Dukovany (Czech Republic)

Map of Dukovany

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4* 440 MW PWR reactors: VVER 440/ V213 constructed by AEE/Skoda; operation started from 1985 to1987
An interim dry storage for spent fuel with a capacity of 600 t is in operation, another one with capacity of 1.300 t started operation in 2006.
Also a LILW storage facility is located on the site. The total volume of the disposal rooms is 55.000 m3 which is sufficient for disposal of all LILW from Dukovany and Temelin, even in the case of a prolongation of their planned lifetimes.

Facilities in Dukovany

plantreactor typconstruction startoperation startshut down
DukovanyLILW Storage1995
Dukovany Interim StorageInterim Storage for Spent Fuel2006

The extended Interim Dry Storage for Spent Fuel is starting trial operation. It will accommodate 1330 tons of spent fuel, thus covering the expected lifespan of the power plant.
In 2006 13 events occured which were rated INES 0 and one which was rated INES 1.


In 2005 19 events occured which were rated INES 0.


SUJB issued a permit for Dukovany unit 1 for another 10 years´ operation (up to 2015).


Manual scrams of Unit 3 occured in August and September because of the unexpected failure of three control element assemblies which could not be identified at the first event but only after the second.


CEZ has announced that the NPP Dukovany will continue to operate until 2035 which means life time extension and that it then will be replaced by new nuclear reactors.


In 2004 12 events occured which were rated INES 0.


In 2003 13 events occured which were rated INES 0, and according to CEZ 1 event rated INES 1.


Vysocina regional authorities confirmed the planning permission enabling a spent fuel storage facility to be built on the premises of the Dukovany nuclear power plant. This permission was previously issued in Hrotovice. In May 2003 the planned construction was blocked by an appeal lodged by the South Bohemian Mothers Association.
An adjustment has to take place concerning the check-up on vehicles entering the premises. The decision, passed on November 11, will enter into force at the beginning of December.
The store has a capacity of 1340 ton and should be put into trial operation in 2006, when the currently used store will be full, and will be in use until the scheduled decommissioning of the power plant in 2030.


In Dukovany the international OSART-Follow-up mission has been completed. The nuclear power plant complies with all recommendations and proposals. 70 per cent of the approx. thirty recommended measures aimed at improving the safety of the plant have already been implemented. The remaining 30 per cent consist of long-term tasks concerning investment, and the plant management is currently dealing with them.
The team of the international mission focused mainly on the safety performance of the plant in eight areas, such as management, training, staff qualification, operation and maintenance, and anti-radiation protection and emergency planning.


In 2002 12 events occured which were rated INES 0, and 2 event rated INES 1.


In 2001 17 events occured which were rated INES 0, and 1 event rated INES 1.


A German sport aeroplane was registered in the forbidden flight space of the atomic power plant Dukovany. In March an Austrian aeroplane over-flew the same place. The security of the AKW cannot be endangered by the crash of such an aeroplane according to specification of the speaker of the AKW.


In 2000 21 events occured which were rated INES 0, and according to CEZ 1 event rated INES 1 (according to SUJB 0 events INES 1).


The regulatory body licensed the use of the new Skoda 440/84 cask at the dry interim storage facility and permitted CEZ, the operator, to expand storage capacity.


Public hearing on the enlargement of the interim storage for spent fuel in Dukovany.
Main issues in the discussion were the safety of the transport casks, the resistance of the building in case of external hazards especially in case of air-plane crash.


The supervisory board of CEZ. has approved the utility's proposal to replace the instrumentation & control (I&C) system at Dukovany, a project plant officials describe as the biggest in an ongoing modernization program.
Dukovany joins the lengthening list of VVER plants which are switching from Soviet-design analog I&C systems to I&C based on digital technology, albeit most with analog backup. The implementation set will begin in mid-2000.
Plant officials are not sure what the eventual proportion of digital and analog technology will be at Dukovany.
The changes are to be implemented during normal outages over four years. Second, management doesn't want to change the plant's safety philosophy nor the number of sensors, valves, and other related equipment involved. Third, Dukovany doesn't want any changes in cabling.
The I&C replacement required board approval because it was considered a major package, expected to cost several billion crowns" The I&C replacement is scheduled to be finished at all four units by 2004 or 2005.
Siemens´ Teleperm XS digital I&C system has been chosen by both VVER-440 nuclear plants in the Slovak Republic, Jaslovske Bohunice and Mochovce, and Hungary's Paks. Both Mochovce and Paks are Model 213 plants like Dukovany. John said the modernization programs at the Slovak plants can be seen as models for Dukovany´s. But this week Kouklik said that, although Dukovany´s new I&C would follow the same philosophy as is used in Teleperm XS,


