Bob and his nuclear “facts”

Dear Reader,

It has come to my attention that a person calling themselves Bob Nichols is publishing “news” on a web site. Being a person with some knowledge and understanding of nuclear matters I thought I would take a look.

Bob as we will call him is making the bold claim that nothing is being done to mitigate the accident or clean up the site. I think that this claim is totally false, I am well aware that waste water on site is being contained, treated and then reused to greatly reduce the amount of radioactivity which is released into the ground and the sea.

Bob has claimed that even industrial robots can not cope with the radiation levels on site, I think that this is deeply wrong. A friend of mine has been on the site and he only got a small dose. I would like to know what location he is talking about. In a normal nuclear plant there are some areas which are off limits to humans for radiation safety reasons during normal operation. After shut down it is possible to enter some of these areas within minutes. There are areas at the Fukushima site (inside the reactor pressure vessels and in some areas of the containments) which might be off limits for humans for many years but I suspect that the vast majority of the plant buildings can be entered by either humans or robots.

He suggests putting the reactor cores under water, this is being done but as some of the reactors have leaks it is not a simple matter. His text suggests that no work has been done to fix the reactors is misleading, while fixing these reactors is not a simple matter the work to fix the site has already started.

He writes about the “evils of uranium”, but I would like to point out that small uranium particles are unlikely to stay in the human body for long. Uranium oxides tend to dissolve in water when oxygen and carbon dioxide are present. The uranium will then be lost via the urine. If he wants to think about any radioisotopes then he should be thinking of the shorter lived beta/gamma fission products which were released back in march 2011.

He also fails to note that the amount of radioactivity in the reactor site is now far less than it was back in march 2011, radioactivity in a nuclear reactor’s fuel tends to decay away greatly after the plant is shut down. He also makes some rather far fetched claims about chernobyl claiming that 30 % of the core was released, trust me only about 3.5 % of the fuel at Chernobyl was able to leave the plant. If Bob had read either an undergraduate text book on nuclear chemistry (I can name two books which would tell him this) or even (dare I saw it) wikipedia then he would have found that the release of radioactivity from a damaged nuclear plant is controlled by the boiling point of the main form of the element.

While iodine, tellurium and cesium are mobile, the real nasties such as plutonium and strontium are much less mobile (thank goodness for small mercies). His suggestion of using atomic bombs to cause a landslide to make the reactor site fall into the sea is very silly. I sincerely hope that nobody ever tries to do this !

Different reports on the same subject

Dear Reader,

In recent times we have had the first serious nuclear accident of the internet age, I am not sure why it is the internet age. The ‘ages’ were named after the materials used to make typical tools.

Stone age : Stone axes

Bronze age : Bronze swords made of a Cu / Sn alloy

Iron age : Iron ploughs

Then later the industrial age came, then we had the atomic age, the space age and then the internet age. My big problem is that for the majority of tools which we use in our lives we do not use atomic (nuclear), space or internet tools to do things like open cans of dog food or dig our gardens. For opening pet food cans and tending the vegetable patch I still use tools based on iron (steel).

While a nuclear powered digging machine or a space satellite which zaps the weeds might make life a little more easy (assuming you can afford to buy it) I think we will be sticking with steel spades and can openers for the forseeable future.

But I think that we do need to move onto something else. Recently a series of different reports have been published about the Fukushima event in Japan. Greenpeace have published a report as have the Japanese government and also Jon. M. Schwantes et. al. in the journal Environmental Science and Technology (DOI: 10.1021/es300556m) have published a paper in which they use the isotope signature of the accident to probe the event. In common with many things it is not always possible to make a direct measurement from samples which can be taken by hand, instead other measurements were used.

Now before we get going I will saw that it is impossible to have a single report which deals with a complex event in perfect detail. The problem is that if we examine one aspect of an event in great detail (using a state of the art study which includes as many details as possible) then this report is likely to become very large and close to impossible to read. If we then couple together a series of sections with a similar level of detail on all the different aspects of the event then we will end up with a wall of words which is impossible to comprehend.

Greenpeace have written about a recent Japanese report that

“The lethally high levels of radiation still present in the damaged reactors have prevented committee members from conducting a full analysis. They should be given all the time they need to complete their investigation.”

While the Japanese writers of the big government report stated that their mandate was

1. To investigate the direct and indirect causes of the Tokyo Electric Power Company Fukushima nuclear power plant accident that occurred on March 11, 2011 in conjunction with the Great East Japan Earthquake.

2. To investigate the direct and indirect causes of the damage sustained from the above accident.

3. To investigate and verify the emergency response to both the accident and the consequential damage; to verify the sequence of events and actions taken; to assess the effectiveness of the emergency response.

4. To investigate the history of decisions and approval processes regarding existing nuclear policies and other related matters.

5. To recommend measures to prevent nuclear accidents and any consequential damage based on the findings of the above investigations. The recommendations shall include assessments of essential nuclear policies and the structure of related administrative organizations.

