[FPSPACE] German Expert Discounts Risk From Old Soviet Satellite

[Allen Thomson]

> Is it really true that these reactors will decline in risk
> over 20 years by a factor of 1000? 

Details will vary with the composition of the fuel and degree of burn-up, but one source (http://www.world-nuclear.org/info/inf60.html) says of spent commercial power reactor fuel,

 "... there is a cooling period of 20 to 50 years between removal from the reactor and disposal, with the conditioned spent fuel or conditioned HLW being retained in interim storage. This is because the level of radioactivity and heat from the used fuel fall rapidly in these years down to about one thousandth of the level at discharge in 40 years."