Hans Blix - Thorium can reduce the risk of nuclear proliferation

In his presentation to the Thorium Energy Conference - ThEC13 in Geneva on 29^th October 2013 Hans Blix stated that it is time for the nuclear power industry to move away from using uranium as its primary fuel towards thorium.

“Even though designers and operators are by no means at the end of the uranium road, it is desirable today, I am convinced, that the designers and the others use their skill and imagination to explore and test other avenues as well,” Blix said.

 “The civilian nuclear community must do what it can to help reduce the risk that more nuclear weapons are made from uranium or plutonium.  Although it is enrichment plants and plutonium producing installations rather than power reactors that are key concerns, this community, this nuclear community, can and should use its considerable brain power to design reactors that can be easily safeguarded and fuel and supply organizations that do not lend themselves to proliferation. I think in these regards the thorium community may have very important contributions to make.”

Thorium is a better fuel
Blix described the obstacles that are in the way of a shift to thorium and other nuclear alternatives as “political” rather than “technical.”  He compared using uranium in civilian nuclear power stations to the use of propeller driven planes which, "although they’ve served us well and continue to do so, have in general given way to a better technology, the jet plane".  He went on to describe other advantages that burning thorium brings, such as less nuclear waste which doesn't remain radioactive as long. It is also at least three times as abundant as uranium.

Hans Blix is known globally as the former United Nations chief weapons inspector at the time of the second Gulf War. 

Between 1981 and 1997 he headed the International Atomic Energy Agency so he understands the technical issues.

Not everyone agrees that thorium reactors are totally without proliferation risks since they require a start-up charge of enriched uranium or plutonium, but it’s very encouraging that someone like Hans Blix is promoting the advantages of thorium as a nuclear fuel and specifically because there is less risk of proliferation. 

Operation Teapot
Inside the breeder version of a thorium reactor fertile thorium-232 is converted to fissile uranium-233. Despite the ease of manufacturing uranium-233 from abundant natural thorium there has only ever been one operational nuclear weapon that has used uranium-233 as its fissile material. It was part of an American test series in 1955 called “Operation Teapot”.

When uranium-233 is used as a nuclear fuel, however, it is inevitably contaminated with uranium-232, which decays rather quickly (78 year half-life) and whose decay chain includes thallium-208, a “hard” gamma emitter. This makes any uranium contaminated with uranium-232 nearly worthless for both official and clandestine nuclear weapons since the gamma radiation would damage electronics and is easily detected because of its unique signature. For the bomb test uranium-233 with very low uranium-232 contamination was generated in special reactors at Hanford, but it cannot be produced in reactors that use the uranium-233 as fuel.

Gas from US fracking increases radioactive pollution in Europe

It’s true and the logic goes like this.

In the USA gas obtained by fracking schist, together with an increase in energy from renewables, has reduced wholesale gas prices per unit of thermal energy to less than the formerly much cheaper coal.  This has in turn lowered coal prices and stimulated US coal exports.

Gas prices in Europe have increased as a result of the Libyan conflict, and after Fukushima, the Japanese decision to shut down its nuclear power stations and rely on imported gas.

These market adjustments have coincided with a dramatic drop in the cost of European carbon credits since 2008 due to the recession.  So it’s much cheaper to burn an inefficient fuel like coal, and produce more carbon dioxide, than it was earlier this century.

There is therefore now an economic incentive to burn coal instead of gas in Europe.

Imports of US coal have increased by a third in the first six months of 2012 with the UK leading the pack. 

There are also nearly 1200 coal fired power plants being proposed worldwide.

Photo credit: Reuters/Staff Photographer (Southern Company’s Plant Bowen in Cartersville, Georgia, one of the biggest coal-fired plants in the United States)

But each year a typical coal fired power station discharges to the environment 100 times as much radioactivity as a nuclear power plant emits.  This radioactivity comes from the uranium, thorium and other radioactive decay products naturally present in coal, which is discharged as ash and particulates.  Coal fired power stations, unlike nuclear, are not subject to the controls on radioactive emissions which make building and operating nuclear power stations expensive.

This comprehensive and well researched article by Alex Gabbard from ORNL written in 1993 gives the details.  It also points out that ash from coal is a source of fissionable fuels and fertile materials, which is likely to be overlooked by authorities attempting to control the proliferation of nuclear weapons.

Additionally he calculates that, both in the US and globally, the waste ash from burning coal contains far more potential nuclear fuels than the entire nuclear industry consumes each year!

So thanks to fracking in the US, and market forces, Europeans are being exposed to more radiation than before.  

13 Million Bananas per day

0.01mrem is equal to 10^-7Sv  
(Picture from http://madartlab.com/2011/03/19/yellow-alert/)

Last week, at an “Echange Linguistique” with two of our friends, the subject of nuclear power came up very briefly. As far as these two French ladies were concerned 
“NUCLEAR POWER  =  CANCER” .  
There were no intermediate steps in the conversation and for them these two things were equivalent and inevitable.

