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Dear Reader,

It has come to my notice that a series of slugs have slithered into Vara, to my great displeasure these brutes have chosen to invade my garden. I have had to do some research work to enable me to respond in the correct manner to these animals. For those of you who do not know this the slugs are a pest which has been accidentally introduced into Sweden, I did some research and discovered a few interesting things about them.

Firstly slugs hate caffeine, in large doses it is fatal to them while in small doses it puts them off their dinner. I have to admit while I find the slugs repulsive I do not wish them all dead. I would rather that they went off into the forest where they can do little harm.

Caffeine is one of those molecules which has been characterised again and again by crystallography, one example is the magnesium bromide dicaffeine solid (M.B.Cingi, A.M.M.Lanfredi, A.Tiripicchio, G.Bandoli, D.A.Clemente, Inorg.Chim.Acta , 1981, 52, 237). Below is the molecular structure of caffeine in all its glory.

Crystal strucutre of caffeine

Crystal structure of caffeine, note it shows bond lengths and not bond orders

I have a rather long and personal history with caffeine, one summer as an undergraduate I devised a total synthesis of the drug only to be disgusted to discover that the book I got the structure from had an error. As a result I was trying to devise a synthesis of a related compound (Isocoffeine). I can not recall all the details of my isocaffeine synthesis but I do recall that it would have used MIC (methyl isocyanate) for one of the steps (Not a nice substance !). To put it bluntly I felt decaffeinated by the experience !

Serious nuclear reactor accidents

Dear Reader,

I have recently published a review article about some of the chemistry of a serious nuclear accident, this is in a new journal named “Cogent Chemistry”. For those of you who do not know what “Cogent” means, it means “Something which appeals to the intellect or one’s powers of reasoning”. I have to confess I had to use a dictionary to look it up.

Now I am waiting for some feed back on this article, I am wondering what will come to me. It is important to note that such a review article is as politically neutral as possible. The role of a review in science is not to act as propaganda for either the nuclear industry or the antinuclear sector. In some ways the antinuclear sector seems as much of an industry as the nuclear industry. Some people seem to make being “antinuclear” as much of a full time job as some of the spokespersons hired by the nuclear sector. I am aware of some “interesting” behaviours which both pro and antinuclear zealots have. I will always refuse to name the zealots from either side, so please do not ask me for a list of them.

Some of the antinuclear zealots might even harm the environmental movement, if a person appears to be a foaming at the mouth antinuclear (anti-GMO, or anti-you add the name of a technology or industrial activity) they may start to appear to be an unreasonable person with a clear axe to grind. They may lose credibility and they might also start to tell lies (be dishonest, economic with the truth call it what you like) as a result of this “crying wolf” people will start to ignore the whole of the environmental movement so when another (and genuine) issue appears people will ignore it thinking “yet another scare story”. I am aware of people making claims of effects which are impossible, I also suspect that some people make up statistics / data and I also see dishonest tricks of argument such as “appeal to authority”, and “abusive ad hominem”. The latter is when a person’s character is attacked as a method of undermining an argument. For example consider one version of “ad hominem” known as “poisoning the well”. Someone might argue their electricity bill is wrongly calculated, and that how can you trust a worker from wicked utility company when their state that  2 + 2 = 4, thus the bill is wrongly calculated.

I assume that most of my readers have a GCSE in maths or some other similar basic maths qualification so they should know that 2 +2 = 1 + 3 = 5 -1 = 6 – 2 = 7 – 3 = 8 /2 = 4

Now while I am sure that none of my readers (antinuclear, pronuclear or otherwise) would want to argue that working for a particular company renders you unable to count. But I have seen some people from both sides of the debate use these types of tricks.

