The potential benefits of a fusion power system are great, though it seems likely that we will see hybrid fusion-fission systems first, and they have safety considerations that are serious. Yet with greenhouse warming fast becomming the most important threat to humanity, developing options independent of fossil fuels is vital. Accordingly, the fusion technology programs that have been put on hold or scaled down should instead be ramped up, and we ought to divert a billion or so from the Iraq War to push fast ignition research, z-pinch, and applications development.

In the U.S. the environmental movement hasn't yet incorporated the new logic of combating global warming, a new logic that will drive some policy shifts, require some new thinking from the leaders if they are to remain relevant.

We must also develop the renewable energy systems, but it's too early to rule out the fusion option just because there are some thorny operational safety issues. Tritium handling comes into play in most fusion cycle plants, and tritium is tricky to handle. Tritium safety is a topic that has been studied and practiced for decades, so there is quite a large body of knowledge to work with. These plants will introduce some new chemical hazards, pressure regimes not seen before such as the cycling as pellets are "burned", liquid lithium blankets, and the need to control the proliferation potential at plant sites.

Never the less, these systems can also breed fuel for the existing fission cycle plants, or better, for third generation fission cycle plants using sub critical assemblies that are only driven to criticality by the fusion burns. The inherrent citicality safety of such power plants was the topic of a talk by a nobel prize winning CERN scientist some years ago at UC Berkeley. He advocated thorium fission power, using a 55 gallon drum sized "core" assembly along with an accelerator beam that brought it to the power production level.

These fusion neutrons are mostly 17 kev to start, definately "fast" neutrons ---- :-)

Following this draft, I came on a very recent paper in Phisics Letters "A" by F. Winterberg that talks about hybrid fusion-fission-fusion using his favorite device, the dense plasma focus....of course. FW has a distaste for lasers, seems to go a bit light on the math in his paper, nevertheless, it confirms my post above ( drafted prior to his article being published), and does give some idea of the design. Clearly with a bit of extrapolation, my idea of a laser initiated DPF system would also go, and likely with less tricky stuff than FW's system. He doesn't get much of a following by the folks with the money for some reason, but his papers point at a simple way to get lots of neutrons.

Combine his approach with the Carlos Rubbia ideas, and it's clear that one could bootstrap with just a bit of laser created dt fuel into a full fuel cycle.

interesting.