This site has an interview of Dr Richard Nebel who is leading the IEC/Bussard Fusion project.
Dr. Nebel commented: I believe we will know the answer for the Polywell [commercial nuclear fusion viability] in ~ 1.5-2 years. I haven't looked at MSimons design, but I know he has a lot of good ideas. We'll probably take a closer look at D-D reactors over the next 2 years.
From the Interview: The project that we hope to have out within the next six years will probably be a demo, which won't have the attendant secondary equipment necessary for electricity generation. Hopefully the demo will demonstrate everything that is needed to put a full-scale working plant into commercial production. So if the concept works we could have a commercial plant operating as early as 2020.
18-24 months : Verification if this approach is commercially viable [boom or bust for Polywell]
6 years: a full-scale demo of IEC fusion
By 2020: A first commercial IEC Fusion plant, with an estimated cost of 2-5 cents per kilowatt hour.
We've looked at the side reaction [ 11B-4He -> 14N + n, 11B + p -> 11C+n, etc) that will produce neutrons,] and it is down 8 orders of magnitude from the P-B11 reaction. The reason for this is that the alpha particles are not well confined and leave the system very rapidly. The alpha-B11 reaction is the dominant side reaction. Note: This was a computational analysis.