Monday, 26 September 2016

What do our Graduates do now?

The graduates at CCFE go on to do some amazing things. This post is a catch up with some of our graduates to see what they've got up to after finishing the CCFE Graduate Scheme.

Sarah Medley
Physicist – I studied physics at university, but I’m now becoming increasingly interested in the engineering side of things!

What year did you finish the graduate scheme?

What’s your current role?
I’m a Tritium Plant Engineer in the Tritium Engineering and Science Group at CCFE. We operate the tritium plant to provide JET with the tritium fuel it needs for fusion experiments, and we also undertake scientific research using tritium.

What are you currently working on?
I’m currently working on a range of different projects, including upgrading some of the tritium plant systems in preparation for the next set of deuterium-tritium experiments at JET, and developing a small experimental facility to investigate the interaction of tritium with fusion-relevant materials.

What’s the most interesting project you’ve worked on so far and why was it interesting?
I’m happy to say that all the projects I’ve worked on so far at CCFE have been interesting, because they have involved learning so many new things!

What advice would you give the fresh-faced, younger version of yourself before starting university (if any!)

I would say don’t be afraid of doing things wrong or making mistakes, as the best way to develop yourself is to go outside your comfort zone!

Ant Shaw
(Picture: Ant Shaw (left) and Alex Meakins (right) presenting the JET Data Dasboard)
Studied physics at university

What year did you finish the graduate scheme?

What’s your current role?
Software engineer with the data and coding group

What are you currently working on?
A number of projects, with the largest 2 being the JET Data Dashboard (a web-based interface for searching and browsing through JET session and pulse data) and the CPF (Central Physics File) System (a high-level database with a small subset of important data for each pulse, allowing more easy data analysis over large numbers of different pulses).

What’s the most interesting project you’ve worked on so far and why was it interesting?
Can I pick 2?
-          Analysing the effects of Resonant Magnetic Perturbations using MAST Doppler Back-Scattering. I was essentially given raw diagnostic data, and had to apply everything I knew of the physics of the situation and data analysis techniques to produce the end results.
-          Creating the JET Data Dashboard. Building a tool which I wanted to use was very satisfying, and I had to learn an awful lot to even start the project, which was very interesting.

What advice would you give the fresh-faced, younger version of yourself before starting university (if any!)
Take any physics-based work you can get, especially talking to academics at your university for summer projects. Also get familiar with computer programming as a concept and with a little practical experience. Regardless of where you end up as a physicist, you will be programming at some point as data analysis is much easier than with a pen and paper!

Matti Coleman
Mechanical engineering with renewable energy (MEng) – University of Edinburgh

What year did you finish the graduate scheme?

What’s your current role?
DEMO Design Integration and Project Coordination Officer at EUROfusion

What are you currently working on?
For the past year and a half I have been on a secondment based near Munich, Germany, at the Power Plant Physics & Technology Department in EUROfusion, coordinating research and design activities on the European demonstrational fusion reactor known as DEMO. I liaise with researchers across Europe, chiefly concerning remote maintenance and superconducting magnets, for which I am responsible. I also design parts of DEMO and coordinate design and analysis tasks on DEMO reactor integration issues, which can incorporate a wide range of topics, such as neutronics, electromagnetic loads, remote maintainability, thermohydraulic efficiency, and structural integrity.

What’s the most interesting project you’ve worked on so far and why was it interesting?
Tough question! I’ve been lucky enough to work on several very interesting projects whilst at UKAEA, including DEMO Remote Maintenance, building the UK’s own MAST Upgrade reactor, the Table Top Plasma, AMAZE, and now DEMO once again. It comes down to personal preference of course, and I have always been more inclined to work at the conceptual level, so for me working on DEMO has been the most interesting. I love coming up with ideas and working with only a few fixed boundary conditions; I enjoy being able to turn the whole design on its head with a simple “what if..?” question. Working on DEMO has that element to it and, as we are designing an entire reactor, it also encompasses all of the tokamak engineering design fields, most of which come up on a daily basis – so I get a little of everything!

What advice would you give the fresh-faced, younger version of yourself before starting university (if any!)
Try to combine doing something you love with making a difference.

Wednesday, 6 July 2016

JExiT: How do our young engineers and scientists feel about Brexit? And how might it affect the UK fusion program?

