How do you turn nuclear waste into a $30,000-per-gram commodity? Tritium, once discarded as a by-product of Canadian nuclear reactors, is now one of the most expensive materials on Earth. This rare isotope of hydrogen powers glow-in-the-dark keychains, exit signs that can stay bright for two decades without power and cutting-edge fusion energy research. How do you turn nuclear waste into a $30,000-per-gram commodity? Tritium, once discarded as a by-product of Canadian nuclear reactors, is now one of the most expensive materials on Earth. This rare isotope of hydrogen powers glow-in-the-dark keychains, exit signs that can stay bright for two decades without power and cutting-edge fusion energy research. Other Phys.org – latest science and technology news stories