Europe must prepare for a nuclear future, says JRC boss.
Rich OECD (Organisation for Economic Cooperation and Development) countries collectively release more than six gigatons of carbon each year, said Mr Schenkel; without nuclear power they would emit a further 1.2 gigatons a year in the future. He pointed out that France, which, at 78%, has the highest share of nuclear energy, has the lowest CO2 intensity and half the world average.
Mr Schenkel believes Europeans must put any qualms about nuclear energy to one side, particularly because the Generation IV plants will further increase safety to unprecedented levels. "Generation IV reactor systems can ensure the sustainability of nuclear energy. The design criteria include the minimisation of waste and better management of natural resources, while four of the six selected systems are 'fast reactors' associated with a closed cycle to burn long-lived actinides. Fast reactors with depleted uranium will produce new fissile material."
However, the evolution and promise of nuclear technologies must also be set against the costs or risks, he said. "Don't get me wrong--there are risks. This is a complex technology that requires highly trained competent staff to run them," he said. "I'm not saying there are no accidents, or no exceeding of dose rates but they are all within the allowed limits--there are 148 nuclear reactors across the European Union, and some have been operating for 30 years and there haven't been any accidents."
The 1986 Chernobyl disaster had paralysed political decision makers for decades, said Mr Schenkel. "But following the accident, the European Commission supported safety improvements of the Chernobyl-type reactors, TACIS and PHARE. You have to remember that this reactor would not have been licensed in any Western country and that safety and design have significantly evolved from Generation I to Generation III reactors."
Mr Schenkel argued that the most accident-prone energy sectors are fuel extraction, refining and transportation in fossil energy chains. "The lowest fatality rates in the energy sector are found in the use of Western hydro and nuclear power. The frequency of severe nuclear accidents is much lower compared to Liquefied Pressurised Gas [LPG], coal and gas." According to the Joint Research Centre, in 2005, there were 1.5 million nuclear transport movements in the EU, with just two minor accidents. "Highly active waste accounts for less than 0.1% of hazardous goods movements," said Mr Schenkel. "Nuclear fission reactors have a safety and environmental track record second to none."
While the International Atomic Energy Association has recorded more than 600 cases since the start of the 1990s of illicit trafficking of radioactive or nuclear material, the security risks surrounding nuclear power stations have been over-stated, said Mr Schenkel. New reactors have built-in proliferation resistant features, and mechanisms have been established to ensure the reliable supply of reactor fuel only to 'bona fide' users. "The shutdown of the EU's civil nuclear reactors would have zero impact on the ability of any other country to obtain nuclear weapons," he said.
Yet, radioactive waste remains a sticking point. According to the JRC, if the waste issue were solved, the number of European states in favour of nuclear energy would rise from eight to 12. "Solutions are already in place for low and medium active waste while solutions are being refined for highly active waste," said Mr Schenkel. Potential solutions for the latter include the creation of geological repositories of vitrified glass to store spent fuel. "This is undergoing tests," said Mr Schenkel. "But acceptance is lacking and there is no real pressure for its quick implementation."
Another option is that of partitioning and the transmutation of the long-lived actinides, americium, curium and neptunium. This was described by Mr Schenkel as "the ultimate solution". The process involves the reduced long-term radiotoxicity of spent fuel after partitioning and transmutation.
In the long term, Mr Schenkel envisages the industry relying on a combination of Generation III (which have a life time of 60 years) and IV reactors (the first prototypes of which are expected to appear between 2020 and 2030). "This combination could provide low carbon, enhanced safety and sustainable production for several hundreds of years," he said. "It could reduce highly active waste by recycling it and 'burning' it in fast reactors and it would provide us with further technological progress to bridge the gap to the introduction of fusion reactors."
Mr Schenkel anticipates that the Generation IV reactors may initially operate as "waste burners" rather than producers of fuel themselves. "Today we reprocess uranium and plutonium but the Generation IV reactors will reprocess the actinides too. At the moment radioactive waste takes 130,000 years to reach the level of natural radiation. If you could partition and transmutate 100% of the actinides, this would drop to just 270 years--that would be fantastic but we can't separate 100% of the actinides. But if we can separate 98% or more, it would take just 2,000 to 3,000 years for the radiation to decrease--that's a dramatic reduction and is a timeframe that the public would be more willing to accept. But it will cost a more probably in the region of 15% to 30% for the fuel cycle."
The issue of storage has also been addressed by the JRC's Institute for Energy, which recently launched a project to establish how radioactive waste would survive in an Ice Age. Working with the Swedish company SKB, the Institute is looking at the integrity of nuclear waste containers. Tests have been conducted on the containers, which are cast-iron inserts with a copper overpack, by exerting on them the equivalent pressure--44 Megapascals--of three kilometres of ice building up above them. The containers withstood the pressure, and only began to fail when the pressure point reached 132 Mpa. "If some of these containers are going to be sealed for hundreds of thousands of years then the fact is that they are going to go through an Ice Age at some point," said Darren McGarry, spokesman for the Institute for Energy. Moreover, the probabilistic analyses indicate that the probability for failure of a canister is less than one in a million at 44 MPa. "The pressure on these containers will be huge but the tests show they can cope and that we exceed the safety margin by a factor of three."