Disclaimer: This blog post is not representative of the opinions of UKAEA but are merely the opinions of some of the people who work here. There are some generalisations which I freely admit are just that! If this post offends you in any way then that was not my intention (unless you’re Michael Gove).

Thursday’s vote has cast a shadow over Culham in Oxfordshire; the site where the “Joint” European Torus (JET) is based. It replicates the process that powers the sun, nuclear fusion. We are a world leading laboratory and possess knowledge about operating and maintaining a fusion reactor that exists nowhere else.

Fusion is too big a problem for any one nation to solve in isolation. It requires a diverse range of scientific, technical and engineering knowledge, as well as manufacturing capability and political will. Commercial fusion energy is a technology which has potentially profound social ramifications; it could revolutionise global energy security increasing quality of life, reduce wars fought over border disputes and drilling rights and increase our knowledge and capability. The development cycle is long and difficult. Wars come and go, governments and countries rise and fall, biodiversity plummets and greenhouse emissions ramp up and all the time fusion development and international collaboration continues to narrow in on our goal, as it has since the 1950s.

JET is the largest magnetically confined fusion device capable of running the fuel mix required for a commercial reactor (Deuterium-Tritium). It is a key device on the fusion roadmap and essential to inform the design and operation of its successor, ITER, currently under construction across the channel in France. Funding for the operation of JET has been secured until 2018. Negotiations will take place to extend this until at least 2020. With ITER not expected to be in an operational state before at least 2025, vital skills and expertise will be lost unless an extension is secured. The majority of work on site is funded through Euratom, part of the Horizon 2020 framework which is ultimately paid for through our EU membership. It may be possible to become a non-EU member (as Switzerland is). At best, this will cost us as much as before and we will have the same privileges as we currently do, with the condition of free movement of people. Again, that's the best case. So what about UK funding? Well, post-Brexit Britain may be headed for a recession. We'll be waiting to see what happens in the coming months and have our fingers crossed that big science projects continue in the UK

JET is not the only project we manage on site, but it is a marvel of European collaboration.

Ramifications for people
What of the individuals who work at Culham and of the wider scientific community?
A poll from Nature published last month showed that 83% of UK researchers backed remain with 5% unsure and 12% backing Brexit. Of those intending to cast a vote, 78% predicted that Britain leaving the EU would harm UK science, 9% thought it would benefit science. Another poll commissioned for the previous general election showed that scientists are in general left leaning which from personal experience does not surprise me, especially in the younger generation.

So what reaction has there been from our graduates?
Soon after the result, after the initial anger and shock most tried to see the funny side. One instance was taking a quiz to determine “Which EU country you should move to”.
I got Iceland (which isn’t in the EU but is part of the single market). I don’t think it has a particularly thriving fusion program but it does have hot springs, volcanoes and most importantly… Björk! (and are better than England at kicking a ball around). Following this more earnest discussion began. I asked some of our graduates how they felt about the result and if they would consider a move abroad. I have attempted to summarise their responses below:

How did you feel on hearing the result?
Shock, anger and sadness. The feeling that politicians are just in it for themselves and that some of the british public fell for their lies (I accept that people on both sides had many different reasons for voting). There was also the feeling that there are clearly vast social and political divisions within the country and that the EU was failing to connect with many British citizens effectively.

Would you consider moving country, where and why?
Everyone I asked said they would consider or actively are considering it. The most popular destinations were France or Germany (because of the Fusion programs and ITER), Switzerland (because of CERN) or Canada. Scotland and Scandinavian countries also proved popular. I think their reasons for leaving the country were broadly similar:

  1. They want to live in a progressive society, at the forefront of scientific/technological and social advancement.
  2. They don’t want to live in a country that they now perceive to be irrational, intolerant and harking back to a bygone era that never really existed.
  3. General uncertainty which will hopefully subside if anyone decides to take responsibility and start sorting this mess out.

One graduate summed it up succinctly: “Europe. I voted with my ballot paper, so I might as well now vote with my feet”. Unfortunately with the changes that will come into force leaving to start fresh in the EU may become more difficult for those without dual nationality.

