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[en] A device is described that permits to simulate and study the deformation of fuel cans with the pebble bed core. The device is designed to increase the precision of sample performance simulation by deforming samples at thermal cycling. For that purpose, the pebble bed is placed into a cylindrical sample under investigation. One of cylinder plugs is made mobile in one direction. It jams and hinders temperature expansion on filler heating. Cyclic heating results in even greater elongation and swelling of the sample and allows to investigate the dynamics of tubular sample forming until its destruction. The device is manufactured in the form of a 1000 mm long tube of the Kh19N9T type steel with outer diameter of 20 mm and steel thickness 0.3 mm. Balls, 1 mm in diameter, made of bearing steel are used as pebble bed filler. The sample is exposed to thermal cycling in the temperature range of 700+-30 deg C. The mockup can is destructed after 420 cycles

[en] This paper addresses known limitations and constraints in eddy current nondestructive testing. Incomplete appreciation for eddy current limitations is believed to have contributed to both under-utilization and misapplication of the technique. Neither situation need arise if known limitations are recognized. Some, such as the skin depth effect, are inherent to electromagnetic test methods and define the role of eddy current testing. Others can be overcome with available technology such as surface probes to find circumferential cracks in tubes and magnetic saturation of ferromagnetic alloys to eliminate permeability effects. The variables responsible for limitations in eddy current testing are discussed and where alternative approaches exist, these are presented. Areas with potential for further research and development are also identified

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[en] The research and development of a welding technology for mechanized welding of heat-exchanger tubes into tables for main components in the primary coolant circuits of power reactors is described. The method and the materials were selected by careful model experiments. A Hobart type welding machine with a welding head for the continuous feeding of welding wire was applied. The optimization of the electrical parameters and the selection of the best protective gas are described. A testing procedure for the welded joints and the results on some typical joints are presented. (R.J.)

[en] SEAMATE-II(Simulated Environmental Apparatus for Material Testing-II) has been constructed in August, 1979 at Takasaki Radiation Chemistry Research Establishment, which is working quite well during one and half a year until now. Development of SEAMATE-II was planned at earlier period of 1976, and the apparatus was designed and built in the fiscal year of 1978. Meanwhile, SEAMATE-I was used to solve the problems for constructing SEAMATE-II. During the time the qualification test condition, guide or standard for electrical equipment used in nuclear power station has been investigated extensively from data published in and out of Japan. This report is a summary and an interpretation of qualification test conditions, testing methods, guides or standards for the electrical equipments used in light water reactors, and also data related to them. Items for the interpretation are selected from those of IEC(International Electrotechnical Commission) investigation. (author)

[en] Several annealing studies by positron annihilation (Doppler broadening, lifetime) on neutron irradiated Cr-Mo-V reactor pressure vessel steels (Soviet type 15Kh2MFA) regarding the influences of irradiation temperature, fluence of fast neutrons as well as different impurity contents are presented and discussed. A possibility of explaining the positron annihilation data by irradiation induced carbide formation is proposed. (author)