Engineering safety evaluation of Dukovany and Bohunice V2:

The engineering safety evaluation was performed by the European Nuclear Assistance Consortium (ENAC) for the Czech Republic's Dukovany and Slovakia's Bohunice V2 NPPs. This project was financed by the European Commission through the PHARE program. The project aims first to determine pragmatic, cost-effective changes to the design and operation of the plants to enable them to achieve adequate safety, and second to develop conditions for plant life extension.

The engineering safety evaluation was performed in three phases:
· Internal Audit of Dukovany NPP
· External Audit of Dukovany NPP
· safety review team led by Siemens with support from Ansaldo and Framatome
· systems review team led by NNC with support from EDF and Empresarios Agrupados
· components review team led by Empresarios Agrupados with support from the Dutch Nuclear Consortium and Siemens
· operations review team led by Belgatom with support from EDF
· Extension to Bohunice V2:
The evaluation recognized that both Dukovany and Bohunice V2 utilize a well-proven design for which extensive operating experience is available. The operating experience is available. The basic design incorporates a number of features beneficial to safety (e.g. the relatively soft response to transients) and both plants are considered to be well operated.

The principal findings and concerns are:
· the vulnerability of the steam and feedwater pipework area on the +14,7 m level of the reactor and intermediate buildings to internal hazards is a concern repeatedly identified by this evaluation (and elsewhere);
· dependent failure of the ECCS due to sump screen blockage is a concern for which an acceptable resolution strategy has been identified and is to be implemented;
· the physical and functional separation of the unit main and emergency control rooms is another acknowledged area of concern;
· the capability of the bubble condenser to actually fulfill its safety function is the subject of a number of international projects in which both Dukovany and Bohunice are involved;
· the adequacy of the I&C systems in general (including the control facilities) is another area of concern for which a number of recommendations were identified for both plants;
· the adequacy of the hazard protection provisions remains a concern even though a large volume of work has been done and continues to be done, particularly on fire hazard;
· the adequacy of the safety and accident analysis performed remains a concern even though, as with hazards, a great deal of work has been, and is being done.
The main Dukonvany NPP reconstruction is planned to take place between 1999 and 2005.


Czech utility CEZ a.s. will seek proposals for an increase in capacity of the dry cask interim storage facility for spent fuel at the Dukovany NPP, following the reversal of an earlier government decision to limit the on-site storage capacity to 600 metric tons and seek a central interim storage elsewhere in the country.
The company intends to ask the firms on its short list for the central storage project, drawn up last year, to propose alternatives for the on-site storage expansion.
The government this year identified on-site storage as the first priority for spent fuel management, notably in light of the difficulty CEZ met in finding a site and building an away-from-reactor storage by 2005, when it is needed. But CEZ will continue negotiating with the four shortlisted firms for the AFR facility, in case it is later decided to build it.
The firms on the short list are Skoda Plzen, Nuclear Assurance Corp., Transnucleaire and Nukem.
The current cask storage facility will suffice only for the plant's spent fuel discharged up to 2005. But the change in strategy, approved earlier this year, would theoretically make it possible to store on-site all the spent fuel discharged during the 30-year design lifetime of the plant.
CEZ must also plan longer-term storage for the fuel that will be discharged from its two VVER-1000 units at Temelin, expected to begin operation in 1999, although 10-year pool storage is ensured at that plant.
The Dukovany storage, which can house 60 Castor-440 casks supplied by Gesellschaft fuer Nuklear-Behaelter m.b.H. (GNR) was originally conceived in 1988, and after CEZ´s choice of the German technology - despite its higher price compared to other proposals, the company notes - construction began in 1994. Following a period of trial operation beginning in late 1995, the facility was placed into commercial service this past March.
So far, 15 casks have been placed in the Dukovany storage hangar, each of which contains 84 fuels assemblies or about 10 MT of spent fuel. Another 384 spent fuel assemblies are still being stored in pools at the Jaslovske Bohunice VVER 110 site in neighboring Slovakia.
Another shipment was made from Bohunice to Dukovany on May 14. Either about 80 or 160 fuel assemblies are shipped at a time under tight security.
The former Czech government decided in 1992 to limit the capacity of the Dukovany fuel store because of opposition by plant neighbors and local mayors, who said it was not fair to impose on the region another nuclear facility besides the PP. CEZ began canvassing the country for suitable sites, the best of which was found to be in a mountain near the Dukonvany plant.
The difficulty in expanding the Dukovany storage is not the construction of the hangar itself, which takes only some months, but getting permission. Another environmental impact statement will be necessary, the first one took 100 person-years.


