History

Our glorious history begins when, in 1959, the Atomic Power Consortium (AKK) submitted an application to build a nuclear power plant on the Simpevarp peninsula, a few miles outside Oskarshamn. A few years later, the plans were implemented, which was the starting point for OKG (Oskarshamn Power Group). The previous industry in the area was fishing and agriculture. Nowadays, our beautiful peninsula is home to everything found in a safe and efficient energy center.

First came O1It was on July 14, 1965 that the order to Asea was submitted. Sweden's first light water reactor was to be built, but a nuclear power plant is not something you build in a few months. It was not until six years later that the plant was ready to be phased into the power grid. Oskarshamn 1, known as O1, was officially inaugurated in 1972.

Between 1993 and 1995, an extensive renovation of O1, called Project Phoenix, took place. The project attracted a lot of attention because it was the first time work had been carried out inside a reactor vessel that had been in operation. At the same time, the reactor's future modernization needs were being investigated, resulting in the Max and Mod projects.

During Max, in 1998, the moderator tank, moderator tank cap and steam shell valves - all significant parts of the reactor - were replaced. The Mod project, carried out in 2002, introduced a new safety concept, a new control system and reactor protection system, rebuilt the control room and installed a new turbine. The result was an efficiency improvement of 22 MW.

Thirteen years later, on October 14, 2015, the then majority owner decided on an early closure of both O1 and O2. The closure of O1 started on Saturday, June 17, 2017, when the plant delivered its last kilowatt hours of electricity.

O2 is emergingLet's jump back a few years. Even before the O1 was inaugurated, in 1967 to be precise, planning for the O2 began. Five years later, in 1974, the reactor was commissioned. Originally, the O2 had an output of 580 MW, which was later increased to 630 MW in 1982.

When OKG's main owner E.ON made the decision in 2015 to close O1 and O2 prematurely, O2 was in the middle of an extensive modernization. In 2007, 2009 and 2013, the most important stages had been completed, including the replacement of the low-pressure turbine and the rebuilding of the control room. In connection with the modernization of the O2, the education and training of control room personnel was also moved from Studsvik to a newly built simulator, located at Simpevarp. The last step was to have been completed in 2015, but was interrupted by the shutdown decision.

At the time of closure, the reactor was 41 years old and had produced 154 TWh during its lifetime. Large-scale dismantling and demolition of the reactor is now underway at O2.

The flagship O3Today, Oskarshamn 3, which we call O3, is the only reactor in Oskarshamn that is in operation. The decision to build a third reactor in Oskarshamn was taken at a turbulent time in the history of nuclear power. Plans for the construction were already in place in 1973, when a so-called concession application was submitted to the Swedish Parliament. The procurement process went smoothly and in 1976 the order for a new reactor was placed with Asea-Atom/Stal-Laval. But by the end of the 1970s, opinions on nuclear power were divided and political uncertainty led to a referendum on nuclear power in 1980. Before the people had had their say, there was no point in starting construction, but after the referendum the shovel could be put back in the ground on the Simpevarp peninsula.

On March 3, 1985, Oskarshamn could finally be phased into the electricity grid for the first time, and in May of the same year, full capacity, which was then 1050 MW, was reached for the first time.

In 1989, it was time for the first power increase at O3, when the maximum power was raised to 1200 MW. And in 2012, the maximum power was increased again to today's 1,450 MW, making O3 the largest reactor in Sweden and one of the world's largest boiling water reactors. To achieve the final increase, a new main circulation system, new turbines, generator and transformer were installed in 2009 and 2010. Increasing the output of a nuclear power plant is no small task.