What you think the outlook for Culham is?
Most agree that nothing will change in the immediate future and that JET will be granted the extension it needs. However there are fears that the fusion program here will be used as a political bargaining chip. Even if we get some access to the Horizon 2020 and the future framework we will not be allowed to lead (any access would almost certainly require signing up to free movement of people just as Switzerland has). The chances of the UK becoming a DEMO design centre are much lower now (EU-DEMO is the first demonstration commercial EU fusion reactor scheduled for the 2040s; the UK is simply too small to fund a UK-DEMO without unprecedented peacetime political will). With all the non-JET contracts we are involved in (ITER, DEMO, ESS) the UK now has far less leverage and bargaining power and will have to rely on our expertise, which are exemplary in these fields, but not necessarily/always unique.

Now that the dust has begun to settle how do you feel about the future?
Uncertain. Especially in the mid-long term it is felt that we as a country will miss out. We will still be a global player in science, technology, engineering, finance etc. but diminished. Future generations will have to suffer the consequences of a poorer, less diverse Britain. The obvious social divisions within the country are also a real worry to many. Practical things like buying a house will probably be more difficult on the whole. Prices will drop (or not go up quite as fast), but mortgage interest rates look set to go up and it may become financially unviable (or at least even less attractive) for young scientists and engineers to put down roots in Oxfordshire with austerity set to continue.

How has this changed your view of Britain and the British?
Many of us who consider ourselves British (or former-European) were angry with our country for allowing this to happen. But it’s not right to blame the British people. There were clearly many reasons people voted on both sides and if anything this should be a wakeup call to prevent this political trend of misinformation and anti-intellectualism from continuing (I’m looking at you Michael Gove). This is also a wake-up call for Europe as it is clear that the EU has failed to connect effectively with some areas of society. Those of us from elsewhere in Europe were saddened and felt like they were not welcome in the country they have been proud to call home. We are also worried about the far-right feeling vindicated opening a door to xenophobia and racism throughout the EU.

We are also lucky to have a large number of European engineers, scientists permanently based on site as well as visiting scientists from various EU institutions. How have they been affected? I asked my French colleague Alexandrine Kantor (@Alexa_Kantor), an electrical design engineer, how she felt, I’ve summarised her heartfelt response below:

"I am a proud French citizen by birth with multiple East European backgrounds, but my heart has belonged to the UK since I arrived in October 2013. When I woke up on Friday, my first feelings were a mix of sadness, anger and disappointment. It is hard to describe but I really felt, and still feel, unwanted. A heartbreaking pain, like the end of a relationship. The UK/Britons just turned their backs on me.
One of the popular reason to vote LEAVE was for immigration. We are hard-working. Some, less qualified, take the jobs that native Britons don't want. With all these jobs, we pay taxes, a lot of taxes. And with those taxes, we help the people in need. Yes, we help other migrants, but also Britons in need.
On a personal note, I have a great job that I am afraid to lose, I am also afraid to lose my eligibility to work in France.  This may be unlikely, but the fact is; no one knows. So yes, unwanted, heartbroken, insecure are my three words to describe how I have felt since The EU referendum.
But my life is in the UK which is now my home, and I truly have faith on the British people to find a solution to rise up stronger from this political and social crisis. "

Alex then went off to the pub to support England in their match against Iceland…

Luckily for us on Culham site, the European fusion program and ITER needs JET. Therefore it is very unlikely that we will down tools at the end of the funding cycle in 2018. That is as long as the British government and EU has enough sense not to throw away a world class facility with unique knowledge and expertise; to quote CEO Steve Cowley “the logic is there”... unfortunately logic gives me scant solace where politicians are concerned…

The question is not whether this lab will continue to some extent over the next decade (it will) - It is whether or not we will be a world leader or merely a participant.

Politicians can make it difficult for the scientific community but we must not turn our backs on each other. We must reach out and continue to collaborate wherever possible because every piece of the puzzle is important. Together we can realise commercial fusion energy. I only hope through this period of uncertainty we and the remnants of the United Kingdom of Great Britain and Northern Ireland don’t get left behind ...If they do; there’s always Iceland.


Thursday, 9 June 2016

A Day in the Life of an Apprentice

A typical day as an apprentice at Culham varies from place to place, as each department is very different. As a mechanical engineering apprentice, I visit many different and fascinating departments with the site, each offering new skills and technologies to learn. My current placement is with the new Materials Research Facility, configuring their microscopes to inspect small samples remotely as they will be in a hot cell.

Usually, my day consists of taking precision measurements from inside of the radioactive hot cell to continue with my project modelling. I use this to make a 3D representation of the microscopes using Computer Aided Drawing.

