URANIUM: DON'T LEAVE IT IN THE GROUND!

Uranium is therefore a polluter only as the parent of radon, which itself is a polluter only as the transporter of its own daughters. The radon formed in the uranium bubbles up toward the surface, which it can reach in its life of a few days only if it is not far from the surface (or if a hole is dug in the ground for any reason, not necessarily uranium mining).

But uranium deposits are almost always mined near the surface (with the notable exception of South Africa, where the uranium ore is gained from deep-mined gold tailings), so that they remove that part of the uranium which caused the trouble, whereas the remainder and the tailings must by law be covered with sufficient earth to allow only a ridiculously small amount of radon to escape (2 picocurie per sq. meter per sec.).

As I have pointed out before, when a uranium 235 atom is split in a reactor, it never gets the chance to decay into radon, so that using nuclear power actually cleanses the earth of radioactivity. Yes, other fission products arise in the process, but the law of the conser-vation of energy says that the original energy has been diminished by what is turned into heat and electric energy, so there is not enough left to support the antinuke scares.

But British scientist Nigel Holloway recently published some in- teresting calculations [1]. The situation is reminiscent of coal ash vs. nuclear wastes: since nuclear wastes decay, but coal ash retains its toxicity indefinitely, the nuclear wastes produced in generating a given amount of electricity are at first more toxic than coal ash; but after 500 years they have decayed below the toxicity of the ash and keep on decaying. (The toxicity of a poison is measured by the amount of water required to dilute it to drinking water standards.) It so happens that with uranium the same magic number of 500 years holds: after 500 years, the fission products contribute less radioactivity (total, not just radon) to the en- vironment than if the uranium had been left to decay by Mother Nature's rules.

Thereafter the fission products keep on decaying faster than the unmined uranium; the total energy given off as radiation is much larger for the unmined uranium than for the fission products. Even after a single year (rather than 500), the biologically effective radiated energy of the wastes would be 200 times smaller than that resulting from the unmined radium. ("Biologically effective" means an increased equivalent energy to account for the more damaging health effects of alpha and beta radiation as compared to gamma radiation of the same physical power.)

[More: D. Bodansky and others: Indoor Radon Hazards, U. of Wash. Press, Seattle, 1987; N. Holloway, "Uranium: don't leave it in the ground!", Atom (Lon- don), June 1990.]