Rob, it might seem obvious to you but I think it’s wrong for several reasons. This is a complex situation. You are dealing with a (human) animal which has natural mechanisms for ridding excess heat (blood flow, sweating) for heat generated internally (e.g. in our ~25% efficient muscles) and externally from the environment. See my previous discussion on this:
The medical models/experiments on which the RF heating limit is based will attempt to take in the heat in (due to the RF) versus the body’s ability to remove the excess heat. If, during the 7-minute test period the former exceeds the latter, the body (part) temperature will rise. If the temperature exceeds some critical value for that time, cell damage will result. Your 1000W case is more likely to cause this situation within the 7-min test period than the 100W case.
You are conflating two different situations. Your 1000W & 100W RF cases are about RF heating of the body. The reactor core case is about very-energetic gamma and x-rays whose ionizing effects would have been shredding the DNA of Alexei Ananenko, Valeri Bespalov and Boris Baranov, the three brave men who made up Chernobyl’s so-called ‘Suicide Squad’.