The two new VVER-1200/V491 units, each with a rated capacity of 1,200 MW, to be constructed at Paks, are identical from several aspects with the unit being constructed in Saint Petersburg. At the same time, site conditions and requirements such as meteorological conditions, soil properties, the construction of transmission lines and substation and the provision of cooling water must also be taken into account during design. The Russian designer has already received the basic data that are already available as a result of the design of the existing four units and their research due to their safety enhancement activities. In addition to relevant information, the currently available most accurate basic geological data will be determined on the basis of the most advanced/cutting edge geological research processes. Therefore, the tasks for 2015 include, among other things, the detailed, accurate characterisation of the site and the delivery of the new data to the design institute, on the basis of which the adaptation of the designs can be carried out. Multiple-level designs are required for the preparation and construction, thus design is a long process.
It is an important difference between the unit at Leningrad and the new units at Paks that in contrast with the cooling tower-based cooling of the Saint Petersburg units, there will be fresh water cooling at Paks; therefore, a water intake plant will be needed and the cooling water will be conveyed to the units in another way, too. In accordance with the local soil conditions, the foundation may also be different from that at Leningrad, while a number of other circumstances from the groundwater level to typical outdoor temperatures will have to be taken into account when the available designs of the unit type are modified.
Preconditions for obtaining an installation licence are the environmental licence and the preparation of a preliminary safety analysis report (PSAR), then subsequently, in possession of the installation and construction licence, works may begin on the site in 2018.