NUCLEAR WASTEEnsuring Safe Nuclear Waste Disposal
Disposal concepts call for the waste to be isolated a third of a mile belowground for safe storage, enclosed within engineered barrier systems and surrounded by subsurface rock. But there’s still the chance radionuclides might leak out if these systems lose their protective properties as it heats up due to radioactive decay. International nuclear waste disposal research effort evaluates maximum allowable temperature for buffer material.
When it comes to nuclear power, the uranium at the heart of fuel rods is also this power source’s Achilles’ heel. When power plants shut down or the fuel rods in nuclear reactors become inefficient, the high-level nuclear waste resulting from the spent fuel created from running these plants could stay radioactive for thousands of years. Disposal concepts call for the waste to be isolated a third of a mile belowground for safe storage, enclosed within engineered barrier systems and surrounded by subsurface rock.
But there’s still the chance radionuclides might leak out if these systems lose their protective properties as it heats up due to radioactive decay. That means a lot of research effort is focused on the temperature limit up to which these systems and the natural geologic environment can be exposed.
Now geoscientists from Lawrence Berkeley National Laboratory (Berkeley Lab) and two other U.S. Department of Energy (DOE) National Laboratories, Sandia and Los Alamos, are collaborating on the HotBENT project. This international field experiment is evaluating how well the natural, clay-based material (bentonite) placed around canisters of buried, high-level nuclear waste retains its safety functions when exposed to simulated long-term heating.
“The concern is that heat emitted by underground nuclear waste will change the geophysical and geochemical properties of the bentonite buffer and the host rock,” said LianGe Zheng, Berkeley Lab’s lead scientist on HotBENT, whose previous computer simulation studies at Berkeley Lab helped initiate the HotBENT research. “For this long-term series of experiments, we will evaluate the thermal, hydrological, chemical, and mechanical changes in the bentonite and how that affects the material’s safety function over time.”