It was very revealing, and I was appalled by their ignorance, but I couldn't immediately enter into an argument which would rapidly have become very heated and found me at the limits of my command of French.

The fundamental problem is that the public lacks any understanding concerning radiation and also lacks any ability to appreciate that the numbers are important when it comes to all environmental challenges to living organisms, including radiation.  Since we are all surrounded by radiation from natural sources it's a very good thing that the body has repair mechanisms and it's only when these can no longer cope, or when the exposure to radiation is too intense over too long a period, that cancers result.

Even radiation units are difficult to understand. Firstly, there are many different ways to measure the intensity of radiation emissions  and then there are the concepts of an absorbed dose of radiation (measured in Grays) and the biological effects of a committed dose of radiation on a human body (measured in Sieverts ). This is dependent on the type of radiation and the tissues which are irradiated.

The Banana Equivalent Dose

Since bananas contain potassium, which has a small percentage of radioactive Potassium-40 they emit radiation. 

One somewhat whimsical attempt to make all of this more relevant to ordinary people is the Banana Equivalent Dose BED, which is usually rounded up to 0.1 µSieverts. 

So I decided to calculate how many bananas were equivalent to the average radiation dose of 2.7mSv per year received by a typical UK citizen, which works out to 74 bananas/day. 

The exposure limit for a worker in a nuclear power station is 0.18mSv/year or 5 bananas /day.

Back in the late eighties I had radiation treatment for cancer and received 5,400 rads across my abdomen over a six week period.  This is equivalent to 54Sv or 12,857,143 bananas/day and I'm still here!

So, if they ever find this post, as well as equating nuclear power with cancer, I expect that these two French ladies will also stop eating bananas! 

Windows 8 - the last in the line of a series of flawed products!

I’ve had it with Microsoft!  After more than twenty years of using their software and putting up with random crashes I’ve decided that I’ve bought my last Microsoft product.

I purchased a tower computer a few years ago from Palicomp running Windows 7. It’s been nothing but trouble ever since.  I don’t blame the manufacturers; although they were not very helpful about finding and loading updated hardware drivers and they typically took two days to reply to an email. So when it crashed I was effectively on my own.  

I’ve had to do a clean install of Windows 7 four times.  The classic symptoms were that, after a few weeks of use following a clean install, something caused it to crash and restart.  Windows system repair found nothing, and more often than not System Restore didn’t work.  The only temporary fix was to reboot it while pressing F8 and then select “last known good configuration”. I say temporary because this means that I can then no longer update Windows.  For some months I’ve been unable to print because the printer service won’t start and no fixes that I could find have worked.  More recently, when I was shutting it down, it got as far as “Installing updates” and then crashed and restarted in the middle of doing so.  Using the "last known good configuration" method on restart allowed me to then shut it down successfully, providing that I'd done nothing before initiating the second shutdown.  I couldn’t find the update in order to kill it and eventually decided to “upgrade” to Windows 8 rather than do yet another clean install of Windows 7.  I put off doing the upgrade for months and reverted to using an old Vista home premium laptop which, after I’d discovered that it had two hard disk drives and I’d installed another gigabyte of memory, (it will only take 2Gb) now works reliably.

Yesterday, after wasting a morning trying to fix Windows 7, and in the process discovering that various pages of the Microsoft support website were unavailable, I decided to take the plunge and load Windows 8.  I naively thought that Microsoft might have fixed the unreliable updates issue but no! 

The installation went OK.  It was a clean install, because any attempt to upgrade from Windows 7 caused it to crash due to something associated with Windows Restore.  I then went to Windows Update and before I’d installed anything, including anti-virus software, I downloaded the usual massive list of “important” updates.  When they tried to install the software froze and it only restarted when I unplugged the USB cable from a WD My Book Essentials external disc drive (there’s probably a clue here).  The computer then stopped and started a few times and, when it had finished, an inspection of the update history showed that 14 had not successfully installed.  I tried unsuccessfully to re-install them and resorted to Microsoft’s tool to check for problems installing updates.  This ran, stopped two services, restarted them and wiped the update history.  It now shows me that I’ve never installed any updates and on top of that when I check for updates it says that I don’t need any! This can only be due to unreliable software from Microsoft!

It seems that the options I have is to “refresh” Windows 8 and start installing updates again or just forget about them!  Really! Life’s too short for this sort of faffing about! 

It was at that moment that I decided not to buy any more Microsoft products.  Their whole approach to issuing software is wrong.  If I update an iPad the entire operating system is updated in one download.  This enables proper testing to be done on the release BEFORE it's shipped.   A piecemeal approach to issuing security patches and fixes is inevitably going to fail at some point.  This is one reason why they have had to include a refresh function in Windows 8.  They know that sooner or later the whole thing will fall over.

