This work was funded by the RCUK Energy Programme
[Grant number EP/P012450/1]
Image by Volker Steger
"Fusion will be ready when society needs it"
Lev Artsimovich, Father of the Tokamak
by Jonathan Shimwell
Fusion Energy, Physics 303 course
Data source WEC, BP, USGS and WNA data from presentation by Steven Cowley
Deuterium (D)
Tritium (T)
Helium 4
3.5MeV
1/5 of the energy
Neutron
14.1MeV
4/5 of the energy
Helium 5
17.6MeV
H3 + H2 = He4 + n
Binding energy before = 3 x 2.83 + 2 x 1.11
Binding energy after = 4 x 7.07
Difference in binding energy is 17.57 MeV
U235 + n= Ba145 + Kr87 + 4n
Mass before = 235.04393u + 1.00866u
Mass after = 144.92752u + 86.91335u + 4 x 1.00866u
Mass difference = 0.17708u = 164.95MeV
proton mass = 1.672623E-27 kg
neutron mass = 1.674929E-27 kg
1 atomic mass unit = 1.660540E-27 kg
17.6 MeV emitted per DT fusion
Assuming every D reacts with a T.
1 gram of material.
~200MeV emitted per U235 fission
Assuming 100% U235 enrichment .
Assuming ever U235 fissions.
Ignoring decay heat.
1 gram of material.
H2 + H2 = H3 + H1 Q=4MeV
H2 + H2 = He3 + n Q=3.3MeV
H2 + He3 = He4 + H1 Q=18.3MeV
N14 + H1 = O15 Q=7.35MeV
H2 + H1 = He3 Q=5.49MeV
C12 + H1 = N13 Q=12.86MeV
He3 + He3 = He4 + 2 H1 Q=1.95MeV
C13 + H1 = N14 Q=7.55MeV
H1 + H1 = H2 Q=0.42MeV
N15 + H1 = C12 + He4 Q=4.96MeV
H2 + H3 = He4 +n Q=17.6MeV
plot of energy distribution of neutron for different DD, DT and 150Kev, 20Kev
Magnetic
confinement
Gravitational
confinement
Inertial
confinement
Indirect drive
Direct drive
Poloidal and toroidal magnets
ITER reactor
800m3 plasma volume
500MW thermal
DEMO reactor
1000-3500m3 plasma volume
4000MW thermal
JET reactor
80m3 plasma volume
16MW thermal
Tore Supra
25m3 plasma volume
0MW thermal
The point where a fusion reaction becomes self-sustaining instead of requiring a constant input of energy. In the case of DT fusion the plasma is heated by the energetic alpha particle that is emitted during fusion reactions. This is also known as self heated plasma
The lawson criteria defines the general requirements (temperature, density and confinement time) of a reactor to reach a self sustaining reaction (ignition).
Confinement time
Boltzmann constant
Temperature of electrons
Number density of electrons
Energy released per fission
Cross section of reaction
Average velocity of ions
Key reactions in breeder blankets
Questions
Which isotope is depleted?
Why at the front?
What is the best isotope for the front?
Neutron spectra at different depths in the blanket.
Neutrons are moderated by the material and lose energy.
Neutrons are also captured by some reactions.
Material 1
Material 2
Neutron birth
(n,n')
(n,f)
(n,n')
(γ,γ')
(n,nγ')
(n,pn')
(n,f)
(n,2n)
(n,α)
(n,γ)
Neutron
Electron
Gamma
Alpha
Proton
Target
Nuclide
n,2n
n,g
n,p
n,pn
n,d
n,t
n,nd
n,a
n,He3
n,pd
n = neutron
g = gamma
t = tritium
p = proton
d = deuterium
He = helium
Common neutron induced reactions
Neutron number
Proton number
Time
Number of atoms
Shut down
Atomic number
Percentage of fission products
Image source www.ccfe.ac.uk/mast_upgrade.aspx
Banana orbits
run away electrons
Stellarators
3D printing components
Neutral particle accelerators
Robotic maintainance
Plasma instabilities such as sausage, kink, balloon and elms
Masters Degrees
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Jobs
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Summer placements, graduate recruitment and work experience at CCFE near Oxford
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