6. To conduct the necessary administrative functions necessary for carrying out the above activities.

I have highlighted in bold the part which interests me most as a chemist, the Japanese panel  also stated that they would not undertake a series of actions which included.

“investigations that would require on-site visits to reactors with dangerous levels of radioactivity.“

My understanding is that they have chosen quite wisely to avoid either waiting for a full examination of the reactor sites (which will take decades) or rushing into a dangerous area to gather data. My view is that samples collected from outside the reactor buildings, eye witnesses from the site, data from those sensors inside the plant which continued to work together with details which can be obtained from undamaged BWR plants. I see the problem of the clash of two cultures.

The scientific and engineering communities are seeking to get the best quality report which is correct, the speed of publication of the report is a secondary factor. In these communities it is better to delay the publication of a report if the delay will allow the quality to be improved. Also the answer has to be traceable, the computational methods used, the persons who did the work, the devices used and the samples used all have to be documented clearly in this type of work.

On the other hand the newspapers and many of the green NGOs (like Greenpeace) are aiming for speed of publication as their highest priority. In these reports the things which were used to produce the final answer are often not as traceable. What is interesting is when both the rapid publication of people like Greenpeace agrees with the slower and more thorough investigation which goes into the official reports. I would say that it is important to avoid being caught by statements by “The findings of both these reports match closely with the Lessons
from Fukushima report released by Greenpeace in February” in a trap where you think that both reports are the same.

The Greenpeace report has some similarities with and some differences from the Japanese government report, but I would say that neither report deals at length with the containment chemistry and the radiochemistry of the accident. I am unsure of what Greenpeace would be hoping for in an extended report which might be written in 20 years time when the insides of the containments have been fully explored. I think that a main part of the final purpose of the examination of the reactor buildings will be to determine what chemical and physical effects occurred during and after the accident.

The Greenpeace report is more dominated by photographs which relate loosely to the event, I am unsure why it is important in a report of 52 pages to include devote ten pages to photographs of things like wrecked buildings with very little explanation of what is going on in the photograph. For example on page 28 a whole page is devoted to a person holding a pair of radiation meters in a field. There are a series of important questions which are not answered in the text such as “what level of radioactivity has the person found in the field”, “what is the testing protocol” and “what is the date of the measurement”. I hold the view that the report should be written in a way to make these things clear rather than forcing the reader to dig deeply in a series of documents for the answers.

The Japanese government report is much more text and far fewer pictures in the main body of the text than the Greenpeace report, towards the end a lot of data is presented in appendix in the form of graphs. These graphs include things like the fraction of the public who were aware at a given time of some key events. While graphs might be less eye catching than photographs, I hold the view that a well labeled graph is a better way to communicate an idea to another person than a photograph which has little if any commentary in the caption.

The problem I see is that if I show 100 people a photograph with very little writing in the caption then a danger exists that each of the 100 people will interpret it in a different way, while in recent years there has been a backlash against science made by people like the postmodernists. Some people value their “feelings” above everything else and express the view that a series of different interpretations of the same evidence are equally valid, I have to disagree. Firstly there is no such thing as an impartial observer (Read the section of the Alan Chalmers book “Whats this thing called science” on induction for more details).

Secondly some interpretations of evidence are deeply wrong, for example if I was photographed by an alien (who has no knowledge of pet ownership) while walking my dog in the forest the aliens might think (based on the photograph) that I am some sort of cruel person who enslaves small white animals and chains them up. While this interpretation might fit the evidence in the photograph it is deeply flawed.

As a result I think that a report which is dominated by photographs which do not have a clear set of captions explaining what is going on is not a good report. But a report which uses the same amount of space for graphs and figures which bear captions which explain all the key points does communicate in a better way with the reader.

The comment that Greenpeace made of “The lethally high levels of radiation still present in the damaged reactors have prevented committee members from conducting a full analysis. They should be given all the time they need to complete their investigation.” suggests to me that Greenpeace want the Japanese government report to be a comprehensive report which deals with all aspects of the event. It might even be understood as Greenpeace suggesting that their report is more comprehensive.

I have read both reports and I can say that some rather important things are missing from both reports. Neither report mentions the transfer of cesium from soil to plants and then to humans via the food supply. I hold a view that this is an important issue, depending on the soil chemistry, the biology of the food production system and what countermeasures are taken the cesium in the diet is either going to be a small issue or a large issue. Also neither report gives a detailed list of the radionuclides released from the reactors and the amounts which were in the cores during the accident.

One of the best reports on this issue is the paper by J.M. Schwantes et. al., this paper uses the relative amounts of the different radionuclides in soil samples taken from Japan to work out what happened inside the cores of the damaged units.

This paper concludes

1. Volatility dictated by temperature and reduction potential dictated the fraction of the radioisotopes which were released.

2. All coolant was likely to have evaporated by the time the containments were vented.

3. The damage to the fuel was extensive.

4. The vast majority of the less volatile elements such as plutonium, niobium and strontium were contained within the reactors.

