| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for storing heavy water that can store heavy water of high purity. SOLUTION: In the method for storing heavy water which is to be used for the processes of manufacturing a semiconductor device in a storage container 1, all organic carbons and metals in the heavy water are removed by a heavy-water purification unit 4 for keeping all the organic carbons in the heavy water at equal to or lower than 20μg/L, and the metals at equal to or lower than 1μg/L. The heavy-water purification unit 4 includes a UV irradiation device 5, a decarboxylation device 6, a mixed-bed type ion-exchange tower 7, a deaeration device 8 and a UF device 9. The UV irradiation device 5 is replenished with supplementary heavy water from a supplementary purification heavy water tank 11. Inner surface of the storage container 1 is coated with fluororesin. COPYRIGHT: (C)2011,JPO&INPIT
|
