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The World Nuclear Association’s Performance Report 2019 shows global capacity rose for the sixth consecutive year, with little variation in capacity factors for both old and new reactors.

Nuclear reactors generated a total of 2,563 TWh of electricity in 2018, up from 2,502 TWh in 2017. This is the sixth successive year that nuclear generation has risen, with output 217 TWh higher than in 2012.

At the end of 2018 the capacity of the world’s 449 operable reactors was 397 GWe, up 4 GWe on the previous year. Nine new reactors were connected to the grid, with a combined capacity of 10.4 GWe, while seven were closed, with a combined capacity of 5.4 GWe. The number of reactors under construction at the end of 2018 was 55.

“The world’s nuclear plants continue to perform excellently. Growth is strong, with more than 20 new reactors scheduled to be connected before the end of 2020,” said Agneta Rising, Director General, World Nuclear Association.

The report says that the global average capacity factor in 2018 was 79.8%, down from 81.1% in 2017. Despite this small reduction, this maintains the high level of performance seen since 2000 following the substantial improvement over the preceding years. In general, a high capacity factor is a reflection of good operational performance. However, there is an increasing trend in some countries for nuclear reactors to operate in a load-following mode, which will reduce the overall capacity factor.

There is no significant age-related trend in nuclear reactor performance. The mean capacity factor for reactors over the last five years shows little variation with age.

“Our analysis shows that, on average, reactors are performing at the same high capacity factors regardless of age,” Johnathan Cobb, WNA’s Senior Communication Manager, told Nuclear Energy Insider.

“Of course, it is more likely that operators will seek to continue operating well-performing plants, but the data shows that reactors can maintain high performance with no age-related decline.”

The report also shows that capacity factors for different types of reactor are broadly consistent with the average achieved in the preceding five years. With more than half the world’s reactors being PWRs, the slight decline in capacity factor for this category had a major influence on the overall capacity factor figure.

Capacity factors in 2018 compared to the previous five years are broadly similar, reflecting the consistently high capacity factors seen over the past 20 years. There is a smaller percentage in the 80-85% capacity factor category, and a greater percentage in the categories between 65% and 80%. The report says this may reflect the increasing use of nuclear generation for load following activities.

“Between the 1970s to the 2000s average capacity factors increased substantially,” said Cobb. “That improvement has been maintained over the last ten years, despite some reactors having to load follow, for example to support a growing share of more intermittent sources.

“Forty years ago, almost half of the reactors had a capacity factor lower than 70%. Now it is less than a quarter.”

Fifty-year milestone

The report also highlighted five nuclear power plants that have achieved 50 years of operation, and how those plants have managed to remain competitive with such a long operating lifetime.

Beznau 1 in Switzerland, Nine Mile Point 1 and R.E. Ginna in the USA, and Tarapur 1&2 in India all started operating in 1969. This is the first time this milestone has been achieved by any reactor worldwide. Tarapur 1 is the oldest operating nuclear power reactor as it was first grid connected on 1 April 1969. Units 1&2 at Tarapur commenced commercial operation on 28 October 1969.

Michael Dost, Head of Beznau nuclear power plant in Switzerland, said comprehensive ageing management, continuous investment in plant safety and reliability and “a dash of foresight” were key.

“Thanks to the many investments in renewal and maintenance, we were able to keep the plant at the state-of-the-art in science and technology, as required by Swiss law,” said Dost. “Thanks to our foresight, we were also able to anticipate technical and also increasing regulatory requirements. It is only thanks to this forward-looking planning over generations that the Beznau nuclear power plant is still able to operate almost trouble-free, safely and reliably today.”

Paul Swift, Plant Manager at R.E. Ginna Nuclear Power Plant in New York, said over the last 10 years, the plant has operated at more than 95% of capacity.

“With decades of smart investments and upgrades, the plant is running better than ever,” said Swift.

WNA Director General Rising concluded that one of the most effective actions to be taken to avoid greenhouse gas emissions and meet growing energy demands is to ensure nuclear reactors continue to operate to their full potential. 

“The average age of the nuclear fleet is around 30 years,” she said. “This year, five reactors have achieved fifty years of operation and reactors today are seeking approval for 60 or even 80 years of operation. Many of our current reactors have the potential to still be part of a fully decarbonized generation mix in 2050.”

Scott Birch