11.   It was unclear at the time whether the North Koreans possessed the technology to use the plutonium at the core of a crude nuclear weapon.

12.   It made it possible to produce the pressure needed to set off a nuclear chain reaction using plutonium, the main bomb fuel of the day.

13.   Japan is banking heavily on conventional uranium-based nuclear power and on advanced systems using plutonium to relieve its almost complete dependence on imported oil and coal.

14.   Japan, Russia and several European countries, though not the United States, have recently made heavy investments in using plutonium for the production of nuclear power.

15.   Most of the details have yet to be negotiated, including the pressing question of how to pay for the Russian program to use the plutonium as reactor fuel.

16.   Perhaps that is just as well because with Monju down, Japan cannot easily use the plutonium.

17.   Some Asian nations worry that Japan might one day use its plutonium to make weapons, which Japan vociferously denies.

18.   The Indians used plutonium from a research rector sold by Canada for peaceful purposes.

19.   The plan also comes at a time of renewed controversy over whether reactor-grade plutonium can be used to make bombs.

20.   They are determined to use their plutonium in a new generation of nuclear reactors that would make yet more plutonium.