the light water reactors where not completed. the fuel for them not sent.
the material came from reactors built in the 80s.
# Yongbyon Reactor I - The construction of this natural uranium-graphite power reactor began in 1980 at Yongbyon, 100 km north of Pyongyang. It is based on a 1950 MAGNOX technology (graphite moderator, aluminum-magnesium clad natural uranium fuel , CO2 gas cooling). The reactor was completed in 1984 and it as was activated in February 1987 under Prof. Ha Kyong Won, a Korean physicist educated in US. After many startup problems, it was operating at 20-30 MW by 1990.
N Korea removed about 30 lb. of plutonium from this reactor in 1988 and built two nuclear bombs. From 1989 to 1991, N Korea may have extracted additional 60 lb. of plutonium, enough for five nukes.
# Yongbyon Reactor II - A 50 MW MAGNOX-type reactor was started in 1984. N Korea built a military nuclear complex next to this reactor. This complex was completed in 1989 and the reactor was tentatively activated in 1992. This reactor alone is capable of producing enough plutonium for 10-12 nukes a year.
# Taechon Reactor I - The construction of a 200 MW MAGNOX-type reactor was started at Taechon, 60 miles north of Pyongyang in 1988 and it is expected to be completed in 1996.
# Taechon Reactor II - A 600-800 MW reactor is also underway at Taechon (completion possible by 1997). This reactor could produce 180-230 Kg of plutonium a year, enough for 30-40 nukes.
# Simpo Reactor I - This 635mw reactor is based on a German design. In May 1989, N Korea and Germany signed a comprehensive agreement on the transfer of "substantial" amounts of German nuclear technology and nuclear weapons materials, including enriched uranium, to Pyongyang. The transfer of the German nuclear know-how has continued via Iran, Libya Syria and Yugoslavia.
and the Taechon where not completed - they stopped construction under the 1994 clinton deal.