There’s a building boom at the Hanford Site, a once-secret complex on the windswept plains of southeastern Washington state. Construction crews are working to finish a 27-metre-tall concrete structure there by June. If all goes well, the facility will finally enable the US Department of Energy (DOE) to begin treating the toxic, radioactive waste that accumulated at the site for more than 40 years, starting during the Second World War. Decades after the site stopped producing plutonium for nuclear weapons, the legacy of Hanford’s activities is still causing trouble. Just this year, a tunnel holding railway carriages full of radioactive material collapsed. Separately, at least a dozen employees who were tearing down a contaminated building reportedly tested positive for plutonium inhalation. But the site’s biggest challenge lies underground, in 177 carbon-steel tanks. Together, these buried containers hold more than 200 million litres of highly hazardous liquids and peanut-buttery sludge — enough to fill 80 Olympic-size swimming pools. More than one-third of the tanks have leaked, contaminating groundwater with radioactive and chemical waste. Scientists have been studying vitrification since the 1950s, and a number of countries have used the process to stabilize nuclear waste, including France, India, Russia and the United Kingdom. The United States vitrifies waste at the DOE’s Savannah River Site in South Carolina. But the size and complexity of the problem is on a different scale at Hanford.
Nature 10th Oct 2017 read more »