The US and Russia are working out a deal to shut down the two plutonium-production reactors at Seversk. The US is to pay much of the cost of shutting them down, entombing the radioactive elements, and building a fossil-fuel plant to replace the electricity and heat produced by the old reactors. The reactors, which can produce enough weapons-grade plutonium for 200 warheads per year, will be shut down "in a few years". That would leave Russia with only one plutonium-producing reactor, the one at Zhelznogorsk, and the US and Russia are also working on a deal to close this down or improve its safety and reduce the amount of plutonium that it produces.--Stephen V Cole