By Brian Schimmoller, Contributing Editor
When Progress Energy shut down the Crystal River nuclear plant in September 2009 to refuel and replace the steam generator, all indications pointed to an uneventful outage. Steam generator replacements had become almost routine in the industry, typically adding only modestly to planned outage length. Eighteen-plus months later, after discovering a “delamination” of the concrete containment structure, that outage continues.
The aging of nuclear plants has become front page news in the wake of Fukushima. Many wonder whether the advanced age of the Fukushima Daiichi plant increased the likelihood of an accident and whether a newer plant would have responded to the crisis more effectively. These are valid, not unexpected questions considering the gravity of the situation in Japan. However, the issues of age and health are regularly conflated, typically viewed as one and the same when they really are distinct elements. A 15-year-old car is old in general terms, but that does not mean a 15-year-old car cannot run safely and smoothly.
Similarly, a 40-year-old nuclear plant with the right maintenance and upgrades should be able to run safely and effectively. What’s different between the car and the nuclear plant is that cars have a much longer history and a much larger population over which to assess the effects of aging. Nuclear plants have to evaluate and assess aging as it happens. A number of aging effects are starting to show themselves in nuclear plants and it will be up the nuclear power industry to demonstrate that it can recognize and respond to these “wrinkles.”
In some cases, nuclear power plants may say the wrinkles are worth addressing; in other cases, it may not be cost-effective to invest in a remedy. At Crystal River, Progress Energy decided the projected value of electricity from the plant exceeded the cost of extensive repairs.
“The Crystal River Nuclear Plant is our least-cost resource to operate, and with it in service, our customers save about $300 million a year in fuel costs,” said Vincent Dolan, Progress Energy Florida’s CEO. Translation: the $300 million in annual savings relative to other generation options will be able to offset the projected $900 million to $1.3 billion repair cost relatively quickly.
In other cases, the calculus doesn’t work out. At the Oyster Creek plant in New Jersey, Exelon decided the remedy wasn’t worth the cost. In early 2010, the New Jersey Department of Environmental Protection issued a water permit that would have required Oyster Creek to install cooling towers to reduce the impact of the plant on aquatic life in Barnegat Bay. The estimated retrofit cost of $800 million was too much for Exelon, which was able to negotiate an agreement with the state to close the plant in 2019 rather than at the expiration of its license in 2029. In light of this agreement, the Department of Environmental Protection backed off its original permit decision.
Admittedly, the Oyster Creek decision was not specifically related to age, in that there was no indication the plant’s existing cooling system was not performing up to design levels. However, the cumulative impact of the plant on the neighboring water bodies over its long life surely impacted perceptions, if not the decision itself.
One aging plant whose fate is still up in the air is Vermont Yankee. The calculus there includes politics, but aging effects have also played a role. A portion of the cooling tower collapsed in 2007 and some of the subsequent repairs were later found inadequate. The plant also has had several tritium leaks that, although not a threat to public health or plant safety, reflect degraded plant components and have negatively impacted public perception. Despite the uncertain political and public situation, Entergy appears committed to the plant, as evidenced by its decision to go ahead with a scheduled refueling outage this fall. Metaphorically speaking, Entergy believes the wrinkles at Vermont Yankee will not result in a permanent scar and are worth ironing out.
These types of tradeoff analyses will become more common as the nuclear fleet ages. And it’s more than concrete containment structures and cooling towers. Other age-related issues that nuclear plants will need to monitor, evaluate and address include buried piping, cables, analog instrumentation and control systems, and reactor internals.
In the end, age is a valid consideration in license extension and utility rate case decisions, just as it is in deciding whether a new transmission is worth the investment for a 15-year-old car. Age will become even more prominent if nuclear plants ultimately decide to pursue a second round of license renewal, which many believe would entail significantly higher costs. Where a nuclear plant owner may have invested $10 to $20 million to conduct the engineering and regulatory tasks involved in obtaining the initial license renewal to 60 years, a second license renewal to 80 years may be five to 10 times more expensive. And that doesn’t include the outlay that may be required for capital improvements to enable extended operation.
Wrinkles are signs of age, but they can also be signs of wisdom. The experience gained from 40-plus years of commercial nuclear power will be essential in making the high-dollar decisions separating continued operation of aging nuclear plants from their potential shutdown.