78 Risks of nuclear (rtg) power sources for space probes
Description
This article is from the Space FAQ, by Jon Leech leech@cs.unc.edu and Mark Bradford tla@surly.org with numerous contributions by others.
78 Risks of nuclear (rtg) power sources for space probes
There has been extensive discussion on this topic sparked by attempts to
block the Galileo and Ulysses launches on grounds of the plutonium
thermal sources being dangerous. Numerous studies claim that even in
worst-case scenarios (shuttle explosion during launch, or accidental
reentry at interplanetary velocities), the risks are extremely small.
Two interesting data points are (1) The May 1968 loss of two SNAP 19B2
RTGs, which landed intact in the Pacific Ocean after a Nimbus B weather
satellite failed to reach orbit. The fuel was recovered after 5 months
with no release of plutonium. (2) In April 1970, the Apollo 13 lunar
module reentered the atmosphere and its SNAP 27 RTG heat source, which
was jettisoned, fell intact into the 20,000 feet deep Tonga Trench in
the Pacific Ocean. The corrosion resistant materials of the RTG are
expected to prevent release of the fuel for a period of time equal to 10
half-lives of the Pu-238 fuel or about 870 years [DOE 1980].
To make your own informed judgement, some references you may wish to
pursue are:
A good review of the technical facts and issues is given by Daniel
Salisbury in "Radiation Risk and Planetary Exploration-- The RTG
Controversy," *Planetary Report*, May-June 1987, pages 3-7. Another good
article, which also reviews the events preceding Galileo's launch,
"Showdown at Pad 39-B," by Robert G. Nichols, appeared in the November
1989 issue of *Ad Astra*. (Both magazines are published by pro-space
organizations, the Planetary Society and the National Space Society
respectively.)
Gordon L Chipman, Jr., "Advanced Space Nuclear Systems" (AAS 82-261), in
*Developing the Space Frontier*, edited by Albert Naumann and Grover
Alexander, Univelt, 1983, p. 193-213.
"Hazards from Plutonium Toxicity", by Bernard L. Cohen, Health Physics,
Vol 32 (may) 1977, page 359-379.
NUS Corporation, Safety Status Report for the Ulysses Mission: Risk
Analysis (Book 1). Document number is NUS 5235; there is no GPO #;
published Jan 31, 1990.
NASA Office of Space Science and Applications, *Final Environmental
Impact Statement for the Ulysses Mission (Tier 2)*, (no serial number or
GPO number, but probably available from NTIS or NASA) June 1990.
[DOE 1980] U.S. Department of Energy, *Transuranic Elements in the
Environment*, Wayne C. Hanson, editor; DOE Document No. DOE/TIC-22800;
Government Printing Office, Washington, DC, April 1980.)
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