Being part of a large organisation means that we have several other apprentices on site to meet up with to discuss the different exciting projects we are carrying out. We have a great sense of community and often get involved in extra projects together.

As an apprentice, it’s important to spread the message that apprenticeships are not a second choice or for the less academic. Many of the outreach activities we carry out in schools and at events emphasize the fact that there are apprenticeships available for every level in almost every job you can imagine. It is important to show young people what they are capable of and running small workshops can be really effective in giving them that first step. We also invite schools to our site to conduct tours of the JET facility to show them the science and engineering behind fusion reactors to inspire them.

Being in an engineering environment can often mean I’m in a male dominated department, which can sound daunting to younger females entering the industry; however, my colleagues and supervisors are all extremely helpful and friendly and treat me no differently from anyone else. It encourages and motivates me to work hard to show that I am capable of doing the same tasks as any other employee on site.

Women are becoming more present in engineering and technician jobs, especially on Culham site, and we often support each other and share our experiences. Culham was awarded the Bronze Athena Swan award to recognise the efforts to improve gender equality.

Every day at work is different and can have unexpected problems which means there’s always an exciting challenge around the corner. Engineering is always growing and developing, which means there will always be something new to learn and get involved with on site.

Monday, 30 May 2016

Culham's great for more than just fusion!

CCFE (or the UK Atomic Energy Authority, I should say) has been earned a reputation for world class fusion research over the years, but there’s more than just materials science and neutral beams to convince people to join us. We’ve got a fantastic apprenticeship scheme which has been running for years, and now our apprentices are in the runnings for the title of Apprentice Team of the Year, a national competition in which the Culham Graduates have already been named the regional title (for London and the South East).

The Brathay Apprentice challenge is being held by the Brathay Trust and the final is on the 15th of June, when our apprentices will be testing their mettle against 7 other distinguished teams of apprentices.

This isn’t the first time the Culham Apprentices have seen national awards, either. Earlier this month, 4 apprentices won national awards, recognising their work and achievements at the 2016 Engineering Trust Awards.

The final stage of the competition will take place at the Brathay Trust in Windermere, Cumbria, and will involve team building and logistical challenges. 

The teams through to the final have all contributed to raising the profile of engineering and STEM in the UK, recruiting 300 businesses to begin offering apprenticeships and presenting to young people to encourage engineering.

As a result of the efforts of these teams, more young people are being encouraged and enabled to find a bright start in engineering. As someone both working in engineering and keen on science communication, it’s fantastic to see the positive impact that our apprentices are making.

Congratulations to our apprentices on their achievements and good luck in the upcoming finale!

Top: Culham Apprentices
Right: Back Row - Tom Cox, Sam Tokelove, Dave Godden, Jake Payne and Peter Blowfield; Front row – Matt Sayer, Elliot Taylor, Emily Swatton, and Joe Woodley

Thursday, 17 March 2016


By Alex Davies

I am part of the Graduate Scheme at CCFE (Culham Centre for Fusion Energy). CCFE operates JET (Joint European torus), which is the largest tokamak, or magnetic ‘star bottle’ in the world, and MAST (Mega Amp Spherical Tokamak), which is like JET but with different geometry.

Figure 1: The Joint European Torus

One of the goals of the Graduate Scheme is to communicate to the outside world about fusion energy and the work that is ongoing at CCFE (hence this blog). Something close to my heart is supporting science lessons in the school in a gender inclusive way. So it wasn’t too much of a leap to know that I wanted to volunteer with a CCFE outreach program called the Sun Dome.
Figure 2: Freeze-frame of footage from the Sun Dome Movie - opening clip

The Sun Dome is essentially a prop. A big, inflatable prop, that is somewhere between pretending to be a star and pretending to be a cinema. Bear with me on this!

In years 5 & 6 at primary school, most students will have learned vaguely about what stars and planets are. A few may have heard the word ‘atoms,’ and a small number might even be able to tell me that atoms are small and make up everything. (Occasional brainboxes go on to talk about electrons, protons and neutrons. Once I even heard the word quark!) But learning this in a classroom is one thing, seeing it in front of you as you float through the Universe is another.

The Sun Dome is a projector inside a big inflatable dome that shows science movies about nuclear fusion. As we lie down watching the movies, we journey into stars and watch Hydrogen atoms fuse into Helium atoms, and then we see the same process happen inside a computer animation of JET. It’s all very exciting!

