High-level Radioactive Waste Management

High-level radioactive waste management concerns management and disposal of highly radioactive materials created during production of nuclear power and nuclear weapons. The technical issues in accomplishing this are daunting, due to the extremely long periods radioactive wastes remain dangerous to living organisms. Of particular concern are two long-lived fission products, technetium-99 (half-life 220,000 years) and iodine-129 (half-life 15.7 million years), which dominate spent nuclear fuel radioactivity after a few thousand years. The most troublesome transuranic elements in spent fuel are neptunium-237 (half-life two million years) and plutonium-239 (half-life 24,000 years). Consequently, high-level radioactive waste requires sophisticated treatment and management to successfully isolate it from the biosphere. This usually necessitates treatment, followed by a long-term management strategy involving permanent storage, disposal or transformation of the waste into a non-toxic form.

Radioactive decay follows the half-life rule, which means that the rate of decay is inversely proportional to the duration of decay. In other words, the radiation from a long-lived isotope like iodine-129 will be much less intense than that of short-lived isotope like iodine-131.

Governments around the world are considering a range of waste management and disposal options, usually involving deep-geologic placement, although there has been limited progress toward implementing long-term waste management solutions. This is partly because the timeframes in question when dealing with radioactive waste range from 10,000 to millions of years, according to studies based on the effect of estimated radiation doses. Breeder reactors can use recycled waste from light water reactors as a fuel, extracting additional energy while transmutating it to isotopes that would be safe after hundreds, instead of tens of thousands of years.