TOKYO — Japan pledged better safety practices for its troubled nuclear industry today after an accident at a government research facility that exposed 33 people to minor excess radiation and wasn’t immediately disclosed.

Education Minister Hakubun Shimomura, whose agency oversees such research, said the government will tighten oversight of such research.

Japan’s nuclear industry has been in crisis since the March 2011 accident at the tsunami-hit Fukushima Daiichi nuclear plant, the worst since Chernobyl in 1986. The government has revamped its regulatory regime and is drafting stricter safety standards, as troubles mount.

Shimomura said the government would set up a panel to discuss reform and safety compliance at the Japan Atomic Energy Agency after the accident Thursday at the Hadron Experimental Facility of the JAEA’s Japan Proton Accelerator Research Complex in Tokaimura, where at least two previous radiation accidents have occurred.

No radiation was released to the outside environment in Tokaimura.