In the paper it has been calculated that the ratio of released cesium to plutonium from the Fukushima event was 100000 : 3 which suggests that the Fukushima event was far closer to a pure cesium / iodine release than the Chernobyl event was. The cesium to plutonium ratio for Chernboyl was about 10 : 1. I had from an early time made this prediction as the Chernobyl and Fukushima events were very different types of accident. One was a power surge while the other was overheating.

The most interesting thing in this paper is the graph of soil activity / reactor inventory against the oxygen potential of the dominate oxide form. This graph suggests that the more thermodynamically stable the oxide is then the less of the element will be emitted. The good news from this graph is that worst elements (plutonium) will not be emitted. The only problem is that the graph has some points which are a long way from the trend line.

More barium was released than this graph suggests while less ruthenium and silver was released than this simple model suggests. I think that I can explain why less ruthenium was released, the most easy ways to release ruthenium are either as fuel particles (which did not happen at Fukushima) or as ruthenium tetoxide which would not form as the reactors stayed under reducing conditions during the accident.

Another interesting document

Dear Reader,

Here is another interesting document it is by a man who explored the basement under the Chernobyl reactor after the serious accident back in the 1980s.

What ever you think of the nuclear sector, I think you have to be impressed with this man for his brave work to establish what happened in the reactor building.

Bhopal cleanup

Dear Reader,

I was glad to read that something is being done about the Bhopal site, I have held the view for a long time that the Bhopal event is a horrible industrial accident which could have been prevented or at least mitigated with great ease. But due to cost cutting at the plant a horrible toxic gas leak occurred which had on off site effect which was far more horrible than Chernobyl.

I may write more about the event later.

If you think that Chernobyl was ugly, then take a look at the Bhopal event ! The reason I think that the Indian accident was worse was that the death toll (general public) was far higher. Chernobyl can not be proven to have killed any member of the general public, while the Bhopal pesticide factory accident gassed to death thousands of local people.

I think that care needs to be taken to make sure that the clean up is done in a careful way which does not create a new threat to either the health / safety of the local people (+ workers) or a new threat to the environment.

Aftonbladet and chernobyl

Dear Reader,

It has come to my attention that a woman called Natalia Kazmierska has seen fit to comment on the Chernobyl event recently. This has made me think about the way in which the general public think about radiation biology.

I doubt if I will be attending a showing of the film “The Chernobyl Diaries”. Frankly I have better things to do  and I think that watching 28 days later gave me all the frights about zombies that I need for the next decade or so. I would like to point out that regarding radiation it is a case that what “everyone knows” is not right. While the general public expect a large number of mutant babies and deformed wildlife (overgrown rats, dogs with snake heads, snakes with dog’s bodies and what ever else you can imagine), I have to disappoint many people and point out that many of these wild (and far fetched mutants) are impossible.

In an adult mammal (and almost all other warm blooded animals) the cells are already differentiated and it is impossible to change an organ by altering a cell as

1. The organ has many cells

2. It is impossible to change the DNA of all the cells in the organ in the same way using radiation.

If we consider the eye as an example, somewhere in your genome is a genetic code which determines your eye colour. If you want to change your eye colour (and you do not want to use fancy contact lenses) then you would need to change the DNA in all the cells which are currently part of the section of the eye which gives the iris its colour. This is a very tall order which I think is currently impossible.

When you were an unborn baby at an early stage there would have been one eye which would have been destined to become your eye, if you had altered the DNA of this cell then you could alter the eye colour. But unless you also changed the cell which was destined to become your naughty bits (opps I mean reproductive organs) then this mutation can not be passed onto the next generation. So it is not possible to mutate adult humans or even human babies (for the purpose of this bit of biology they already have their organs locked in this way).

I know that newspapers would love to be able to report a “real life mutant associate prof who marks his students work using psychic powers to read student’s minds before writing the results down using a biro held using his tentacles”, but I have to tell you that such a story is totally impossible. If you want to print such a thing then I think other than vanity publication or writing in a novel/comic book your only chance would be to write it for the “Sunday sport“. For those of my readers who do not know, the Sunday sport is a comic like news paper which is packed with wild tales about sexual matters, sport, showbiz gossip and plainly silly things such as world war two bomber found on moon, aliens going on drinking binge in a UK pub and a monkey landing an airplane.

I think that the main reason why radiation is so bad at mutating humans (and most animals) is that the likelihood on inducing a mutation in the reproductive organs which can be passed onto your children is only 1 % per sievert (Sv). It is important to distinguish between a mutation which can be passed onto your children and the case of a child which does not develop normally due to irradiation in utero. Most of the horror pictures which people may have shown you are likely to be either fetuses which were deformed for some reason which is unrelated to radiation or a child which developed in an abnormal way due to the action of some agent such as (alcohol or radiation) on the unborn child.

It is important to bear in mind that the chance of inducing cancer in a human (typical adult over 16 or 18) is also low, it is widely accepted as being at 5 % per sievert, as a dose of about 4 sievert delivered over a short time is likely to send a person to the other side (assuming no specialist medical care) it is very hard to mutate a person’s gametes to enable them to have abnormal children let alone children with superpowers.

