Krško Nuclear Power Plant
|Krško Nuclear Power Plant|
Location of Krško Nuclear Power Plant in Slovenia
|Commission date||January 1, 1983|
|Operator(s)||Nuklearna Elektrarna Krško|
|Units operational||1 x 730 MW|
|Annual generation||5,289 GW·h|
The Krško Nuclear Power Plant (Slovene: Jedrska elektrarna Krško, JEK, or Nuklearna elektrarna Krško, NEK, Croatian: Nuklearna elektrana Krško) is located in Vrbina in the Municipality of Krško, Slovenia. The plant was connected to the power grid on October 2, 1981 and 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 plant is a 2-loop Westinghouse pressurized water reactor, with a rated thermal capacity of 1,994 thermal megawatts (MWt) and 696 megawatts-electric (MWe). It runs on enriched uranium (up to 5 weight-percent 235U), fuel mass 48.7 t, with 121 fuel elements, demineralized water as the moderator, and 36 bundles of 20 control rods each made of silver, indium and cadmium alloys to regulate power. Its sister power plant is Angra I in Brazil.
The operating company Nuklearna elektrarna Krško (NEK) is co-owned by the Slovenian state-owned company Gen-Energija and the Croatian state-owned company Hrvatska elektroprivreda (HEP). The power plant provides more than one-quarter of Slovenia's and 15 percent of Croatia's power.
In the early 1970s, Tito's government of Yugoslavia recognized the need for additional electrical production in the constituent republics of Croatia and Slovenia. With a domestic source of uranium available, proposals were obtained from Siemens (Germany) and Westinghouse (USA) for a single nuclear power of a practical size. With the agreement of the U.S. government, Westinghouse won the competition to supply a plant based upon the Angra power plant being constructed in Brazil at that time. The Yugoslav management in 1975 consisted of personnel from both the Slovenian and Croatian power companies and a representative from the central government in Belgrade. As the design began, it was recognized that Westinghouse had a more modern design underway for the KORI-2 plant which is now the sister plant of Krsko. Indeed when the Krsko Plant began producing power in 1981, it preceded both the Angra and Kori-2 plants.
The reason why the plant is co-owned by two countries was that these then-constituent republics of Yugoslavia planned to build two plants, one in each republic, according to the original 1970 agreement and its revised version from 1982. However, that plan was abandoned in 1987 by Slovenia due to a referendum held in 1986. From that point on, there arose an issue with nuclear waste storage, because the only existing waste storage site was in Slovenia.
In 1997, ELES and NEK decided to increase the operational and decommissioning costs billed to both ELES and HEP, but the latter refused to pay. In 1998, the Government of Slovenia nationalized NEK, stopped supplying power from Krško to HEP, and sued HEP for the unpaid bills. In 1999, HEP counter-sued for damages because of lack of supply. In January 2001, the leaders of the two countries agreed on equal ownership of the Krško plant, joint responsibility for the nuclear waste, and the compensation of mutual claims. The joint management of the plant was to begin on January 1, 2002. The plant was expected to start supplying Croatia with electricity by July 1, 2002 at the latest, but the connection was only established in 2003 because of protests from the local population. Since then, HEP has additionally sued the Slovenian side for damages during the latest one-year period when Krško wasn't supplying power to it.
Waste disposal and retirement plans
The high level nuclear waste from the plant is stored in the spent fuel pool, as is the usual practice for nuclear power stations. The spent fuel pool at Krško has the capacity to store all high level (spent nuclear fuel assemblies) until the end of plant life (2023). Low level waste is stored at power station and secondary repositories. Croatia also has a contractual obligation to take in one half of the nuclear waste by 2025.
The planned retirement date is January 14, 2023. The decommissioning plan that was ratified by Slovenian and Croatian parliaments schedules the start of disassembly shortly after that, and the taking apart of the plant would last until 2036.
Lifetime extension for 20 years, extending the plant lifetime till January 14, 2043 has been made to the Slovenian regulatory body (URSJV).
June 2008 incident and false alarm
After a coolant leak on June 4, 2008, the European Commission set off an EU wide alarm through the European Community Urgent Radiological Information Exchange (ECURIE). The power plant was safely shut down to the hot zero power mode after a small leak in the cooling circuit. The leak was immediately located and treated. According to the Slovenian Nuclear Safety Administration (the country's nuclear watchdog agency), no radioactive release into the environment occurred and none is expected. The event did not affect employees, the nearby population or the environment . Slovenian authorities immediately alerted the proper international institutions, including the International Atomic Energy Agency (IAEA) and ECURIE. The EU then notified (through ECURIE) the remaining EU member states, issuing an EU-wide alert. Several news agencies around the world then reported on the incident. According to Greenpeace such an EU-wide alert is very unusual. Surprisingly, the Croatian authorities were not directly informed about the incident, although Croatia is a participant in the ECURIE system. Many Croatians heard the news first through foreign media and expatriates, although Krško is located a mere 15 km from the Croatian border.
According to Nuclear Expertise groups, national entities within the European union, such as the ASN in France, this incident was wrongly reported to ECURIE. ECURIE, when receiving a notification, has an obligation to forward it to all parties. In this particular situation, the notification turned out to be useless (i.e. false alarm). This type of incidents (a small leakage on primary pumps) are relatively common occurrence in nuclear power plants.
- Olga Ramljak (2001-09-24). "Hrvatska Sloveniji oprašta 200 milijuna dolara duga". Slobodna Dalmacija (in Croatian). Retrieved 2010-07-13.
- Slovenian Nuclear Safety Administration website
- EU issues radiation alert after incident at Slovenian nuclear plant - AFP
- EU löst Atom-Alarm nach Zwischenfall in Slowenien aus - AFP (German)
- Bellona: Croatia complains it was kept in the dark after Slovenian reactor incident, while others were told leak was an 'exercise', 05/06-2008
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