Tokyo ? Japan is poised to declare its crippled nuclear plant virtually stable nine months after a devastating tsunami, but the facility still leaks some radiation, remains vulnerable to earthquakes and shows no prospect for cleanup for decades.

Prime Minister Yoshihiko Noda said last week that temperatures inside the Fukushima Dai-ichi plant’s three melted reactor cores are almost consistently below the boiling point and radiation leaks have significantly subsided — two key conditions in a hoped-for “cold shutdown.”

Officials say the government is expected to hold a news conference Friday to declare something close to cold shutdown.

However, experts caution it will be, at best, a tenuous stability.