Video of Monju fast-breeder reactor 1995 sodium leak

On Dec. 8th, 1995, a sodium leak and fire at the Monju fast-breeder reactor in Fukui prefecture, Japan, threatened to spark an explosion which could have sent deadly plutonium into the local environment. The original incident and a subsequent attempted cover up by the operator in charge of Monju, the Power Reactor and Nuclear Fuel Development Corporation (PNC), left a lasting trace on the nuclear power industry in Japan.

On Friday of last week, a video (the so-called "2 o'clock video") taken the morning after the leak and fire -- and subsequently covered up by the PNC -- finally made its way onto YouTube (with subtitles at dotSUB), posted more than 12 years after the original incident by Japanese blogger tokyodo-2005. Described in a February 1996 New York Times article as "show[ing] men in silver space suits exploring the room in which sodium compounds hung from the air ducts like icicles", the raw video reveals the full extent of the leak in a way never before seen.

To understand the significance of the video, however, a bit of background to fast-breeder reactor technology is required. Unlike other nuclear reactors, fast-breeder reactors "breed" plutonium, a process which requires sodium rather than water as coolant. Japan has been eagerly eying fast-breeder technology as a way to overcome its chronic energy deficit: advocates claim that such technology would create a never-ending source of energy by converting uranium unusable in conventional reactors into plutonium which can then be re-used.

Similar fast-breeder reactors in USA, Britain, France, and Germany, developed as part of energy and weapons programs, have however all been abandoned. The sodium used as coolant in fast-breeder reactors is highly corrosive and is explosive when in contact with air and water. This last fact emphasizes the extreme hazard posed by the leak exposed in the "2 o'clock video", and explains why the PNC went to such trouble to hide it.

Although the video is now over 12 years old, its relevance remains more important than ever as the Japanese gov't is moving ahead with plans to re-open Monju, despite what appears to be only a minor upgrade. While information about the video has been picked up throughout the English-language web, the leak of the video remains virtually unknown within Japan. It would help greatly to spread the word about this incident to other countries in Asia, particularly to activists with an interest in nuclear issues.

For more background issue see this Global Voices article. The video was made public in the context of a trial currently underway between the wife of a PNC official, Nishumura Shigeo, and the PNC itself. Nishimura jumped to his death shortly following the Monju incident, in early January, 20006. His wife alleges that his death was not a suicide. For more information see this 2004 Japan Times article.