Nuclear power station in Olkiluoto, Finland: The 1.6 billion watt baby

It's just as well they widened the road to Olkiluoto. It has to cope with a medium-sized army of construction workers, engineers, government officials and journalists, all travelling the 7.5 miles between the main road and the tip of this remote peninsula on Finland's west coast, where work on Europe's first new nuclear power station in a decade is under way.

Olkiluoto 3 will be the third reactor to be located here, and according to its designers it will be the world's first "third-generation" plant. This means it has been designed to cope with the risks of a post-9/11 world, including a direct hit by a fully loaded airliner. And, unlike its two sisters, it is being built and run without government subsidy.

"Electricity produced by nuclear is more competitive than that produced by any other investment and that includes reprocessing the spent fuel, putting it into the waste repository and closing down the existing plants," says Martin Landtman, senior vice-president on the project for the client, power generation company Teollisuuden Voima Oy.

Olkiluoto 3 under construction. It will join two existing plants and a wind turbine.

The plant is based on a design called the European Pressurised Water Reactor, a name that demonstrates the ambitions of its designer, a consortium made up of French company Areva and Germany's Siemens. It would certainly be a model for plants in this country if third-generation nuclear power gets the green light - which is looking increasingly likely (see below - "Britain's nuclear options"). Indeed, Finland is nearing the end of a road on which the UK has just taken its first steps. So what lessons do the Finns have for us?

Compared with them, we have it pretty good when it comes to energy supply. They have to import 67% of their fuel, including coal and gas, from Russia, and their domestic demand is increasing. Furthermore, Finland has no hope of meeting its Kyoto Protocol targets if it opts for fossil fuel power stations and, according to Landtman, 6000 wind turbines would be needed to equal the capacity of Olkiluoto 3. So the Finnish predicament is rather like ours, but with the volume turned up.

Given these constraints, the nuclear option looked attractive to the Finns. But there were two additional factors that tipped the scales in its favour. First, the four nuclear power stations that Finland has now have excellent safety records. And second, TVO claims to have sorted out the waste storage problem - Olkiluoto enjoys particularly stable ground conditions and construction work has started on a repository 500 m underground in which waste will be sealed. According to TVO, this will be unaffected by rising sea levels or any new ice ages - and in any case the radioactivity of the waste will practically have disappeared after a few hundred years."If there was a bad track record and if the fuel could not have been taken care of, it would not have been easy to get approval," says Landtman. This part of the equation will be harder for the UK's politicians to square with the public: power stations in this country have a good record but the waste reprocessing facility at Sellafield has a terrible one, and there is no permanent disposal facility in Britain. Also, in the wake of the bitter CND protests of the 1980s, all things nuclear acquired a sinister glow in the mind of the British public.

The economic case for Olkiluoto 3 was also good. "There is no state subsidy - it's financed purely on free market terms," says Landtman. Twenty per cent of the funding will come from big industrial companies in the form of equity stakes, 5% will be lent to TVO by financial institutions, and the remaining 75% will be loaned directly by private companies. These companies will take the output from the station and either use it themselves or sell it on. Critics have questioned the figures, saying the fixed price of €3.2bn (£2.2bn) has been subsidised by cheap loans - an allegation the European commission is investigating. Despite this, the financing of the plant is radically different from the days of wholesale state subsidy and this financing method could be a model for the UK, as large companies have indicated they would be interested in funding new nuclear here.

Reinforcement being positioned inside the reactor liner ready for its concrete base

The plant is being built as well as designed by the Areva Siemens consortium: Areva is constructing the reactor building and Siemens is responsible for the turbine hall. It is rather like design and build, with one important difference. Nuclear power stations are subject to intensive scrutiny by the regulators to ensure their safety. Every element of the design has to be checked and approved, then checked again to ensure there is no deviation from the specification.

TVO reports to STUK, the Finnish radiation and nuclear safety authority. "The authority only talks to us and has no contract with the consortium so that puts us in the driving seat," says Timo Kallio, senior manager in the construction department. "We check on the design and comment directly."

This process would probably be repeated in Britain. "The way STUK works in Finland would be fairly similar to the way the Nuclear Installations Inspectorate would operate in this country," says David Boath, international reactor development director at Amec NNC, Amec's nuclear division.

The audit process means TVO has to employ an army of people to help. "The amount of documentation issued is huge so we use consulting companies to help," says Kallio. "If I'd known, I'd have formed my own audit company. Everyone is auditing everyone else."

