 Complete the following phrase:  On April 6, 1993 submarine 664 received the honorific name Belgorod after the old Russian city with that name and the tactical designation K-139. In 1995, crew training began at the Obninsk-based 510th Naval Training Center named after L. G. Osipenko of the Russian Navy 510-й учебный центр Военно-Морского Флота имени Л.Г. Осипенко, but in 1997, construction was put on hold due to the severe economic crisis after the collapse of the Soviet Union with the submarine three-quarters finished, mainly for ficial reasons. On January 22, 1998, the crew was disbanded and the unfinished hull was mothballed. The 