The final nail in the coffin of Microsoft is their decision to only allow three installs of Microsoft Office 2013 before you have to buy it again.  This is a great idea which no one is going to be stupid enough to buy into.  Deliver an unreliable operating system that has to be clean installed on a regular basis and then charge people for buying Office 2013 after the first three clean installs!  That will really help the sales figures!  I can’t believe that they are so arrogant and think that we are so brainless!  When you combine this policy with the slow uptake of Windows 8 it amounts to commercial suicide! With the rise of tablet computing, and the decline in sales of desktops and laptops, I think that Microsoft is now in an irreversible slow decline and it will only be sustained if it can persuade the large installed base of existing users to buy their products, but most won't see a good reason to upgrade their operating systems to Windows 8 so Microsoft's income stream is going to diminish.  (This morning, 3rd September, Microsoft's purchase of Nokia was announced.  How can one failing company be turned around by another which is going down the same path?)

I used to say that I have a lot of Windows software which I don’t want to have to repurchase but now that I no longer produce complex documents, or do a lot of animated graphics, I don’t really need Microsoft Office and could get by with one of the free versions.

So I will struggle on with Windows 8 for now, but if and when I decide to buy a new computer, as opposed to a tablet, it will be a Mac or even something running Linux, if it’s less techie orientated by then.  

Update at 3rd September 2013
I have now downloaded a trial version of "Start8" which adds a Windows 7 style start button, a start menu and a shutdown button.  All of this is very configurable so that you can make it fit your needs.  I'm impressed with this cheap no fuss extension to Windows 8 and can fully recommend it to anyone frustrated by the unnecessary screens that one has to click through to start up and shutdown Windows 8. Since the computer is only used by me, I've also got rid of the password entry screen so it's starting to feel more like the computer I wanted to own.

I still have 33 important updates to install, which I am doing one at a time due to my previous bad experiences with Windows 7.  I am also manually creating Restore Points before each update session, since when Windows 7 went sick it frequently showed no restore points at all. 

To be fair I should add that Windows 8 is definitely faster than Windows 7.

The WD Mybook Essentials 3.0, which has all my backup files on it, finally stopped being recognized by either of the two Windows computers in the house.  From looking at the forums this seems to be a common problem that appears to be a hardware fault, because it was running the latest firmware and there have been no fixes suggested by the manufacturers.   I dismantled it and tried to get the data off directly by installing it in the desktop computer but Windows 8 is asking to initialize the disk, which would wipe all the data.  I now intend to get the data off the disk using a USB hard disk adapter, then I will install the bare disk in the desktop machine, reformat it (initialize it) and use it as a second hard drive.  

Update at 8th September 2013
The hard disk adapter didn't work and neither did WD's data recovery tool.  The former showed that the drive had no data on it and the latter just hung and stayed like that for hours.  When I checked properly I found that I had, in fact, managed to copy all the data off the disk before it had failed so I carried on to reformat it and created two volumes E: and F:.  I then copied further data from C: onto the F: volume to act as my primary backup.  I still need another backup device and I may try to resurrect a Seagate Black Armor NAS drive that I abandoned when it appeared to have been responsible for corrupting my printer service in Windows 7.  Incidentally Windows 8 found and installed an HP 5150 wireless network printer without any intervention from me at all.

Update at 11th September 2013
Another 15 important updates today! This is for Windows 8 and Office 2007.  It's hard to believe that they are still discovering security flaws in six year old software. 
Also I tried to create a system image onto the second hard disk drive and it failed giving error 0x008007000D "invalid data" and no other clues.  As usual with Microsoft that's very helpful.

Update at 14th September 2013
Now I am once again updating because I've done a system restore to before the last batch of updates. I downloaded one Windows update and instead of pressing the button on the update page to restart the computer I carried on working thinking that it would install it when I shut the computer down from the desktop.  When I tried to do this it wouldn't shut down.  Eventually I switched it off at the mains. On restarting it took forever to start up, with a message saying that it had repaired the F: volume. Disk management was also taking so long to open that I gave up. On another day I managed to do a System Restore of the C: drive, but this also took hours.  From the command line I ran chkdsk on the F: volume and it found and repaired a number of bad sectors but hung at step 4 out of 5.   Finally I left disk management running and when it eventually opened I discovered that Volume E: had reverted to "RAW". Once it was reformatted this cured the very slow opening of Windows 8 and the computer behaved normally except that when I tried to create a restore point for the F: volume it timed out.  That still needs to be investigated.  So now I am downloading updates again one at a time and restarting the computer from the updates dialogue box!

