The Washington Post has an interesting blog post from Brad Plumer on the nuclear energy industry’s stealthy increase of electricity output via uprates. Here’s how Plumer defines an uprate:
According to a new analysis by the U.S. Energy Information Administration, the operators of 98 of the country’s 104 commercial nuclear reactors have asked regulators for permission to boost capacity from their existing plants.
Or, as Plumer points out, the equivalent output of six new reactors (though I would add that it is spread out among 30 or more states instead of six – a net positive. Altogether, there have been 145 instances of accepted uprate application – some reactors have been uprated more than once.)
Uprates aren’t peculiar occurrences, but you knew there had to be a catch:
In recent years, however, nuclear operators have started applying for much larger “extended uprates,” which can increase the output of a plant by as much as 20 percent. This process can include big changes to high-pressure turbines and other equipment.
Do these “big changes” create a danger? Well:
Utilities and regulators have used computer modeling to show that “a properly uprated reactor is no more vulnerable than one operating at its original capacity.”
It’s worth remembering that making a facility “vulnerable” does no one any good, so the conservative approach typically taken at nuclear facilities would dictate that plants avoid uprates if there were multiple instances of their being problematic.
That doesn’t mean there has never been a problem. But where there have been problems, there have been solutions.
In 2002, both reactors at the Quad Cities Nuclear Plant were restarted after having their capacity boosted by 17.8%. Pipes began to shake, and cracks formed in a steam separator, which removes moisture from the steam before it enters the turbines. In one case, a 9-by-6-inch metal chunk broke off and disappeared.
Broken parts were replaced, but the problem continued. Exelon Corp., which owns the three plants, and the NRC were mystified.
Eventually the problem was uncovered: acoustic waves caused by the geometry of the steam pipes. The pipes were acting like a musical instrument. Their geometry was modified to "detune" them.
Solution. And the story also notes that the NRC has held up two uprate applications until “steam separator” questions are answered. These are industrial and regulatory issues that are handled in the course of doing business.
To be honest, while Plumer is looking for a way to make uprates newsworthy, building from an L.A. Times story, he’s honest in noting that they have not been problematic so far: the Quad Cities story above comes from the Times may seem to put a more sinister cast on uprates, but still nothing came from the incident. A problem occurred, caused no harm and was fixed. That’s not very diabolical.
Let’s be fair here. You want reporters to go after hidden and/or malignant behavior in industry – and nuclear energy facilities have been in the journalistic loop since the accident at Fukushima Daiichi – but the American nuclear energy industry just hasn’t been cooperating by revealing itself as a scandal ridden cesspool run by uncaring monsters.
The AP series last year ran several parts and ended up being about nothing because there was nothing really to find. That was an epic fail. Plumer and the Post more or less admit that the biggest scandal surrounding uprates is that they have supplied some 6500 additional megawatts of cleanly generated electricity. So at least we know that.