Patent Number: 053655540
Section: summary

The present invention relates to an instrumentation probe for use in the on-line measurement and recording of physical parameters within a fluid duct without connection to external instrumentation. A particular application of the instrumentation probe is to the measurement and recording of structural, thermal and hydraulic data within a fuel channel of a fluid-cooled nuclear reactor, and such data may include fuel channel coolant pressure, in-channel flow magnitudes and variations, fluid and pressure tube temperatures, pressure tube vibration, fuel bundle displacements, and the like. However, the invention is not exclusively concerned with nuclear applications, but is applicable to analogous systems in which physical parameters within a fluid duct are to be measured and recorded. In the case of fluid-cooled nuclear reactors, problems associated with fuel bundle damage have underlined the need to have a capability to obtain accurate measurement data directly from within any fuel channel during any phase of reactor operation. The inability to obtain structural integrity measurement data directly from locations within fuel channels during reactor operation has resulted in uncertainty as to quantifying activity within the fuel channels, such activity relating more particularly to the pressure tubes, coolant flow and fuel bundles. This uncertainty has in turn resulted in severe information constraints regarding structural and thermal-hydraulic concerns with fuel channels. In order to deal with these concerns, accurate on-line measurements within the fuel channels are required. According to the present invention, there is provided an instrumentation probe for measuring and recording one or more physical parameters within a fluid duct, which may be a fuel channel of a nuclear reactor, although the invention in its broadest aspect is not limited to nuclear applications. The instrumentation probe basically comprises an elongate support frame adapted to be located within the fluid duct, and self-contained measuring and recording means mounted on the frame. The self-contained measuring and recording means comprises one or more sensors each responsive to a physical parameter to be measured and recorded, and a scribe coupled to the or each sensor, which scribe cooperates with a volume driven recording chart, such as a rotary drum, disk or tape for recording variations in the respective physical parameter over time. The recording chart is driven by a longitudinally extending rotary shaft carrying an impeller which is responsive to fluid flow for rotating the shaft at a constant speed, the shaft being coupled to the recording chart through a speed reducing mechanism. In the case of a nuclear reactor application the fluid flow is itself maintained constant and so the constant speed of the recording chart is thereby maintained. In applications where the fluid flow is not constant it is necessary to govern the shaft rotation by any suitable speed governing device, or alternatively to apply signal reference markings to the recording chart at regular intervals of time during monitoring periods so as to provide a time scale. It will be appreciated that, in the latter case, the chart will be driven at a measurable speed since the speed can be later deduced from the known time periods between the applied reference markings.