UK Protests against “Fracking” gain momentum

After nine days of protests outside Cuadrilla’s site at Balcombe in West Sussex,the company started drilling at 11:15 am on Saturday 3^rd August 2013.  The protests continue even though Cuadrilla insists that it is only prospecting for oil using conventional drilling techniques.

Cuadrilla has stated that the operation on the Balcombe oil well site, which was plugged and abandoned after an evaluation by Conoco in 1986, is for an exploratory borehole only and no “fracking” will be carried out.  If you look at the Balcombe page on Cuadrilla’s website they have carried out a comprehensive set of studies and assessments since planning permission was granted by West Sussex County Council in 2010.  They are also working very closely with the Environment Agency, which has advised them of those applications that should be made for permission to enable them to legally handle the resulting waste materials from the drilling process. This includes applying for a licence to handle radioactive materials such as the water derived from the oil bearing strata, which is naturally contaminated with radioactive substances like uranium.

Frack Off!
Of course none of this is of any interest to the anti-fracking protesters who have effectively rallied support for their cause around this site.  They have been very successful in gaining media attention and the arrests, the heavy police presence and even the tents on the side of the road remind one of the Greenham Common protests which lasted from 1982 to 2000.

Tina Rothery

Tina Rothery of Residents Action on Flyde Fracking RAFF, said any plans to drill on the Lancashire coast, where fracking has already caused earthquakes, will be met with protest.

“If anything we have learned from the protests at Balcombe and they will help us to be more effective,” she said.

On BBC news today (03/08/2013) she used her media experience to fill a precious few seconds of air time with a highly articulate explanation setting out why the protests should continue, in spite of the fact that permission for “fracking” has not yet been applied for by Cuadrilla.  The drilling itself will create disruption, noise and waste disposal issues. There is also likely to be flaring of any gas found in the oil deposits. 

Fracking bribes may well be misplaced

When he announced tax subsidies for fracking companies George Osborne also said that local communities should be rewarded for allowing fracking in their area, but the idea may well backfire. 

In his recent book What Money Can’t Buy, Michael Sandel tells an interesting story about the Swiss village of Wolfenschiessen, reported by the FT and Mr Leo Von Bülow-Quirk. The proposal for a financial incentive to accept a nuclear waste depository near their village reduced the percentage of residents in favour from 51% to 25%. The offer of money converted what the residents were prepared to accept as a civic duty into a mere matter of financial gain.

In my view this is an example of the moral bankruptcy of some UK politicians, which is typified by the MP's expenses scandal, ongoing lobbying payments, "cash for questions" and the blatant cronyism of the latest honours list. It is the politician's cynical use of their privileged positions to make money or to dole out rewards to the faithful, which has already led to a lack of trust between politicians and the electorate.  I think that the idea that people will risk their local environment and health, for a financial gain which will not begin to match the losses that they will make if they are property owners, is a non-starter.

If the money goes to Local Councils nobody will trust them not to spend it on expenses, increased salaries and fact finding trips. At best it's likely to get absorbed into general budgets to offset cuts elsewhere. 

On the other hand individuals tempted to accept financial payments, in exchange for allowing fracking to be established in their area, should know that they will be signing away all their rights to any compensation for whatever damage they, or their children, might suffer in the future.  

UK Announces Tax Breaks for Fracking Companies

from a UK Parliamentary report

Yesterday the UK Chancellor of the Exchequer  announced that companies prospecting for and producing shale gas will be entitled to the same tax breaks as those prospecting in the smaller and more difficult offshore oil fields.  Following in the footsteps of the USA, which has dramatically reduced wholesale gas prices by subsidizing shale gas production, the UK government is planning to do the same. 

So UK residents can look forward to wide swathes of the UK countryside being covered with drilling and production sites, which will rapidly be established in the unfortunate areas where this will take place.  Those people unlucky enough to live nearby can expect falling property prices, contaminated aquifers, polluted watercourses, many heavy vehicle movements, noise, atmospheric pollution and even minor earthquakes. As the price of gas falls, and consumption increases to fuel economic growth, the rest of us can all expect an increase in carbon dioxide levels in the atmosphere and consequent effects on climate change.

Fracking's effect on water resources
The hydraulic fracturing process pumps large volumes of water underground at high pressure, which reappears contaminated with many pollutants, both from the addition of chemicals to assist fracturing and the extraction of heavy metals locked in the shale.   UK water companies are already warning of the potential problems that this will cause, not just in satisfying the volumes of water required but also in treating the waste water.  Smaller sewage treatment plants risk their biological treatment stages being adversely affected and the sludge produced by the treatment process being rendered unsuitable for disposal to agricultural land.  Water companies are not obligated to accept and treat industrial effluents and are allowed to charge for doing so.