One use of a related trick was an incident where a meeting regarding a renewal of a license for a nuclear forensics / research site was being discussed. At one point the subject of radioactivity levels was being discussed, one activity was smaller than that due to potassium in a normal person. One person became angry and was saying “how dare you say that you know nothing about me and my body”. I think that this is a rather silly reason to become upset and angry (example of poisoning the well) as I can tell you that if you lost most of the potassium from your body you would die of a heart attack. Hypokalemia is the term for low blood potassium which when taken to an extreme results in a heart attack.

On the other hand some of the lunatic pronuclear lobby (One man who works in a national nuclear research centre calls them “atomheads“) are likely to harm the nuclear industry (and all other sectors which use radioactivity) by overselling nuclear technology and doing questionable things to prop up the image of their favourite industry. Promises of “electricity too cheap to meter”, nuclear powered cars (like the Ford Nucleon) and other outlandish things will result in disappointment. Also some statements which were later shown to be wrong on safety issues will in the long run do a lot of harm, during the three mile island accident a series of ambiguous and contradictory statements were made which in the long run did a lot of harm to the reputation of nuclear power. In terms of the flow of information to the public the three “big” reactor accidents were very different. Three mile island had a series of statements made to the media / public by the utility / the state, the Soviet Union tried to suppress the news about Chernobyl (that failed big time when workers at a Swedish plant arriving for work were found to be contaminated) while Fukushima was the internet age nuclear accident where lots of organisations were racing to post news and updates (some of which contained or were based on bad data). But a discussion of the way in which the early information was released for these accidents will have to wait for another day and another post.

I suspect that the article will enlighten and entertain the reasonable people from both sides of the nuclear / antinuclear debate rather vexing them. However both the most hardline opponents and staunch supporters of nuclear power will find the article disagreeable. The most antinuclear zealots will hate it as it fails to paint the picture of hopeless total doom which they so want while the pronuclear zealots will hate it as it discusses some of the things which can go wrong. Those who are protruth and proenlightenment should have no problem with it.

Alternative fuel for RTGs

Dear Reader,

I was reminded by a reader that a shortage of Pu-238 exists, for those of you who are not in the know. Pu-238 is a proper radioisotope of Pu. In comparison Pu-239 is quite low in terms of activity per gram. As a possible replacement for Pu-238, Am-241 has been suggested.

For other applications other radionuclides such as Sr-90 have been used in RTGs, this is what the Soviets used for a lot of the RTGs which were used at remote lighthouses or substations in the middle of nowhere.

It is back in action

Dear Reader,

It has come to my attention that the space probe which landed on the comet has started working again. I have to ask the question why did the probe lack a RTG (RadioThermal Generator) based on something such as Pu-238 or Am-241. If it had been equipped with such a nuclear battery then it would have been able to operate without a need for sunlight.

While these battery packs are not very PC, I am aware that some of these radioactivity powered generators have survived launch accidents. If they are well designed then even in the event of a rocket blowing up on the lauch pad then no threat is posed to the general public.

Good luck to her

Dear Reader,

It has come to my attention that Elizabeth Wurtzel has got married, I say good luck to the young lady. I hope it works out well for her, in case you do not know she is a woman known for her rather shocking autobiographical writing about things like depression. I have read two of her books and they were interesting and shocking in places.

Sadly I have also discovered that she has had some health trouble (breast cancer), I hope that her treatment has cured her and that she has a long and healthy life.

Morbid horror from the graveyard

Dear Reader,

We have in the news a horrible sounding story about carcinogenic ammonia and formaldehyde leaking from graves in Northern Ireland into the ground water.

Lets make something clear ammonia is not a carcinogen, also the soil bacteria may well be able to degrade formaldehyde. Zhao, Geng, Fan, Tao and Hou in BIOTECHNOLOGY AND BIOPROCESS ENGINEERING, 2013, Volume:18,Issue:2, Pages:300-305 report how a soil bacteria (Paracoccus sp FD3) is able to degrade formaldehyde. This paper also lists some other bacteria which can degrade formaldehyde.