Figure 3: Sun Dome from the outside

The Sun Dome has a specific format, with 4 parts:
1. Introduction
2. First movie
3. Game
4. Second movie


This is where you tell them about atoms, and how atoms make all solid, liquid and gaseous matter in the universe. You ask the pupils to pretend to be atoms in a solid, by sitting as close to their neighbours as possible with their arms around their neighbours. Then they might name solid things such as brick, floor, window etc. Then they are asked to be atoms in a liquid and they spread away from their neighbours, but always within arm’s reach of at least one other person. They can name milk, washing up liquid and water. Then you ask them to be atoms in a gas by standing up and finding a space as far away from anyone else as possible. They can name air, steam and sometimes Oxygen and Carbon Dioxide, with reference to how humans and plants need these to live respectively.

Afterwards you tell them that the Sun is a ‘hot gas’ with a core temperature of 15 million C. Reactions to this vary from absent-mindedly staring at the floor while toying with their shoelaces to gasps of shock and awe.

You talk about how two Hydrogen atoms in the core of the Sun are moving so fast that they can collide and become a Helium atom – in a bit of a hand wavy sort of way. And when this Fusion Reaction happens it gives off an explosion of energy.

I am very aware of how this is an extremely hand wavy description; but honestly, the point isn’t to turn them all into plasma physicists. The point is to make them aware of fusion and enthusiastic about science. 

First Movie

When you tell them that inside the Sun Dome is a projector that is going to show them movies about the Universe the reaction is nearly always one of excitement. Who doesn’t like going to the movies, right? Then you tell them no popcorn is allowed and no whispering and they always groan ‘Nooooo’ with massive grins on their faces.

Inside the Sun Dome they are told to find a space on the floor and look up at the ceiling as a short movie describes how stars live in galaxies, and how the Sun was created, and how Hydrogen atoms in the Sun move and fuse into Helium.

Figure 4: Freeze-frame of footage from the Sun Dome Movie - the Sun


Then it’s time to play a game. It helps keep the students focussed if we break up the movies with a game in the middle. The objective of the game is to get the students moving around the hall as if they were Hydrogen atoms in the Sun. 

On the Surface of the Sun it is cooler, so they walk slowly. As we journey closer to the centre of the Sun it gets hotter and hotter, and the students run faster and faster to replicate this. Then, when you shout ‘FUSION’ they have to find a partner and collide with them to produce a Helium atom.

Often, at this point, I ask them ‘Are you all worn out, now?’ to which the answer is invariably ‘NO!’ Which prompts us to do the whole thing over again, and the chaos continues.

Second Movie

Afterwards we have one more movie to show, so the students all return inside the Sun Dome. This movie focusses on the Science and Engineering that CCFE does, when we use our tokamaks. There are clips of JET and MAST during a pulse, and I narrate that MAST can reach the same temperature as the core of the Sun (15 million C), but JET can reach ten times hotter than that. We talk about how our remote handling system, MASCOT, helps maintain and repair the inside of JET when it isn’t pulsing.

Figure 5: Freeze-frame of footage from the Sun Dome Movie - MASCOT making repairs to JET

Then we talk about the future. The plan is to build ITER (the International Thermonuclear Experimental Reactor) to investigate materials that a tokamak should be made out of amongst other things, and DEMO (Demonstration Power Plant) as a future fusion power plant. By this age, most pupils know about fossil fuels and that they are bad for the environment. Some will have heard about greenhouse gasses, and there is a vague awareness of needing to build a power plant that doesn’t pollute.

Figure 6: Children watching the Movie

At the end there is time for questions. Not all students will have a question to ask, but occasionally they do. Usually they want to know if a tokamak will explode if its goes wrong– the answer is no! All of the engineering for fusion goes into making the reaction happen. In contrast to nuclear fission, where all of the engineering goes into slowing the reaction down. If something were to interrupt the systems that let JET function, then the reaction would just stop – which we call a disruption.

Once I had a pupil ask if we had heard of Adamantium – the material that Wolverine’s skeleton and claws are made from. If we made our tokamaks from that then we wouldn’t have any problems with melting, because it’s the best material in the world. We said that we would let our material scientists know!

I love that I work for a company that lets me communicate science to students! As a female engineer and physicist, I am aware that it is very easy to opt out of science due to peer pressure. Giving all students an enthusiasm for science early in their education is so important.

