Nuclear fusion and the helium supply problem

Abstract

The natural resources required for the operation of fusion power plants are -with the possible exception of the neutron multiplier beryllium -readily available. On the other hand, the supply of helium, which is required as cryogenic medium and coolant, may be a problem due to losses during operation and decommissioning. Helium is a rare element obtained as a by-product in the extraction of natural gas. The danger exists that the natural gas will be used up without the helium being conserved. We estimate the helium demand for a global 30 % base-load contribution of fusion to electricity supply and also calculate the amount produced by the power plants themselves.

Force cooled quench tanks for the ITER cryogenic system

“…During a possible accidental loss of superconducting state of the magnets (quench), most of the He inventory contained will be rapidly expanded and shall be promptly evacuated to prevent excessive pressure increase. Expelled He has to be captured and subsequently used for the re-cooling of magnets as He is quite an expensive commodity, to such an extent that global He supply problems are predicted by some researchers if its operational losses continue to be substantial [2]. Apart from capturing gas during a quench event, the Quench Tanks shall also be used for storing part of the He inventory during ITER system maintenance, when it is necessary to remove gas from the system and keep it in a storage for prolonged periods of time (months).…”

Helium Production and Possible Projection

“…In the future, large quantities of helium may be required for nuclear fusion reactors [3,4]. Since the early 1960s, the U.S. government has stockpiled helium in the federal reserve [2,5].…”

“…One of the major issues of helium production is that a large amount of helium is lost, due to the venting of helium rich gases in the natural gas industry [10]. Other than from gas wells helium's only other possible source on Earth is from the atmosphere, where helium is present at 5.2 parts per million [3,11]. This potential backstop solution could potentially supply some helium in the future; however, there would be significant engineering challenges, as it would take more than a hundred cubic kilometres of air to produce the current helium demand [11].…”

Helium Recovery by Membrane Gas Separation Using Poly(o-acyloxyamide)s

“…But actually helium is required both as a cryogenic gas and as a coolant in fusion plants 2,4,5 and it will continue so unless spectacular advances were done in superconductivity at high or medium temperatures. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 In the last years prices of helium scaled up 2 going from 50 $ in 2000 to 160 $ in 2011 per thousand of cubic feet. A helium shortage would cause anarchy in large areas of the global helium-dependent economy, from medical scanners to solders and including optical fibers and LCD screens manufacturers.…”

“…The product is a gas rich in helium containing 50 to 70 percent helium, and including mostly nitrogen, argon, neon, and hydrogen. Final purification of helium is normally done using: (1) activated charcoal absorbers at liquid-nitrogen temperatures and high pressure that can produce 99.9999 percent helium or (2) pressure-swing adsorption (PSA) processes that can yield helium with 99.99 percent purity.…”