I think before we assume that the gravedigger is right that the graves are a menace to the living, someone should consider how much of the formaldehyde will be able to migrate out of the graveyard into the ground water and how much will be degraded by the bacteria.

Thorium fueled reactors

Dear Reader,

It has come to my attention that the thorium based fuel cycle is being discussed in magazines such as “Chemistry World” which is the magazine of the Royal Society of Chemistry. As with all technology it is important that we have a honest and reasonable debate about it.

One attractive thing about the thorium fuel cycle is that it tends to form less of the transuranium elements such as plutonium, one idea for a nuclear fuel would be to make a mixture of thorium and plutonium dioxides. The idea is that the plutonium will provide the seed fuel while new fuel can be made from the thorium. Natural thorium  (232Th) can be converted by thermal neutrons into  233Th which will decay via  233Pa into  233U.

In many ways a thermal reactor is better than a fast one, I assume that many of my readers have heard of the term “fast breeder”, the idea of a fast breeder reactor is that it uses fast neutrons to make more fuel than it consumes. Commonly a fast breeder is fueled with a mixture of  238U and something fissile such as  235U or  239Pu. The reason why a fast neutron spectrum is better is that thermal neutrons can cause fission of 239Pu but the fission to capture ratio for fast neutrons is more favoring fission than capture. The capture (nγ reaction) of neutrons with 239Pu tends to form a neutron poison (240Pu) which is activated further to form 241Pu which undergoes beta decay to form minor actinides such as 241Am and even curium. These minor actinides can be a right royal pain. Another problem is that in a thermal reactor the formation of 236U by the nγ reaction of 235U can occur, the 236U is long lived and can be activated further to make short-lived 237U which can decay into 237Np. The 237Np can then form by another capture reaction 238Np which does a beta decay into the house of horror bugbear isotope of plutonium (238Pu). It is interesting that while the greens complain about the “evils of plutonium” they never seem to mention the fact that a lot of plutonium formed in power reactors is more alpha active than pure 239Pu. They seem to be trapped in their thinking by the long half life of the nicest plutonium isotope, 239Pu is not very radioactive gram for gram when compared with many other things such as radium.

As the 239Pu undergoes less activation and more fission in a fast reactor it is a logical choice for making and using plutonium, but on the other hand a fast reactor is bad for the thorium based fuel cycle. Here the desired outcome is neutron capture by natural thorium. The intended reactions are the neutron activation of 232Th to form 233Th (t½ 22 min) which decays by beta decay to 233Pa (t½ 27 days) which in turn undergoes a beta decay to 233U (t½ 159200 years). While 233U can be used for both reactor fuel and bombs, it is interesting to note that it is normally contaminated with some 232U. The decay of 232U forms high energy gamma emitters which will increase the dose rate near the 233U, this could make bomb and fuel fabrication more difficult.

The unwanted reaction in the thorium containing reactor is the n,2n reaction on 232Th to form 231Th, the 231Th then does a beta decay to get to long lived 231Pa. The next neutron capture then forms 232Pa which decays into 232U.

Some of the daughters of 232U (208Tl and 212Bi) emit very high energy gamma rays (up to 2.6 MeV) which will be much more troublesome than the gamma rays from 241Am which is commonly found in plutonium which has been allowed to age for some years. The majority of the gamma rays from 241Am are much lower in energy (60 and 33 keV) are much lower in energy and thus can be shielded against with a lead apron (circa 1 mm Pb) or a sheet of glass attached to a glove box. To attenuate the 208Tl gamma rays a very thick layer of shielding would be required making glovebox work impossible unless the glove box worker is willing to incur a large hand dose and happens to look rather like Mr Tickle of the Mr Men.

The key thing to understand is that a slow or thermal neutron has too little energy to do the n,2n reaction on the natural thorium. While a thermal neutron is able to do the neutron capture which we want. With some luck we can consider some reactor designs which reduce the formation of 232U.


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