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http://dx.doi.org/10.7474/TUS.2014.24.6.405

R&D Review on the Gap Fill of an Engineered Barrier for an HLW Repository  

Lee, Jae Owan (Korea Atomic Energy Research Institute)
Choi, Young-Chul (Korea Atomic Energy Research Institute)
Kim, Jin-Seop (Korea Atomic Energy Research Institute)
Choi, Heui-Joo (Korea Atomic Energy Research Institute)
Publication Information
Tunnel and Underground Space / v.24, no.6, 2014 , pp. 405-417 More about this Journal
Abstract
In a high-level waste repository, the gap fill of the engineered barrier is an important component that influences the performance of the buffer and backfill. This paper reviewed the overseas status of R&D on the gap fill used engineered barriers, through which the concept of the gap fill, manufacturing techniques, pellet-molding characteristics, and emplacement techniques were summarized. The concept of a gap fill differs for each country depending on its disposal type and concept. Bentonite has been considered a major material of a gap fill, and clay as an inert filler. Gap fill was used in the form of pellets, granules, or a pellet-granule blend. Pellets are manufactured through one of the following techniques: static compaction, roller compression, or extrusion-cutting. Among these techniques, countries have focused on developing advanced technologies of roller compression and extrusion-cutting techniques for industrial pellet production. The dry density and integrity of the pellet are sensitive to water content, constituent material, manufacturing technique, and pellet size, and are less sensitive to the pressure applied during the manufacturing. For the emplacement of the gap fill, pouring, pouring and tamping, and pouring with vibration techniques were used in the buffer gap of the vertical deposition hole; blowing through the use of shotcrete technology and auger placement and compaction techniques have been used in the gap of horizontal deposition hole and tunnel. However, these emplacement techniques are still technically at the beginning stage, and thus additional research and development are expected to be needed.
Keywords
gap fill; buffer; backfill; engineered barrier; high-level waste repository;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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