Design of In-DEBS (In-situ Demonstration of Engineered Barrier System) and Analysis on Optimized Manufacturing Conditions for EBS

The objective of this study is to propose a design for the In-DEBS (In-situ Demonstration of Engineered Barrier System) and suggest optimized conditions for manufacturing engineered barriers. The In-DEBS design was made from the AKRS (Advanced Korea Reference disposal System of HLW), based on performance experience carried out at KAERI (Korea Atomic Energy Research Institute) and from literature reviews. The optimal manufacturing conditions were derived from the test production with regard to the canister and the bentonite buffer. The performance of the manufactured engineered barriers was also evaluated in advance of in-situ application. In-DEBS was designed at 1/2.3 scale of AKRS. An aluminum mold-type heater of 4.2 kW was used to simulate the heating from nuclear fuel. A new methodology using a floating die press and CIP (Cold Isostatic Press) was introduced to fabricate a reliable engineering-scale buffer block for in-situ experiments, leading to a homogeneous and uniform distribution in the densities of the buffer blocks. From the test results, it was found that a floating die press of 40 MPa and CIP of 50 MPa are necessary to satisfy AKRS design premises for the buffer blocks (dry density > 1.6 kg·cm-3). With regard to the THM sensor installations, CNC (Computer Numerical Control) was applied to shape the sensor holes.