Later this year, Nuclear Electric, the state-owned company which owns and operates nuclear power stations in England and Wales, is expected to apply for permission to build two PWRs on the site. The proposed new twin- reactor station, to be known as Sizewell C, would join Britain's first PWR, which is currently under construction at Sizewell and due to start operating in 1994.
In 1989, the Government imposed a moratorium on building new nuclear reactors, following its failure to privatise nuclear power along with the rest of the electricity supply industry. This ban may be lifted, however, if the industry can secure a favourable outcome from the Government review of nuclear economics in 1994.
A spokesman for the company said: 'We are keen to go for Sizewell C, it would be our first option for post-1994, if we get a favourable outcome.' The company already has planning permission for a single reactor at Hinkley Point in Somerset, although its plans to build there were stymied by the Government's moratorium.
Nuclear Electric hopes that its proposed twin-reactor station next to Sizewell B will require no more than a local planning inquiry. The company maintains that the safety of the design has been exhaustively tested at both the Sizewell and the Hinkley Point public inquiries.
Economics lies behind the change of site from Somerset to Suffolk. The company estimates that it can build the twin reactor station at Sizewell for a total cost of about pounds 3.5bn whereas the single Sizewell B reactor will cost about pounds 3bn in 1992 money values. The cost reduction comes about because some PWR-specific infrastructure is already present at Sizewell and because all the development costs of the PWR design have been written off against the capital costs of Sizewell B.
But the twin reactors at Sizewell C would not be exact replicas of the first PWR. Nuclear Electric is still reviewing options, but it is thought to favour a modified design which would produce power for about 2.95 pence per kilowatt hour - competitive with coal- fired stations and, possibly, with combined cycle gas turbines.
If all goes according to the nuclear industry's proposals, there could be a brief period when five nuclear reactors are operating at the site. Sizewell A started operating in 1966 and Nuclear Electric is studying how to extend the life of its twin Magnox reactors to 35 years and beyond.
There may, however, be several obstacles in Nuclear Electric's path, including the provision of finance and concern about projections of massive over-capacity of supply by the end of the century.