“The Switkowski report says at least 10 and possibly 15 years would be a realistic time scale for building one nuclear power station in Australia. It would take more time still to “pay back” the energy used in construction and fuelling, so it would take 15 to 20 years for any such station to make any contribution to cutting greenhouse pollution. Fifteen to 20 months is a more realistic time scale for large-scale renewables. Global warming is an urgent problem that demands a concerted response now, not a half-baked response after 2020.”
— Prof. Ian Lowe, September 7, 2007, ‘Heeding the warning signs’, Sydney Morning Herald,

Summary: Expanding nuclear power is impractical as a short-term response to the need to urgently reduce greenhouse emissions. The industry does not have the capacity to rapidly expand production as a result of 20 years of stagnation. Limitations include bottlenecks in the reactor manufacturing sector, dwindling and ageing workforces, and the considerable time it takes to build a reactor and to pay back the energy debt from construction.

Nuclear power generating capacity has been stagnant for the past 20 years as the following two graphs illustrate:

Source: Mycle Schneider et al., 2009, 'The World Nuclear Industry Status Report 2009', .

Source: World Nuclear Association

In recent years:
* In 2007 world nuclear electricity generation fell by 2% – more than in any other year since the first reactor was connected to the grid in 1954. (Schneider et al., 2009)
* In 2008 not a single new plant was connected to the grid – the first time that happened since 1955; and uprates were offset by plant closures resulting in a net world nuclear capacity decline of about 1.6 gigawatts. (Schneider et al., 2009; BP, 2009)
* In 2009 there were two reactor start-ups but four permanent shut-downs and net capacity fell by 0.86 gigawatts. (World Nuclear News, 2010)
* In 2010, new nuclear capacity entering commercial operation amounted to 2839 MWe net − an increase of 0.7%. (World Nuclear News, 2011)

A large, short-term increase in nuclear power generation is impossible for the following reasons.

One constraint is the considerable time it takes to build reactors. An average construction timespan is nine years based on the 14 most recent grid connections as at late 2009 (Schneider et al., 2009). There is great variation in reactor construction times, from five years to well over 20 years.

Construction delays are common. Schneider et al. (2009) noted in late 2009 that of the 45 reactors then under construction around the world, 22 had encountered construction delays and 13 had been listed as under construction for over 20 years.

For Australia and other countries without existing nuclear power plants, the lead time for planning, licensing and construction would likely take 15-25 years. As Prof. Ian Lowe (2007) notes: “[N]uclear power is far too slow a response to the urgent problem of climate change. Even if there were political agreement today to build nuclear reactors, it would be at least 10 years before the first such reactor could deliver electricity, while some have suggested that between 15 and 25 years is a more realistic estimate. We can’t afford to wait decades for a response given the heavy social, environmental and economic costs that global warming is already imposing. If we were to start today expanding the use of solar hot water in Queensland to cover half the households in that state – a similar level to the Northern Territory – we could save about as much electricity as a nuclear power station would provide, and do it years before any reactor would be up and running.

In addition to reactor construction, some further years elapse before nuclear power has generated as much as energy as was expended in the construction of the reactor. A report commissioned by the Switkowski Review states that: “The energy payback time of nuclear energy is around 6½ years for light water reactors, and 7 years for heavy water reactors, ranging within 5.6–14.1 years, and 6.4–12.4 years, respectively.” (University of Sydney, 2006) By contrast, construction times for renewable energy sources are typically months not years, and likewise the energy pay-back period is typically months not years.

Another constraint is bottlenecks in the reactor manufacturing sector. (Schneider et al., 2009, section II.5; Ferguson, 2007). Squassoni (2009) notes that: “A significant expansion will narrow bottlenecks in the global supply chain, which today include ultra-heavy forgings, large manufactured components, engineering, and craft and skilled construction labor. All these constraints are exacerbated by the lack of recent experience in construction and by aging labor forces. Though these may not present problems for limited growth, they will certainly present problems for doubling or tripling reactor capacity.”

