[ RadSafe ] RE : Spent fuel and decay

[Pete_Bailey at fpl.com]

> ... how long it takes spent fuel to decay to
> the Aactivity level it had before going into the reactor?

If by 'activity level', you mean 'curies', one very very long time.

> I realize it is highly dependant on factors such
> as level of enrichment, amount of burn-up,
> activation of cladding, etc, and breeding of Pu.

Level of enrichment & 'burn-up'(MWT/MTU)
drive the length of time.
Most activation products (active...of clad)
fizz out in  a decade or so...
The breeding of Pu....it ain't there to
start with (for all intent and purposes),
and has mega-year half-life.