X-Ray Ablation and Debris Venting for the HIF Point Design

This paper presents detailed design and analysis for x-ray ablation and venting in the 120-beam, 7-MJ heavy-ion fusion (HIF) "robust" point design. The HI Robust Point Design ("RPD-2002") is a self-consistent, non-optimized system design that has been generated as a point of reference for ongoing research in the HIF program. The point design uses a thick-liquid protected chamber, derived from HYLIFE-II - no structural surfaces face the target. A ternary salt mixture called flinabe (LiNaBeF₄) has been selected for the liquid structures. Detailed two-dimensional, axially symmetric TSUNAMI calculations have been performed to determine the mass of ablation debris generated by the target x-rays following ignition and to predict the venting of the debris from the inside of the pocket into the main chamber and beam lines. These calculations provide predictions of the impulse loading to the surfaces of the liquid pocket - The closest liquid structures will experience a somewhat strong impulse, but further optimization of the design will easily decrease this impulse. The integrated mass and energy fluxes of ablation and target debris reaching the beam-line magnetic shutters are given as well: A small and acceptable magnetic dipole will prevent any debris ingression up in the final focus magnet region.