Simulation of the VVER-1000 pump start-up experiment of the OECD V1000CT benchmark with CATHARE and TRAC-PF1

In the framework of joint effort between the Nuclear Energy Agency (NEA) of OECD, the United States Department of Energy (US DOE), and the Commissariat a l'Energie Atomique (CEA), France a coupled three-dimensional (3D) thermal-hydraulics/neutron kinetics benchmark for VVER-1000 was defined. The benchmark consists of calculation of a pump start-up experiment labelled V1000CT-1 (Phase 1), as well as a vessel mixing experiment and main steam line break (MSLB) transient labelled V1000CT-2 (Phase 2), respectively. The reference nuclear plant is Kozloduy-6 in Bulgaria. The overall objective is to assess computer codes used in the analysis of VVER-1000 reactivity transients. A specific objective is to assess the vessel mixing models used in system codes. Plant data are available for code validation consisting of one experiment of pump start-up (V1000CT-1) and one experiment of steam generator isolation (V1000CT-2). The validated codes can be used to calculate asymmetric MSLB transients involving similar mixing patterns. This paper summarizes a comparison of CATHARE and TRAC-PF1 system code results for V1000CT-1, Exercise 1, which is a full plant point kinetics simulation of a reactor coolant system (RCS) pump start-up experiment. The reference plant data include integral and sector average parameters. The comparison is made from the point of view of vessel mixing and full system simulation. CATHARE used a six-sector multiple 1D vessel thermal-hydraulic model with cross flows and TRAC used a six-sector, 18-channel coarse-mesh 3D vessel model. Good agreement in terms of integral parameters and inter-loop mixing is observed.     

Measurement of the relative reduction of strip on the 1200-model temper-rolling mills in flat-rolled products shop No. 3

The temper-rolling mills in flat-rolled products shop No. 3 at the MMK has been equipped with the Vytyazhka automated system to measure the elongation of strip (ASEMS) rolled on the mill. The elongation (relative elongation) of the strip is determined through a frequency-based method of measuring the speed of the strip before and after reduction. The system transmits and displays information on the temper-rolling of each coil. The information is shown as a diagram on the monitor of an industrial computer. The reliability of the system allows it to be in continuous use. Introduction of the automated elongation measurement system makes it possible to monitor the reductions being made during temperrolling, which in turn enables the shop to reduce the number of products having properties that do not meet customers’ requirements. __________ Translated from Metallurg, No. 1, pp. 62–63, January, 2007.     

New technological solutions to protect the lining of blast-furnace hearths

The use of schungite as a partial replacement for coke is practiced in Russia at a number of metallurgical plants, both in the production of foundry iron (its primary use) and in making conversion pig iron. The largest amount of coke is replaced when foundry iron is being made, the replacement coefficient in this case having a value within the range 0.8–1.3. Studies that included continuous monitoring of the temperature of the carbon blocks in blast furnaces with volumes of 1719, 3200, and 5580 m³ unambiguously demonstrate that the thickness of the slag crust in blast furnaces increases with the use of schungite. Protecting the lining of the hearth through the use of schungite is also accompanied by a decrease in coke consumption. __________ Translated from Metallurg, No. 8, pp. 53–57, August, 2007.     

Corrosion resistance of a bent plate from a high-nitrogen nonmagnetic 05Kh22AG15N8M2F steel in aggressive media

The corrosion resistance of the convex and concave sides of bent plates from a high-nitrogen non-magnetic steel has been studied in aqueous solutions of sulfuric and hydrochloric acids. Weighing and hydrogen methods are used to control the corrosion rate of bent-sample sides and to find a number of effects that complement the picture of the stress corrosion of iron alloys and support the existence of the mechanochemical deformation sign effect.     

Organ distribution of bovine serum albumin administered intragastrically in the rat

Radioimmunoassay was employed to examine distribution of antigenic structures of bovine serum albumin (BSA), absorbed by the gastrointestinal tract, in the blood serum and organs of intact rats. It was shown that 3 h after administering 3H-BSA an appreciable amount of its antigenic structures could be identified in the blood serum, liver, spleen, and carcass of the animals. The total amount of antigenic determinants of BSA which got into the internal environment of the body from the intestine amounted to about 0.2% of the dose administered. The highest specific content of antigenic structures of BSA supplied via the intestinal barrier was detected in the spleen.     