In the US operators are refusing to fully disclose all the chemicals used in fracking but I hope that the UK Environment Agency is strong enough, and sufficiently independent from government, to apply its stated policy of full disclosure and then, as a condition for issuing the appropriate permits, only allow companies to use chemicals which the EA considers to be safe for the environment. This might limit the damage to aquifers. Once an aquifer is contaminated there is no going back and to use water from such a contaminated source would require extensive additional treatment facilities to remove the contaminants.

Why subsidize fracking?
So if shale gas production is considered by governments to be such an economic "no-brainer" then why subsidize the operators? The truth is that the wells are productive only for short periods, with production peaking early and then tailing off rapidly.  So the production costs can only be recovered over a short time for each site, and the operators need to maintain a rolling programme of new sites creating progressively more ongoing environmental impact. In the US, however, they have found that, even with tax subsidies, the reduction of gas prices caused by the rapid increase in overall gas production has made natural gas profitable but not shale gas, due to its greater production costs. 

Shale gas is a very short term, highly environmentally damaging solution to the problem of peak oil and declining fossil fuel stocks. Encouraging the burning of yet more fossil fuels with subsidies is folly.  The unrestricted burning of fossil fuels has recently caused the concentration of atmospheric carbon dioxide to exceed 400ppm, a level not seen for 3-5 million years, long before homo sapiens existed.

France has recently stated that the law passed in 2011 banning fracking will remain. France is much less dependent on gas due to its investment in nuclear power.  The French population is also much better organised when it comes to protesting and getting people out on the streets.

A risky political quick fix?

UK politicians, who only ever think as far as the next election, should be ashamed of themselves for going for this quick fix approach to energy policy, and using our money to do so. Those Tories MPs, who are likely to find themselves having to support drilling in Sussex and Surrey, will find that their decision will rebound on them later because the environmental effects and the industrialization of the countryside will not go away for decades. In the north there are no Tory MPs, so there's not much hope for the residents of Lancashire, where drilling has already started and has caused minor earth tremors.


Shale gas production from fracking is an environmental disaster waiting to happen and I am angry and ashamed that the UK is planning to subsidize its production.  It should be investing in research into long term sustainable energy sources and 4th generation nuclear power plant designs, to replace and extend the UK's ageing fleet of nuclear power stations. 

This video uploaded by Danielle Spears deals specifically with the UK situation.

China’s faces technical challenges to develop thorium based nuclear power

By 2017 the Chinese are expecting to be running an experimental molten salt reactor, whilst other countries and commercial organisations, are being left behind. China’s first step towards liquid fuelled thorium reactors is, in essence, to reproduce the work done by Oak Ridge National Nuclear Laboratory (ORNL) in the sixties, when ORNL built and ran the Molten Salt Reactor Experiment MSRE. But what are the problems and challenges facing the Chinese as front runners in the drive to start up a liquid fuelled thorium reactor (LFTR)? 

Alvin Weinberg

Under Director Alvin Weinberg, back in the sixties and seventies a number of them were identified by the MSRE at Oak Ridge National Nuclear Laboratory.  In the test environment some of these challenges seemed to have answers, whilst others are still to be solved.  They are all written up in reports and published papers, now freely available on the internet, or at the ORNL archives.  You can be sure that they have been well studied by the many Chinese visitors to Oak Ridge.

Materials Hastelloy - N

The MSRE ran at around 670 deg C and the combination of high temperature and radiation made the selection of materials critically important.

The Molten Salt Reactor Experiment

Based on laboratory tests Hastelloy –N (originally known as INOR-8), a nickel alloy with molybdenum and chromium developed by ORNL, was chosen for the reactor containment vessel and for piping and heat exchangers. 

 Chemical Composition of Hastelloy N™

•     Carbon 0.04-0.08

•     Chromium 6.00-8.00

•     Molybdenum 15.00-18.00

•     Iron 5.00 max

•     Manganese 0.8 max

•     Aluminum + Ti 0.5 max

•     Boron 0.01 max

•     Sulfur 0.03 max

•     Nickel remainder

During construction questions arose concerning the stress-rupture life and fracture strain, which were found to be drastically reduced by thermal neutron irradiation. 

An out-of-pile corrosion test program was carried out for Hastelloy-N^[9] which indicated extremely low corrosion rates at MSRE conditions.  Capsules exposed in the Materials Testing Reactor showed that salt fission power densities of more than 200 W/cm³ had no adverse effects on compatibility of fuel salt, Hastelloy-N, and graphite.  With their chosen salt mixture (see below) and at the operating temperature, they found that Hastelloy N was adequately resistant against corrosion and embrittlement for its design life in the MSRE.  Since this was an experimental reactor, however, this is not the same as saying that it will last the 30 years necessary for a commercial reactor.

Later experience showed that the mechanical properties of Hastelloy – N do deteriorate as a result of exposure to thermal neutrons but that the addition of small amounts of titanium and hafnium significantly improve its performance. to select the most resistant alloy much more long term operational experience is needed.

