Wyman91 said:
Thank you very much for your information and suggestions.
"The successful operation of a fusion power plant will require the use of materials resistant to energetic neutron bombardment, thermal stress, and magnetic forces." http://www.pppl.gov/fusion_basics/pages/fusion_power_plant.html
What materials are they using now, and what materials could they use?
Wyman,
Right now the materials used are not important.
The fusion experiments that PPPL does / has done - do result in the
release of energetic neutrons - but only for a short period of time.
Therefore, the test reactor isn't damaged by the neutrons - they don't
bombard the structure of the test reactor long enough to cause
significant damage.
They are just saying that, in the future, when fusion power reactors are
in existence - they will operate continuously - and thus sufficient
neutron bombardment may damage reactor materials.
This will have to be taken care of in the design of the future fusion
reactor. For example, if energetic neutrons are a problem - for example
the Deuterium-Tritium reaction releases 14.1 MeV neutrons - then some
way needs to be engineered to deal with these high energy neutrons.
Probably what one would do is to use some light isotope - like the
hydrogen in water, or lithium to slow the neutrons down so that they
are slow neutrons. Slow neutrons are more easily absorbed by such
materials as cadmium and boron.
Slowing the neutrons down is also how one would extract the fusion
energy which is mostly in the neutrons with a D-T fusion reaction.
One way of doing this is by using a "wall" of liquid lithium as scientists
at Princeton are experimenting with:
http://www.pppl.gov/publications/pics/info_bull_cdxu_0703.pdf .
Dr. Gregory Greenman
Physicist