Slovenia's only nuclear power plant is the Krško Nuclear Power Plant, which went into commercial operation on January 15, 1983. It was built as a joint venture by Slovenia and Croatia which were at the time both part of Yugoslavia. The operating company Nuklearna Elektrarna Krško (NEK) remains co-owned by Slovenian and Croatian state-owned companies and provides more than one-quarter of Slovenia's electrical power along with roughly a fifth of Croatia's. The plant is scheduled to close by 2023, and there are no plans to build further nuclear plants. Nonetheless, the debate on whether and when to close the Krško plant has intensified since the 2005/06 winter energy crisis. In May 2006 a Slovenian newspaper claimed that the government had held internal discussions on adding a new 1000MW block into Krško after 2020. Nuclear waste is disposed in storage facilities. Slovenia has left the possibility of reprocessing spent fuel open.