establishing the reputation of fusion power as an elusive goal. Some of the key
issues that still have to be addressed are: understanding of turbulent transport in
magnetized plasma’s, suppression of edge localized modes, realization of an
effective fuel cycle based on tritium breeding, improvement of particle and energy
exhaust systems, development of the materials able to handle extreme conditions in
the reactor. Materials can rightfully be singled out as the most critical issue. Large
heat loads and particle fluxes cause melting, sputtering, erosion, re-deposition,
swelling and displacements of atoms from their lattice structure. This further results
in fuel dilution, changes in size of the components, changing of properties of the
material.
In general effects of incoming neutrons result from three types of interactions
with the target material:
absorption (transmutation)
elastic scattering
inelastic scattering
The first reaction is responsible for creating transmutation products (such as He)
that over time build up in the material. This consequently leads to deteriorating of
material properties, making it swollen as the amount of helium increases, brittle as a
result of accumulation of helium bubbles along grain boundaries, causing the
change in thermal conductivity, activation of the material etc.
The second reaction is mostly responsible for damage expressed in terms of
dpa-displacements per atom. Neutrons kick the lattice atoms out of their original
position in the crystal lattice causing defects in the structure of the material by
creating interstitials, substitutions and vacancies.
1 Accumulation of such defects
can even lead to phase transitions.
The third reaction is in the focus of my research. Knowledge of it is limited [1]
yet it is important for modeling of 14 MeV neutron interactions that originate from
the D-T reaction. Change in the neutron energy spectrum along the propagation
path will also be taken into account. Materials that are planned to be included in this
analysis are the ones relevant for MCF: steel, tungsten, beryllium and carbon.
2 Description of the Actual Work
In order to address the problem of neutron transport and investigate the importance
of inelastic neutron scattering both experimental and theoretical analysis will be
conducted. Work can be divided into two conceptual parts. First part is related to
nuclear reaction data evaluation while the second part deals with application of
acquired knowledge to MCF systems.
1
Types of defects in the lattice structure.
230
I. Abramovic
issues that still have to be addressed are: understanding of turbulent transport in
magnetized plasma’s, suppression of edge localized modes, realization of an
effective fuel cycle based on tritium breeding, improvement of particle and energy
exhaust systems, development of the materials able to handle extreme conditions in
the reactor. Materials can rightfully be singled out as the most critical issue. Large
heat loads and particle fluxes cause melting, sputtering, erosion, re-deposition,
swelling and displacements of atoms from their lattice structure. This further results
in fuel dilution, changes in size of the components, changing of properties of the
material.
In general effects of incoming neutrons result from three types of interactions
with the target material:
absorption (transmutation)
elastic scattering
inelastic scattering
The first reaction is responsible for creating transmutation products (such as He)
that over time build up in the material. This consequently leads to deteriorating of
material properties, making it swollen as the amount of helium increases, brittle as a
result of accumulation of helium bubbles along grain boundaries, causing the
change in thermal conductivity, activation of the material etc.
The second reaction is mostly responsible for damage expressed in terms of
dpa-displacements per atom. Neutrons kick the lattice atoms out of their original
position in the crystal lattice causing defects in the structure of the material by
creating interstitials, substitutions and vacancies.
1 Accumulation of such defects
can even lead to phase transitions.
The third reaction is in the focus of my research. Knowledge of it is limited [1]
yet it is important for modeling of 14 MeV neutron interactions that originate from
the D-T reaction. Change in the neutron energy spectrum along the propagation
path will also be taken into account. Materials that are planned to be included in this
analysis are the ones relevant for MCF: steel, tungsten, beryllium and carbon.
2 Description of the Actual Work
In order to address the problem of neutron transport and investigate the importance
of inelastic neutron scattering both experimental and theoretical analysis will be
conducted. Work can be divided into two conceptual parts. First part is related to
nuclear reaction data evaluation while the second part deals with application of
acquired knowledge to MCF systems.
1
Types of defects in the lattice structure.
230
I. Abramovic