Reading Repair Cafe


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Toss it away? No way!
Repair, Recycle, Reuse, Remake, Reskill, Relearn, Reboot, Rework and Relax, all in Reading(!)

Transition and Greater Reading Environmental Network are teaming up to launch Reading Repair Cafe! This initially a one-off event but with the possibility it could become a regular occurrence if successful.

The event is on Sunday 20 October at Highbridge House, 16-18 Duke Street, RG1 4RU and everyone is welcome!

We have confirmed experts to help with the following repairs / improvements:
Clothing Repair / altering / sewing
Simple computer fixing
Tool sharpening
Draught proofing

If you don’t know what to bring along, just pop in, get some advice on draught proofing your home and stop by for a cuppa and cake. The event is entirely free but donations will be welcome for repairs and refreshments.

This is a one-off event, but with the hope we can start to run it regularly if successful and popular. Please get in touch if you would be interested in getting involved.

To get involved in helping on the day please get in touch with
for more information about the Repair Cafe concept, visit



Is your house draughty and cold? Is it expensive to heat?

Transition Town Reading’s draught-busting project may be able to help! The materials could be paid for by a grant from Reading Borough Council if you meet certain conditions and the work is done by the end of March. The work should only take a couple of hours. If you know of people who need our help please contact us. And if you would like to help with this project please join us. We can show you how easy it is to carry out draught proofing for yourself and to help your friends and neighbours do their homes. Please contact or contact Summreen at Reading Borough Council on (0118) 937 2100.

See TTR’s draught-proofing in action on BBC South Today!

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The Thorium Age Waits in the Wings.


There is much written to the effect that thorium might prove a more viable nuclear fuel, and an energy industry based upon it, than the current uranium-based process which serves to provide both energy and weapons – including “depleted uranium” for armaments and missiles. There are different ways in which energy might be extracted from thorium, one of which is the accelerator-driven system (ADS). Such accelerators need massive amounts of electricity to run them, as all particle accelerators do, but these are required to produce a beam of protons of such intensity that until 10 years ago the prevailing technology meant that it could not have been done. As noted below, an alternative means to use thorium as a fuel is in a liquid fluoride reactor (LFR), also termed a molten salt reactor, which avoids the use of solid oxide nuclear fuels. Indeed, China has made the decision to develop an LFR-based thorium-power programme, to be active by 2020.

Rather like nuclear fusion, the working ADS technology is some way off, and may never happen, although Professor Egil Lillestol of Bergen University in Norway is pushing that the world should use thorium in such ADS reactors. Using thorium as a nuclear fuel is a laudable idea, as is amply demonstrated in the blog “Energy from Thorium” ( to which there is a link on this blog (above left). However, the European Union has pulled the plug on funding for the thorium ADS programme, which was directed by Professor Carlo Rubbia, the Nobel Prizewinner, who has now abandoned his efforts to press forward the programme, and instead concentrated on solar energy, which was another of his activities. Rubbia had appointed Lillestol as leader of the CERN physics division over two decades ago, in 1989, who believes that the cause is not lost.

Thorium has many advantages, not the least being its greater abundance than uranium. It is often quoted that there is three times as much thorium as there is uranium. Uranium is around 2 – 3 parts per million in abundance in most soils, and this proportion rises especially where phosphate rocks are present, to anywhere between 50 and 1000 ppm. This is still only in the range 0.005% – 0.1% and so even the best soils are not obvious places to look for uranium. However, somewhere around 6 ppm as an average for thorium in the Earth’s crust is a reasonable estimate. There are thorium mineral deposits that contain up to 12% of the element, located at the following tonnages in Turkey (380,000), Australia (300,000), India (290,000), Canada and the US combined (260,000)… and Norway (170,000), perhaps explaining part of Lillestol’s enthusiasm for thorium based nuclear power. Indeed, Norway is very well endowed with natural fuel resources, including gas, oil, coal, and it would appear, thorium.