For example if we consider the associate prof with two superpowers (mind reading) and the tentacles which he can write with then it should be clear to most of my readers that such differences are a long way removed from what is the norm. I imagine that to get either of these “superpowers” would require a long series of mutations, this long series of mutations would require a large number of genetic changes to occur which are very unlikely to occur in the lifetime of one human. A typical mutation which could occur in a human would be a change in a gene which stops a person making a protein or some other biomolecule which is needed for normal life, this would include hemophilia appearing in a family which never had it before.

An alternative would be for the genetic code for the mutant prof to already be common in the human genome but to have a single gene which switches off this weird stuff. We can quickly discount this as if this was the case then every now and then we would see a person born who could read minds and had the extra limbs. As I have never heard of such a human then either the authorities are doing a good job of hushing it all up or more likely it has never occurred. I hold the view that it is very hard to keep something wild and exciting secret for a long time, a secrete organisation is only as strong as the weakest member so it is likely that a secret organisation will within decades become a publicly known one.

So I think we can discount the likelihood of an associate prof who mind reads and can write using extra organs appearing by mutating a “normal” human.

I would like to point out that the nuclear industry is one of the few which has worked out a method for isolating the worst forms of its waste from humans / the environment until it is no longer a threat. Wastes from other sectors will stay nasty and horrible forever. For example asbestos waste will remain hazardous forever and so will heavy metal waste from electrical batteries (NiCd cells). I would like to suggest that Natalia that she should consider this issue.

I would also like to point out that the worst accidents I can think of in the energy sector have been outside the nuclear industry, for example back in the 1960s a spoil heap at a Welsh coal mine slide down a hill and killed almost every last child in a primary school (Aberfan). If society or Natalia wants to have a debate on the safety of the nuclear sector that is fine by me, but we need to consider the whole of the energy sector rather than cherry picking the parts we want to discuss or be opposed to. I will be blogging on this in greater detail in the near future.

Testilying and the environmental movement

Dear Reader,

Twenty years ago or so the late Dennis Evans told me a story about some cops who thought that they would tell a “white lie” to protect society (I have no idea where this vile story occurred or if Dennis had made it up or not). What happened was these boys in blue raided a drug dealer’s hotel room. They find some packets of cocaine. Then to make sure that the man went away for longer they plant some extra packets of cocaine. I imagine that they wanted to make sure that the judge sent the vile coke dealer away for decades rather than just sending him to HMP holidaycamp for a few years.

The core thesis of the prosecution was that the man was a cocaine dealer who was mixing cocaine with sugar to turn a larger profit and that all the packets had come from a common source. The fact that different packets had different sugar levels made it look like the dealer was mixing purer cocaine with sugar to make a less pure grade.

The police’s expert issued a report on on cocaine content of each packet where he/she lumped all the adulterants together. It is a common habit for people in the illegal drug trade to mix illegal drugs with other materials to increase their profit. So it should not be a total shock for the police to have observed some evidence of such behaviour.

Dennis was contracted as an expert witness for the defence, he retested the cocaine and made a point of measuring the different sugars (glucose, fructose, sucrose etc) in the cocaine batches. He found a purer packet which the police claimed was the parent of the less pure cocaine contained a sugar which did not appear in the less pure packets.

Armed with this information the defence was able to prove that the story that the police were telling was false. They showed that someone (the police) had planted at least one packet in the room. They then suggested to the jury that all the cocaine had been planted in the room. The man then was acquitted on all charges and walked away from the court, I imagine without a stain on his vile character.

While some people might think “I have nothing to do with drugs” and “I am not a policeman” so this story has nothing to do with me. I would say that these people are being very foolish, this is a cautionary tale about telling a “white lie” to get the job done. This is an example of testilying and the vile perils it brings.

It is better to tell the truth about something even if you think by exaggerating that you will be more likely to get the outcome that you want.

Before we go any further I would like to make something clear to those of you who are not regulars here on my blog, I have to agree with the greens, antinuclear lobby or whatever you want to call them or be called yourself (if you are a member of the antinuclear lobby) that the Chernobyl and Fukushima events are horrible. These are events which need to be avoided where possible, and if total avoidance is not possible then these types of events need to be mitigated to eliminate the threat to the general public.

My (or your) revulsion at serious nuclear accidents is not however a license to exaggerate or attempt to use these events to score cheap political points. Frankly those who use these events for selfish ends disgust me just as much as the 19^th century mill owners who thought it was quite reasonable to force young children to work in dangerous factories, clean chimneys or go down the coal mine.

My loathing of serious nuclear accidents is one of the reasons why I devote time and energy doing research on trying to prevent a nuclear accident causing harm to the general public. In order to protect ourselves against reactor accidents we need to understand them, part of the quest to understand them involves a quest for truth and an insight. During this quest I am doing my best to share whatever grains of truth I uncover with others, and also to point out silly ideas when I find them. One of the things which irks me is when people exaggerate the consequences of an event, the fact that an event is horrible is not a license to lie. To me the exaggeration of the event is as wrong as a person falsely claiming that it is less bad than it really is.

