STUDIES ON THE EFFECTS OF BLOCKAGE UPON LWR EMERGENCY CORE COOLING SYSTEMS
This report makes an extensive presentation of data obtained from a bundle containing a centrally placed 4 x 4 array of balloon shapes. The balloon sleeves were hydraulically formed to give a wall thickness of 0.325 mm typical of reactor fuel pin balloons. They were 196 mm long with a maximum subchannel blockage of 61% over a 175 mm length. These sleeves represent the condition where adjacent fuel pin claddings just touch. The reflood tests showed very early quenching of the blockage sleeves compared with the bypass rods or an undistorted bundle. Sleeve quench times were shorter by a factor between about 2 and 4 than the undistorted bundle over the parameter range investigated. The effect of adding 1 kW power to all rods prior to reflood was to move sleeve quench times closer to the undistorted bundle values. In the steady power reflood tests all thermocouples above the elevation of the bottom of the sleeves quenched well before the undistorted bundle. Pulse heated platinum/platinum-13% rhodium thermocouple probes were built and used in these experiments to measure steam temperatures under two-phase conditions. The probes installed below and above the blockage gave steam temperatures in good agreement with conventional 0.5 mm diameter mineral insulated thermocouples during the steady state phase prior to reflood. Under two-phase conditions of the reflood tests they usefully extended the period over which steam temperatures could be measured.
Bibliographic Reference: EUR 10079 EN (1985) MF, VOL II PART 3 194 P., BFR 300, BLOW-UP COPY BFR 970, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989123121900 / Last updated on: 1987-01-01
Available languages: en