Dukovany in April opened its spent fuel storage - to hold 60 Castor 440-type casks by year 2005.
Thereafter, the nuclear power plant wants to enlarge the store, so that all the plant´s spent fuel can be held longterm on site.


CEZ plans to invest about $750-million on a hardware maintenance, backfitting, and monitoring program for four model-213 VVERs, which is expected to allow the reactors to operate at least 10 years beyond their planned design lifetime.
The lifetime extension program for Dukonvany got underway in 1992 and during the last two years, was furthered by a plant-wide "technical audit" by CEZ experts and outside consultants, an Asset mission from the IAEA, and compilation of an operational safety report for Dukovany-1.
Outside consultants including Siemens, Belgatome, and Electricite de France (EDF) evaluated the conformance of the Dukovany reactor design to international standards. In support of the life extension program, a two-part IAEA safety mission was held in October 1995.
The station could be backfit to replace components and upgrade safety systems, allowing Dukovany-1, which went on line in 1985 and was originally planned to be operated until about 2010, to operate until at least 2020, and maybe until 2025. Dukonvany-4, the last unit, which started up in 1987, might be operable until 2030.
Life extension experts at CEZ singled out 10 major components for monitoring: pressure vessel, bubbler/condenser tower, primary circuit steam lines, SG´s, main circulation pumps, pressurizer, control rod drives, primary circuit isolation valves, SG piping, and the turbogenerator.
In 1994, a probabilistic safety assessment (PSA) for Dukovany calculated a core damage frequency of 3,1 x 10 E-5 per reactor-year. Not included in the PSA were accidents caused by a high-pressure pipe rupture, internal fires or flooding, plane crashes or earthquakes, interfacing loss-of-coolant accidents, anticipated transients without scram, or human factor-caused events. After including these, the PSA results were reduced to a core damage frequency of 1,77 x 10E-4 per year for each unit.
Before the PSA was carried out, similar improvements were made to those at V-213 VVERs at Jaslovske Bohunice in Slovakia, including replacement of Soviet-manufactured high-pressure components and of switching gear, reduction of the leak rate in the confinement system, provision of advance heating for emergency coolant water, and installation of primary system diagnostic equipment.
Still to be implemented are hardware improvements including: instrumentation and control (I&C) system modernization, replacement of steam and water pipes between the TU and the reactor building, installation of a fullscope simulator, an overhaul of the secondary-side chemical regime, replacement of main circulation pumps and emergency feedwater pumps, and installation of pressure and relief valves to allow for bleed-and-feed accident management measures. A contract has been signed with Siemens for supply of hydrogen burning equipment for the confinement of each unit.
CEZ anticipates spending about US$ 48-million for upgrades and component replacement in 1996. Until 1990-91, upgrade spending at Dukonvany held steady at about $8-million.
Annual plant investment at Dukovany will increase to nearly $90-million in 1997 and 1998, fall just over $37-million in 1999 and 2000, and then rise again to over $74-million by 2003. Through 2005, CEZ expects to spend about $750-million for upgrading and life extension-related investment at the four reactors.


Transformer fire.


Failure of PRZ safety valve.


Fire outside of the reactor building. Probably transormator - no proper information to the public.