Great Power, Great Responsibility: The Perils of Aging Nuclear Reactors

Cade May
May 15, 2018

Submitted as coursework for PH241, Stanford University, Winter 2018


Fig. 1: A nuclear reactor pressure vessel (RPV) diagram. (Source: Wikimedia Commons)

The nuclear industry is losing stability by the day. The incredible power of nuclear reactors comes with a substantial inherent price. Studies have shown that as nuclear reactors get older, there is an increased probability of malfunctions and serious accidents occurring. [1] Due to the limited lifespan of nuclear reactors, the world may be entering an era of nuclear insecurity.

The Planet's Nuclear Fleet is Getting Old

Nuclear reactors around the globe are approaching their expiration dates in large numbers. Industry expert Jan Haverkamp says that "After three or four decades of operation under high pressure, temperature, radiation and chemical impacts as well as changing load cycles, the risk of ageing becomes more and more significant". [1] This is particularly concerning when accounting for the considerable age of the average operational nuclear reactor. In Europe, "46 out of 151 operational reactors are older than their original design lifetimes". [1] As time moves forward, society's nuclear energy system is becoming more precarious. The powerful nature of nuclear fission processes puts a limit on the sustainability of nuclear energy in its current form--the components of nuclear reactors can only last for so long under such high- energy, high-pressure conditions.

On the Aging Process of Nuclear Reactors

There are numerous ways that nuclear processes can jeopardize the security of a reactor over time. According to Haverkamp, "Unexpected combinations of various adverse effects such as corrosion, embrittlement, crack progression or drift of electrical parameters may result in the failure of technical equipment, leading to the loss of required safety functions". [1] For systems as complex as nuclear reactors, there are lots of things that can go wrong. One particularly vulnerable component of reactors is the reactor pressure vessel (RPV) (see Fig. 1). RPVs are susceptible to embrittlement through neutron irradiation, which can lead to serious issues. "If an embrittled RPV had an existing flaw of critical size and certain severe system transients were to occur, the flaw could very rapidly propagate through the vessel, resulting in a through-wall crack and challenging the integrity of the RPV". [2] Since nuclear reactors deteriorate as they age, the large number of aging reactors worldwide is a safety concern.

Economic Implications and Consequences

Performing maintenance on aging nuclear reactors is extremely expensive. A Greenpeace report notes that the "Replacement of the RPV (like the replacement of the containment) is impossible for economic and practical reasons". [1] As nuclear reactors around the world approach and exceed their intended lifespan, many nations will be forced to evaluate their relationships with atomic energy. For example, consider France, one of the global leaders in nuclear electricity exports. In order to maintain accordance with safety standards, in the near future France will have to spend an estimated $110 billion on the lifetime extension of its aging nuclear reactors. [3] When it comes to nuclear energy, even the most advanced systems can not guarantee absolute safety. Could it be time for society to divest from nuclear energy?

© Cade May. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] J. Haverkamp, ed., "Lifetime Extension of Ageing Nuclear Power Plants: Entering a New Era of Risk," Greenpeace, March 2014.

[2] M. Erickson et al., "Probabilistic Fracture Mechanics - Models, Parameters, and Uncertainty Treatment Used in FAVOR Version 04.1," U.S. Nuclear Regulatory Commission, NUREG-1807, June 2007.

[3] Y. Marignac and M. Besnard, "The French Nuclear Industry in Deadlock," Wise-Paris, 23 Jun 2015.