Abstract: The aim of the invention is to measure the partial pressure of very small amounts of free hydrogen gas at various sites in the core of a nuclear reactor. A further aim is to construct such a device to be so rugged as to survive in the reactor environment. Another aim is to construct such a device of materials which will not significantly affect reactivity.

Abstract: A nuclear fuel element comprises plutonium-containing fuel pellets filled in a cladding with both end sealed with end plugs. One end plug has a filter at the inside and a passage communicating with the space in the cladding through the filter. The passage is sealed at the surface part of the end plug by welding. The filter and the passage in the end plug are utilized for withdrawing a gas in the cladding filled with the fuel pellets in a process for fabricating the nuclear fuel element. The filter traps nuclear fissionable materials in the cladding to prevent its leakage to the outside. After the withdrawal of the gas, a helium gas is filled in the cladding through the passage in the end plug. After completion of these operations, the passage in the end plug is sealed as mentioned above.

Abstract: The counting system includes a portable gamma ray detector having a detecting portion electrically connected to instrumentation for analyzing the radioactivity of nuclear reactor fluids, a radiation shielded panel including a plurality of openings for receiving the detecting portion of the detector, and sample vessels for receiving a radioactive fluid located behind the panel. Samples of radioactive fluids such as reactor coolant, reactor coolant off-gas and containment air, are selectively introduced into the sample vessels. The reactor coolant is cooled, de-pressurized and de-gassed and the off-gas and the liquid are routed to separate sampling vessels. The radioactivity of the radioactive fluid contained in each sample vessel is determined by simply inserting the detecting portion of the detector into a corresponding panel opening. Radiation shielded plugs are inserted into each of unused panel openings to shield the operator against radiation.

Abstract: A hydrogen measuring apparatus comprising two gamma thermometers. Both gamma thermometers are mounted adjacent and parallel to each other. Each is provided with a plurality of annular enclosed spaces formed in an elongated rod. Each annular space is provided with a hot junction of a difference thermocouple. The annular spaces of one of the gamma thermometers is either filled with a gas other than hydrogen, or surrounded by a hydrogen blocking material to prevent hydrogen contamination of the annular spaces. The annular spaces in the other gamma thermometer are placed in a vacuum and become contaminated with hydrogen. By comparing the power generation readings of the two thermometers free hydrogen partial pressure can be calculated.

Abstract: A device for collecting fission gas released by a failed fuel rod which device uses a filter to pass coolant but which filter blocks fission gas bubbles which cannot pass through the filter due to the surface tension of the bubble.

Abstract: Sound waves are generated in a sonic cell and propagated through a gas to a sensor which is coupled to a microcomputer. A gas mixture is first directed into a chamber and the attenuation and transit time of sound waves are calculated. Then, a calibrated gas is directed into the chamber, and the attenuation and transit time are again calculated. With these measurements, the microcomputer calculates the concentrations of at least two gaseous constituents such as hydrogen and water vapor, in the gas mixture. The microcomputer acts also as a control for operating valves and heater coils in response to pressure and temperature sensors coupled with the chamber.

Abstract: A compensator device for providing direct and automatic correction of electrolytic gas sensor performance anomalies caused by exposure of the sensor to high levels of ionizing radiation. The compensator device, which compensates for changes in sensor performance while operating in a radiation field, provides an electromotive force which directly cancels that portion of the electromotive force developed by the active electrolytic gas sensor produced by the radiation rather than by presence of the gas. The compensating device is constructed in the same configuration as the active electrolytic sensor with the exception that the sensing electrode of the compensating device is not exposed to the sample gas environment. The sensor and compensator device are connected in a circuit such that their electromotive forces oppose one another, thereby determining the difference between the signals so that the radiation induced component is removed, and only the signal representing the partial pressure of gas remains.

Abstract: A method and apparatus is shown for establishing a predetermined concentration of gas in the reactor core coolant for a pressurized water nuclear power system. Gas is added to core coolant water in a bubble column. The gas-water mixture flows through static mixers in the column to produce the desired gas concentration in the water.

Abstract: This invention relates to monitoring the condition of a nuclear power generating facility and has particular applicability to isolating samples of primary coolant from a pressured water reactor to enable analysis in a post accident environment.

Abstract: Apparatus for measuring a parameter relating to at least one substance possibly present in at least one chamber of a set of measurement chambers kept under very low residual pressure. The chambers (12) are connected, on the one hand to a single vacuum pump installation (14), by low conductance elements (18) offering great resistance to the passage of molecules, and on the other hand, to a device (23) for measuring the parameter common to the set of chambers (12) by a selector (20) allowing each of the chambers (12) to be put in communication successively with the device (23) for measuring the parameter. The invention is particularly suited for measurement of the hydrogen content of the liquid sodium in a steam generator of a fast neutron nuclear reactor.