The Japanese government says it will not allow the operation of nuclear reactors that are 40 years or older.

Nuclear disaster minister Goshi Hosono told Japanese media Tuesday that reoperating nuclear reactors older than 40 years is impossible.

The minister’s remarks suggest Tokyo will not reactivate two 42-year-old nuclear reactors in Tsuruga and Mihama which have gone offline for checkups.

This is the first time a Japanese nuclear-related minister has made detailed comments on the operational life of older nuclear reactors.