[en] Purpose: To provide a reactor container system for preventing the leakage of radioactivity at the time of a reactor accident, wherein spraying water is sprayed without mutual interference thereby to carry out the heat removal and the removal of radioactive gas within the reactor container spray system. Constitution: On the circumference of a reactor container there are provided a group of upward spray nozzles at its upper stage and a group of transverse spray nozzles at the lower stage. Each of nozzle groups at both stages is provided with a feedwater system consisting of a pump for exclusive use thereof, a heat exchanger, and a pipe. Furthermore, one of these feedwater systems is connected through a valve to another nozzle group. When the valve is opened, spraying water from a suppression chamber is sprayed without interference on the periphery of the pressure vessels from the above described spray nozzle groups, and the heat removal and the removal of radioactive gas within the reactor container are carried out efficiently. (Horiuchi, T.)

[en] This invention concerns the transfer of toxic or radioactive substances between a containment and a flask in which such substances are transported. When toxic or radioactive substances are being transferred, it is important to ensure that such substances cannot escape into the surrounding atmosphere and, preferably, the appliance utilized has to be capable of making a misuse impossible, whether accidental or calculated. The flask to which this invention applies is of the type comprising a flange near an open end which can marry with a sliding blocking component inside the containment to hold and maintain the flask against the wall of the latter. Its open end is aligned with an access opening in the wall of the containment

[en] This invention concerns the transfer of toxic or radioactive substances between a containment and a flask in which such substances are transported. When toxic or radioactive substances are being transferred, it is important to ensure that such substances cannot excape into the surrounding atmosphere and, preferably, the appliance utilized has to be capable of making a misuse impossible, whether accidental or calculated. The flask to which this invention applies is of the type comprising lugs, near its open ends, which act in combination with a groove made around an access opening to hold and maintain the flask in position against the wall of the containment, so that its open end is aligned with an access opening provided in the containment wall

No abstract available

No abstract available

[en] Generally there is a large number of pressure vessels containing high pressure gas on power stations and chemical plant. In many instances, particularly on power plant, these vessels are within the main building. If a pressure vessel were to fail, the surrounding structures would be exposed to blast loads and the forces resulting from jets of fluid issuing from the breached vessel. In the case where the vessel is in a relatively closed chamber there would also be a general overpressurisation of the chamber. At the design stage it is therefore essential to demonstrate that the plant could be safely shut down in the event of a pressure vessel failure, that is, it must be shown that the chamber will not collapse thus putting the building at risk or hazarding equipment essential for a safe shut down. Such an assessment requires the loads applied to the chamber walls, roof, etc. to be known. (author)

[en] A bursting safeguard for reactor pressure vessels is described which provides favourable transport possibilities and allows easy assembly. (TK/LH)

[en] Stability is dealt with, in accordance with the regulations and specifications, as the deformation of a cylinder under external hydrostatic pressure. The inner rings/tubes can, in fact, become instable. However, the load capacity depends on the size of the disturbance which in real components always exists between inner and outer walls. With real disturbances, the limit load is most always determined by yielding point and stress at failure; it is within the stable range of equilibrium. With loads in the plastic range of the material, the critical load can be determined taking into account a plastic joint, and subsequently compared with the load resulting from the stress computational method developed by Cozzone. In this calculation, a non-linear stress distribution accross the cross section is assumed. (orig./HP)

[en] For reactor containment vessels, one of the most important installations for the safety of nuclear power stations, the works of improving the conventional design and standardization have been forwarded, based on the experiences of construction, operation and maintenance. No. 2 plant of the Fukushima No. 2 Nuclear Power Station, Tokyo Electric Power Co., Inc., designed, manufactured and being constructed on the basis of these results is the first plant adopting this improved standard containment vessel, and the pressure endurance test and leaking rate test of the containment vessel were able to be completed without any trouble on August 30, 1980. The features of this containment vessel were to give some margin to the internal space by enlarging the diameter of the containment vessel in order to make the works of maintenance and inspection easy and to reduce the radiation exposure of workers, to provide the exclucive opening for taking out a relief safety valve and control rod-driving mechanism, to adopt high strength steel stronger than the conventional material, to improve the construction of the welded parts in bottom linear plates, and to adopt diaphragm floor seal bellows made of stainless steel. The basic structure and features of the improved standard Mark-2 containment vessels, the basic specifications for the design, and the stress calculation for the important parts are explained. (Kako, I.)

[en] Purpose: To minimize the activation of shielding materials and effectively confine tritiums in the buildings for thermonuclear experiment facilities. Constitution: Water vessels made of less activatable aluminum alloys are disposed to the outside of pillars and beams and the floor made of less activatable aluminum alloys disposed to the outer circumference of experiment facilities, so as to entirely surround the facilities with no gaps. The water vessels are filled with shielding purified water, and connected with a cleanup and cooling device for purified water for nuclear facility disposed outside the buildings, a recycling device for shielding purified water and feeding and returning pipeways therefor. Purified water in the water vessels are circulated to eliminate activated impurities in the purified water, and radiolysed gases are processed. As the result, activated materials can be processed at a predetermined position of the buildings, operator's access after the end of the experiment is facilitated, and the amount of activated materials to be handled upon dismantling of the buildings can significantly be reduced. (Moriyama, K.)