Oxidative stability of the lipids in whitefish

The manometric technique was employed to study the initiated oxidation of 7 samples of whitefish lipids of varying sites, to measure the kinetic parameters depending on the fatty acid composition and concentration of tocopherol. Changes in oxidative stability of lipids of varying localization was shown, a higher stability of muscle tissue lipids was noted as compared with brain and depot lipids. The possibility of testing oxidative stability of lipids according to the kinetic parameters is discussed.     

An assessment of the θ-projection method for the representation and extrapolation of creep data for a 1%Cr, 12%Mo, 14%V steel tested at 565°C

Constant stress creep data for a wrought 1%Cr, $\text{1}\text{2}\text{\%}\text{Mo}$, $\text{1}\text{4}\text{\%}\text{V}$ steel obtained from six tests carried out at 565°C have been fitted and extrapolated using the θ-projection method. Creep curves for high stresses were fitted well, but curves extrapolated to stress levels below those used in the θ-projection did not represent well the available data for primary-secondary creep. To enable a satisfactory extrapolation of results, it was found necessary to redefine the failure condition to be less sensitive to the shape of the latter sections of the tertiary creep curve. This was achieved by defining lifetime as the point on the curve at which the strain rate reached a fixed multiple of the creep rate at half the rupture time. The extrapolated data compare well with the results of tests carried out independently on a cast 1%Cr, $\text{1}\text{2}\text{\%}\text{Mo}$, $\text{1}\text{4}\text{\%}\text{V}$ steel. The extrapolation procedure not only predicts the ‘knee’ in the log stress-log lifetime curve but allows extrapolation of lifetimes by over a factor of thirty. In addition, acceptable predictions have been made of constant load experimental data.     

Oxydation catalytique des phenols par le peroxyde d'hydrogene: Etude structurale des catalyseurs Fe/Al2O3 et Fe-Cu/Al2O3 par spectroscopie Mossbauer

This study recalls the results obtained on the oxidation by hydrogen peroxide of a number of hydroxyl aromatic compounds with alumina supported catalysts and more particularly the structural study of these catalysts. The catalysts were prepared under different conditions: without thermic treatment, by oxidation in air at 450°C and by thermic reduction at 500 and 700°C, under hydrogen flow. The structural study by Mössbauer spectroscopy of the catalysts Fe/Al₂O₃ and Fe-Cu/Al₂O₃ made it possible to specify in what form was found the iron, as a function of the conditions under which the catalysts were prepared. For the catalyst prepared by impregnation without thermic treatment the iron on the support was in hematite form (α-Fe₂O₃) well crystallized in small particles with 10–20% iron which could be ferric ions (Fe³⁺) chemically adsorbed on alumina or iron within the structure of the alumina (Figs 7 and 8). Thermic oxidation in air brought about the appearance of hematite in the form of large particles (Fig. 9) whereas the thermic reduction under hydrogen flow led to the formation of crystallized metallic iron (α-Fe) (Fig. 12). The reducibility of iron on the support increased with the increase in temperature of reduction and with the presence of copper (Figs 11 and 13). As for the activity of the different catalysts in oxidation reactions of phenols by hydrogen peroxide, we notice that whatever the form of the catalyst, the activity was more important for pyrocatechol than for phenol (Fig. 3). As far as stability of the metals on the support was concerned, during the oxidation reaction we noticed that it was greater with an oxidized catalyst than with a reduced one (Figs 4 and 5). The comparison between the results obtained in a batch and in a continuous reactor made it possible to show that the first phase of the reaction was probably due to the superposition of the phenomena of homogeneous (by the Fe ions passed into solution) and heterogeneous catalysts (Fig. 6). The comparative structural study reduced before and after use was quite in agreement with the solubilization of iron that we observed during oxidation (Figs 15 and 13). However on the oxidized catalyst hematite was not modified after use and the most significant change on the spectrum was a slight decrease of E_Q (0.1 mm s^?1) in the central doublet (Figs 14 and 9).