(Repeats Jan. 21 item)
By John Kemp
LONDON, Jan 21 (Reuters) - Nuclear power is the energy dream that refuses to die, despite serious accidents at Windscale (1957), Three Mile Island (1979), Chernobyl (1986) and Fukushima (2011).
Many of the arguments that were employed in favour of nuclear in the 1950s and 1960s as a solution to oil supplies running out are now being resurrected in favour of nuclear as a solution to climate change.
But the promise of safe, clean and reasonably priced nuclear power seems as far away now as it was 60 years ago. We are still waiting for the safe, cheap and reliable reactor designs that were promised in 1956.
Back in the 1950s, plentiful and cheap energy from fissioning uranium and thorium was seen as the only alternative to fast-depleting fossil fuels such as oil, gas and coal.
Shell geologist M. King Hubbert is best known as the grandfather of "peak oil" for his theories about the imminent exhaustion of oil resources in the United States and around the world.
But he was also a strong advocate for nuclear power. The 1956 paper that made him famous explicitly linked it to peaking oil production ("Nuclear energy and the fossil fuels").
"It appears that there exist within minable depths in the United States rocks with uranium contents equivalent to 1,000 barrels of oil or more per metric tonne, whose total energy content is probably several hundred times that of all the fossil fuels combined," Hubbert wrote.
"The world appears to be on the threshold of an era which in terms of energy consumption will be at least an order of magnitude greater than that made possible by fossil fuels."
On a time-scale spanning millennia, "the discovery, exploitation and exhaustion of the fossil fuels will be seen to be but an ephemeral event".
By contrast, nuclear offered an energy supply adequate to meet the planet's needs for thousands of years.
Writing in the 1950s, when the United States and the Soviet Union were racing to build ever-bigger nuclear weapons, Hubbert could not be unaware of the perils associated with splitting the atom.
Nuclear scientists were still learning to master the peaceful uses of atomic energy to build utility-scale civilian power reactors.
However, provided the superpowers did not wipe each other out in the meantime with a devastating exchange of nuclear weapons, Hubbert thought civilian nuclear power would become a viable alternative to oil and gas by the 1970s.
"It will probably require the better part of another 10 or 15 years of research and development before stabilized designs of reactors ... are achieved," Hubbert predicted, but after that "we may expect the usual exponential rate of growth".
Hubbert would probably have been surprised and disappointed about how little progress has been made in the intervening years.
Climate scientists are now revisiting many of the same arguments in favour of nuclear as a way to avert global warming.
In November 2013, James Hansen, formerly head of NASA's Goddard Institute for Space Studies, and the doyen of the climate science movement, published an open letter, with three colleagues, addressed "to those influencing environmental policy but opposed to nuclear power".
"As climate and energy scientists concerned with global climate change, we are writing to urge you to advocate the development and deployment of safer nuclear energy systems," Hansen and his colleagues said in the letter.
"In the real world there is no credible path to climate stabilization that does not include a substantial role for nuclear power," they wrote.
"Continued opposition to nuclear power threatens humanity's ability to avoid dangerous climate change."
While acknowledging the risks associated with nuclear power, including accidents and the possibility of weapons proliferation, the scientists said these are dwarfed by the risks associated with pumping vast quantities of carbon dioxide into the atmosphere as a result of burning fossil fuels.
Echoing Hubbert, they insisted: "We understand that today's nuclear plants are far from perfect. Fortunately, passive safety systems and other advances can make new plants much safer. And modern nuclear technology can reduce proliferation risks and solve the waste disposal problem."
Hansen and his colleagues argued that wind, solar and biomass simply cannot scale up fast enough to provide cheap and reliable energy on the scale required, so anyone concerned about global warming cannot afford to rule out nuclear as a way to displace substantial amounts of fossil fuel combustion.
Nuclear power arouses strong emotions. Hansen's letter was immediately blasted by climate specialists at the U.S. Natural Resources Defense Council (NRDC) and other environmental groups, many of which have campaigned against nuclear power for more than three decades on safety grounds.
"The authors of this letter (and other nuclear energy proponents) are on the wrong track," the NRDC wrote in a withering response.
"Given its massive capital costs, technical complexity, and international security concerns, nuclear power is clearly not a practical alternative," they added ("Response to an Open Letter on the Future of Nuclear Power", Nov. 5, 2013).
The NRDC wants policymakers to focus on energy efficiency and renewables such as wind and solar, and not become distracted by dreams of cheap, plentiful and clean nuclear energy.
"The open letter suggests that it is the environmental community that is somehow holding back a nuclear power surge. Nothing could be further from the truth," the NRDC complained.
"No one can or should close the door to the prospect of improved nuclear power technology. But in a world with constrained capital resources and an urgent need to find the lowest-cost ways to cut carbon pollution, nuclear power ranks far down the list of promising or likely solutions," according to the council.
"A U.S. nuclear renaissance has failed to materialize, despite targeted federal subsidies, because of nuclear power's high capital cost, long construction times, the lower demand for electricity due largely to improvements in energy efficiency, and competition from renewables," the NRDC said.
The NRDC's critique is not the whole story, however. The industry's hoped-for "nuclear renaissance" has been thwarted by three developments: cheap natural gas from the shale revolution; regulatory delays due to environmental activism; and the disaster at Fukushima.
Like renewables such as solar and wind, nuclear power plants have very high capital costs but low fuel and other operating costs. In contrast, gas and coal-fired power plants are cheap to build but relatively expensive to run.
In the United States, the economics of nuclear power have been fatally disrupted by cheap gas, and in Western Europe as a result of cheap coal.
The shale revolution also imperils renewables. But unlike wind and solar, nuclear has not benefited from the same level of subsidies and renewable portfolio standards to help it compete (except in Britain, where the government has guaranteed special high electricity prices for nuclear power producers, as it has for wind power).
A big part of nuclear's high capital costs has been caused by regulatory and construction delays, most of which stem from a dogged campaign waged by environmentalists to tie up projects in administrative and legal delays to make them uneconomic and force their sponsors to abandon them.
So, it is not entirely true to say the environmental community has failed to hold back nuclear power.
However, the industry is not blameless. For 60 years, nuclear engineers and operators have been promising safer and cheaper designs. By the early 2000s, the industry had recovered from memories of Chernobyl and was promising a fourth generation of standardised reactor designs with more passive safety features. Then Fukushima revealed a host of design flaws and unsafe operating practices, damaging public confidence.
It is possible that large-scale nuclear power could offer part of the solution to global warming, just as it promised to avert Hubbert's fears about peak oil. But the industry appears no nearer than it was then to building a favourable consensus or solving its cost and safety problems.
Hansen, like Hubbert, looks set to be disappointed. (Editing by Dale Hudson)