This year marks the 10th anniversary of the start of operation of Sizewell B. The plant first achieved criticality in January 1995, and was synchronised to the grid on February 14th. Full power was first achieved in June and the plant formally entered commercial operation in September 1995. The construction of Sizewell B marked a move from UK-designed gas cooled reactors to what was seen as the international mainstream: light water reactors. The plan was to adopt well-proven technology, and to establish a "UK Standard PWR" design.

Sizewell B was to be the first of four identical plants. The intention was that the design should use the best available technology but would seek to follow, not to lead. It is clear that not all these plans came to fruition. In particular, Sizewell remains the lone UK civilian PWR. In addition, reviewing the plant design after 10 years, it is also clear that the plant did end-up leading in a number of aspects of its design and can claim to be the earliest example of an evolutionary advanced PWR.

The paper reviews the history of the Sizewell project and the factors, which influenced the design. The lessons learned from 10 years of operation are outlined and the implications for the future are discussed.