海洋投棄用放射性廃棄物容器に関する研究 (第1報)

Abstract

Investigations were carried out on form, strengih, and corrosion resistance of containers for waste disposal in the sea. Three different sizes of mortar containers of cylindrical form were constructed and collapse tests were made. Among the results of the tests the values of wall thickness/mean radius (t/ r) against collapse pressure of the three containers were similar. The value of t/r of the cylindrical container corresponding to the critical collapse pressure of 200 kg/cm/sup 2/ is 0.25. This shows that the cylindrical part of the container will be able to be designed dependent only upon the value of t/r, if the size of the cylinder is not extremely different from that of the body to be tested. From the results of similar experiments on the end-plate of the container it became clear that the container will be able to withstand the hydraulic pressure of 200 kg/cm/sup 2/, if the end-plate thickness/inner diameter of the cylinder (t/d) is 0.26. Various kinds of metallic materials may be considered to be suitable as metal used in the cover of the container; however, the steel plates of drums are not only economical in using large numbers at a time, but are also used asmore » containers for disposing radioactive wastes. An apparatus capable of reproducing oceanic conditions such as temperature of sea water, dissolved oxygen, and current velocity, was constructed and used in corrosion tests on the steel plates of drums in an artificial sea water. The weight loss by corrosion during 168 days was about 15 x 10/sup -3/ g/cm/sup 2/ in conditions, where the temperature of the artificial sea water was 2 deg C, the dissolved oxygen was 2.65 ml/l and the current velocity was 1.5 cm/sec. It was found that not only is the dissolved oxygen a primary factor in the corrosion of steel plate in artificial sea water, but also the current velocity plays an important role. (P.C.H.)« less