Ok, let's see...

1. Gaianne claims that "cancer rates increased 10-fold at Seascale"
   
2. You claim that that is absurd because since 1/5 of all people die of cancer, that would require everyone to two die of cancer twice.
   
3. I point out your argument about death rates doesn't hold, because you are confusing "cancer rate" with "fraction of deaths due to cancer in a cohort". I show that multiplying UK cancer death rates by 10-fold would put the death rate at the level of the highest death rates in any country in the world.
   
4. You conclude that reduces Gaianne's claim to absurdity. You also make a comment to the effect that "suffering from cancer is not that bad if you don't die from it".

I don't know why you think this exchange makes me look "desperate to find models where an unsupported number is not outright impossible". You seemed "desperate" to make an absurd claim about a different quantity in order to make said unsubstantiated claim seem outright impossible.

Anyway, since Gaianne is not gracing us with a reference, I decided to go fishing for one.

New Scientist: Science: Leukaemia and nuclear power stations ( 17 June 1989)

Subsequent investigations confirmed an excess of leukaemia and other cancer among children living near Sellafield, the complex British Nuclear Fuel runs in northwest England. ...

Depending on which statistics are quoted, the excess represents up to a tenfold increase in the number of cases expected on the basis of conventional dose/risk models.

The whole (short) article is full of qualifications, and what I walk out of it with is that "standard dose/risk models underestimate the expected number of additional child leukemia cases by a factor of up to 10". A far cry from "cancer rates increased by a factor of 10".

Anyway, for anyone interested there is the COMARE 10th Report: The incidence of childhood cancer around nuclear installations in Great Britain (10 June 2005).

Nothing is 'mere'. — Richard P. Feynman