Slovenia shuts down Krško nuclear power plant. Leak repairs could take several weeks

Slovenia’s only nuclear power plant has been shut down since last Friday after a leak from the primary circuit inside the containment building. The plant’s operator says it has managed to locate the microleak, but it is not yet clear when the plant could resume operations. Initial estimates suggest the shutdown could last several weeks.

The Krško Nuclear Power Plant (NEK), located near the Slovenian-Croatian border, generates around 5.6 TWh annually, covering roughly one-fifth of electricity consumption in both countries. The plant, which has a single 700 MW unit, was shut down last Friday after a leak was detected in the primary circuit inside the containment building. The operator announced the unit’s shutdown on Thursday, even though the leak rate did not exceed the limits set out in the unit’s technical specifications.

On Monday, the plant operator said the leak had been located during the cold shutdown, which the unit entered over the weekend. The leak occurred at the boundary of the primary circuit. The operator said a detailed analysis of how the leak developed and an action plan for its repair were needed. This could take several weeks, and as of the start of the week it was too early to set a specific date for restarting the unit.

"Nuclear safety has been ensured from the first indications of the leak. All decisions have been and will be based on the principles of conservatism and a strong safety culture, which ensure the safety of employees, the public and the environment," the nuclear power plant operator said on its website on Monday.

The plant operator also said it was in close contact with domestic and foreign institutions to ensure the fastest possible resumption of operations and reconnection of the unit to the grid.

The plant has another 20 years of operation ahead

Commercial operations at the Krško nuclear power plant began in early 1983, and the governments of Slovenia and Croatia began discussing a 20-year extension in 2016. Earlier this year, Slovenia’s environment minister announced that the plant had completed its environmental impact assessment and received the safety permit needed to extend its operations until 2043. In addition to Slovenia, Croatia, Austria, Italy, Hungary and Germany also took part in the process.

Alongside extending the operation of the first unit, Slovenia is also preparing to expand the plant with a second unit. In late September, a working group met in the country for the first time to coordinate preparations for the Krško 2 New Nuclear Power Plant project.