Abstract
It has been shown by calculations that it is possible to extend considerably the capabilities for control of temperature conditions in an ampoule channel with natural coolant circulation, using the proposed hydraulic circuit layout, on samples during irradiation in the SM-3 reactor reflector cell by changing the circulation circuit geometry through the arrangement of a bypass heat removal line formed in the upper part above the flow limiter as compared to control only by changing the thermal conductivity of the gas gap in the channel body (through changing the gas pressure or composition). The ampoule channel test conditions, layout and simulation model for thermal-hydraulic analysis using the RELAP5/MOD3.2 code are presented. An investigation was conducted to study the effects of the bypass cooling circuit on the temperature conditions during irradiation of samples in an ampoule channel. The bypass flow rate change is achieved by varying the passage area of the flow limiter orifice. Options have been considered for filling the channel body gas gap with helium and a helium mixture. The calculation showed that the heat removed by the bypass line could reach 40% of the total heat released in the channel. With helium used in the channel body gap, the temperature conditions during irradiation are adjusted in a broader range (200–330 °С) than with a gas mixture of a lower thermal conductivity (279–330 °С), the major temperature variation taking place with the flow limiter orifice area being less than 0.2–0.3 cm2. Any further increase in the flow limiter orifice area does not lead to a major temperature change in the coolant flowing about the samples.
Highlights
SM research reactor, natural-circulation ampoule channel, investigation results, irradiation temperature conditions, power density
Reactor tests in an experimental channel with natural circulation are often accompanied by the coolant temperature deviations from the calculated values
To analyze the influence of the bypass heat removal circuit formed above the flow limiter on the ampoule channel temperature conditions, a series of calculations was performed with the constant initial conditions, channel geometry and thermal conductivity of the gas layer in the body
Summary
SM research reactor, natural-circulation ampoule channel, investigation results, irradiation temperature conditions, power density. Reactor tests in an experimental channel with natural circulation are often accompanied by the coolant (and sample) temperature deviations from the calculated values.
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