The project is now being broadened out to look at the pressures exerted on transport containers and related structural integrity issues, as well as fuel cladding. "Not all countries use this method of storing waste so this can be used as an example of best practice and provides a lot of guidance for the construction of capsules for waste," said Mr McGarry. "We need to look at the whole multi-barrier process."
The issue of energy supply overshadows the nuclear industry but some recent research may help to give governments more time to decide which route they take by suggesting that there may be a case for reassessing whether some nuclear power stations are really reaching the end of their working lives. In the United Kingdom, for example, the British government has made it clear it is looking to nuclear energy to provide a significant proportion of future energy needs, but the JRC's recently conducted Amalia (Assessment of Materials under the Effect of Load and Irradiation-assisted Stress Corrosion Cracking) experiment suggests that the need to decide may not be as immediately pressing as thought.
JRC-IE's recently conducted several projects on neutron embrittlement of reactor pressure vessel steels, showed that current normatives are conservative with respect to the forecasted loss of ductility of the vessels. Indeed, for example in the USA, NPP license extensions have been allowed on the basis of surveillance programmes results and improved estimates. With the purpose to look at other effects on other safety related components, JRC Institute of Energy has recently started the Amalia testing loop. It is dedicated to simulate stress-corrosion conditions of core internals in Pressurised Water Reactor (PWR) and Boiling Water Reactor (BWR) conditions and verification of safety margins.
Tests provide a measurement for displacement controlled fracture toughness in typical operation conditions. Start-up tests of the loop were carried out on corrosion-sensitive ferritic steel in Boiling Water Reactor conditions (temperature 285C, pressure 80 bar and oxygen 200ppb). Experiments continued for two weeks to prove the reliability of the water preparation loop and the autoclave, and of the sensors. Scientists recorded what was described as a "remarkable" increase of potential drop signal, giving evidence of stress-corrosion effects and the reliability of the monitoring chain and LVDT transducer.
"The results were very significant because so many reactors in Europe are coming to the end of their life," said Mr McGarry. "We have to balance safety with economics. The results showed that safety models we have used are extremely conservative. That means we can ask whether we shut a reactor down because when it was built we said it had a certain life limit, or can we easily keep it open for a few more years? That would buy us time to look at how we want to move forward on energy."
The key to the success of Amalia, however, will be the ability of governments of some countries to convince their public. "In the past there has always been a slight web of secrecy that has caused controversy, mainly because of the mix of energy and weapons-type work that surrounded nuclear energy," said Mr McGarry. "We have to separate the two and be open. We need to address public awareness and perception just as much as we as look at the scientific problems."
This shift of emphasis towards the non-proliferation side of nuclear energy was seen in the recent launch of the High Flux Reactor (HFR) at Petten, which in May for the first time started with a complete core of low-enriched uranium fuel. Operated by the Dutch group NRG (the JRC was the former licence holder), the reactor uses low-enriched uranium (LEU), in which the amount of fissionable 235U is less than 20%. Until recently, the HFR used high-enriched uranium (HEU) containing 235U of 89-93%. This high enrichment made the HEU proliferation-sensitive, meaning that the fuel, which the HFR used until recently for civil purposes, was suitable for nuclear weapons. "Petten offers an important contribution to the global effort of diminishing the use of proliferation-sensitive high-enriched uranium," said Mr Schenkel.
"It took a long time to finally do it, but it is significant," said Mr McGarry. "We had to look at the effect of LEU on isotope production--they didn't want to have an interruption to that."
Despite the successful switch to LEU, the Dutch group NRG is proposing to build a second reactor, along similar lines. This is because the current reactor is scheduled to reach its end of life in 2015. For the moment, the European Commission has yet to make its position clear on how to move forward.
Aware that rapid developments are taking place within the nuclear energy, the Joint Research Centre will later this year launch a nuclear science web portal, aimed at professionals, academics and students. Called Nucleaonica, the portal (www.nucleaonica.net) will have four main centres when it launches in September: a data centre with online, interactive nuclide charts and searchable databases with internationally evaluated nuclear data; an application centre featuring modules on decay, fission yields and other relevant issues; a knowledge centre that will draw on thousands of websites for news reports on nuclear issues; and a training centre with online access to all training courses and workshops.
"A large number of people are leaving the nuclear industry," said Dr Joseph Magill of the Institute for Transuranium Elements. "There's a worry that young people coming into the industry don't have the specialist knowledge that takes many years to build up. If there were to be a resurrection of interest in nuclear industry then Nucleaonica will fill much of that knowledge gap."
BY MARK ROWE, in Munich
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|Publication:||International News Services.com|
|Date:||Jul 1, 2006|
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