An alternative technology to the ADS is the “Liquid Fluoride Reactor” (LFR), which is described and discussed in considerable detail on the blog, and reading this has convinced me that the LFR may provide the best means to achieve our future nuclear energy programme. Thorium exists naturally as thorium-232, which is not of itself a viable nuclear fuel. However, by absorption of relatively low energy “slow” neutrons, it is converted to protactinium 233, which must be removed from the reactor (otherwise it absorbs another neutron and becomes protactinium 234) and allowed to decay over about 28 days to uranium 233, which is fissile, and can be returned to the reactor as a fuel, and to breed more uranium 233 from thorium. The “breeding” cycle can be kicked-off using plutonium say, to provide the initial supply of neutrons, and indeed the LFR would be a useful way of disposing of weapons grade plutonium and uranium from the world’s stockpiles while converting it into useful energy.

The LFR makes in-situ reprocessing possible, much more easily than is the case for solid-fuel based reactors. I believe there have been two working LFR’s to date, and if implemented, the technology would avoid using uranium-plutonium fast breeder reactors, which need high energy “fast” neutrons to convert uranium 238 which is not fissile to plutonium 239 which is. The LFR is inherently safer and does not require liquid sodium as a coolant, while it also avoids the risk of plutonium getting into the hands of terrorists. It is worth noting that while uranium 235 and plutonium 239 could be shielded to avoid detection as a “bomb in a suitcase”, uranium 233 could not, because it is always contaminated with uranium 232, which is a strong gamma-ray emitter, and is far less easily concealed.

It has been claimed that thorium produces “250 times more energy per unit of weight” than uranium. Now this isn’t simply a “logs versus coal on the fire” kind of argument, but presumably refers to the fact that while essentially all the thorium can be used as a fuel, the uranium must be enriched in uranium 235, the rest being “thrown away” and hence wasted as “depleted” uranium 238 (unless it is bred into plutonium). If both the thorium and uranium were used to breed uranium 233 or plutonium 239, then presumably their relative “heat output” weight for weight should be about the same as final fission fuels? If this is wrong, will someone please explain this to me as I should be interested to know?

However, allowing that the LFR in-situ reprocessing is a far easier and less dangerous procedure, the simple sums are that contained in 248 million tonnes of natural uranium, available as a reserve, are 1.79 million tonnes of uranium 235 + 246.2 million tonnes of uranium 238. Hence by enrichment 35 million tonnes (Mt) of uranium containing 3.2% uranium 235 (from the original 0.71%) are obtained. This “enriched fraction” would contain 1.12 Mt of (235) + 33.88 Mt of (238), leaving in the other “depleted” fraction 248 – 35 Mt = 213 Mt of the original 248 Mt, and containing 0.67 Mt (235) + 212.3 Mt (238). Thus we have accessed 1.79 – 0.67 = 1.12 Mt of (235) = 1.12/224 = 4.52 x 10*-3 or 0.452% of the original total uranium. Thus on a relative basis thorium (assuming 100% of it can be used) is 100/0.452 = 221 times as good weight for weight, which is close to the figure claimed, and a small variation in enrichment to a slightly higher level as is sometimes done probably would get us to an advantage factor of 250!

Plutonium is a by-product of normal operation of a uranium-fuelled fission reactor. 95 to 97% of the fuel in the reactor is uranium 238. Some of this uranium is converted to plutonium 239 and plutonium 241 – usually about 1000 kg forms after a year of operation. At the end of the cycle (a year to 2 years, typically), very little uranium 235 is left and about 30% of the power produced by the reactor actually comes from plutonium. Hence a degree of “breeding” happens intrinsically and so the practical advantage of uranium raises its head from 1/250 (accepting that figure) to 1/192, which still weighs enormously in favour of thorium!

As a rough estimate, 1.4 million tonnes of thorium (about one third the world uranium claimed, which is enough to last another 50 years as a fission fuel) would keep us going for about 200/3 x 50 = 3,333 years. Even if we were to produce all the world’s electricity from nuclear that is currently produced using fossil fuels (which would certainly cut our CO2 emissions), we would be O.K. for 3,333/4 = 833 years. More thorium would doubtless be found if it were looked for, and so the basic raw material is not at issue. Being more abundant in most deposits than uranium, its extraction would place less pressure on other fossil fuel resources used for mining and extracting it. Indeed, thorium-electricity could be piped in for that purpose.