MSRE core

Graphite Moderator
As in Light Water Reactors, the graphite moderator blocks were found to swell and crack in the high radiation environment.  As a minimum this creates a maintenance issue since the blocks have to be replaced.  More seriously, depending on the reactor design, it can block fluid pathways and lead to hot spots.

Research into graphite production methods and coatings was carried out by ORNL but it remained an unsolved problem in the early seventies.

There are many ways to design a nuclear reactor and other possibilities of moderating the neutron flux may need to be tried.  

Alternatively one could opt for an un-moderated molten salt reactor design working in the fast spectrum.  Such a reactor would be able to burn actinides and eliminate almost entirely the production of highly radioactive waste having a long half life.  This is the subject of research at Grenoble, France but it has never been attempted on the scale of an experimental reactor so far.

Tritium removal

Tritium is generated in small quantities within the molten salt as a breakdown product of lithium 6. Tritium, or hydrogen-3, is made by bombarding lithium-6 (⁶Li) with a neutron (n). This neutron bombardment will cause the lithium-6 nucleus to fission, producing helium-4 (⁴He) plus tritium (³T) and energy.

Tritium is highly radioactive and must be sequestered in a secure storage facility.  If, however, the lithium salt used is purified to 99.995% Lithium -7, then the quantities of tritium produced amount to only a few hundred grams per year from a 1GWe reactor. 

At the temperatures concerned, however, tritium can pass through the heat exchanger material and get into the secondary cooling loop from where it could escape into the environment.  ORNL developed a secondary loop coolant system that would chemically adsorb the few hundred grams of residual tritium to a less mobile form, so that it could be trapped and removed from the secondary coolant, rather than diffusing into the turbine power cycle.  ORNL calculated that this technique would, by itself, reduce tritium emissions to the environment to acceptable levels 

The tritium was then extracted and successfully oxidized over copper oxides and captured in a pair of water bubblers.  No tritium was found in the exhaust gases.  

The process of capturing the already low concentration of tritium from the molten salt was found to be not very straightforward and more work is need to develop this or other process options.

The Lithium Problem

ORNL chemists did extensive pioneering work to find the best mixture of salts to give the desired physical and chemical characteristics.  Many were tested but they opted for Flibe, a mixture of lithium and beryllium fluorides.

Present day research programmes may need to revisit the choice of lithium because it’s necessary to use only lithium 7 and to remove the 7.5 % of the naturally present lithium 6 isotope.  Otherwise, depending on the concentration, lithium 6 would either transmute in the reactor into tritium, as mentioned above, or prevent the reactor from starting up due to its high neutron absorption characteristics.

But this is only part of the lithium problem.   At present only two countries are carrying out lithium isotope separation, China and Russia.

Since lithium 6 can be used to make tritium its production is strictly monitored. 

Interestingly in the US Castle Bravo hydrogen bomb, tested at Bikini Atoll on 1^st March 1954, it was assumed that only the 30% of lithium-6 present in the lithium charge would react in a hydrogen bomb, but the contribution from an overlooked reaction due to the presence of the remaining 70% of lithium-7  caused an unexpected increase in yield of 250%,  making the 15 Megaton explosion the largest thermonuclear device tested at that date.

The US stopped separation of these isotopes, using the mercury amalgam method, a number of years ago due to concerns about its toxicity and the fact that large quantities of mercury had been lost from the Oak Ridge National Nuclear Laboratory inventory in an unknown manner.

So the lithium problem presents a difficulty to any private sector group not working in co-operation with a government having a form of lithium isotope separation technology. 

Other salt mixtures not using lithium are possible and many were tested at ORNL in the laboratory but so far they are completely untested in reactors and may affect the choice of reactor materials.

Storage of Solidified Salts

At the end of the MSRE programme the molten salts were stored as a solidified material.  It was found that fluorine and uranium hexafluoride were continuously released by radiolysis.   As a temporary measure the solidified contents were periodically reheated to induce recombination, but eventually the uranium was removed from the salts in an expensive and challenging cleanup programme.  A solution to this problem would be to remove the uranium prior to storage of the solidified salt by sparging the molten salt with fluorine gas, to create uranium hexafluoride which can be re-introduced into the reactor. 

Plutonium must also be removed to prevent radiolysis, which can be done by the addition of sodium carbonate to create plutonium dioxide. 

