Heat released by vitrified waste
Like spent fuel assemblies, vitrified waste packages release heat. The heat output decays more rapidly. A waste package, which has a total volume of approximately 200 litres and contains 150 litres of glass, initially releases 3000 W, tapering to 700 W after 35 years, 170 W after 100 years and less than 30 W after 300 years.