The Department of Earth & Environmental Sciences is pleased to present
"Deep Geologic Repository of Radioactive Waste: Pros and Cons"
by Namir Al-Aasm
Proper containment and long term disposal of the highly radioactive waste by-products created in nuclear energy production, nuclear weapons manufacturing, nuclear medicine and scientific research is a complicated problem requiring unique solutions and tactics. These extra considerations not needed in the disposal of other types of waste management are due to the unique challenges and concerns that must be considered when handling the various forms of waste products created in the many industries relying on the radioactive nature of unstable fissile isotopes. Due to the variance in waste created, the large amount of residual heat and radiation these waste products can emit, and the extremely long timescales on which these products can remain dangerous (months to millions of years depending on the radionuclides present and their respective half-lives), there is currently no unified consensus on the ideal storage and containment procedures required.
As of now, even 70 years after the discovery and harnessing of the ability for elements to radioactively decay, there is currently no operating permanent nuclear waste repositories accepting the high level waste and spent nuclear fuel used in nuclear power generation. Since the inception of nuclear power generation and weapons, the consensus has been that the only long term viable solution for proper and safe disposal of nuclear waste is deep burial within the subsurface in specially constructed geologic repositories as many radionuclides have half-lives in the millions of years.
Many differing opinions upon the ideal host rock geology, repository design, and waste packaging design have been proposed by various nations over the years. This talk will discuss the advantages and disadvantages unique to the 4 most widely proposed potentially viable host rock geologies: clay, crystalline rock, salt and tuff. There is also no currently unified consensus on what the measures of success for a geologic repository to be considered effective and safe at isolating radioactive waste from the surrounding biome are; although many countries agree the compliance period should be one million years. In the case of the Swedish KBS-3 concept, a repository is considered safe if the engineered barriers contain the radiation until the decay of the waste has reached a point where the emitted radiation matches that of the ore from which it was originally derived. This talk will discuss the various strategies considered by the various nuclear powers around the world, as well as the approach considered in our own backyard here in Canada.