Figure 7: Letters from children who have seen the Sun Dome.

When you get feedback like this it’s easy to see that you’re making an impact. The Sun Dome is so useful to getting the next generation of scientists and engineers enthusiastic! After all, once JET is being decommissioned, we are going to need people from the next generation to run ITER and DEMO. Big science projects like these last generations, and the knowledge that is learnt creates a legacy for future scientists and engineers to build upon. This is why science communication is so important. This is why I volunteer at the Sun Dome.

Tuesday, 1 March 2016

Graduate Intake!

Some new graduates have joined us at Culham, ready for two years of  trials and tribulations (not really) of the graduate scheme. As is becoming standard, they've been asked silly questions and had their photographs taken for the world to see!

From the left, we have...

Jonathan Horne  University of Cambridge, MEng Aerospace and Aerothermal Engineering
Department  RACE (Remote Applications in Challenging Environments
Which movie do you want to live in?  Back to the Future – for the wealth of possibilities!
Favourite cheese  Stilton (sorry about the smell)
Hopes for the graduate scheme  To get loads of experience of the world of work and to contribute to the progress towards fusion energy.


Luke Jones  University of Birmingham - MEng Nuclear Engineering
Department  Diagnostic & Fusion Engineering Group
Which movie do you want to live in?   If you’re going to live in a movie then it has to be one with Arnie! I’d go for Last Action Hero
Favourite cheese  Personally I think the true quality of a good cheese is one that comes in a plastic wrapper. Or cheese-cake if that counts?
Hopes for the graduate scheme  My hope for the graduate scheme is to survive. It’s like the Hunger Games, right? Only one can survive and succeed? Maybe this is why fusion is always twenty years away…

Leon Knight  University of the West of England, BEng hons Electrical/Electronic degree 
Department  Power Supplies and RF Heating, working within the ICRH (Ion Cyclotron Resonance Heating) group
Which movie do you want to live in?  How to Train your Dragon, so I can train my own dragon to keep the neighbour’s cat out of my garden.
Favourite cheese  Austrian smoked cheese
Hopes for the graduate scheme  To further develop myself as an engineer whilst progressing the development of fusion energy.


Ross Mckean University of the West of England (Bristol UWE), BEng (Hons) Electrical & Electronic Engineering
Department  Tokamak & Neutral Beam Dept, Pellet section
Which movie do you want to live in?  Definitely Iron Man or the Avengers universe, apart from all the war and destruction being Iron Man or even working at Stark Industries would be amazing.
Favourite cheese  Baked Camembert
Hopes for the graduate scheme  Working on some interesting projects, gaining valuable experience and helping to progress fusion
Thanks for reading! Lastly, we have a silly photo!

Tuesday, 19 January 2016

Radiation and Nuclear Safety

by Samuel Ha

I’ve recently noticed a lot of negative news articles about the dangers of nuclear power and I have some points I’d like to raise to counter these arguments. The advances in nuclear power plants over the decades is something that is rarely mentioned and is very relevant to us here in the UK, as it looks ever more likely that we will have newly built nuclear power plants at sites like Hinkley Point and Sizewell.

Over the years, rigorous safety systems have been added to old reactors and the designs of new reactors have included inherent safety features, but public perception of nuclear power still harks to the disasters of Fukushima and Chernobyl (plants designed in the 1960s). If new designs have inherent safety features and are still received as though they didn’t have them, then we need to address the fear of a nuclear accident.

The points I’m going to make in this post are about how the dangers of nuclear power are perceived.

Fukushima and the Consequences

On the off chance that you didn't know, Japan was struck by an earthquake in March 2011 that measured 9.0 on the Richter scale. This led to a tsunami that left only devastation in its wake.

Nearby were the Fukushima Daiichi reactors (Boiling water reactors (BWR) operated by Tokyo Electric Power Company, or Tepco, and supplied by Toshiba and Hitachi) [1]. Upon notification of the nearby earthquake, the reactors had control rods inserted into the core (they were turned off, in other words) and emergency cooling systems were initiated. These comprise four diesel generator driven pumps. Four, to make sure that the failure of an individual pump doesn’t present a danger.

When the tsunami arrived at the reactor sites, the waves breached the 12m sea walls and flooded the basement.
It is necessary, at this point, to say that the diesel generators were stored in the basement. All four.

