I've often seen this structure on my journeys to and from North Wales and wondered what it was.

The Trawsfynydd Nuclear Power Station is off the A470, in a rather picturesque area of North Wales, alongside the Trawsfynydd Lake.

The station began generating electricity in 1965, and stopped in 1991, according to a DTI report. Other sources put the last breath of the station between 1993 and 1996.  There was initially an attempt to put forward proposals for measures to extend the life of the station but these were rejected and the site was decommissioned.

The lake itself has an interesting history, and ironically it was originally created (by damming the valley) in order to provide hydro-electric power for the region.

Gwynedd Archeological Trust article

The land on which the Maentwrog hydro-electric power station, and the lake and dam necessary to supply water to it, was purchased in the mid-1920s by the North Wales Power Company: work began in 1925 and the station was opened in October, 1928.  It originally had an 18 megawatt output from three turbines driven by generators, but a fourth was added in 1934 increasing its output to 24 megawatts.

Work on the construction of Atomfa Trawsfynydd (power station) begun in July, 1959, by which time Snowdonia had been designated as a National Park. Over 800 non-local workers lived in the Bronaber camp (area 20), recently vacated by the Army.  Both of the station's reactors were in operation by March 1965 and the station was finally opened in October 1968.  Built at a  cost of £103 million, Trawsfynydd power station was the former Central Electricity Generating Board's (CEGB) first inland power station, and the first to use a lake to obtain water for cooling the condensers of its turbo-alternators.

A Friends of the Earth breifing note on renewable energy, highlights the alternatives that are available to Wales.  There is a wind farm not all that far from the nuclear power station. I don't have any photos of it but I always love seeing the windmills, there's something graceful about them. I find them an interesting addition to the landscape.

Remote and beautiful, the south of Snowdonia National Park is host to a decaying and dangerous nuclear power station. Trawsfynydd lake and the site will be polluted with radiation for thousands of years, even though the power station itself closed in 1993. Electric pylons wend their way through the surrounding park in two directions, carrying electricity to keep the defunct power station cool. Nearby, the Centre for Alternative Technology (CAT) and local windfarms testify to alternative methods of generating energy.

Cefn Croes windfarm is one such local windfarm near Aberystwyth which opened recently. Its 39 powerful turbines are now supplying half of Ceredigion's annual electricity demand. Mid Wales could in fact generate much of its own electricity demand from the regions' own wind resources.

What I find fairly astonishing, is that the site had barely run for 35 years or so.  There are more people working on the site now to decommission it, than there were running the station when it generated electricity. And for 35 years worth of use, the immense and long term operation needed to get rid of everything left over hardly seems worth it.

Can old reactors take the Strain? - New Scientist, 1992

Safety inspectors threatened to close down the oldest commercial nuclear power stations in England and Wales last year unless the company operating them, Nuclear Electric, could confirm that the steel pressure vessels surrounding the reactors were fit enough to go on working. Their concern was prompted by evidence that welds in the pressure vessels at the Trawsfynydd station in North Wales had aged faster than expected.

The ageing at Trawsfynydd was mainly the result of long-term exposure to neutron radiation. Nuclear Elec-tric, which regularly assesses the level of neutron damage at its stations by monitoring the condition of samples of construction materials placed in the reactor, decided to shut down the plant's two reactors to investigate what was happening more thoroughly.

The decommissioning process is likely to take at least 100 years.  Various bits of information can be gleaned from places such as;

Public participation in EIA of nuclear power plant decommissioning projects: a case study analysis(Feb 2004)

Info on the Nuclear Decomissioning Authority website

Archives and photos of the site

And (quite possibly linked to from here before)A fairly comprehensive blog article on the issue, looking at problem of decommissioning the sites. It has researched the decommissioning age of 11 sites - which ran for between 25 to 47 years. I notice Starvid has made comments on this article!

BBC online article on the decommissioning of the site, 2006.

The labour, energy and taxpayers' money (about £45m this year) being devoted to this site are all part of the decommissioning process which will continue here for nearly another century.

...470,000 cubic metres of waste - enough to fill the Royal Albert Hall five times over.

This is the estimated quantity of waste material from existing nuclear plants, including those like Trawsfynydd which are being dismantled, for which there is still no long-term disposal plan.

That process is only projected to be completed by the end of this century, as it is not considered safe to start dismantling the highly radioactive core until the 2080s.

The bulk of the waste produced at Trawsfynydd is debris of various materials not radioactive in themselves, but which were in prolonged contact with nuclear fuels.

Another key component of the Trawsfynydd waste is the sludge and resin extracted from the water ponds adjacent to the reactors, used to cool spent nuclear fuel before it was removed for re-processing.

a building behind the Trawsfynydd reactors, 90m long and 20m high, which will act as a temporary store for the waste containers, probably for around 30-40 years.
This building and the reactor towers themselves, whose height will be reduced, will be clad in local Welsh slate designed to make them blend better into the landscape.

An example of the slate cladding that is starting to go up. Certainly more aesthetic that the current crumbling concrete, especially when the height is reduced.

I know there has been plenty of discussion on ET already about nuclear power and what shold be done with all the waste, and whether or not we should press ahead  with a new generation of nuclear power stations. I found it quite useful for me to put it into the context of the energy resources of my own country, and the corresponding problems that have arisen from having a nuclear power station here.

So, has the site caused a rise in cancer incidences in the area? According to a report, published last year, yes it has.  It also suggests that the cancer rates have been covered up by various authorities.
The report examined cancer rates between 1996-2005 and 2003-2005.

Western Mail article on cancer rates around the power station.

Cancer rates in villages near the Trawsfynydd power station are 'alarmingly high' leading to new concerns about the side-effects of nuclear power, a new investigation reveals.

The study claims that women under 50 are particularly at risk, with their level of cancer during the past three years being 15 times more than the national average.

But Dr Busby is adamant that his conclusions should be taken seriously. He said that fallout from Chernobyl in 1986 could have had a bearing on the results. But he believes the most obvious suspect is Trawsfynydd nuclear power station.

The 'Busby' Report, 2006:

Trawsfynydd nuclear power station is the only inland nuclear station to be built in the UK. The power station has two MAGNOX type CO2 cooled graphite moderated reactors and is situated on a lake, Llyn Trawsfynydd, which acts as a cooling water source and is also a sink for radioactivity released from the plant. Very large amounts of radioactive material exist in the lake bed sediment (Fern, Odell, Cobb 1988) ) at
concentrations which under UK legislation ought to require it to be controlled as Low Level Waste.

The Trawsfynydd lake sediment contains serious contamination from Plutonium, 10 Caesium Americium, Strontium and other radioactive isotopes. Astonishingly, it has been advertised as a tourist amenity with people swimming and fishing in the contaminated lake.

The report found that a number of people who had reported incidences of cancer had also eaten fish from the lake.

I don't know as much as I ought to about the pros and cons of nuclear power, but given this small amount of research into my nearest power station, I'm finding it hard to be convinced of the merits of nuclear power. Especially in a country like Wales where we have alternative energy options available to us.

Finally I will end on the note that I actually like these rather odd looking pieces of architecture, and I enjoyed walking around them and getting a closer look.  They loom with great atmosphere over the landscape when you see them from the road. Closer up, you can see the decay and crumbling at the edges and realise it isn't all quite as it seems from a distance.