[ RadSafe ] Japanese Nuclear, Weather, Etc.

[Jim Darrough]

Radioisotope Thermoelectric Generators, or RTGs, provide electrical power
for spacecraft by converting the heat generated by the decay of
plutonium-238 (Pu-238) fuel into electricity using devices called
thermocouples. Since they have no moving parts that can fail or wear out,
RTGs have historically been viewed as a highly reliable power option.
Thermocouples have been used in RTGs for a total combined time of over 300
years, and a not a single thermocouple has ever ceased producing power.

http://solarsystem.nasa.gov/rps/rtg.cfm

Jim Darrough, Oregon State University Health Physicist