For example, here is something about Japan's nuclear program:
http://www.fas.org/nuke/guide/japan/nuke/"To enhance its energy security, the government advocates uranium and plutonium recovery through reprocessing of spent fuel. The Power Reactor and Nuclear Fuel Development Corporation (PNC) operates a reprocessing plant with an annual capacity of 90 tons but a larger reprocessing plant, Rokkasho-Mura, with a capacity of 800 tons per year, planned for 2003, is under construction. Reprocessing is expensive and costs can quickly rise with new safety requirements and the development of new technologies. Estimated in 1993 to cost about $8 billion, a more recent estimate for Rokkasho-Mura places the total at $15 billion. Japan also is interested in recycling recovered plutonium. In 1999, Japan began, in two prefectures, a controversial mixed-oxide utilization plan, which involves burning a highly toxic mix of plutonium and uranium on a commercial scale."
But this comes a bit further on:
"Weapon-grade plutonium is nearly pure plutonium 239, whereas the plutonium in commercial fuel is much lower in plutonium 239 and higher in the isotopes that are undesirable for weapons use. This, however, is not a crucial difference, since all plutonium can be used in weapons. The US nuclear weapons arsenal does not utilize commercial (reactor grade) plutonium from spent fuel. Tests were completed, however, to confirm that reactor grade plutonium could be used in a nuclear explosive and is therefore a nonproliferation concern."