The interaction of fast neutrons with shielding and fusion blanket materials
In the present work the neutron emission spectra from a graphite
cube, and from natural uranium, lithium fluoride, graphite, lead and
steel slabs bombarded with 14.1 MeV neutrons were measured to test
nuclear data and calculational methods for D - T fusion reactor
The neutron spectra measured were performed by an organic
scintillator using a pulse shape discrimination technique based on a
charge comparison method to reject the gamma rays counts. A computer
programme was used to analyse the experimental data by the
differentiation unfolding method.
The 14.1 MeV neutron source was obtained £ran T(d,n)4He reaction by
the bombardment of T - Ti target with a deuteron beam of energy 130 KeV.
The total neutron yield was rronitored by the associated particle method
using a silicon surface barrier detector.
The numerical calculations were performed using the one -
dimensional discrete - ordinate neutron transport code ANISN with the
ZZ - FEWG 1/ 31 - lF cross section library. A computer programme based
on Gaussian smoothing function was used to srrooth the calculated data
and to match the experimental data.
There was general agreement between measured and calculated spectra
for the range of materials studied. The ANISN calculations carried out
with P3 - S8 calculations together with representation of the slab
assemblies by a hollow sphere with no reflection at the internal
boundary were adequate to model the experimental data and hence it
appears that the cross section set is satisfactory and for the materials
tested needs no modification in the range 14.1 MeV to 2 MeV. Also it
would be possible to carry out a study on fusion reactor blankets, using
cylindrical geometry and including a series of concentric cylindrical
shells to represent the torus wall, possible neutron converter and
breeder regions, and reflector and shielding regions.