficiency of various energy sources, including nuclear power and renewable energy sources such as wind power and solar energy. He was the principal author of the first evaluation of energy end-uses and energy efficiency potential in the U.S. economy (published by the Electronics Research Laboratory, University of California at Berkeley in 1971). He was also the principal author of the first overview study on Energy and Agriculture in the Third World<2> (Ballinger 1975). He was one of the principal technical staff of the Ford Foundation Energy Policy Project, and a co-author of its final report, A Time to Choose,<3> which helped shape U.S. energy policy during the mid-to-late 1970s. He is a co-author of Investment Planning in the Electricity Sector, published by the Lawrence Berkeley Laboratory in 1976. He is also the principal author of Nuclear Power Deception<4> (Apex Books 1999), an analysis of the costs of nuclear power in the United States and a co-author and principal editor of the first global assessment of the health and environmental effects of nuclear weapons production (Nuclear Wastelands,<5> 1995 and 2000), which was nominated for a Pulitzer Prize by MIT Press. Most recently, Dr Makhijani has authored Carbon-Free and Nuclear-Free<6> (RDR Books and IEER Press 2007), the first analysis of a transition to a U.S. economy based completely on renewable energy, without any use of fossil fuels or nuclear power. He has many published articles in journals such as The Bulletin of the Atomic Scientists and The Progressive, as well as in newspapers, including the Washington Post. Dr Makhijani has appeared on ABC World News Tonight, the CBS Evening News, CBS 60 Minutes, NPR, CNN, and BBC, among others.<7>

http://en.wikipedia.org/wiki/Arjun_Makhijani

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bananas Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Mar-14-10 08:50 AM
Response to Reply #7
9. The Nuclear Power Deception
Wikipedia lists some of his books, including "The Nuclear Power Deception."
http://www.ieer.org/pubs/index.html#npd

The Nuclear Power Deception
U.S. Nuclear Mythology from Electricity "Too Cheap to Meter"
to "Inherently Safe" Reactors

Apex Press, 1999 -- 266 pages, paperback
by Arjun Makhijani and Scott Saleska



This book provides critical analysis and historical evidence to refute claims that nuclear power can alleviate the build-up of greenhouse gases and reduce U.S. dependence on foreign oil. It also reveals the hazards of further proliferation of nuclear weapons from the growing quantities of plutonium generated by existing nuclear power plants throughout the world. Essential background reading for students, teachers, peace and environmental activists, and others concerned about nuclear power.

The authors base their analysis on a sound grasp of the technology and a sophisticated understanding of the subterranean military, economical, political, and technical issues that lead to the failure of the first nuclear power era. Makhijani and Saleska successfully demystify the technology with lucid and accurate explanations.

-- Professor Lawrence Lidsky, Department of Nuclear Engineering, Massachusetts Institute of Technology
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Mar-14-10 08:28 AM
Response to Reply #6
8. Kick.
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bananas Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Mar-11-10 12:02 AM
Response to Original message
2. link
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Mar-11-10 12:45 AM
Response to Reply #2
3. Yes, they warned of the South Texas Project cost overruns in 2008.
Edited on Thu Mar-11-10 12:46 AM by kristopher
The overall finding of this report is that NRGs range of $6 billion to $7 billion is obsolete.
The best available estimates indicate that capital costs would likely be about a factor of two
or more higher, even without taking into account the potential for real cost escalations
during construction, delays, and other risks. The risks to CPS, as a municipal utility and to
its ratepayers as well as to the taxpayers of San Antonio are great. Due diligence demands
that CPS participation in the project should not be pursued until an independent, detailed
study with current cost estimates of the plants and alternatives to it are complete and have
been publicly disclosed and discussed.

Assessing Nuclear Plant Capital Costs for the Two Proposed NRG Reactors at the South Texas Project Site
Arjun Makhijani, Ph.D.1

March 24, 2008


Here is the sales pitch the public heard from Texas in 2008: http://www.window.state.tx.us/comptrol/fnotes/fnEnergy0...

And here is the reality today:
Nuclear Renaissance Dealt Blow by South Texas Project Troubles

January 29, 2010 by citizensarah

A critical court ruling today rang the first chime in what could be the death knell of the so-called nuclear renaissance, starting with the failed expansion of the South Texas Project (STP).

This afternoons ruling by 408th District Court Judge Larry Noll that CPS Energy can safely withdraw from the proposed STP expansion project without losing all its investment offers the utility and the city of San Antonio the cue theyve been waiting for to exit the national nuclear stage. Combined with the NRG Energy CEOs announcement during a shareholder and press conference call this morning that NRG would wind down the project as quickly and economically as possible if CPS withdraws or STP does not receive federal loan guarantees, this news marks a major blow to those who claim nuclear power is a viable alternative to fossil fuel energy. The expansion project calls for two new nuclear reactors at a site with two existing reactors.

These events give credence to the contention made over the past five years by opponents of nuclear power that it is a needlessly expensive and risky way to meet future energy needs.. In less than a year, the price of the STP nuclear expansion ballooned from around $5 billion to more than $18 billion. Given this case study of nuclear powers failure, we must call into question the federal governments decision to increase federal loan guarantees to support oversized, untenable projects that are already proving too risky for private investors....
http://texasvox.org/2010/01/29/nuclear-renaissance-deal... /






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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Mar-16-10 04:36 PM
Response to Reply #3
11. Kick
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Mar-13-10 01:15 AM
Response to Original message
5. kick
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Mar-15-10 11:10 AM
Response to Original message
10. Kick...
...because the "thorium will save us" myth just resurfaced.
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