It has been claimed that the cesium from the Chernobyl accident causes heart disease in adults and children, the core of the idea is that cesium goes into the heart and that the radioactive cesium then damages the heart. Next the person falls down dead from heart disease or at least becomes in invalid.

We need to ask ourselves if the radioactive cesium is able to damage the heart, some time ago (2008) a Yann Gueguen et. al. published a paper (Cardiovascular Toxicology, 2008, 8(1), 33-40) in which they exposed rats to cesium in their drinking water. The amount of cesium was 150 Bq per day for three months. Now the rats weighed 560 grams, which means that they were drinking 267.85 Bq per kilo. Now if we scale this up to a 75 kilo man then he would have drinking 20 kBq per day. As each year has 365.25 days then this 75 kilo ratman will be drinking 7.338 MBq of cesium each year.

We are making the assumption that the cesium behaviour in rats and humans is the same and that the same dose / activity coefficient should be used for both species.

Based on my ALI as a classified radiation worker which is 1.5 MBq of cesium-137 (oral), the rat man will be drinking 4.9 times the ALI which is based on a 20 mSv dose. So the 75 kilo ratman will get a 97.84 mSv dose from the cesium. So this amount of cesium is a very large amount of cesium.

I hold the view that if a member of the general public is getting a 98 mSv dose from an nuclear accident which happened decades ago that something is deeply wrong. This is a dose which is far in excess of what I am allowed to be exposed to at work. So while this study might be an interesting one it is set at a level of cesium which I think is too high.

I suspect that some differences between rats and humans exist, I have checked and the biological half life of cesium in rats is shorter (11 days) than it is in humans (B. Le Gall et. al., Biochimie, 2006, 88(11), 1837-1841). So rats are able to get rid of cesium from their bodies faster than humans can. The estimates for the biological half life of cesium in humans range from about 1 month to 4 months. If we take the UN’s estimate that biological half life to be 100 days then we can compare rats and humans.

I have done some calculations for rats and humans and based on the difference in the biological half life I think that cesium should be 9.1 times less toxic to a rat than it is to a human. So we should revise down out doses for the “rat man”. If we take this correction factor then the rat man used in this experiment if it had been a human would have had a 10.78 mSv dose (0.8 MBq intake)

Now I think a key part of the reasoning behind “chernobyl heart” is the idea that the cesium goes into the heart, I was looking in the literature at animal studies where the experimental animals were fed cesium-137. I found a second paper (Jean-Marc Bertho et. al., Radiation and Environmental Biophysics, 2010, 49(2), 239-248) where mice were contaminated with cesium-137 (20 kBq per litre) in their drinking water.

This paper stated that human exposure to cesium-137 in contaminated areas is in the range 20 to 2100 Bq per day, which works out as giving a worst case amount of 767 kBq per year. While I think that this amount of cesium is a large amount in the general public’s diet it is well below my ALI (Annual Limit of Intake) and far below the level which I worked out by scaling the rat up to the 75 kilo “rat man”.

The mice were feed the cesium in their diet from the age of four weeks onwards, I looked at the intake of the these mice and the females drank 465 Bq per week and the males drank 507 Bq per week. As the female mice (at 20 weeks) had a weight mass of 23 grams and the male mice had a weight mass of 30 grams we can make a first guess of what human level of exposure we are considering.

The 75 kilo “mouseman” would be getting 1.27 MBq per week while a 65 kilo “mousewoman” would be getting 1.31 MBq of cesium per week. This will work out as 66 MBq per year for the mouseman and 68 MBq per year for the mousewoman. This is a lot of radioactivity.

We are assuming here that the biological half life of cesium in mice is the same as it is in humans and that all other cesium biochemistry and biophysics is the same in both species. Again if we work out the biological half life of cesium in mice it works out being shorter than it is in humans. Using the data from J.M. Llobet et. al., Journal of Environmental Contamination and Toxicology, 1998,61, 289-296 it appears that the biological half life in mice is about 7 days. Thus based on the different biological half-lives the cesium will be 14 times less harmful to mice than men.

So micemen will now be getting an intake of 4.7 MBq per year. This is still a lot of cesium-137 to get in your diet.

Now back to the paper of Bertho, the important thing in this paper is that no clear signs of damage to the mice were seen. Also if you read the paper the radioactive cesium content of the heart (in Bq per gram) is less than the kidneys and the normal muscles of the mice. This paper makes me think that we need to take great care when we consider the possible link between chernboyl cesium and heart disease. This is because the cesium does not seem to be localizing inside the heart in the same way as iodine localizes inside the thyroid.

