This scheduled regularity might sound mundane, however it’s fairly the feat that operational reactors are as dependable and predictable as they’re. It leaves some huge sneakers to fill for next-generation expertise hoping to hitch the fleet within the subsequent few years.
Typically, nuclear reactors function at fixed ranges, as near full capability as attainable. In 2024, for industrial reactors worldwide, the common capability issue—the ratio of precise vitality output to the theoretical maxiumum—was 83%. North America rang in at a median of about 90%.
(I’ll notice right here that it’s not all the time honest to only have a look at this quantity to match completely different sorts of energy crops—natural-gas crops can have decrease capability components, however it’s largely as a result of they’re extra more likely to be deliberately turned on and off to assist meet uneven demand.)
These excessive capability components additionally undersell the fleet’s true reliability—loads of the downtime is scheduled. Reactors have to refuel each 18 to 24 months, and operators are likely to schedule these outages for the spring and fall, when electrical energy demand isn’t as excessive as once we’re all working our air conditioners or heaters at full tilt.
Check out this chart of nuclear outages from the US Vitality Data Administration. There are some days, particularly on the top of summer time, when outages are low, and practically all industrial reactors within the US are working at practically full capability. On July 28 of this 12 months, the fleet was working at 99.6%. Examine that with the 77.6% of capability on October 18, as reactors have been taken offline for refueling and upkeep. Now we’re heading into one other busy season, when reactors are coming again on-line and shutdowns are getting into one other low level.
That’s to not say all outages are deliberate. On the Sequoyah nuclear energy plant in Tennessee, a generator failure in July 2024 took one among two reactors offline, an outage that lasted practically a 12 months. (The utility additionally did some upkeep throughout that point to prolong the lifetime of the plant.) Then, simply days after that reactor began again up, the whole plant needed to shut down due to low water ranges.
And who can neglect the incident earlier this 12 months when jellyfish wreaked havoc on not one however two nuclear energy crops in France? Within the second occasion, the squishy creatures bought into the filters of kit that sucks water out of the English Channel for cooling on the Paluel nuclear plant. They pressured the plant to chop output by practically half, although it was restored inside days.
