Pretty much every single entire Fall outage in the South Florida plants, before the early 90's when the accountants decided to A/C the containment. There was a reason we worked 2-in/2-out; the daily temps ran between 100-105. By the third and last jump, you were just counting the minutes left. The 'safety guy' would cruise through containment shouting out, " One hundred four!" or similar. Thanks a lot, dude.
And no, no hydrating in the can. We did call the count room to deliver a lot of 1 liter marinelli samples,"...hey, make sure the water's cold, would ya?.."
As for short term heat, somewhat same as Marlin; top of enclosed doghouse PZR, at power, Furmanite. Single PPE, triple shoecovers,(melting) and cannister face pump.
I'm sure I couldn't do it, now.