The next thing to be careful of is the fact that cesium-137 (together with its daughter barium-137m) emits three different forms of radiation. The average beta decay energy of cesium-137 is 188 keV, this is quite a low average beta energy when compared with yttrium-90 (933 keV) and phosphorus-32 (695 keV) but it is about the same as Sr-90 (196 keV). But it is a bit higher than carbon-14 (49 keV). So we can safely assume that some of the beta energy of the cesium which is in the heart will be deposited in the heart.

But 662 keV of the decay energy of the cesium will be in the form of gamma rays, even if the cesium is in the heart then much of this energy will escape from the heart. On average 363 keV of energy will fly away in the form of neutrinos. These are particles which are unlikely to interact with a slab of lead as think as the earth. So I think we are safe to assume that only part of the decay energy of the cesium which is in the heart will be delivered to the heart tissue.

Also bear in mind that the beta and gamma radiation are both low LET (Linear Energy Transfer) radiations. This means that ionization tracks formed by these radiations are long and diffuse, as a result these radiations are less able to damage living tissues. The issue of self repair needs to be considered, the background of radioactivity in a normal human body together with cosmic rays causes all tissue to be subject to ionizing events. The damage from most of these are repaired by the cells.

I think it would be a good idea if those who are making statements supporting the idea that cesium-137 causes cardiac damage to people should address the issues of how much cesium is in the heart and how much of the radioactive decay energy of the cesium is delivered to the heart.

Also they should consider the natural radioactivity (carbon-14 and potassium-40) which is in a normal clean and uncontaminated human body.

Well that is all for now, I will return with more of my thoughts later.

More on the subject of clay and cesium

Dear Reader,

It has come to my attention that only a small fraction of the debris created by the tidal wave in Japan has been disposed of. A report from Japan indicates that only 6 % of the waste has been disposed of, part of the problem it that due to concerns that the debris is radioactive the disposal actions (land filling and incineration) has not been done.

I hold the view that the national government in Japan needs to devise a safe, environmentally acceptable and cheap plan for dealing with the waste. Then it should impose the solution using national law, my worry is that if consent needs to be obtained from each municipality then it is likely that nothing will ever happen. If the Japanese do nothing then after 300 years the waste will be almost totally non radioactive (regardless of the radioactivity in it today) but I do not think that they can wait 300 years for the problem to go away on its own.

I think that the debris should be sorted according to its radioactivity, the debris below 400 Bq per kilo should be treated as non radioactive waste. I hold the view that if the waste is slightly over 400 Bq per kilo but bulk of the additional radioactivity is due to short lived radioisotopes then the waste should be either be allowed to stand for some time before being burnt in a normal incineration plant or it should be land filled.

I think that the contaminated top soil from schools, residential areas and commercial areas (shopping areas) is an important thing to deal with. While in the ideal world it would be best if this decontamination waste was either made to vanish into thin air by a magic genie but in the world we are stuck with someone needs to do something with the soil. While a good quality hazardous waste landfill would be the best place to put contaminated soil, I think that for low level beta active decontamination waste it is better to put it in an ordinary landfill rather than leaving this waste at the site it was dug up from.

If the waste is a lot more than 400 Bq per kilo then it needs to be managed as radioactive waste. One option is to land fill it. The land fill must be equipped with a barrier layer to prevent the radioactivity leaking out of the landfill. If it is cesium then one of the best barrier layers is clay. The cesium will bind to clay, I have found in the literature a crystal structure of a cesium exchanged clay. (D. Gournis, A. Lappas, M. A. Karakassides, D. Többens and A. Moukarika, Phys. Chem. Minerals, 2008, 35, 49-58).

The clay is a layered solid, it has an set of anionic layers of aluminium, oxygen and silicon. These layers are like slices of bread, and the cationic cesium ions go between the slices of “bread” to form layers. I think that the strong binding of clay to cesium will slow the movement of cesium in the barrier layer so that the cesium will decay by the time it escapes from the landfill.

Here is a picture of the clay with the cesium in it. Aluminium is green, oxygen is orange, silicon is purple and the cesium is blue.

 

The clay with cesium cations in it.

 

If the waste is very radioactive then it may be best to put it into drums, add some cement to make the waste into a hard block (less dust and no chance of a liquid spill). The steel drum will then improve the safety of the transport of the waste to the landfill and it will give some decades of additional containment. If the waste is only cesium-137 then assuming that we choose the right drum then it could last for several half lives. A carbon steel is normally passive if it is in contact with cement so we will not get much corrosion on the inside of the drums. If the outside of the drums are painted or better still galvenised then the drums will be very long lasting.

Now whatever the extreme greens say what you need to do is to isolate the waste from humans for a finite time, they hard part is making a choice of how low the threat has to be at the time when you lose the ability to contain the waste. Once the experts work out how much much activity the dump can release per day without breaching the limit then we can work out a design for the land fill.

For example if our release limit is 1 kBq per day and we know that the dump will release 1 % of its contents per year after the barrier has failed. Then if the dump starts with 1 GBq of activity then we can work out how long the dump must contain the waste.

1 kBq per day works out as 365.25 kBq per year.

So if the dump must not start to leak until the total activity is 36525 KBq (or 36.525 MBq).

