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[en] The author represents a method for the assessment of a tomographic effect in longitudinal tomography: to determine maximum sizes in 2 mutually perpendicular directions in a figure of a trajectory reproduced on a plane, to measure the value of these segments in arbitrary units of length. Then the greater one is taken for 1 and the lesser one is expressed in fractions of a whole number in the form of a decimal fraction up to the first sign after the point. Unlike other known method the proposed one possesses some advantages: simplicity and convenience of the calculation of values, a high degree of accuracy of the assessment of a tomographic effect; its indices characterize not only uni- and multidirectional but also purposeful types of blurring, values of the blurring efficacy index do not depend on a tomography angle but are related with a trajectory outline only. The determination of the blurring efficacy index in various types of movement of tomography systems permitted the solution of the problem of an optimum trajectory in longitudinal tomography

[en] In the tomography of the lumbar part of the spine circular blurring of the interfering shadows allows the structure of the layer to be examined more distinctly than linear blurring. The spiral movement of the tomographic system, despite its more complicated tra ectory, allows producing an image similar to a zonographic one

[en] The decisive role in revealing gastrocolonic fistuals is played by X-ray investigation. Observations supporting this fact are presented

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No abstract available

[en] The paper is concerned with a qualitative evaluation of the shape of X-ray images of the surfaces of spheroid joints: hip and shoulder joints. The authors give some quantitative indices that characterize the curvature (radius of the curvature of a circle with which the contour of the articular surface is drawn) and the extension (that was evaluated by the value of central angles of circumscribed cUrvatures) of articular surfaces based on the measurement of 391 hip joints.and 52 shoulder joints. The measurements were done by radiograms in direct standard projections. The authors also touch upon the problem of the shape of the wrist joint. In accordance with the quantitative evaluation of the shape of its articular surfaces this joint cannot be regarded as elipsoidal. It should be attributed to discoidal, i.e. to a new joint shape

[en] At present the commercial fast sodium cooled reactor (BNK) is under development in Russia. Initially electric power output of this reactor was chosen 1800 MW(e). However, further power output was decreased down to 1200 MW(e) to provide transportation of the main equipment by rail. The main concept of the core for this reactor was taken from BN-1800 reactor: low core specific power, internal self-protection (close to zero sodium void reactivity effect (SVRE) value, decreased reactivity margin for fuel burn-up). This paper presents the results of theoretical and calculation studies on choosing and optimizing physics parameters of BNK-1800 type reactor core and BNK-1200 type reactor core more detail. There is a set of possibilities for improving the core for BNK-1200 type reactor, staying within limits of new design. These possibilities are to improve flattening of the core power field, to provide close to zero value of reactivity margin for fuel burn-up and other. Unique enrichment of fuel and flattening of the power field by steel absorbers was optimal solution for BNK-1800 core with diameter of above 6 m, but for BNK-1200 core of smaller dimensions flattening of power field by two enrichments allows an essential decrease (down to 10%) of maximum specific power and maximum fuel burn-up (at the same average fuel burn-up). In 2008 in Russia Nuclear Safety Rules (PBya RU AS) had been changed. The requirement of negative reactivity coefficient on coolant density was removed. Concerning SVRE, new Rules state the following: the interval of allowable positive SVRE values should be defined in the design of Reactor Installation. It allows to extend the area of optimal values of the core parameters and, in particular, to increase the core height up to 100 cm. It is possible to realize it at the expense of decreasing sodium plenum dimension. Increase of the core height (with corresponding decrease of its radial dimension) leads to essential increase in efficiency of CSS rods that, in principle, allows to avoid the use of expensive high-enriched boron in CSS rods. Moreover, the increase of the core height simplifies the problem of providing zero reactivity margin for fuel burn-up. For this purpose, it is necessary to increase fuel volume fraction (up to ∼ 0.53) and to increase the number of SAs within the limits of design with the aim to avoid the hydraulics problems. In principle, introduction of the upper blanket above the core allows to reach breeding ratio (BR) value of more than 1.4 as in the case with nitride fuel with old fuel volume fraction (∼0,4). Critical loading of the core together with BR is the principle issue for nuclear power. It can restrict the pace of fast reactor introduction. Decrease of the critical loading is possible only at the expense of increasing core specific power. Comparison of consumption of plutonium amounts in the cores with low specific power and high specific power with external fuel cycle duration of 3 years showed that the benefit of high specific power core concept by plutonium consumption has been observed only during 5-7 years, and this benefit has been lost on the large time interval. (authors)

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No abstract available