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In a first for the intrepid Discovering Zürich and Switzerland members, a group of 21 ZIWA ladies and one brave man were able to see inside the nuclear power plant at Gösgen near Däniken last week.
Taking up a recommendation from one of our members, chairlady Francesca had arranged the fascinating tour which began at Aarau station when we were collected in a minibus to take us on the short drive to the nuclear power plant, one of five in Switzerland. Our guide for the afternoon, Eliane Spichiger, explained the security procedures to us, and divided us into groups of seven for the tour of the command building, the turbine hall and even inside the cooling tower.
The power station entertains 25,000 visitors per year, and indeed we saw several school parties during our visit, and the guides were more than happy to answer all our questions.

After an airport-style security check and having left behind all metal and electronic objects, we used our security cards to enter the command centre, where 3 shifts of 6 trained operators work round the clock at computer terminals to control the flow of fuel and power. Eliane explained the amount of training that each employee has; it takes between 4 and 15 years to become fully qualified, and the workers must renew their license annually.
The power plant equipment is built by Kraftwerk Union, owned by the German company Siemens.
We learnt that 40% of Switzerland's electricity is generated by nuclear power and 60% by hydroelectricity. This power station works on the water cooling system to slow down the neutrons in the reactor, rather than the graphite cooling system employed at Chernobyl; the most dangerous possibility at Gösgen would be a core meltdown, and the strictest safety measures are in place to prevent such an occurrence or minimise its impact. We also learnt that nuclear waste must be stored within Switzerland, and they are always pursuing ways of making the storage as safe as possible.

We then proceeded to the huge turbine hall, passing the dome-shaped reactor building on the way. Inside the machine room it was necessary to wear earplugs against the 80 decibel sound level. Eliane explained that the reactor uses nuclear fission to generate heat, which creates steam, which is then used to turn the turbines, creating electricity. Water from the steam process is cooled and fed back to the steam generator.
After viewing the condensers downstairs in the machine building, we crossed to the massive cooling tower, which is visible for miles around. We were even able to climb up and enter the cooling tower on a metal gantry, where we were hit by a wall of steam as if in a Turkish bath!

After the fascinating tour, we went back to the visitors' centre to recover our hairstyles and collect our wits and our handbags, before enjoying a refreshing drink.
Then we were taken through the museum to learn more about the nuclear fission process by means of two films and a number of models. We saw samples of the uranium which is extracted from ore, enriched by yellowcake to a level of 4% yield, and made into pellets which are inserted into zirconium rods. One small pellet of enriched uranium can produce enough power to serve a family of four for six months! One fascinating glimpse we had in the museum was of radioactive traces in a darkened cabinet which shows up the alpha and beta particles produced by everyday minerals such as granite.

Thanks to our hosts at Gösgen and to Francesca for arranging such a revealing and enlightening tour.

Julia Newton, 12 April 2008

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