Preliminary study on the method of dissolving/removing the buffer with salt solution

Abstract

  In high-level radioactive wastes disposal, it may be decided to free and retrieve the emplaced overpack for some reasons. We have been paying attention to the method of slurrying bentonite buffer around overpack with fluid (salt solution) as an option method for freeing overpack. Some laboratory tests performed for finding out the fiesibility of this method. The results from the tests indicate that the buffer material, constituted of bentonite and quartz sand, can easily be dissolved in NaCl 3 or 4wt% solution, and dissolved material is deposited soon in the slurry. The results from the flushing experiments applied to a small specimen of buffer material suggest that flushing NaCl solution is effective for speedy stripping of buffer material.