continuing….

(12) Most mainline systems (except for liquid-metal-wall ICF reactors, such as HYLIFE) have steel first walls, which are necessary to maintain a good quality vacuum and to endure the intense x-ray and neutron radiation. The first walls of all such reactors will be highly radioactive (2 to 5 billion curies). In addition, these first walls will require replacement every few years because of neutron-induced damage, either from helium embrittlement or from atomic displacements. Because both neutron energy and neutron population are reduced in the steel first walls of these reactors, neutron multipliers (such as lead or beryllium) or isotopic enrichment of Li-6 are usually required to achieve acceptable tritium breeding ratios. The same applies to magnetic fusion reactor chamber walls. For example, the STARFIRE tokamak walls will have a radioactivity of more than 5 billion curies and must be replaced every four or five years. The significance of this should not be ignored, chamber walls exposed to damage rates of 35 dpa/yr (displacements per atom per year) will require replacement every 5-7 years. Assuming that only the inner structural walls need to be replaced at 30% of the original reactor vessel cost, then about 5% of the plants lifetime must be devoted to replacement activities.
(13) ICF laser firing times need to be increased. NIF requires a timeout for cool-down and recovery after each firing. The high precision laser optics that ICF uses must cool for several hours between firings to recover from thermal expansion.
(14) Cooling the laser medium is very inefficient. NIF uses external flash tubes that create significant amounts of non-recoverable low level waste heat which must actively be removed (requiring extra energy) from the gain medium.
(15) The Halite-Centurian tests in Nevada apparently showed the DT targets might require up to 20 MJ to ignite. Current ICF designs produce less than 3 MJ.

I should point out that, none of these 15 are obstacles to Bubble-confined Sonoluminescent-laser Fusion (BSF).