It all sounds great: however, the infrastructure would be huge to switch over entirely to thorium, as it would to switch to anything else including hydrogen and biofuels. It is this that is the huge mountain of resistance there will be to all kinds of new technology. My belief is that through cuts in energy use following post peak oil (and peak gas), we may be able to produce liquid fuels from coal, possibly using electricity produced from thorium, Thorium produces less of a nuclear waste problem finally, since fewer actinides result from the thorium fuel cycle than that from uranium. Renewables should be implemented wherever possible too, in the final energy mix that will be the fulcrum on which the survival of human civilization is poised.

Thorium Nuclear Power – A Lesson From Norway.


Norway holds a resource of 170,000 tonnes of thorium, which amounts to 15% of the world’s total of 1.2 million tonnes. There is far more thorium than that within the earth’s crust all told, averaging 8 ppm compared with around 2.8 ppm for uranium, but the above figures refer to richer ores, most commonly monazite sand which contains up to 12% of thorium. There is some opinion that thorium nuclear power might be a better environmental/energy-strategy for Norway than relying on carbon-capture which many consider to be uneconomic. However, the matter of thorium reactors is not straightforward. Professor Egil Lillestol of Bergen University has been pushing thorium for some years now, and thinks that Norway should set the trend in building a prototype accelerator-driven reactor in which a massive particle accelerator converts thorium-232 to uranium-233 by irradiating it with slow (spallation) neutrons generated by the impact of a 1.6 GeV proton beam on a lead target. The conversion is not direct, and involves the initial formation of thorium-233, which decays rapidly to protactinium-233, and then to uranium-233 over a period of about a month. Hence presumably reprocessing is involved in the final stage, since if the protactinium-233 is left in the reactor it will be at least partly converted to protactinium-234, which is not a useful fissile material.

It may well turn out that thorium is the better nuclear fuel as compared with uranium, since it offers the advantages that: (1) it is present in around 3 times the abundance of uranium on Earth, overall, (2) it can be bred into the fissile nuclear fuel uranium-233, (3) far less plutonium and other transuranic elements are produced than is the case from uranium fuel, (4) the thorium fuel cycle might be used to consume plutonium, thus reducing the nuclear stockpile while converting it into useful electrical energy.

However, it is a very big accelerator that will be needed to do the job, and the estimated costs for the project are about 500 million Euros. There are various advantages cited for this type of reactor, including the claim that it can be stopped easily if things get out of hand, and that it produces less long-lived nuclear waste than the uranium-fuelled fission reactors that are currently in common use. However, there are a whole host of scientific and engineering challenges that need to be overcome, and even identified in the first place because nobody has ever built one of these reactors, and hence the plans are still only on the drawing board.

As I have already stressed, it is a very big accelerator that will be needed if the project has any chance of success, so big in fact that there are none with sufficient power anywhere in the world. Some of the suggestions include using molten lead as the coolant for the system, but the reactor would run at a temperature above 700 degrees C. when the material becomes corrosive. A number of countries (including the US, Russia, the UK, France and Japan) have entrenched firm investments in uranium based reactors, and will use them for as long as they can. There are sizeable quantities of uranium on the world market, although the price has recently soared. Nonetheless, there is likely to be resistance to the research and development of a brand-new technology based on thorium, in view of huge costs that will effectively be borne by the Norwegian taxpayer if they go it alone down this unlit path.

The immediate future doesn’t look optimistic for thorium, certainly with the untested accelerator-driven reactors, and yet two thorium reactors have been operated, which were of the far simpler molten-salt reactor kind. Thus it might prove more expedient to invest in this at least tried technology, which could extend the useful lifetime of nuclear power by hundreds of years. The reason is that converting thorium-232 to uranium-233 is a form of “breeder” technology meaning that practically 100% of the thorium can be processed ultimately into nuclear fuel, rather than just the 0.7% uranium-235 isotope that exists in naturally occurring uranium, and which requires enrichment before it can be used. Indeed, the 99+% of uranium-238 can be converted into plutonium-239 and this used in fuel-rods, but there are many negative connotations attached to plutonium, which is almost the “p-word” for the nuclear industry: i.e. unmentionable, certainly in the tabloid press. There are serious issues of terrorism – dirty bombs at the very least, if not an out and out A-bomb detonation involving plutonium. The word alone would swathe a city and the world with fear. Uranium-233 made from thorium is harder to conceal than plutonium, since it is always contaminated with uranium-232, a strong gamma-ray emitter, and accordingly quite easily detected “in a suitcase” than plutonium which is principally an alpha-particle emitter and far more readily hidden.

