[en] Hydrogen permeation in steel type 12Kh18N10T in reactor-radiation with neutron - and gamma-quantum density flux 3x10¹⁰nxcm^-2xc^-1 and 10⁹cm^-2xc^-1 correspondently with summarized radiation dose 5x10¹'5cm^-2 in temperature range 673-973 K, with hydrogen pressure 0,3 MPa is studied. Description of technique and test plant is given and the achieved results are discussed here. The remarkable unreversible increase of hydrogen permeation through steel and some reduction of energy activation under reactor irradiation was found. 7 refs.; 4 figs. (author)

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[en] A procedure is proposed for determining the average velocity (flow rate) of water and/or steam for the case of essentially three-dimensional velocity profile in the pipe. The monitored system of steam flow rate measurement (SSRM) consists of three pressure tubes (PT). Monitoring of this system shows its functional reliability and, in particular, absence of erosion and mechanical failures of primary gauges. The signal lag of SSRM is less than 1-2 s. The quantitative differences of readings of pressure tubes located in the same pipeline cross-section were stated. Results of experiments modeling the Balakovo NPP steam pipelines are presented

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[en] In November 2003, an experiment simulating station blackout accident was carried out in the PSB-VVER integral test facility at the Electrogorsk Research and Engineering Centre (Russia). The purpose of the experiment was to provide missing data for code validation as well as to investigate the VVER thermohydraulics in the blackout conditions. The experiment covers a wide range of phenomena relating not only to transients but also to small break loss-of-coolant accidents. The data gained in the test has been used to assess the RELAP5/MOD3.3 code. In this paper, a special attention has been paid to the code assessment regarding the mixture level and entrainment in steam generator secondary side. The analysis of the recorded transient has shown that the calculation of the heat transfer on the secondary side of steam generators is very sensitive to the steam generator nodalization. (authors)

[en] New design of nuclear power plant with pressurized water reactor entitled NPP-2006 is under progress in Russia. It is an evolutionary type of design based on existing NPP with VVER-1000 reactors. Intensive thermal-hydraulic experimental activities support design development. They are aimed at increasing the NPP safety and efficiency. Integral test facility PSB-VVER, modeling main components of the primary system of VVER, is the main tool for experimental studies. Volumetric-power scale of the test facility is 1:300, elevations are 1:1. New passive safety systems: hydro-accumulators of second stage (HA-2) and passive heat removal system have been tested at the PSB-VVER under conditions of guillotine rupture of hot leg. When the primary pressure drops below 1.5 MPa, the valves of HA-2 open and cooling borated water is supplied to the reactor by gravity. HA-2 has been designed to provide core cooldown for 24 hours after the beginning of the accident. The results show that the new passive systems are effective because they prevent the cladding temperature from exceeding the safety limits

[en] In channel reactor and non-reactor experiments on research of hydrogen permeation through X18H10T austenitic class's stainless steel are conducted. Research were carried out under 1·10¹⁴ cm^-2·s^-1 neutron flux density within 773-973 temperature range by mass spectroscopy registration of gas quantity. The effective constants of hydrogen: permeability, diffusion, solubility into X18H10T steel under reactor irradiation are determined. The mix n-γ radiation stimulates of hydrogen permeability through this steel. Irradiation effect reducing with temperature increasing. 2 refs.,1 tab., 4 figs

[en] A purposes of this work are research of following points: - a hydrogen mass-transport; - sorption characteristics of beryllium and graphite; -hydrogen release from graphite and beryllium under reactor irradiation. Results of this work could be use on forecasting of thermonuclear reactor materials behaviour under conditions of simultaneously influence both hydrogen and reactor irradiation. 2 refs., 2 tabs., 7 figs