Isotopic Separation of ³He/4He From Solar Wind Gases Evolved from the Lunar Regolith

by William R. Wilkes, EG&G Mound Applied Technologies, Miamisburg, United States,
Layton J. Wittenberg, EG&G Mound Applied Technologies, Miamisburg, United States,

Document Type: Proceeding Paper

Part of: Engineering, Construction, and Operations in Space III


The potential benefits of 3He when utilized in a nuclear fusion reactor to provide clean, safe electricity in the 21st century for the world's inhabitants has been documented. Unfortunately, 3He is scarce on earth. Large quantities of 3He, perhaps a million tonnes, are embedded in the lunar regolith, presumably implanted by the solar wind together with other gases, notably H2 and 4He with minor amounts of CO2 and N21. Several studies have suggested processing the lunar regolith and recovering the valuable solar wind gases. Once released, these gases will be separated for use. The separation of helium isotopes is described in this paper. 3He exists in the lunar derived 4He at a concentration of 400 at.ppm, too dilute to separate economically by distillation alone. A 'superfluid' separator is being considered to preconcentrate the 3He. The superfluid separator consists of a porous filter in a tube maintained at a temperature of 2.17 K or less. Although the 4He, which is superfluid below 2.17 K, flows readily through the filter, the 3He is blocked by the filter, and becomes enriched at the feed end. 3He can be enriched to about 10% in such a system.

Subject Headings: Filters | Lunar materials | Construction materials | Solar radiation | Nuclear safety | Electric power | Isotopes | Wind engineering | Colorado | United States

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