Apparatus for removing impurities in the sodium of sodium cooled reactors

An apparatus is provided for removing oxygen liquid sodium flowing in a sodium cooled reactor. The removal of oxygen is complete with high efficiency. The liquid sodium to be purified is disposed outside a cylindrical wall and negatively charged, whereas sodium as a reducing material is disposed inside the same wall. The cylindrical wall is made of zirconia-calcia (ZrO2)sub(0.87)(CaO)sub(0.13) solid electrolyte, the cylinder having a thickness of 2.5mm, a diameter of 3cm and a depth of 20cm under the sodium level. Electric resistance of the solid electrolyte is 2.3 ohm at 5000C. A current of 1A by the application of 25 volts treats 0.3g of oxygen. Consequently, 1 liter or 1kg of liquid sodium containing 1,000ppm of oxygen can be purified for about 3 hours at an electrical consumption of 7.5 watt-hour. In one embodiment, a cylindrical electrolytic solid made of zirconia-calcia or zirconia-yttria was disposed in a container. Liquid sodium containing oxygen flowed outside of the cylinder. Liquid sodium as a reducing material was present inside the cylinder and the container and the cylinder were electrically insulated. An electrode was inserted at the center of the cylinder and a baffle plate at the upper portion of the electrode to shield heat and rising sodium vapor was provided. The space above the container was filled with an inert gas. The oxygen in the liquid sodium to be purified transferred through the wall of the cylinder into the interior of the cylinder so as to oxydize the reducing sodium material. The supersaturated sodium oxide inside the cylinder was deposited. (Iwakiri, K.)