Fission in flux1 December 2006
The recently published and appropriately titled Stern review: the economics of climate change is a must-read for all of us with an interest in the future of the power industry. Commissioned by the UK Treasury and carried out by Sir Nicholas Stern, the report provides, as you’d expect from the Head of the UK Government Economic Service and a former World Bank Chief Economist, a distinctly market orientated view of climate change, describing it as “the greatest market failure the world has seen” and suggesting that “if we take no action to control emissions, each tonne of CO2 that we emit now is causing damage worth at least $85 – but these costs are not included when investors and consumers make decisions about how to spend their money.”
The Stern report also sees huge business opportunities arising from the shift to a low-carbon economy (a point touched on in last month’s Comment) suggesting that markets for low-carbon technologies will be worth at least $500 billion, and perhaps much more, by 2050, if the world acts on the scale required. “Tackling climate change is the pro-growth strategy; ignoring it will ultimately undermine economic growth,” says Stern.
The Stern report provides yet more encouragement to the nascent carbon capture and storage business: “Even with very strong expansion of the use of renewable energy and other low-carbon energy sources, hydrocarbons may still make [sic] over half of global energy supply in 2050. Extensive carbon capture and storage would allow this continued use of fossil fuels without damage to the atmosphere, and also guard against the danger of strong climate-change policy being undermined at some stage by falls in fossil-fuel prices.”
And for the power industry as a whole perhaps the key message from Stern is his assessment that around the world this sector “will have to be at least 60%, and perhaps as much as 75%, decarbonised by 2050 to stabilise at or below 550 ppm CO2e” (e = equivalent). For comparison, the present concentration of greenhouse gases in the earth’s atmosphere is about 430 ppm CO2e and pre-industrial levels were 280 ppm CO2e.
Although specific discussion of the merits of the nuclear option seems to be strenuously avoided in the Stern report, this ambitious target for decarbonisation is a message will not be lost on the world’s nuclear power industry as it prepares for its long-hoped-for renaissance.
It will be particularly well received by Toshiba, which has recently successfully completed its $5.4 billion purchase of Westinghouse (with Shaw taking 20% and IHI 3%) and is banking on nuclear new build aspirations becoming reality over the next few years.
The Toshiba move seems to have sparked the announcement of two major other new fusions in the fission business, an alliance between MHI and Areva, and most recently one between GE and Hitachi. This creates essentially three strong new groupings in the nuclear power supply business, in addition to, and by no means forgetting, the Russian incumbent Atomstroyexport, which has just distinguished itself by winning the award to construct (or should that be to finish?) a twin 1000 MWe plant at Belene in Bulgaria (see p 37) – one of only about three nuclear power new-build projects currently actually happening in Europe.
The Bulgarian decision to press ahead with Belene can be seen as a further piece of evidence that nuclear power really is back on the agenda. Another strong indicator is the overt and unequivocal embracing of the nuclear option by the British prime minister Tony Blair, who said in parliament “I’m in favour of it” and ... “without it we will not be able to meet any of our objectives on climate change or our objectives on energy security.”
But while the nuclear option may have gained new momentum from the growing importance being attached to decarbonisation in the power sector, coupled with security of supply concerns, it remains a very challenging technology and one that is hard to get right. The existence of well resourced new alliances on the supply side is therefore to be welcomed.
Among the challenges are dealing with ageing plants, for example the UK’s gas cooled reactor population, which is experiencing problems with its boiler plumbing and which also faces some difficult regulatory decisions to address the issue of graphite cracking.
As recent events at Forsmark 1 have shown – which included failure of two out of four emergency diesels to start automatically and failure of two converters in the UPS – even the Swedes are not immune from occasional surprises in the field of nuclear safety. The Forsmark 1 incident was triggered by a switchyard short circuit, causing a loss of offsite power and consequent scramming of the reactor. But lack of emergency power meant that control rod position was for a number of minutes unclear. The Swedish regulator, SKI, has said that “finding out that safety functions proved to be linked together in a delicate way” is “extremely serious” – although the event was only ranked 2 on the International Nuclear Event Scale.
And then there’s the issue of coping with the sheer scale of new light water reactor designs.
When they are running smoothly on baseload the economies of scale are attractive but when they shut down for any length of time the financial consequences for owner/operator and, in the case of new plants, the supplier, are of course catastrophic and can soon impact the balance sheet of even the largest corporation.
Supporters of small-scale distributed generation must be looking with a certain degree of Schadenfreude at the recent problems encountered with the Hitachi steam turbines at the Hamaoka 5 ABWR, which took this 1380 MWe plant off line in June and look like keeping it out of action for a few months more.
According to a report on the event submitted to the Japanese government on 27 October and very well summarised, with informative illustrations, on the Chubu Electric website (www.chuden.co.jp), the initiating cause of cracks in the forks of vanes in the 12th stages of the LP turbines was “simultaneous occurrence of random and flashback vibration in 20% load cutoff tests during test operation...” These combined stresses caused high cycle fatigue, and the resulting cracks were enlarged during subsequent commercial operation. “Design and manufacture of new vanes is expected to require a considerable amount of time,” says Chubu, so an interim solution is to be implemented, involving replacement of the affected vanes with pressure plates.
The designers had considered the effect of random and flashback vibration on the 13th and 14th stages but not the 12th. “When turbines are increased in size in future,” says the report, “manufacturers will be requested to closely investigate the scope of applicability of existing knowledge and to conduct thorough tests and analyses to ensure reliability.”
As we enter the era of the 1700 MWe and 1750 MWe 50Hz nuclear steam turbine (to be deployed at Olkiluoto and Flamanville respectively), as well as the 1455 MWe 60 Hz machines for Shin Kori and MHI’s proposed 1700 MWe unit for the 60 Hz market, with 70 in last stage blades (see pp 33-35), the lessons of Hamaoka 5 will need to be taken fully on board.