Development of sodium conversion technology. Fabrication of sodium conversion test apparatus and results of previously test run

It prepares for a large amount of radioactive sodium processing accompanied by final shutdown/decommissioning of First Reactor Plant, and/or dismantling of sodium experimental facilities in a domestic one, and the technical development for sodium processing safely, efficiently, and economically is carried out in the future. The sodium processing method with caustic soda, which has application in the actual sodium processing of abroad, was adopted, and the experimental research was started aiming at establishment of the fundamental processing method when applying this in our share-flow coupling model was built up using GIS technology. (aiming at grasp of the basic reaction property of sodium and caustic soda, and the optimum specification determination of a sodium conversion processing system, was designed and fabricated. As a result of checking the system function of this apparatus and carrying out a small reaction test as a previously tests run, the following findings and subjects of future were obtained. (1) In the functional test of each performance in this apparatus, the design performance was sufficiently satisfied on each function and controllability. (2) In the calibration test of a caustic soda concentration meter, the correlation data between ultrasonic velocity and caustic soda concentration as a function of caustic soda temperature was obtained in the condition range extended conventionally, and the calibration curve was proposed by multiple regression analysis. (3) In the reaction test which carries out very-small- quantity pouring of the sodium at caustic soda, the problem on the safety was not recognized a reaction phenomenon or a process behavior. However, some problems, such as fluctuation of the sodium flow meter indication by noise influence, plugging in the spray nozzle, and involvement atomizing gas in a caustic soda circulation line, were occurred in this test run. In the future, it will be coped with from both sides of the equipment modification and the operation point about extractive subjects. (author)