[en] On December 7, 1988 a severe earthquake occurred at Spitak, approximately 90-100 km far from the Armenian Nuclear Power Plant in Yerivan. Another one named Vrancea earthquake which occurred on 4 March, 1977. During this earthquake, the Kozloduj NPP (Bulgaria) was strongly damaged. Until this event, seismic loadings had received scant attention in the siting of WWER's. However after the Kozlodui damage Soviet designers changed their opinion. In this study, the seismicity of the Black Sea region and eastern Europe, seismic requirements for WWER's and the changes in plants for which to resistant against to the earthquake are given. During the earthquake radiation levels obtained by Turkish early warning system is also given

[en] The modernization of the VVER-440/230s is not fundamentally different from backfit projects on older pressurized water reactors which Westinghouse has completed elsewhere. However, carrying out such programmes only makes sense if the plants are expected to continue operation for their projected life or beyond. This clearly requires some licensing and political stability; both are essential if investors in the upgrading project are to be found. (author)

[en] The basic features of the WWER-440/213 reactor design are highlighted. (P.A.)

No abstract available

[en] Physical aspects of subcritical Nuclear Power plants driven by proton accelerators are considered. Estimating theoretical calculations are made for subcritical regimes of various type reactors. It is shown that creation of quite effective explosion-safe NPP is real at existing level of accelerator technique by using available reactor blocks. 20 refs

[en] A new-generation high-capacity power-generating unit based on an improved water-moderated water-cooled UVR-1200 reactor is being developed with the idea of producing a large series of standardized units which would replace the power-generating capacity that has been shut down and would expand the production of electricity based on nuclear fuel in Russia as well as a competitive product for the foreign market

No abstract available

[en] The minutes of three working groups on 'VVER-400 Bubble Condenser Containment Research Work' is presented

[en] The paper investigates various computational modelling issues associated with VVER-440 fuel depletion, relevant to burnup credit. The well-known SCALE system and the TRITON sequence are used for the calculations. The effects of variations in depletion parameters and used calculation methods on the isotopic vectors are investigated. The burnup behaviour of Gadolinium, a burnable poison in nuclear fuel, is quite important in actual core analysis, but its behaviour is somewhat complicated, requiring special treatment in numerical modelling and calculations. Therefore, a special part of the paper is devoted to the treatment of Gadolinium-bearing fuels. Moreover, some discussions on power normalization, which plays an inevitable role in burnup calculations, are also included. The analyses in the paper include determination and ranking of the most important actinides and fission products and while emphasis is put on the fuel temperature distribution and its influence on the final isotopic vector of depleted fuel. To assess the acquired modelling experience used to predict the VVER-440 spent fuel nuclide composition, the measured compositions of Novovoronezh NPP irradiated fuel assembly are compared to data calculated by TRITON sequence. The samples of fuel assembly with 3.6 wt. % U-235 enrichment underwent 4-cycle campaign of totally 1109 effective full power days in the core and cooling period of 1-13 years. Calculated concentrations are compared to measured values burdened with their experimental uncertainties for totally 47 nuclides. The calculated results show overall a good agreement for all nuclides, differences from measured are pointed out and discussed in the paper. (author)

[en] Possibility is investigated of fueld element bundle stainless steel spacing grid replacement by zirconium ones. Application of fuel assemblies with zirconium spacing grids in the WWER-440 reactor demonstrated increasing efficiency of fuel utilization on the fulfilment of design criteria and reactor operation safety conditions