The First Wall Problem

I have been discussing with Dr. Mike the problem of alpha sputtering. What Dr. Mike calls the First Wall problem.

Alpha impacts on the grid(s) is going to be a problem. If alpha impacts knock metallic elements from the grid(s) they could poison the reactions or at the very least waste electrons and energy.

One solution is to coat the grids with a sufficiently thick layer of Boron and run the machine such that the Boron in the reactor replenishes the Boron on the grid(s).

Thus - any elements knocked off the grids are a reaction species and thus do no harm to the reaction.

Dr. Mike replied that Boron is not very structurally strong. A fact I was unaware of. Dr. Mike suggested that embedding the Boron in some kind of plastic might do the trick. I had some objections to that.

So I went to the 'net and did some research.

I believe ITER uses a Boron coating evaporated on the surfaces to solve the sputtering problem.

If you use pure Boron you have one segment of the problem solved (reaction species) the other problem is to maintain a balance between the coating and the reactants.

Once you get into hydrocarbons you have problems with non-reactant species.

The question then is do thin films have significantly different properties from bulk Boron.

This might be a place to start:

really long url

Search Boron on this page:

Diagnostic Needs

also a look here:

Energy Citations

and here:

Abstract of an interesting Paper

I'm pretty confident that the thermal problems can be solved. So this is the next hump IMO. BTW I'll go into my ideas on how the thermal problems can be solved in another post.

Let me note that Dr. Mike thought this was a good approach. At least to start.