Hello! My name is Asad and I’m a
PhD student at the School of Mechanical, Aerospace and Civil Engineering at the
University of Manchester. Within my PhD, I work in the relatively recent field
of nuclear fusion. More specifically, I look at the effects of plasma damage
and neutron irradiation (both known phenomenon that occur within nuclear
fusion) on materials that could be used to build a potential fusion reactor.
A little bit about my background
first. Before I embarked on my PhD, I completed a Master of Engineering (MEng)
in Mechanical Engineering with a minor focus on Nuclear Engineering. I also did
some part time study in mathematics and research projects within fluid
mechanics. Of the latter, a noteworthy one is that I constructed a mathematical
model of the acoustics of a banjo!
Science has always intrigued
mankind. Some of the foremost questions we have been obsessed with are the
“Where did we come from?”
“Why are we here?”
“What do we do?”
No matter who you ask, you will
realise that we still don’t really know the answers to these; whether we look
for philosophical reasoning or scientific. We search high and low for answers.
Our universe is at the centre of such research. And at the centre of our
universe: the sun.
The sun can be considered a giant
ball of energy. The manner in which this energy is generated is referred to as
nuclear fusion. As the human species observed this, we felt the urge to exploit
the process to aid our need for energy, in order to survive on a world where
resources are rapidly depleting.
What exactly is nuclear fusion?
The answer is a result of work done by pioneering scientists such as Ernest
Rutherford, Pierre Curie and Marie Curie. We find that certain atoms of
elements undergo interesting transitions. We have been able to exploit these,
such as nuclear fission which is currently a dominant process to generate
electricity. Within fission, we find that under the right conditions, some of
the atoms will split and become smaller releasing energy in the process. Fusion
is the opposite; some atoms combine and through the process release energy. It
has been found that the energy released through fusion could potentially be
more sustainable, cleaner, and less fraught with the risks associated with the
energy generated through fission.
Thus we are now engaged in a
global technological race to be able to achieve the right conditions for fusion
on earth. Thus far we have managed to recreate the conditions. However, we
still haven’t managed to be able to maintain these for long enough, nor have we
been able to extract power from it. We have some ideas on how to achieve both.
One of the questions however is, do we have the materials to be able to do so?
This is where people like me come
in. Thus far I have spoken about how this is a relatively new process mingled
with a plethora of difficulties. Therefore, it will not be surprising when I
say that we don’t exactly have the appropriate facilities to be able to
entirely comprehend the extreme effects taking place. So how do we go about
solving the problem? Some people try and use proxies, alternative approaches
that in some way mimic certain effects we expect. Others try to use
computational techniques and our understanding of physics to paint a picture.
I’m involved in the latter. I use modelling and simulation to try and deduce what
we expect. It isn’t as simple as pushing a button however. One needs to be
aware of a lot of inter-related pieces of physics. Sometimes, we also find that
we don’t have the computational power to actually be able to process all of these
(surprising isn’t it given the progress in the field of IT). Sometimes my job is therefore to see which
processes are negligible. At other times, it is to check and draw conclusions
from the results of my simulations. To name a few of the techniques I use; I
use solvers for the neutron transport equation, binary collision approximation
and molecular dynamics. The last considers how atoms are likely to behave. This
generates some interesting perceptions of important chemical and atomic
I’ll stop here. I’ll end on a
note that the human race is currently engaged in very exciting things. But to
see this realised; we need young, ambitious and creative minds that are keen to
learn as well as try new things.
If you want any more information, please feel free to contact me at: firstname.lastname@example.org .
To find out more about the chemical and atomic processes generated in molecular dynamics: http://lammps.sandia.gov/movies.html
A more comprehensive yet elementary guide on nuclear physics can be found at (http://hyperphysics.phy-astr.gsu.edu/hbase/nuccon.html)
Here are also
some web links pertinent to what I have written:
Culham Center for Fusion Energy: http://www.ccfe.ac.uk/introduction.aspx
Nuclear Energy Agency: http://www.oecd-nea.org/workareas/
Fusion Center for Doctoral
My name is Robert Worth and I am
currently part way through a PhD in Nuclear Engineering with the Nuclear
Graphite Research Group at the University of Manchester – how did I get here?
