> >>
>>>
>>> We *had* to leave Euratom *because* it is part of the EU...
>>>
>>> One thing I didn't get is that the lad says we are fusing deuterium
>>> and tritium only and then goes on to say we need a lump of lithium as >>> well.
>>>
>>> It looks like lithium absorbs neutrons and makes tritium? Not sure.. >>>
>>
>> Yes, the only way for hydrogen or deuterium to become tritium is to
>> absorb a neutron or two.
>>
>>
>>> Ah... definitive...
>>>
>>> "Tritium is a fast-decaying radioelement of hydrogen which occurs
>>> only in trace quantities in nature. It can be produced during the
>>> fusion reaction through contact with lithium, however: tritium is
>>> produced, or "bred," when neutrons escaping the plasma interact with
>>> lithium contained in the blanket wall of the tokamak."
>>>
>>> That rather answers the 'what happens to all those high energy
>>> neutrons that will embrittle the containment?' question. They end up
>>> making tritium out of sacrifical lithium.
>>>
>>>
>>
>> "All" I think you meant to say "Some" of them breed tritium. What
>> percentage would be? My guess would be an exceedingly small proportion. >
> No, the implication is that nearly all of them are absorbed by the blanket. >
>>
>> You do tell crackers. That one was almost as good as your 5 sigma one. >
> Wanker
>
Fair enough.
Yes, I misread it as neutrons absorbed by cooling water and transmuted into tritium. It was always apparent the neutrons had to be absorbed by something and a 1 meter thick liquid lithium blanket would do it. Obviously neutrons would still degrade the fusion facing pipes/framework holding the lithium and holes in the blanket would be needed.
The thing I realised almost immediately after posting was that tritium has to come from somewhere. For tritium-deuterium fusion This introduces the idea of neutron economy very similar to that of a fission reactor. It seems it is actually very hard to generate enough tritium, and fusion without it is much harder to achieve.
Here is an article outlining the economic problems faced by a fusion reactor. Obviously I like it due to confirmation bias, but I think others might find it interesting to see the economy argument made by someone competent.