After the basement was flooded, emergency cooling to the reactor stopped. But what's the issue? The nuclear reactions have stopped, thanks to the control rods! However, fuel pins contain a substantial amount of fission products after a sufficient amount of time in operation. The power given off in the decay of fission products can be as much as 7% of the total thermal power, and without active cooling, the reactor cores began to heat.

Once the core of the reactor heats up enough without active cooling, interesting things can happen. The ceramic fuel pins can melt and release fission products at an elevated rate, but more importantly, zirconium cladding (the kind used in many Light Water Reactors) can react with water. This reaction has two important outcomes: production of hydrogen and increased pressure in the pressure vessel.

In the case of multiple Fukushima Daiichi reactors, it was assumed that the pressure build up that was observed was from steam produced from the heated water, so they vented the gas into the containment buildings, not realising the gas was actually hydrogen. This was a catastrophic mistake that led to the damage of containment buildings, as the vented hydrogen gas exploded.

It was this breach of the confinement building that led to the spread of radioactive matter into the surrounding areas.
Caesium-137 and Iodine-131 are two fission products that pose some of the largest risks for humans. Iodine-131 has a half-life of approximately 8 days, while Caesium-137 has a half-life of about 30 years. Caesium, a toxic substance can be absorbed and can replace potassium in the body. Iodine is an element that is readily absorbed into the thyroid.
For anyone that’s interested, a very useful map has been created that shows radiation measurements from across Japan. It shows how much damaging radiation you would absorb if you were in different locations across Japan.

Another issue is the release of contaminated water into the Pacific Ocean from the reactor sites. There are reports of fish being caught in the Pacific testing positive for Caesium-137, above the allowable limit of 100Bq/kg.

You may be thinking “How dangerous is it that these fish have such high levels of radiation?” I’ll cover that in a few paragraphs.


So what has this talk about Fukushima got to do with nuclear fusion? Well, fusion energy uses two isotopes of hydrogen: deuterium and tritium. Deuterium has one proton and one neutron, and is stable, whereas tritium has one proton and two neutrons, and is unstable.

Tritium has a half-life of 12.3 years and undergoes beta decay (the emission of an electron) with an average energy of 5.7keV. Since tritium is an isotope of hydrogen, it behaves almost identically to hydrogen and is readily absorbed into water and into organic tissue (e.g. humans). However, it is also very easily removed from the body.

In June 2007, Greenpeace released a report about the hazards of tritium, highlighting the seemingly alarming levels of tritium released into the Canadian environment.
And the numbers do not seem to bode well for the Canadians:


Just look at all of those enormous numbers! MILLIONS OF TERABECQUERELS!
But what’s a terabecquerel? Or even a Becquerel?
Tera is the prefix for 1012. So in Canada, over 20,000,000,000,000,000,000 Becquerels of tritium were released in one year over 6 sites. That does sound a lot, right…? The reader is definitely inclined to believe that this much radiation being released is unacceptable, and quotes a rule of thumb that anything ‘greater than 100,000 Bqs would trigger the need for some kind of action or investigation’
Well here is where it’s important to know what a Becquerel, as a unit of measurement, is. One Becquerel is equal to one radioactive decay process in one second, and is commonly referred to as a unit of radioactivity or ‘activity’ and attached to some quantity (such as 100Bq/kg, the activity level for Caesium-137 in fish).

However, before we can know what this means, and  how much danger our beloved Canucks are in, we need some more information. We know how much tritium was released, but we don’t know how much has reached any people. Luckily these numbers have been evaluated for anybody waiting with their trusty calculator, and are shown below. The following table shows the content of radioactive tritium in water and organic molecules, at different distances from a Canadian CANDU  nuclear power plant. The numbers are taken from a Greenpeace report [4] and reproduced here. For the keen beans out there, HTO is water in tritium (Hydrogen-Tritium-Oxygen) and OBT is tritium in organic matter (Organically Bound Tritium)

So now we have all the information that is needed to see what the resulting risk is of tritium actually is, which is also provided in the Greenpeace report: someone who lives within 2km of a nuclear power plant and only eats food grown in their garden will receive 20 micro Sieverts (μSv) per year.
Wait (I hear you say), now we’re using Sieverts? I thought that Becquerels were how we were doing this? What is this new unit that has been thrown at me? What does THIS MEAN?!

