Abstract: Probe-holding apparatus for holding a probe for checking steam generator tubes particularly in a nuclear reactor installation. The apparatus comprises a telescopic arm supported via a ball and socket joint from a support mounted in or near an access aperture in a chamber at one end of the steam generator. A probe guide is carried by a carriage pivotally mounted at the other end of the telescopic arm. The carriage includes an endless belt having a series of spaced projections which engage into the ends of the tubes, the projections being spaced by a distance equal to the tube pitch or a multiple thereof. The belt is driven by a stepping motor in order to move the carriage and place the probe guide opposite different ones of the tubes.

Abstract: The leakage of gases in gas cooled nuclear reactors is detected by an arrangement utilizing a flexible material to cover areas of potential leakage and create detection cavities inside the concrete vessel of a nuclear power plant. The detection cavities are connected to the gas collector housed within the concrete vessel by means of gas-tight connecting conduits or lines. A negative pressure is applied to the gas collection device connecting conduits and detection cavities to extract any gas leakage within the power plant. Gas measuring devices and display devices are included in the system to identify, quantify or locate gas leakage.

Abstract: A plurality of sampling tubes are connected with a selector valve and the selector valve selects one of the sampling tubes so that the sample gas is lead through the selected sampling tube and a pipe way downstream of the selector valve to a leakage detection system. The pipe way is provided with a gas flushing section for flushing with high pressure gas and the gas flushing operation is performed before each change-over of the selector valve. The flow of sucked gas is kept constant by providing a gas flow control device downstream of the leakage detection section. A pressure sensor is provided for the pipe way leading to the detection section, to detect the gas pressure in the pipe way and the output of the pressure sensor is used to detect an abnormality occurring in the detection section inclusive of the pipe way thereto and also to correct the output of the pressure detector in the detection section.

Abstract: A sub-assembly for detecting leaks of a liquid metal circulating in a component of a circuit such as a conduit or a valve or contained in a storage means such as a reservoir, comprising electrically conductive elements arranged inside an electrically insulating material, wherein said insulating material consists of a rigid shell the inner surface of which is adapted to the outer surface of said component, while open grooves are formed on the inner surface of the shell for receiving said electrically conductive elements, the grooves having a widened portion remote from the inner surface of the shell, receiving the electrically conductive elements, and a portion of reduced width located between the widened portion and the inner surface of the shell and maintaining the electrically conductive elements at a spacing from said inner surface.

Abstract: Channels running along the cooling tubes, between the cooling tube and the liner to which the tubes are attached, serve to collect leakage gas through lateral openings connecting the channels to the boundary between the liner and the concrete. These channels can be produced in the extrusion of the cooling tubes and provide considerable saving in the construction of the leak monitoring system as well as efficiency in bringing the leakage detecting channels close to the liner. The channels are connected to a known form of piping tree equipped with valves for determining leak location after the presence of a leak has been found with all the branches connected to the detector unit. A conventional set of perforated pipes embedded in the concrete running at right angles to the cooling tubes may be used to complete the detection raster where large surfaces are to be monitored.

Abstract: A fluid circulation system for heat exchangers having two groups of tubes through which primary and secondary fluids flow, the tubes of one group being interdigitated with the tubes of the other group, and a heat transfer material interposed between the two groups of tubes, whereby heat is transferred from the primary fluid through the heat transfer material to the secondary fluid. A shell forms a closure around the tubes and the heat transfer material, and the shell has tertiary fluid inlet and outlet means. Openings in the heat transfer material form passageways through which the tertiary fluid can flow from the inlet means, through the heat exchanger, to the outlet means. Piping connects the tertiary fluid outlet means to the tertiary fluid inlet means, forming a complete cycle. Installed in this piping is a heat removal system. If the secondary fluid flow is interrupted, the tertiary fluid provides a redundant means by which the heat of the primary fluid can be removed from the heat exchanger.