So the waste must decay by a factor of 27.379 before it starts to leak.

As A = Ao exp -λt

We can work of how long t has to be, if the half life is 1 year, then λ will be 0.693 year^-1

exp -λt must be equal to 0.03652 at the time when leaking can start.

So we start with

exp -λt = 0.03652

-λt = ln (0.03652)

-t = ln (0.03652) / λ

t = ln (0.03652) / -λ = -3.3098 / (-1 x 0.693 year ^-1)

t = -3.3098 / – 0.693 year ^-1 = 4.77 years

So if we can build a waste store which will not leak for five years then we can be sure that not release too much radioactivity per day. I choose a half life of one year to make the maths easy but the same ideas can be used with real waste dumps.

Radiation and your heart

Dear Reader

Well a lot has been written about cardiac damage and radiation, I keep seeing the claim that the Fukushima / chernobyl fallout is giving people heart attacks. I would like to point out that the best evidence I have seen for cardiac damage was in a very special group.

It was women who have been treated with radiation for breast cancer (See Paul McGale et. al. in Radiotherapy and Oncology, 2011, 100(2), 167-175). While Women treated in the left breast have in the past sometimes suffered some cardiac damage while those treated for cancer in the right breast do not get damaged hearts. In the paper I cited the women with left hand breast cancer were getting doses of about 6 Gy while the women with cancer in the right hand breast were getting cardiac doses of about 3 Gy.

This paper suggests to me that the heart can tolerate doses in the 1 Gy range, I think it is impossible for a member of the public in Japan to either get a 1 Gy dose in a year from external gamma rays from the Fukushima event or from internal exposure to cesium.

As a result I think that the cesium radioactivity from the Fukushima event does not pose a threat to the cardiac health of the Japanese population. I think that many of the claims which are made in Japan and the former Soviet union that radioactive cesium is killing people’s hearts are deeply wrong.

While the stress of a nuclear accident might increase the rate of heart attacks and the dire social conditions / diet in some parts of the Ukraine might lead to heart disease I think that rushing to blame every ill on Chernobyl or Fukushima is deeply wrong. It is a childish and stupid response to what is a very real problem which will either do no good or it will do a lot of harm.

One worry is the “worried well” who will divert scant resources away from where they are needed.

Another worry I have is that people will take a view that they are already doomed so then they no longer care about their wellbeing. The UN have made a statement which included some answers to long running and important questions. Which included.

“Q: Did the trauma of rapid relocation cause persistent psychological or mental health problems?

A: Stress symptoms, depression, anxiety and medically unexplained physical symptoms have been reported, including self-perceived poor health. The designation of the affected population as “victims” rather than “survivors” has led them to perceive themselves as helpless, weak and lacking control over their future. This, in turn, has led either to over cautious behavior and exaggerated health concerns, or to reckless conduct, such as consumption of mushrooms, berries and game from areas still designated as highly contaminated, overuse of alcohol and tobacco, and unprotected promiscuous sexual activity.”

My understanding is that if you put a population under dire stress, imagine that me and my friends had been shipped off to deal with the Fukushima then if the stress was not managed then a series of mental health effects might occur as a result of the intense stress.

Person A might turn to drink, by picking up the bottle. He might use the booze to blot out what he perceives as the horrible reality. Ten years later he becomes a drink driver and then he runs down a little old lady / young mum plus pram / a whole line of nuns / (insert some other shock horror outcome for a drunk driver).

Person B might start to smoke again after having abstained from smoking for decades. Now if he assumes he will get lung cancer from radioactive dust he might think what is the harm in having a smoke.

Person C might find solace during the event by having sex with person D. I expect that when C’s wife and D’s husband discover this then C will end up being thrown out of the house by his wife. This wild filng of C and D will be likely to lead to a series of divorces which is a form of social harm.

Person E might start to over eat as a result of the stress of the event, he might even get a taste for puffer fish and then falls down dead when one day in his stressed out state he prepares the fish in the wrong way.

I would like to point out that sometimes a moment of intense stress does have a good effect in a person, for example one lady I know did “see the light”, find religion and she then put her life in order. She has told me that as a result of seeing the light she is a happier person who has a better quality of life. So perhaps person F who had been a heavy drinking nihilistic womanizer might after a week in the highly radioactive environment reexamines his life and then become a good man and a piller of his society. He might then become a priest / monk / good husband / (insert some other good type of man) and then make a positive contribution to society.

This is a good blog entry on risk which you might want to read.

The big earthquake one year on

Dear Reader,

We are coming up to the first anniversary of the Fukushima accident which was provoked by a big earthquake. Now as ever it is important to avoid going to one extreme or another. When we get sick a spoon full of medicine might make us feel better but that fact is not a license to drink the whole bottle in one go !

While I am very strongly in favour of improving safety standards in the nuclear industry and I am sure that some important lessons can be learnt from the Fukushima event, but we should not close down the whole nuclear industry just because of this accident. I always do point out that the burning of coal does release a vast amount of radioactivity into the air.