Conclusion

This is by no means a full list of the issues which arose during the operation of the MSRE. (Section 7 of the Weinberg Foundation's recent Report on Thorium-Fuelled Molten Salt Reactors gives several more). So there are plenty of technical challenges to address as the Chinese firstly repeat the MSRE experiment, and then extend it into larger reactor designs.  Personally I’m extremely pleased that the Chinese have the vision, the money and the forward thinking to restart and extend the pioneering work that was done at ORNL in the sixties and seventies   The use of thorium reactors running at atmospheric pressure will be much safer and will produce much less radioactive wastes than the current 50 year old designs of the existing Light Water Reactor fleet.  For me safe and abundant nuclear power is the only way of avoiding the prospect of runaway global warming, because conservation of energy, and the intermittent nature of the main renewable sources, cannot provide more than a part of the answer to the rapidly increasing global demand for energy.

Under Weinberg's leadership ORNL had a world leading  combination of nuclear scientists, engineers, chemists and metallurgists all working under one organisational umbrella.  They were capable of taking any brief concerning nuclear power generation and turning it into reality quickly and efficiently.  The USA allowed much of this expertise to dissipate when the Nixon administration fired Alvin Weinberg because he disagreed with the administration’s chosen programme of liquid metal cooled fast breeder reactors.  By the time that programme was closed down the USA  had forgotten about the highly promising liquid fluoride technology that is once again coming to the fore. 

It’s a pity that the US, like other western countries, has not yet found the courage or political will to overcome the inertia inherent in the nuclear establishment, which is committed to the Pressurised Light Water Reactor and the uranium–plutonium fuel cycle.   Coming from the UK, I’ve seen many examples over the years where pioneering research is done by underfunded organisations, only to be developed by other better placed countries.  It’s a symptom of the West’s debt-burdened economic decadence in the face of the challenge of the Far East, but in fifty years time, if all goes well, we’ll thank the Chinese for picking up and developing ORNL’s 50 year old Liquid Fluoride Reactor research, even if we have to pay the licence fees to China for our neighbourhood power station.

Although there are some signs of increasing openness, and their thorium programme is a good example, it’s also worrying that the Chinese, as communists, do not have a fully representative form of government.  I sincerely hope that the Chinese thorium programme doesn't get caught up in some sort of revolutionary “Chinese Spring” that could set their programme back decades.



Here are some other posts that might interest you if you have read this far.

An outline of the Chinese thorium program given by Kun Chen,Professor and Deputy Director, Department of Nuclear Safety and Engineering, Shanghai Institute of Applied Physics.
http://johnpreedy.blogspot.fr/2012/08/the-chinese-thorium-programme.html

A detailed review of Robert Hargraves' book "Thorium- energy cheaper than coal".
http://johnpreedy.blogspot.fr/2012/11/thorium-energy-cheaper-than-coal.html

China has a virtual monopoly on the production of rare earth elements of which process thorium is a byproduct.
http://johnpreedy.blogspot.fr/2012/09/the-thorium-problem.html

Horace Preedy - A Tribute



Horace Preedy on his 107th birthday

Dad was born on 17th January 1906, in East Ham, the third of four children. At the age of three he caught diphtheria and was taken to hospital in a hansom cab. He survived but contracted a heart murmur for which he was grateful later.

He left school at fourteen and worked for a while as an apprentice painter and decorator.  He progressed to working in the City, starting as a messenger then as a clerk for a firm of stockbrokers. Here he met Mum and she recalled the event in the reminiscences that she wrote at the age of 91. She says:-

“There was one customer who fancied the country girl who served him in the teashop at Stratford Broadway where she worked and asked if he could see her after work. The other girls asked his name. She said she didn’t know and they laughed and teased her saying, “It’s not Horace is it?” At their next meeting she asked him his name, “It’s not Horace is it?”, she said. He burst out laughing and said that it was. She said “I can’t call you that! Don’t you have any other names?”

He told her that his other names were Horace Robert Arthur, and so Bob was chosen, and he remained Bob in the office for years.”

They were married in Chingford in June 1935, and in the late thirties they lived in a bungalow in Billericay, owned by Horace’s parents, on a third of an acre, with a garden lovingly tended by Horace. They had two dogs and they used to play badminton and tennis at the local club. They’d achieved the dream life style of a young couple in the 1930’s and the only thing missing was a child or two.

A year and a half later the slump of the thirties had caught up with the City and Horace, always cautious, was concerned that he might be next to be sacked: so he took a part-time job with the GPO in the Brentwood Telephone Exchange. Some days he would come home from the City and then cycle six miles to the Exchange for an evening’s work. In August 1939, after a year’s probation, his status as a civil servant became permanent. He left his job in the Stock Brokers and went to work as a telephonist.

On 3rd September 1939 war was declared. He continued to work as a telephonist, frequently riding his bike to work at night whilst air raids were in progress. In 1942 he was drafted into the Signals Regiment and was well behind the front lines as the invasion advanced across France in 1944.