The Sievert is a unit used to describe radiation exposure to people and is the real decider for how dangerous exposure to radioactivity is. Not Becquerels, not Grays, not Curies and not Roentgen.

The international rules on radiation exposure for radiation workers (IRR99) states that no qualified radiation worker shall receive more than 20 milli Sieverts (mSv) in one year (that is equal to 20,000 microSieverts – 1,000 times more than is quoted above for Canada). Members of the public should receive no more than 1mSv (1000 microSieverts) from any nuclear activities or events in the UK (if a nuclear power plant were to release something radioactive to the environment, for instance).

To put this into perspective, a resident of the UK will receive an average of 2.2mSv per year, almost all coming from from natural sources, although this varies based on where you live.
Here’s a table of doses I’ve compiled for your reading pleasure!

Notably, the World Health Organisation announced that they that no deaths or cancer cases were directly attributable to Fukushima [6], including the member of staff who received an enormous dose of 678mSv. Since that report was published, the Japanese government has said that one case of cancer may be attributed to the disaster, and has received compensation. This worker received a dose of 19.8 milliSieverts over a year – which is still below the international limit. To put this into perspective, Greenpeace are concerned that a member of the public living next to a nuclear plant may receive 0.02mSv.
Notice the entry about Pacific Tuna? A radioactivity of 200Bq/kg puts these fish at twice the legal limit for radioactive caesium content. But how dangerous is it to eat this fish?

If you were to take a flight from London to Tokyo and eat five 120g tins of this tuna every day for a week and fly home, your dose from flying would be at least 300% higher than what you’d get from eating the highly radioactive tuna. On top of that, the dose you absorb from the tuna would be spread out over years. [10]

Ask yourselves: Would you be scared of eating radioactive fish from the coast of Japan?
How about the radiation dose you receive from flying? You shouldn’t be scared of either.

Better Safe than Sorry?

That’s been the gist of radiation protection since the risks were understood. Be cautious, not optimistic. Be careful and you’ll save more lives.

A piece in World Nuclear News evaluated the evacuation of Fukushima (standard procedure after any nuclear incident) and argued that the obsession with reducing the risk of radiation exposure has missed the forest for the trees; that by displacing so many people with evacuations we endanger those we wish to protect. The stress and panic that is caused by evacuation causes far more deaths than the radiation dose would.
A summary given by the World Nuclear Association [9] puts it very well:
Many evacuated people remain unable to fully return home due to government-mandated restrictions based on conservative radiation exposure criteria. However, over 1000 premature deaths have been caused by maintaining the evacuation beyond a prudent week or so. Decontamination work is proceeding while radiation levels decline naturally. The October 2013 IAEA report makes it clear that many evacuees should be allowed to return home.”

Don’t Panic

If there’s one point I have in this entire rant, it would be Do Not Panic when media outlets raise their collective voices about radiation. There is a plethora of information that describes harmless radiation, which can be used in a way to make it seem no less dangerous than the grim reaper himself, and how to work out how dangerous radiation is, is not easy.

It’s hard not to believe everything that is written in the media, and to know what counts as a reliable source. However, as soon as you hear the term Sieverts, make sure you compare the numbers with the table above, to see how much that really is. The misinformation spread about the harm that radiation, and in turn nuclear energy, does to us isn’t helped by the approach of many governments, to try to eliminate exposure to radiation at the expense of absolutely everything else, even reliable energy sources. There will be a ‘sweet spot’ for how much we should limit radiation, at the expense of useful technologies. I can’t say where that is, but I can say that it’s treated far too dangerously by the media and should be re-evaluated by governments, because losing over a thousand people through the after effects of evacuation shouldn’t be seen as the better alternative.


[1] TEPCO report on core damage of units 1, 2 and 3 – (Referenced on 12/04/15).
[2] Radiation map of Japan - (Referenced on 12/04/15).
[3] Greenpeace report on the hazards of tritium, prepared by Dr. Ian Fairlie -
[4] Review of Dr. Ian Fairlie’s report by R. V. Osborne -
[5] IRR99 -
[6] World Health Organisation report on the Health Risk Assessment carried out after the nuclear accident at Fukushima -
[7] UK Radiation exposure -
[8] Malcolm Grimston, “What was deadly at Fukushima?” -
 [9] World Nuclear Association quote -
[10] CDC Toxicity Profiles: Caesium-137 -