Water containing radioactive substances leaked at the decommissioning site of the Fugen advanced converter reactor in Fukui Prefecture, central Japan, on Tuesday. 

According to the Japan Atomic Energy Agency (JAEA), the leak occurred shortly after 3 p.m. on Tuesday. Three workers were on site, but no one was exposed to radiation either from "internal exposure" by inhalation or "external exposure" by being splashed with water. There was also no report of impact on the surrounding environment.

JAEA said a total of 20 milliliters of water contaminated with tritium leaked from a pipe during dismantling work. The leak is now stopped.

Radiation levels recorded by surrounding monitoring posts show no irregularities. However, tritium levels inside the demolition area exceeded regulatory levels, triggering the report to the Nuclear Regulation Authority.

The Fugen reactor operated as a research facility for the government's nuclear fuel recycling policy. The operation of the reactor stopped in 2003, and the reactor has been decommissioned since 2008.

(With input from Xinhua)