Krško Nuclear Power Plant
Encyclopedia
The Krško Nuclear Power Plant ( or Nuklearna elektrarna Krško) is located in 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 (MWth) 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 rod
s 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 company Gen-Energija, a daughter company of the state-owned Elektro-Slovenija
(ELES), 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 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.
In the early 1970's, 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 Siemans (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 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).
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 a EU-wide alert. Several news agencies around the world then reported on the incident. According to Greenpeace
such a EU-wide alert is very unusual. Surprisingly, the Croatia
n authorities were not directly informed about the incident, although Croatia is 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.
Also, an incorrect form was used to report this incident to the other states in Europe. The error, however, was noticed and corrected within 5 minutes by a telephone call.
This incident resulted in a relatively large amount of media attention for what was a minor incident. This raised questions over the procedures for reporting nuclear accidents in Europe.
Krško
Krško is a town and municipality in eastern Slovenia. The town lies on the Sava River. The area is traditionally divided between Lower Styria and Lower Carniola...
, Slovenia
Slovenia
Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...
. 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
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
which were at the time both part of Yugoslavia.
The plant is a 2-loop Westinghouse
Westinghouse Electric Company
Westinghouse Electric Company LLC is a nuclear power company, offering a wide range of nuclear products and services to utilities throughout the world, including nuclear fuel, service and maintenance, instrumentation and control and advanced nuclear plant designs...
pressurized water reactor
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
, with a rated thermal capacity of 1,994 thermal megawatts (MWth) and 696 megawatts-electric (MWe). It runs on enriched uranium
Enriched uranium
Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight...
(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 rod
Control rod
A control rod is a rod made of chemical elements capable of absorbing many neutrons without fissioning themselves. They are used in nuclear reactors to control the rate of fission of uranium and plutonium...
s each made of silver, indium and cadmium alloys to regulate power. Its sister power plant is Angra I
Angra Nuclear Power Plant
Angra Nuclear Power Plant is Brazil's sole nuclear power plant. It is located at the Central Nuclear Almirante Álvaro Alberto on the Itaorna Beach in Angra dos Reis, Rio de Janeiro, Brazil...
in Brazil.
The operating company Nuklearna Elektrarna Krško (NEK) is co-owned by the Slovenian company Gen-Energija, a daughter company of the state-owned Elektro-Slovenija
Elektro-Slovenija
Elektro-Slovenija, d.o.o. is a state-owned electricity transmission company of Slovenia. The company was funded in 1991 by the Government of Slovenia. It is an only power transmission system operator in the country. ELES operates the network of 400 kV, 220 kV and 110 kV...
(ELES), and the Croatian state-owned company Hrvatska elektroprivreda
Hrvatska elektroprivreda
Hrvatska elektroprivreda is a national power company in Croatia which has been engaged in electricity production, transmission and distribution for more than one century, and with heat supply and gas distribution for the past few decades...
(HEP). The power plant provides more than one-quarter of Slovenia's and 15 percent of Croatia's power.
History
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.
In the early 1970's, 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 Siemans (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.
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 CommissionEuropean Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
set off an EU wide alarm through the European Community Urgent Radiological Information Exchange
European Community Urgent Radiological Information Exchange
The European Community Urgent Radiological Information Exchange is the European early notification system in the event of a radiological or nuclear emergency....
(ECURIE). The power plant was safely shut down to the hot zero power mode after a small leak
Leak
A leak is a hole or other opening, usually unintended and therefore undesired, in a container or fluid-containing system, such as a tank or a ship's hull, through which the contents of the container can escape or outside matter can enter the container...
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 a EU-wide alert. Several news agencies around the world then reported on the incident. According to Greenpeace
Greenpeace
Greenpeace is a non-governmental environmental organization with offices in over forty countries and with an international coordinating body in Amsterdam, The Netherlands...
such a EU-wide alert is very unusual. Surprisingly, the Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
n authorities were not directly informed about the incident, although Croatia is 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
Autorité de sûreté nucléaire
The Autorité de sûreté nucléaire is an independent French administrative authority set up by law 2006-686 of 13 June 2006 concerning nuclear transparency and safety. Its task, on behalf of the State, is to regulate nuclear safety and radiation protection in order to protect workers, patients, the...
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.
Also, an incorrect form was used to report this incident to the other states in Europe. The error, however, was noticed and corrected within 5 minutes by a telephone call.
This incident resulted in a relatively large amount of media attention for what was a minor incident. This raised questions over the procedures for reporting nuclear accidents in Europe.