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Neutronics Analysis of Fusion Systems |
Presentation slides for the fusion energy neutronics workshop |
Jonathan Shimwell |
fusion,neutronics,neutron,photon,radiation,simulation,openmc,dagmc |
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- Activation
- Activity build up and decay
- Emission spectra
- Shut down dose
- Analysis needed to lift or cool components
- Impact of burn up on TBR
- New isotopes created during irradiation
- Radioactive isotopes decay and will eventually reach a point where decay rate is equal to activation rate.
- Decay is more noticeable once the plasma is shutdown.
- The activity is related to the irradiation time and the nuclide half life.
- High energy neutron activation
- Low energy neutron activation
- Fission of large atoms (e.g. U235)
- Results in two fission products far from stability
- Characteristic gamma energies and intensities emitted
- Reduces with half life of unstable isotope
- Problematic sources in fusion Co60
- Neutrons also emitted by isotopes such as N17 found which is formed by Oxygen irradiation in water
- Post irradiation gamma and even neutron emission from radioactive isotopes continues.
- Gamma and neutrons emitted cause dose field that makes human maintenance difficult.
- This causes components to generate self heating
- Reduced strength of components due to temperature, lift carefully
- Activated coolant pumped outside of the bio-shield
Image source Eurofusion
