Features: Underground Repositories
Belgium´s Underground "Hot" Lab
Finding Solutions for Radioactive Waste
Staff Report
8 June 2005
Underground laboratory at Mol, Belgium. (Photo credit: Mol (HADES))
In a laboratory 230 meters beneath the earth in Belgium, scientists are studying ways to safely dispose of highly radioactive waste. Some of the experiments they monitor have run for two decades in an underground rock laboratory at Mol (HADES), in the country´s North.
What scientists are investigating is how to isolate extremely hot, hazardous radioactive waste by burying it deep under the ground. Experts call it a "geological repository". The idea is to isolate the waste from humans and their environment while it loses its radioactivity. That process takes tens of thousands of years. A geological repository works by cocooning the high level waste in man-made barriers like steel casing, concrete and sealing materials, then using the earth´s rock as the final leak-tight vault.
"We want to know if is it feasible, both technically and financially, to design and build a geological disposal repository on Belgium territory that is safe," says Mr. Marc Demarche, Director of EURIDICE, which operates the underground lab at Mol. Indications from the rock lab, which started in 1980, look promising.
Mol is part of an IAEA "centre of excellence" network that links seven other underground rock labs dotted across globe. The programme effectively unites the worlds´s best minds focused on finding safe solutions to dispose of high-level waste in geological repositories.
For now Belgium´s high level nuclear waste is stored at "Building 136" - a facility designed to withstand earthquakes, external explosions, extreme winds and airplane crashes. Part of the thinking behind disposal of the waste deep underground is the security it provides against terrorist attack.
Belgium has relied on nuclear power for 30 over years. It meets half of the country´s energy needs. Each year the world produces about 10 500 tonnes of high level waste, to generate 16% of the world´s electricity.
Research to study the long-term management of Belgium´s high-level waste started in the 1970s. Today some 3.5 million Euro is spent each year on investigative experiments at Belgium´s underground laboratory. Mr. Demarche says that the underground laboratory enables the experiments to be conducted in conditions close to those encountered in a real repository. The experiments focus on worst-case scenarios and how to prevent them - like the possibility of radioactive gases seeping into a water supply.
One experiment is investigating the performance of a glass material - in which radionuclides are embedded - under close to real radiation and temperature conditions. The information helps scientist around the globe learn about the best-engineered materials and rock types to contain the waste.
Building a repository in clay induces damage to the clay host rock, says Mr. Demarche. So experiments at the Mol lab examine the impact of the induced damage over time. Investigations show that the fractures in Boom Clay close very quickly. "It is now clearly stated that in clay formations, the impact of the excavation on the performance of the repository system is not a critical issue," says Mr. Demarche. "Such experiments constitute strong scientific foundations for the performance assessment of a geological repository. They take into account the complex combination of changing environmental conditions," he said.
At Mol, and other rock laboratories scattered across the globe, scientists continue to gather information about the geological, hydro-geological, geochemical and geotechnical characteristics of rock types suitable for geological repositories. The information and lessons learnt are shared through the IAEA´s centre of excellence network. Now the decades of research is starting to pay off, as conclusions are steadily drawn. Global scientific consensus holds that disposal of radioactive waste in these deep underground repositories is the best and safest option.