Following the break-up of the Soviet Union, the entire Central and Eastern European region experienced a major transition. The nuclear industry was directly affected, due to the accident at Chernobyl Unit 4 in 1986. Western assistance programs, financed either on a multilateral basis, through the TACIS and PHARE programs of the European Union and the Nuclear Safety Account of the European Bank for Reconstruction and Development (EBRD), or by bilateral programs, e.g. those of the Department of Energy (DOE) in the US or of the German Federal Ministry for the Environment (BMU), have helped these countries with this transition
       Partly in the framework of these programs, partly under direct contracts with plant operators, both Framatome and Siemens have been conducting major upgrades on Russian-designed nuclear power plants in these countries. While not being involved in Chernobyl-type reactors (known as RBMK), they accumulated comprehensive experience with all generations of VVERs, the Russian variant of the pressurized water reactor (PWR).

Background
Nuclear energy provides a significant percentage of electricity generated in many countries of Central and Eastern Europe. The few exceptions are countries with large indigenous fossil reserves such as Poland (coal) and Estonia (oil-bearing tar sands). Elsewhere, nuclear power accounts for between 30% and 50% of electricity generation, and as much as 75% in Lithuania. In the Russian Federation, nuclear power supplies 15% of electricity on a country average basis, but this figure rises to 40% for the European part of the country.
       The Russian design approach in the 60s and 70s demonstrated significant differences from US and Western European developments. Large inherent safety margins, low specific power and large water inventories are examples of design features for VVER models. On the other hand, the designs did not include the double-ended break of primary loop piping. Plant design was based on control of leaks, not of breaks, and pressure retaining containment was not adopted in the early VVER models. The result was a lower-capacity emergency core cooling system, less attention to separation of redundant trains in layout, and high-energy line break issues. Loviisa in Finland however, has operated two units of VVER 440 design successfully since the 70s because of major safety improvements installed during construction, in particular Siemens instrumentation and control (I&C) systems. In the early nineties, both Framatome and Siemens participated individually or in cooperation with each and/or other Western and Eastern European partners, in the various safety and plant design evaluation programs launched at the time. International teams of experts, assembled as part of the IAEA extra-budgetary program, collaborated in the preparation of detailed reports comparing VVER plant design against Western standards. These IAEA reports provided an internationally recognized basis for establishing safety upgrade and modernization programs. The reports identified required safety measures as well as their classification in terms of safety significance. Three VVER reactor models were reviewed: VVER-440-230, VVER-440-213 and VVER-1000.

Central and Eastern Europe
With experience in all VVER generations, major plant upgrade and completion programs were launched for units whose construction was already under way, at the end of the eighties, but which were interrupted by the transition: the VVER-1000 Temel’n Units 1 and 2 in the Czech Republic, and the Mochovce Units 1 and 2 (VVER-440-213) in Slovakia. A consortium formed by Siemens and Framatome, together with their Russian partners, supplied SlovenskŽ Elektr‡rne the majority of safety upgrades in Mochovce. This collaboration proved to be highly successful. The Mochovce units, now in commercial operation since 1998 and 2000, are recognized as the first VVER units completed to a safety level consistent with Western standards.
       Other plant operators in Central Europe, with units in operation since the late eighties, have adopted more gradual plant upgrade programs spanning several annual refueling outages. In all of these, Siemens and Framatome have been involved either individually or as part of a consortium for individual upgrade items (e.g. I&C) or for a comprehensive upgrade package based on the IAEA reports. Siemens, together with its Slovakian partner, the engineering company VUJE Trnava, has contributed to the modernization of the Bohunice plants Units 1 and 2 (VVER-440-230) completed in 2000. Siemens also was contracted to supply the I&C upgrading for four units at Paks in Hungary. Two of these now have been equipped and the other two will follow during upcoming refueling outages. Bohunice and Paks are thus the first VVER plants using Siemens TELEPERM™ XS I&C systems.
       Framatome and its French partner, Schneider Electric, recently were awarded, as subcontractor to the Czech company, Skoda Plzen, the I&C upgrading project for the four units at Dukovany. These programs will be implemented during successive refueling outages.
       For the Kozloduy Units 5 and 6, a consortium of Siemens, Framatome and Russian partner Atomenergoexport just completed the basic engineering phase in the upgrading program. Implementation is scheduled to start in early 2001.
       Framatome and Siemens played a major role in plant completion and upgrade projects in Central Europe. In fact, the new joint venture Framatome ANP, is the leading western supplier for nuclear parts and upgrading services to these countries. It has been helping these countries to position themselves for admission to the European Union. The inherent safety margins of the VVER plants have demonstrated reliable performance for base load generation with high load factors (e.g. cumulative capacity factor of 86% average for the four units at Paks and 85% for the two units at Loviisa). This experience positions the new joint venture, Framatome ANP, as a reliable partner in achieving continued optimum performance.

Russia and Ukraine
In Russia and in Ukraine, plant operators experienced a more difficult transition period. Nevertheless, various individual plant upgrade measures have been completed at many units, using TACIS and EBRD-NSA funding. Framatome and Siemens participated in many of these (for example, plant upgrades at Kola and Novo Voronesh, together with other European partners in the European Nuclear Assistance Consortium (ENAC)). Even though no major plant modernization projects have been completed, the nuclear plants have performed reliably during the transition years.
       In Ukraine, nuclear power generation accounts for a large percentage of electricity, therefore reducing the country's heavy dependence on imported supplies. Ukraine has brought the Zaporoshe Unit 6 online using its own resources, with Russian help and in spite of the consequences of the Chernobyl accident. The G7 agreements in 1995 committed western help to this major environmental remediation project and to the accompanying upgrade of the Ukraine energy sector.
       Although this assistance has been slow in coming, at least from the Ukrainian viewpoint, significant progress has been made recently with the final closure of the last operating unit (#3) at Chernobyl and the approval by EBRD and Euratom of a major financing package for the completion and upgrading of VVER-1000 units Kmelnitsky 2 and Rivne 4. A Framatome, Siemens and Atomstroyexport consortium was selected as the general contractor for this project and will be able to draw upon their previous successful experience, once the project start date for these units is decided this year.


Modernization of the safety I&C system was a central part of the refurbishment of the two Bohunice units. Other safety-related systems were also upgraded in addition to the reactor protection system.