Plants Lifetime Extensions and Retirements
Most nuclear power plants originally had a nominal design operating lifetime of 25 to 40 years, but engineering assessments have established that many can operate longer.
By the end of 2016, the Nuclear Regulatory Commission (NRC) had granted license renewals to over 85 reactors, extending their operating lifetimes from 40 to 60 years. Such license extensions at about the 30-year mark justify significant capital expenditure needed for the replacement of worn equipment and outdated control systems.
In France, there are rolling ten-year reviews of reactors. In 2009 the Nuclear Safety Authority (ASN) approved EDF's safety case for 40-year operation of its 900 MWe units, based on generic assessment of the 34 reactors. There are plans to take reactor lifetimes out to 60 years, involving substantial expenditure.
The Russian government is extending the operating lifetimes of most of the country's reactors from their original 30 years, for 15 years, or for 30 years in the case of the newer VVER-1000 units, with significant upgrades.
The technical and economic feasibility of replacing major reactor components, such as steam generators in PWRs, and pressure tubes in CANDU heavy water reactors, has been demonstrated. The possibility of component replacement and license renewals extending the lifetimes of existing plants is very attractive to utilities, especially in view of the public acceptance difficulties involved in constructing replacement nuclear capacity.
On the other hand, economic, regulatory and political considerations have led to the premature closure of some power reactors, particularly in the USA, where reactor numbers have fallen from a high of 110 to 92, as well as in parts of Europe and likely in Japan.
Importantly, it should not be assumed that a reactor will close when its existing license is due to expire, since operating license extension is now common. However, new units coming online have more or less been balanced by the retirement of old units in recent years often due to poor government decisions. Over 2002-2021, 108 reactors were retired as 97 started operation. There are no firm projections for retirements over the next two decades, but the World Nuclear Association's 2021 edition of The Nuclear Fuel Report has 123 reactors closing by 2040 in its reference scenario, using conservative assumptions about license renewal, and 308 coming online.