There is no doubt that we will see a rise in nuclear power and for a number of reasons – cutting CO2 emissions, and securing energy supplies. Most of current thinking is based around using uranium as the fuel to drive it, but thorium could prove a very useful supplement and might power a new generation of reactors when we are short of uranium and do need to “breed” fuel if it proves uneconomic to mine poor quality uranium ores. I maintain my reservations about how long other resources, e.g. oil and gas will last, with which to mine and process either uranium or thorium, but if the latter appears viable in the longer run, I suggest that molten salt (liquid fluoride) reactors would be a better approach than the far more complex (and as yet untested) accelerator-driven systems.

The latter are reminiscent in scale to the putative nuclear-fusion reactors, said to mimic processes in stars, e.g. the sun, of which a working model is not expected for at least another 60 years. No one should forget that we need to make our energy provisions against a backdrop of 10 – 20 years at best, as oil and then gas begin to run short (the “Oil Dearth Era”). We do not want to back a loser now, as it is a one-off bet with the future of civilization resting on the outcome of this particular race.

Related Reading. There is also a link at the top left hand corner of this blog.

The Achilles Heel of Algal Biofuels – Peak Phosphate.


The depletion of world rock phosphate reserves will restrict the amount of food that can be grown across the world, a situation that can only be compounded by the production of biofuels, including the potential large-scale generation of biodiesel from algae. The world population has risen to its present number of 7 billion in consequence of cheap fertilizers, pesticides and energy sources, particularly oil. Almost all modern farming has been engineered to depend on phosphate fertilizers, and those made from natural gas, e.g. ammonium nitrate, and on oil to run farm machinery and to distribute the final produce. A peak in worldwide production of rock phosphate is expected by 2030, which lends fears over how much food the world will be able to grow in the future, against a rising number of mouths to feed. Consensus of opinion is that we are close to the peak in world oil production too.

World rock phosphate production amounts to around 140 million tonnes, and food production is already being thought compromised by rock phosphate resource depletion. In comparison, we would need 472 million tonnes of the mineral to grow sufficient algae to replace all the oil-derived fuels used in the world. The US produces less than 40 million tonnes of rock phosphate annually, but would require enough to produce around 25% of the world’s total algal diesel, in accord with its current “share” of world petroleum-based fuel, or 88 million tonnes of rock phosphate. Hence, for the US, security of fuel supply could not be met by algae-to-diesel production using even all its indigenous rock phosphate output, and significant further imports would be needed. This is in addition to the amount of the mineral necessary to maintain agriculture.

It is salutary that there remains a competition between growing crops (algae) for fuel and those for food, even if not directly in terms of land, for the fertilizers that both depend upon. This illustrates for me the complex and interconnected nature of, indeed Nature, and which like any stressed chain, will ultimately converge its forces onto the weakest link in the “it takes energy to extract energy” sequence. It seems quite clear that with food production already stressed, the production of (algal) biofuels will never be accomplished on a scale anywhere close to matching current world petroleum fuel use (>20 billion barrels/annum). Thus, the days of a society based around personalized transport run on liquid fuels are numbered. We must reconsider too our methods of farming, to reduce inputs of fertilisers, pesticides and fuel. Freshwater supplies are also at issue, in the complex transition to a more localised age that uses its resources much more efficiently.

There is a Hubbert-type analysis of human population growth which indicates that rather than rising to the putative “9 billion by 2050” scenario, it will instead peak around the year 2025 at 7.3 billion, and then fall. It is probably significant too that that population growth curve fits very closely both with that for world phosphate production and another for world oil production. It seems to me highly indicative that it is the decline in resources that will underpin our demise in numbers as is true of any species: from a colony of human beings growing on the Earth, to a colony of bacteria growing on agar nutrient in a Petri-dish.

The full article may be found at: