It’s August in DC. It may be hyperbolic, but there are times when I feel like bursting into flames is an appropriate reaction to the horrible atmosphere that greets me when I leave the safe confines of air-conditioning. Strangely enough, nuclear reactors and I share this same intolerance to heat. Nuclear reactors have shown time and again that extremes in climate can negatively affect performance.
Reactors have to take in water to keep cool. Reactors, in fact, take in a whole lot of water. Lots more than other energy sources. Sixty reactors in the US use a once-through cooling system, in which they intake water to cool the reactors, and spit out the warmer water back into the lake or river. The problem is that in hot weather the water is too hot to cool the generators sufficiently, and thus reactors can’t run at full capacity. The other problem is that hot weather is often accompanied by droughts, which mean low water levels in lakes and rivers. Environmental regulations require that lakes and rivers maintain a certain amount of water and keep the temperature below a certain level so that there is enough water and it isn’t so hot it will cook the fish. That becomes a challenging thing to manage during heat waves. This is why the TVA reactors in Alabama were only operating at 50% power yesterday. And why they’re operating at just 70% today. It’s why several French reactors had to shut down in the European heat wave a few years ago. The economic side is that surprise shutdowns, like in France, require them to buy power at a premium elsewhere.
Thanks to climate change, we can expect hotter summers. So here we are, just finishing the hottest month on record in DC, and we all know August is usually worse. Can nuclear power take heat? Apparently not any better than I can.