Three-dimensional nuclear analysis of the final optics of a laser driven fusion power plant

• Published in: Fusion engineering and design Vol. 83; no. 10; pp. 1879 - 1883
• Main Authors: Sawan, M.E., Ibrahim, A., Bohm, T.D., Wilson, P.P.H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2008; Elsevier
• Subjects: 3-D modeling; Applied sciences; Controled nuclear fusion plants; Dielectric mirrors; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Installations for energy generation and conversion: thermal and electrical energy; Metallic mirrors; Radiation damage; Radiation streaming; Shielding; Radiation streaming; Shielding; Metallic mirrors; 3-D modeling; Dielectric mirrors; Radiation damage; Neutron flux; Modeling; Nuclear fusion reactor; Silicon carbide; Laser beam; Environment impact; Laser; Fast neutron
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2008.04.004

The High Average Power Laser (HAPL) power plant has targets that are directly driven by forty KrF laser beams. The final optics system includes a grazing incidence metallic mirror (GIMM) located at 24 m from the target. Several options were considered for the substrate material. We performed three-dimensional (3-D) neutronics calculations to assess the impact of the GIMM design options on the nuclear environment at the dielectric focusing and turning mirrors. We used the recently developed MCNPX-CGM Monte Carlo code that allows performing the neutronics calculations directly in the exact CAD model. Neutron traps are used behind the mirrors to reduce radiation streaming. The results indicate that material choice, density, and thickness for the GIMM impact the nuclear environment at all mirrors. The neutron flux and nuclear heating at the dielectric mirrors are a factor of ∼1.6 higher when AlBeMet is used instead of SiC as substrate in the GIMM. The fast neutron flux decreases by about three orders of magnitude as one moves from the GIMM to the focusing mirror with an additional two orders of magnitude attenuation at the turning mirror accompanied with significant spectrum softening.