[en] Development of SM-2M and M-7000 computer base softwares for designing dynamic program simulator is carried out at Novo-Voronezh NPP. The near real-time simulator model simulates technological process as a whole one, due to which the most efficiency in solving problem of preventing accident development is attained

[en] Short communication

[en] The paper describes the analysis of two transients of loss of flow in a VVER-1000 reactor performed with the Plant Analyser ASTRA compared with the data recorded during the same transients performed at Kozloduy NPP (Bulgaria). The first transients is a coast down of one primary loop pump at a power level of about 70% while the other 3 pumps continue to run at normal speed. The second transient essentially consist of the exclusion of one of the two turbine driven feedwater pumps: 38 second after the beginning of the transient, one of the feedwater regulation valves remains stuck open, the level of one steam generator starts to raise until it reaches the maximum allowed value so that the transient was stopped. These two transients have been simulated by ASTRA: the attention has been focused on the primary side behaviour and on the heat transfer models, taking the secondary side parameters as boundary conditions. The experimental and calculated trends of the addressed parameters are in a good agreement, showing the capability of ASTRA to properly simulate the analyzed transients. (author)

[en] The construction technology of four PGW-1000 steam generators for the WWER-1000(e) reactor is described in sufficient detail. The PGW-1000 steam generator represents a horizontal tubular heat exchanger producing 1469 of steam pep hour and weighing 320. The steam generators are transported from a manufacturing plant by railway, that limits their dimensions. It is concluded that the construction technology of the steam generators and technological equipment may be recommended for using in construction of the following NPP. Transportation of the steam generators by water would further simplify and accelerate their construction in site

[en] Results of investigations into applicability of energy and force parameters of concrete specimen fracture used for evaluation of complete serviceability of NPP containment material are stated. Expected economic effect from their successive application in corresponding calculations is given

[en] A catalogue is offered for geometric measurements during construction and for long-term inspection of a 1000-MW-reactor building

[en] Short communication

[en] It is well known that eight nuclear power plants with VVER-1000 reactors have been constructed in Russia, Ukraine, and in the Republic of Belarus and they have been operating successfully without any serious accidents since 1980. These facilities have been analyzed for various accident scenarios, and measures have been incorporated which will prevent core damage during these possible events. However, an off-design accident can occur, and in such a case, the radiological consequences would exceed the worst design accidents. This paper reviews a number of potential off-design accidents in order to develop an accident plan to mitigate the consequences of such an accident

[en] For VVER-1000-type reactors severe accident scenarios and possible mitigation strategies are investigated. The Station blackout sequence is chosen as reference case. At first a comparison between the cases with and without working spray systems is discussed. Afterwards the results of a parametric study investigating the influence of different water volumes on the course of the accident are presented. It can be shown that most of these accident mitigation measures will maintain the containment integrity and reduce the source term. (author)

[en] The IAEA safeguards implementation experience gained at the 5th unit of the Novo-Voronezh NPP with the WWER-1000 reactor is described. IAEA inspection procedures and practice of nuclear material control at NPPs with WWER-1000 are considered. Analysis of certain problems related to safeguards implementation at the 5th unit of the Novo-Voronezh NPP is carried out. (author)