Almost by accident. It was during my A Level study in Physics that I first came
across the phenomenon of radioactivity, which I thought was a bizarre and
exciting process that I had not encountered before, and I needed to know more! This
eventually led me to my degree in Mechanical (Nuclear) Engineering at the
University of Manchester, which was very enlightening and encompassed many
aspects of both mechanical and nuclear engineering. It was during my degree
that I stumbled across an email containing upcoming PhD research projects – did
I know what a PhD involved? Nope, not really. Did I want to do one? I wasn’t
sure. I’m glad I applied, however, as it turned out that this is the sort of
work I’d wanted to do all along, I just hadn’t realised it. You are no longer
just absorbing information from others – I am also now doing the finding out, and
helping answer questions that nobody in the world yet has answers to!
I’ve been very lucky with this
PhD project, and have been encouraged to attend many prominent events and
conferences around the country, talking with and working alongside some of the
most inspiring people and minds in the country. I’ve been fortunate enough to
travel further afield too, as far as Lithuania, where we stood on the top of a
nuclear reactor core of the same basic design as the famed Chernobyl, and even
over to the United States, to visit a research group at Idaho State University
and to help on an experiment at a synchrotron particle accelerator in
My specific research project is
on thermal treatment of irradiated
graphite waste. It turns out that there is an awful lot of it (around
96,000 tonnes) in our small country, the UK. So far, there are good ideas about
how we might deal with this large volume of radioactive waste, and the Nuclear
Decommissioning Authority (NDA) have plans to bury most of it in a future
geological disposal facility, a large controlled facility far underground that
could house and contain all of our radioactive waste for thousands of years to
come. Since a location for this facility is yet to be found, and it is yet to
be built, you could argue that a disposal route is not set in stone. Which is
where treatment comes in – can we do something else with the graphite waste to reduce
the hazard, instead of burying it, which could potentially save money and may
leave valuable space in the repository open for other more hazardous wastes? This
is a point of controversy amongst the nuclear waste research community!
What is graphite and how is it used?
Graphite is a very stable hexagonal
formation of carbon atoms, that can be found naturally but is also artificially
manufactured to very high purities, at great expense! This involves many
different processes to reach the final product including heating to around 3000oC
for a number of days. It is essentially many planes of the material ‘graphene’
all layered up on top of each other, and is found in pencils; the ‘lead’ in
your pencil is actually graphite, and it is these layers of carbon atoms sliding
relatively easily over each other that allows you to write and draw quite
Graphite is used in many nuclear reactors in the
UK in the shape of enormous blocks, which can be over a metre in height, all
stacked on top of each other and arranged into a large reactor core. Its purpose
is to slow the neutrons in the core down, by acting as a physical barrier for
the neutrons to bounce off, a little like billiard balls, so that they will
react more easily with the nuclear fuel, producing energy for us to power our
Why is it radioactive?
Carbon has been selected as a
fairly ‘neutron transparent’ material so that neutrons will bounce off and
scatter away from the carbon atoms instead of being absorbed. This does not
happen every time, however, and on occasion a neutron will be absorbed into the
carbon atom, making the nucleus of the atom heavier and larger than it was
previously. This can make the atom become unstable, as it can no longer
physically sustain itself in a stable state, and so the atom will ‘decay’ by releasing
some energy – in this instance, a radioactive carbon-14 atom will spit out an
electron from the atom and transmute into nitrogen-14, which is a stable atom.
Voila! This is the process of radioactive decay.
What do I actually do?
I spend a lot of time working in
a laboratory with radioactive samples, taken from a nuclear reactor, wearing a white
lab coat, goggles, layers of gloves, and working with tongs behind special
shielding or in a glove box, like Homer Simpson. I also wear a dosimeter to
record the amount of radiation I have received from the samples, so that I know
I am well below safe levels for working. I then take these samples and place
them in a specially designed tube furnace, and very carefully oxidise them
using a gas flow of 1% oxygen to try and remove a good fraction of the surface
radioactivity as a gas. The radioactive portion of this gas is then trapped and
collected in a ‘bubbler system’, where the gas is forced to bubble up through a
clever fluid, before it is taken away for analysis to determine how much
radioactivity has been successfully removed. I can then use this data to make a
reasoned judgment of how I might improve the process, by adjusting the
temperature, for instance.