Take concrete. Vast amounts are needed, so a huge batching plant has been put in place, supported by two backup plants with a total capacity of 300 m³ an hour. "The biggest challenge is co-ordinating all the concrete work on the nuclear island as it's all cast in situ. We're casting between 10,000 m³ and 14,000 m³ of concrete a month at the moment," says Kallio. "The logistics and quality of the concrete casting is the key issue to keep on schedule."

Unfortunately, the team found out the hard way how stringent quality control policies can affect a programme. "There was a deviation from the specification in the batching plant - there was too much water in the mix. Technically, it was not a problem, but because it was a deviation it had to be addressed," explains Landtman. "The plant was shut down for eight weeks and procedures were put in place to ensure that this would never happen again."

But it wasn't just a case of more training for the batching plant operatives. The specification of the wet concrete that had been poured had to be checked and documented. "There was a hell of a lot of back documentation and recalculation,"

says Kallio. "The lesson we learned was this was the last time that was going to happen. Everything has to be done before." He points out this is the crucial difference between conventional heavy civil engineering projects and nuclear power schemes. "With conventional construction if you know the product is good, you just continue."

Indeed, the work that has been completed so far doesn't look particularly complicated - apart from the paperwork. But the scale of it is impressive. TVO, which was responsible for preparing the site before handing it over to the consortium, started work at the beginning of 2004. This wasn't just a case of cutting down a few trees: 320,000 m3 of solid granite had to be removed to level the ground and create the hole in which the plant will sit. "You have to explode it - there is no other way," says Kallio. "And we had to bear in mind there were two operating nuclear power plants next door so we had to control the vibrations."

The plant is set deep into the ground so cooling seawater can flow into it through a large channel. Extensive grouting was necessary to waterproof this excavation, as it was up to 14 m below sea level. The channel has been dammed to prevent the site being flooded, and this will be removed at the end of the project. TVO has also built a harbour for ships bringing in materials and a 1.6 km long ringmain to supply services to the site.

A total of 52,000 tons of rebar is needed for the project

Areva and Siemens took over the site in February 2005 with just five years and three months to complete the project. "It's the world's fastest schedule," says Kallio. Work commenced on installing the first of 52,000 tonnes of rebar needed on the project. Much of this will be 42 mm in diameter. "It's the biggest rebar allowed in Finland without special testing."

Once the rebar for the plant's 3.5 m base slab and the lower part of the reactor building walls was in place, concrete pouring could begin. This has been done in three stages, but the bulk of it was done in one go - 12,000 m³. "It was the biggest single casting done in Finland ever," says Kallio. "It was done continuously over six days with a lorry coming from the batching plant every three minutes. It went perfectly."

The next stage was to install the base part of the steel liner, used to make the reactor building gas-tight. The 50 m diameter liner arrived by ship in two halves and has been welded together on site. One of the world's three largest cranes with a lifting capacity of 1600 tonnes was used to lower the liner into position on the slab. "It was a big day when that was lifted," says Kallio.

Work has now started on welding together the next part of the liner, which will sit on the base. There are four intermediate rings of steel sitting on the base and these will be capped by a steel lid.

In an out-of-the-way spot, a team is busy constructing a full-scale mock-up of one corner of the reactor building. This is to work out the most effective way of doing it and to check quality. The reactor has an inner and an outer wall, both more than 1 m thick (See attached - "Reactor section diagram"), and concreting work is due to start this August. Work is also progressing on the building just outside the reactor shell, and construction has started on the turbine hall - the concrete columns for the turbine are in position.

Check and check again

Construction is scheduled to finish at the end of 2007. But that isn't the end of the story: it takes a year to get an operational licence. This involves yet more checking - the authorities sift through the material to make sure the plant has been built properly. The plan is for Olkiluoto 3 to come on stream in 2009, providing the team can claw back a nine-month delay. Problems with the concrete haven't helped, but according to Landtman: "The real reason for the delay is because the detailed engineering designs are delayed. This is because of design changes such as the hardened reactor building shell."

The plan is to work harder. There are two eight-hour shifts a day and this will rise to three if necessary. Work will also be re-sequenced. "We will have to see how these measures work out on site," says Landtman.

Despite these glitches, Olkiluoto 3 can provide good lessons if Blair's government decides to go down the nuclear road: private funding, productive client-contractor relations, bold engineering and a mature approach to auditing. Let's hope the UK is paying attention.