The majority of radioisotopes from nuclear power plants are short lived beta emitters which tend to go away quickly, the radioactivity in coal tends to be long lived alpha activity. As the alpha emitters tend to be so much more toxic and as they are long lived this is a nasty menace which people tend to forget about. So do not allow anyone to talk you into switching to coal as a way to close down scary looking nuclear plants.

Now on the subject of radioactivity, it is important to bear in mind that wind farms need neodymium for the magnets. The extraction of this metal often requires it to be extracted from monazite which is a radioactive mineral. So before anyone trys to sell you the idea of clean green wind power as an alternative to nuclear power then ask where the neodymium for the magnets comes from. The great problem with “greenness” is that you need to look at the whole life cycle of the object or the system, you also need to look at where the materials required for a device come from as well as what waste the device forms and how you are going to dispose of the device when it is no longer wanted.

I worry that unless the right degree of care is taken with the ore processing that the extraction of the neodymium will create large amounts of radioactive waste which might not be managed in a safe, environmentally sound or reasonable way.

But lets think for a moment about the radioactivity from the Fukushima accident, in common with chernobyl after the short lived iodines the most important radioisotope is Cs-137. This is a medium to long lived isotope which contributes to much of the dose which members of the public will get in the medium and long term after the accident. I saw a paper in the literature by J. Jandl, J. Novosad, J. Francová and H. Procházka, Veterniarni Medicina (Praha), 1989, 34(8), 485 to 490 which is on the subject of cesium removal from deer meat. What these Czech workers did was to pickle meat, by ion exchange the cesium came out of the meat and was lost into the pickling liquid. As only the meat and not the pickling liquid is consumed by humans this offers a method for the decontamination of meat.

The same idea has been written about by some Germans (R. Wahl and E. Kallee) in Nature, 1986, 323, 208. These workers reported that after five days 95 % of the cesium had been lost from the meat. They also reported that the meat tasted very good. So based on this work I would like to suggest that we should consider treating some foods after gathering them to lower their radioactivity content and thus make them fit for human consumption.

Cesium and cardiac effects

Dear Reader,

I am aware that some people from the antinuclear lobby have started to ask the question of “does radioactive cesium damage the heart ?”. I hold the view that in science a question which is testable is a good thing to have. I hold the view that a true scientist tests a hypothesis (fancy term for a theory) in an experiment using a research question.

To my mind the research question which these people who are opposed to nuclear power have raised up is “Does radioactive cesium damage the heart ?”. This is an interesting question but I must warn my readers that very little has been written on the subject. It has been shown in goats by M. Kaikkonen et. al. (Acta Physiologica Scandinavica, 2005, volume 183, pages 321-332) that cesium tends to concentrate in the kidneys (x 50 plasma concentration), urine (x 5 to 28 plasma concentration), salivary gland (x 11 plasma concentration), cardiac muscle (x 7 plasma concentration) and small intestine (x 6 plasma concentration). The fact that the cesium concentration in the urine / kidney is higher than it is in the plasma of the animal suggests that the goats will lose a lot of the free cesium in them via the urine and that it might be a better idea to look for kidney damage in humans who have been exposed to radioactive cesium.

I hold the view that anyone who wants to prove that radioactive cesium damages the heart needs to do the following.

1. Prove that Cs-137 (or Cs-134) in the diet of animals causes some harmful change to the heart, use two groups of animals one fed radioactive cesium and the other group fed no radioactive cesium.

2. Prove that the effect of the radioactive cesium is not due to a toxic effect exerted by normal stable cesium. I know that a sudden change in the plasma concentration of potassium will cause a heart attack in humans. Part of the lethal injection which the americans use to kill convicts is an injection of potassium chloride. So as potassium cations have an effect we can not rule out that cesium will have an effect.

3. Prove that the effects of internal exposure to radioactive cesium is more harmful to the hearts of the experimental animals than external exposure to the gamma rays from cesium-137. I am sure that at very high doses of external gamma rays that it is possible to damage the heart (or any other organ for that matter).

But lets think about point two for a moment, stable cesium has been used for some time in some alternative cancer treatments. Petr Melnikov and Lourdes Zélia Zanoni have written a review paper on the subject of the toxic effects of stable cesium. This paper had the title “Clinical Effects of Cesium Intake” and was published in Biological Trace Element Research (2010, volume 135, pages 1 to 9). The authors of the paper state that cesium salts do not cure cancer, they also do warn that large amounts of (nonradioactive) cesium salts do cause the heart to behave in an abnormal way. I would like to suggest that anyone considering treating themselves for radioactive cesium contamination should not try to flush the radioactive cesium out of them with stable cesium, instead I would suggest that you use prussian blue to greatly increase the rate at which cesium is lost from the gut.

A friend of mine used to work on cesium in farmyard animals, the work done years ago indicates that small doses of cesium in the diet do not work well as a means of flushing out the cesium from pigs. So if it fails to work on pigs then the use of stable cesium in humans is unlikely to work.