Work begins to retrieve fallen device inside Monju reactor

Work to retrieve a device that fell inside the vessel of the prototype fast-breeder reactor Monju got under way in Tsuruga, Fukui Prefecture, on Thursday night.
The Japan Atomic Energy Agency, which operates the reactor, said it aims to complete the task by Friday and then conduct preparations to resume normal operation of the reactor by this autumn.
Last August, the cylindrical 3.3-ton device used for fuel exchange fell inside the reactor vessel while it was being lifted out after work to exchange fuel was completed.
Attempts made in October to collect the device failed because it got deformed and caught against the vessel's upper lid. The agency aims this time to remove the device together with part of the upper lid where it got stuck by using a crane.
As part of the device is soaked in sodium, a coolant that reacts vigorously when exposed to water or air, it will be retrieved through a large container in which argon gas has been injected to prevent the sodium from being exposed to air.
The start of retrieval work Thursday was delayed by several hours as a rubber part attached to a tube at the lower part of the container was found to be damaged after workers discovered that argon gas was leaking from the tube, according to the agency.
The device will be lifted from the vessel at a pace of about 6 centimeters per minute, so the whole process is expected to take around eight hours. The device will then be cooled before being taken outside the nuclear facility as it got heated inside the reactor, the agency said.