It's pretty obvious that Wasserman either has no grasp whatsoever of the most basic elements of thermal physics, or is deliberately lying to advance his agenda.
There are much more honest and intelligent ways to make an argument against nuclear energy. If you want to advocate against nuclear power without being made to look foolish, you would do well not to accept these claims at face value.
One tiny example: "There are no credible estimates of the global warming damage done by the intensely hot explosions at the four Fukushima reactors, or at Chernobyl, or at any other past and future reactor meltdowns or blowups." Utter nonsense! You can easily set upper limits on the energy releases in all these events, add them up, and on a global scale the result is undetectable and negligible.
The fact is, he's not interested in "credible estimates" of anything, as there is no quantitative analysis on offer here. He mentions some real things and implies they mean things that they do not. Yes, local water heating is a genuine issue for any large thermal power station (whether powered by fission, coal, or natural gas), but the fact that this heating is unimportant on a global scale is obvious from the argument solar advocates have made for years - Earth receives vastly more energy from the Sun each year than all our other power sources release, combined, by an overwhelming margin. This means the effect of the thermal energy released by everything we burn, on warming the planet, is similarly negligible compared to the effects that the products of combustion have on making the atmosphere trap more of the Sun's energy.