[en] Reference is made to instruments responsive to small changes in the inclination of a body relative to a fixed datum and capable of providing remote indication of such changes. The instrument described is stated to be suitable for checking fuel channels in a nuclear reactor for any deviations from the vertical, and for this purpose is mounted in a unit designed to be traversed along the fuel channel. It comprises essentially a pivoted pendulum weight, a pair of transducer devices, and output signal-producing and recording means. A computer may be associated with the output signals. Full constructional details are given. (U.K.)

[en] Buckling behavior of square tubes under bending load depends on the direction of the bending moment. This paper deals with two directions. The first has an axis that crosses the side of a cross-section at right angles; the second has an axis that crosses the diagonal of a cross-section at right angles. Four-point bending tests are conducted at room temperature and at 300 C, using square tubes of three thicknesses (2.0, 2.5, and 3.0 mm), but having the same inside width (115 mm, excluding corner radius) and length (4000 mm). Local deformations and ultimate bending loads are measured. An empirical formula of the relationship between buckling wave growth and bending load is obtained by analogy with an equation derived from the results of bending theory for plates with an initial curvature. An empirical formula of the ultimate bending moment is also obtained by applying to square tubes Karman's effective width theorem for critical loads in plates. These formulae are proved to accurately represent the behavior of test and analysis values. ((orig.))

[en] The construction and fabrication of furnaces for reactor irradiation equipment are described in which temperatures up to 850⁰C may be obtained by means of miniature heat conductors. In order to guarantee perfect thermal contact, the heat conductors had to be embedded in a flame-sprayed metal layer. The heaters thus fabricated were tested in fatigue tests (at 500 or 1,000⁰C) and for thermal shocks. (orig.)

[en] The prototype integral reactor has many fuel channels in a relatively small reactor core with different channel characteristics. The fuel handling system for the integral reactor should be designed as specific system considering reactor specification. Each nuclear reactor has its own fuel handling system design. Therefore the design requirements and bases for the integral reactor should be settled simultaneously with reactor development. In this paper, design requirements for the fuel handling system of the integral reactor are developed

[en] Fuel elements are composed of bundles of parallel heating rods that are cooled by interconnected fluid subchannels. Mixing between these subchannels is an important factor to know in order to assure an efficient cooling. Different methods are used to measure the mixing rates. This paper is devoted to a new method that allows direct enthalpy mixing measurements through the use of small thermal traces generated by means of a sophisticated superficial heater developed together with a high precision thermometry system. The results show the feasibility of this technique for the direct measurement of inter-channel mixing parameter required for numerical codes that are usually employed to study the thermo-hydraulic behavior of new fuel elements designs. In the present work the technique is applied to the quantitative study of the performance of mixing vanes for a compact bundle of rods in completely turbulent flow using water as fluid at ambient conditions. Due to its simplicity this method seems feasible to be a useful fuel element design tool. The experimental results shown asymmetric behaviors not previously reported

No abstract available

[en] As a part of development the evaluation system of safety margin effects for degradation of CANDU reactors, it is required the selection of ageing elements to analyze the thermal-hydraulic effects using RELAP-CANDU code. Unfortunately, it is not easy to make an explicit relation between the RELAP-CANDU parameters and ageing mechanism because of insufficient data and lack of applicable models. So, in this study, to compensate lack of data and applicable models, measured data of fuel channel flow rate related with ageing are used for determination of range and uncertainty of ageing elements. Then, degradation model is upgraded through application of this result

No abstract available

[en] Problems related to evaluation of temperature distribution over volume of cross section of a nuclear reactor core, playing significant role in reactor thermal calculations, are considered. Universal analytical approach is proposed, which makes it possible to obtain the necessary form of the channel distribution function by temperature, reflecting the totality of conditions of the core element operation, by changing the function coefficients

[en] This invention relates to a closure mechanism for tubular irradiation surveillance specimen assembly holder used in nuclear reactors. The closure mechanism is composed of a latching member which includes a generally circular chamber with a plurality of elongated latches depending therefrom. The latching member circumscribes part of an actuator member which is disposed within the latching member so as to be axially movable. The axial movement of the actuator actuates positioning of the latches between positions in which the latches are locked and secured within the actuator member. Means, capable of being remotely manipulated, are provided to move the actuator in order to position the latches and load the articles within the tube