[DennisP]

I guess literally anything can be "PPB concentration" if you don't care how many parts it is per billion.

A 1GW fusion reactor would consume about a ton of fuel per year.[1] That's about 600 kilograms of tritium. Over the course of the year a reactor with a positive breeding ratio will produce more than that.

The breeding blanket for ITER will be about 2000 tons[2] and ITER is designed to produce 500MW.[3]

This means that ITER will produce at least 300 kg tritium in 2000 tons of blanket, over the course of a year. Collect the tritium annually and you've got a concentration level of 150 parts per million, or 150,000 PPB.

[1] https://ccfe.ukaea.uk/fusion-energy/fusion-in-brief/

[2] https://www.iter.org/mach/Blanket

[3] https://www.iter.org/proj/inafewlines

[pencilguin]

You need to get that tritium out every day to have something to operate the reactor on. Look up the worldwide stock of tritium sometime.

[DennisP]

Doesn't mean you have to do it every day. CFS ARC is a 270MW reactor. In a month it will consume 13.5kg tritium. Current world tritium supply is 20kg, though we could produce more from fission reactors if we really wanted to. 13.5kg out of 2000 tons is 7 parts per million, but with a breeding ratio over one, more than that would be produced. Tritium inventory to start up the ARC reactor is 100 grams.