IFMIF d-Li neutron source: Status of codes and nuclear data

IFMIF d-Li neutron source:Status of codes and nuclear data S.P. Simakov Institut für Reaktorsicherheit, Forschungszentrum Karlsruhe IEA Neutronics Meeting, Baden-Baden, 18 October 2001

Area/Motivation/Aim • International Fusion Material Irradiation Facility (IFMIF) is an accelerator driven d-Li intense neutron source for the irradiation of fusion relevant materials • The accuracy of the assessed induced radiation effects will depend on the prediction quality of the spectral and angular neutron yield from the Li-target • Aim of researches: • developing the computational procedure (MCDeLicious) for the generation of d-Li source term making use of evaluated d + 6,7Li cross-section data • checking the MCDeLicious code against available experimental data • intercomparison MCDeLicious with MCDeLi and MCNPX, both of which use built-in analytical models for the Li(d,xn) reaction.

IFMIF: Principal overview

3dview Basic Nuclear Processes in Li target, HFTM & Reflector Elevationview Beam directionview EF = Eurofer: 89%Fe, 9%Cr, 1.1%W,0.4%Mn...

Methods/Codes/Computing • Method: Monte Carlo (sampling independently each event/cascade starting from d+) • Codes description: MCDeLiMCDeLiciousMCNPX(2.1.5) - dual d+-beam configuration ++? - d+ slowing down in Li +++ - d + Li cross sections model: Semi-empir.formula INPE Eval.FileINC (only Li+d => n)(6,7Li+d => n, γ,p,α..)(Li + d => n) - n- and γ- transport MCNP-4BMCNP-4CMCNP-4B • Recently a newly evaluated d-Li data library in Institute of Nuclear Power and Engineering, Obninsk (INPE) in collaboration with FZK: • deuteron energies up to 50 MeV, • calculation models: diffraction theory and a modified cascade evaporation, • evaluated quantities: double differential cross sections of the cumulative particle yields (d,xn), (d,x), (d,x), etc. • Processing from ENDF (evaluated data) to ACE (for MCNP) format: • NJOY 99

Basic Nuclear Process: Deuteron slowing down in Li-target MCDeLicious & MCNPX codes results:

Table 1. Li + d reactions channels , Q values and thresholds. Basic Nuclear Process: Deuteron-Lithium interaction (new eval. data) Reaction Channels for d-Li interaction

Table 1. Li + d reactions channels , Q values and thresholds. Source Model Verification: n - yield from thick Li-target bombarded by d+ Total & Forward Yields Angular n-Yield Spread of experimental data & uncertainty resulted from Li(d,xn) source modelling amount dozens-hundreds percents, INPE evaluation should be improved

Table 1. Li + d reactions channels , Q values and thresholds. Source Model Verification: n - yield from thick Li-target bombarded by d+ Forward Average Neutron Energy Spread of experimental data & uncertainty resulted from Li(d,xn) source modelling amount dozens-hundreds percents, INPE evaluation should be improved

Table 1. Li + d reactions channels , Q values and thresholds. Source Model Verification: n-yield from thick Li-target bombarded by d+ Energy-angle differential neutron yield at Ed = 32 MeV MCDeLicious with INPE d-Li evaluated data is more successeful then MCDeLi and MCNPX

Table 1. Li + d reactions channels , Q values and thresholds. Source Model Verification: n-yield from thick Li-target bombarded by d+ Energy-angle differential neutron yield at Ed = 40 MeV MCDeLicious with INPE d-Li evaluated data is more successeful then MCDeLi and MCNPX

Table 1. Li + d reactions channels , Q values and thresholds. Source Model Verification: γ-yield from thick Li-target bombarded by d+ -yield Sources: primary process - Li(d,x) secondary process - Li(n,x) Total & Forward  - Yield Energy differential -yield at Ed = 40 MeV MCDeLicious with INPE d-Li evaluated data is capable to predict the photon yield

Conclusions • Deuteron bombarded thick Li-target yield experimental data has been compiled: • neutron production: scattering of the original data is relatively large ( 50%), • photon production: no data available, • there is need for further measurements. • Code MCDelicious has been developed which makes use of the d-Li cross section library evaluated in INPE: • MCDeLicious predicts the neutron yield better then MCDeLi & MCNPX do, • it also is capable to predict the production of photons and charged particles, • further improvements of IFMIF source parameters could be now easily accomplished as soon as updated d-Li libraries become available.

IFMIF d-Li neutron source: Status of codes and nuclear data