Another constraint is the general pattern of ageing nuclear workforces. In addition, research and training facilities and courses have been on the decline. (Schneider et al., 2009, section II.6).

Another constraint is that significant new build will be required simply to maintain existing nuclear generating capacity let alone to expand that capacity. The reason is that the global fleet of reactors is ageing. The mean average age of operating reactors is 25 years, older than the average age of all shut-down reactors – 22 years. By the year 2019, 135 reactors will have operated for 40 years or more. In the following decade no less than 216 reactors – more than half of the global fleet – will have their 40th birthday (apart from those that are shut down before that time). In total, 351 reactors – over 80% of the current global fleet of 436 reactors – will be at least 40 years old by 2029.

The average lifespan of reactors currently operating or under construction is a matter of considerable uncertainty. Schneider et al. (2009) assume 40 years and they note that the OECD’s World Energy Outlook 2008 estimates a 40-50 year time frame with an average 45 years expected operation.

Source: Mycle Schneider et al., 2009, 'The World Nuclear Industry Status Report 2009', .

Reactor databases show growing numbers of reactors listed as ‘under construction’, ‘on order or planned’ and ‘proposed’. However a very large number of reactor projects have been cancelled over the years – at least 253 cancelled orders in 31 countries, including 138 cancellations in the US alone (Schneider et al., 2009).

‘Next generation’ or ‘generation 4’ reactors are still far off. For example the Generation 4 International Forum website states that “commercial deployment of Gen-IV reactors is not foreseen before 2030 at the earliest, and all current activities involving Gen-IV designs are at the level of R&D.” The World Nuclear Association (2009b) is also downbeat, noting that “progress is seen as slow, and several potential designs have been undergoing evaluation on paper for many years.”

Uranium resources

Nuclear power expansion is impractical as a short-term response to the need to urgently reduce greenhouse emissions. A significant expansion of nuclear power is theoretically possible over the medium- to long-term. However a major expansion of nuclear power may be constrained by limited uranium reserves. According to the World Nuclear Association (2009), “the world’s present measured resources of uranium (5.5 Mt) in the cost category somewhat below present spot prices and used only in conventional reactors, are enough to last for over 80 years.”

There are numerous ways to extend the 80 year period – new uranium discoveries, mining higher-cost conventional uranium deposits not included in the above calculations, more efficient use of uranium in conventional reactors, greater use of uranium from reprocessing plants, re-enrichment of depleted uranium, etc. It can be reasonably anticipated that conventional uranium resources can be stretched to 200-300 years at the current rate of consumption. Nevertheless those resources would be exhausted much more rapidly in the event of a major expansion of nuclear power. For example, they could be depleted by the end of this century in the event of a three-fold increase in nuclear power. Unconventional uranium sources (e.g. phosphate, seawater) could further extend uranium resources. Other options to extend the use of nuclear power include the use of alternative nuclear fuels or nuclear fuel cycles (e.g. fast neutron reactors or thorium-fuelled reactors).


* BP, June 2009, Statistical Review of World Energy Production, <>.

* Ferguson, Charles, 2007, ‘Nuclear Energy: Balancing Benefits and Risks’, Council on Foreign Relations, <>.

* Generation 4 International Forum <>.

* Lowe, Ian, September 7, 2007, ‘Heeding the warning signs’, Sydney Morning Herald, <>.

* Schneider, Mycle, et al., 2009, ‘The World Nuclear Industry Status Report 2009’, <>.

* Squassoni, Sharon, 2009, ‘Nuclear Energy: Rebirth or Resuscitation?’, Carnegie Endowment Report, <>.

* University of Sydney, 2006, ‘Life-cycle energy balance and greenhouse gas emissions of nuclear energy in Australia’, Report for UMPNER, <>.

* World Nuclear Association, September 2009, ‘Supply of Uranium’,


* World Nuclear Association, 2009b, ‘Fast moves? Not exactly…’, <>.

* World Nuclear News, 4 January 2010, ‘Two up, four down’, <>

World Nuclear News, 4 January 2011, ‘New capacity entering commercial operation in 2010 amounted to 2839 MWe net’, <>