He liked to tell the story that in 1944 his unit was due to be sent to Burma. Dad was 38 at the time. The doctor who examined him at the medical looked at his papers, in which he was classified as A1, and said,

“You don’t want to go do you?” He certainly didn’t want to be sent to fight the Japanese in the jungles of Burma so he said “ No sir!” .
The doctor said “You have a heart murmur, but it’s well compensated and nothing to worry about,” and classified him C3. This meant that he was unfit for tropical service! It was a lucky escape because there were few survivors from his unit after their tour of duty!

The bungalow in Billericay was sold during the war and Mum, by now pregnant with Brenda, was sleeping on her brother’s sofa. Brenda was born in October 1944. Accommodation was very scarce by the end of the war and in the winter of 1944 Mum and Dad found a few rooms to rent in Westcliff on Sea, where they lived for the next 38 years.

At first the gloomy house, with navy blue wallpaper, was shared with two old ladies. In the scullery there was a stone sink, a copper to heat water over a gas ring, and a bath, which was not plumbed in and had to be bailed out. Needless to say, in my childhood, baths were only a weekly event.

After discharge from the Army he went back to the GPO, but soon he took the Civil Service Officers exam, passed and was allocated to the War Damage Commission. This meant getting up at 5 o’clock, walking to the station to catch the steam train to Liverpool street and then taking the tube to Acton. They still worked Saturday mornings so on Saturdays he had to travel for a total of six hours to work for four!

He applied for promotion, passed and was transferred to the National Assistance Board, which later became the Department of Social Security. His job was to visit claimant’s on Canvey Island to assess their cases. He had an auto-cycle, a sort of primitive moped, which meant dressing up in waterproofs and driving to work in all weathers. When he found old people struggling to get by he applied his own discretion and was able to give them some extra money for household items, but he was not at all sympathetic to men who wouldn’t work.

He bought a car in the early sixties. I remember that one day we took it to Canvey Island to fetch a little Yorkshire terrier from an old man who could no longer look after it. It was filthy and smelly, with matted hair and an aggressive nature. It was my job to restrain it on the back seat! When we got home Dad dressed up in a plastic mac and sou’wester, dumped the little dog in the bath, cut off most of his fur and gave him a good wash. In the next few months a beautiful silver-haired Yorkie, called Nobby, became one of the family, but he was definitely Dad‘s dog. Several years later, when Nobby was dying of heart trouble, my father would sleep in a deck-chair downstairs in order to stay with him at night, and reassure him when he was in pain.

Dad was a pioneer of DIY in the fifties and bought a table saw, which was dangerously plugged into an unearthed lighting fitting. He was very practical, he knew about carpentry and even how to "wipe" a lead pipe joint, but where he learnt it from I’ve no idea! As a child I used to watch him working and whenever I asked a question he patiently explained what he was doing.

While he worked steadily at modernising and improving the house, which by now he had bought, he sang songs from the 1930’s especially the Fred Astaire numbers that he used to dance to in his twenties. He always had a tune going on somewhere in his head. He‘d wanted to learn the violin when he was young but couldn’t persuade his parents to buy him one. He never did learn to play a musical instrument, but he was, none-the-less, very musical. When she was helping him with the decorating, Brenda remembers him singing “When Father Papered the Parlour” a hit from 1910. Less characteristically, she also remembers him dancing with her down the hill to the station to the tune of “ We’re off to see the Wizard…“ when we were going to a cousin’s wedding.

Normally though, he liked peace and quiet. In the evenings after work he was always outside in the small garden patiently chopping up things with his secateurs to feed the worms. Brenda and I both owe our love of gardening to him.

In 1982 Mum and Dad moved from Southend to Wantage to be nearer Brenda, and her husband Les. Here, as well as having a larger garden to keep him busy, he could still be seen painting the bungalow at the age of 92.

It was typical of him that he almost never complained and accepted what life sent his way. He was very patient, stoical and only rarely showed any anger. He didn’t need a lot of people around him but he had a strong sense of duty to his parents, his family and to a few close friends. He was polite right through to the end of his life, a real gentleman, and always said thank you when you took him a cup of tea or a meal.

In his later years, unlike my mother, he was still mobile, but he suffered progressively from memory loss, so he acted as my mother’s arms and legs while she told him what she wanted, and where to go to find it!

When Mum died from a massive stroke at the age of 97 we asked Dad, on the way back from the funeral, if he knew where we’d been and he said no. Sometimes Nature can be kind as well as cruel.

He never smoked and only drank alcohol at Christmas. He owes a good part of his very long life to these things, but Brenda has been his carer for the last ten years, whilst he slowly declined, and she has looked after him attentively. I’m quite sure that without her care he would have died some years ago.

She has also made it possible for him to die peacefully at home, in his own bed, at 107, the seventh oldest man in Britain. He died in his sleep on 2nd June 2013.

Thanks Dad for providing a stable and loving family home for us to grow up in. We’ll both miss you.

John Preedy