[Trawsfynydd] station aims to be third time lucky [with re-opening]

The Trawsfynydd Magnox power station in the United Kingdom was shut down last year after it was discovered that welds in the reactor's steel pressure vessel were becoming brittle. The Nuclear Installation Inspectorate (NII) says that the reasons for shutting down Trawsfynydd and refusing to allow the power generator to reopen the facility centre rest on two key issues. Firstly, says the NII, there are uncertainties regarding the changes in vessel material properties because of neutron irradiation that came to light in late 1990. The inspectorate also says that there is concern over the extended operation of parts of the vessel below the temperature at which the steel within it can be confidently predicted to exhibit ductile properties. The generator, Nuclear Electric, is optimistic that it will be able to allay these fears at its third attempt in September. The problems are examined in this article. (Author)