nuclear-news

Fuel debris possibly found in Fukushima Daiichi’s Reactor 3

Images show possible fuel debris

Engineers at the Fukushima Daiichi nuclear power plant are working to scrap the facility’s damaged reactors. For the first time, they’ve found what’s likely to be fuel debris in one of them.

The engineers have been trying to locate molten fuel in the No.3 reactor. The fuel is thought to have melted and fallen to the bottom of the containment vessel.

They lowered a submersible robot into the 6-meter-deep cooling water in the vessel. The image sent back by the robot shows an orange substance on a device that operates the fuel control rods. Objects shaped like icicles are also visible.

The engineers plan to use the robot to look for fuel debris at the bottom of the containment vessel.

Removing the molten fuel from the reactors is the biggest hurdle to decommissioning them.

https://www3.nhk.or.jp/nhkworld/en/news/20170722_04/

TEPCO surveys bottom of reactor containment vessel

The operator of the Fukushima Daiichi nuclear power plant has carried out another robotic survey in one of the damaged reactors. The probe is meant to confirm the existence and status of fuel debris consisting of molten fuel and reactor parts.

Officials of Tokyo Electric Power Company, or TEPCO, say the probe took place at the bottom of the containment vessel in the No.3 reactor on Saturday. The vessel’s bottom is thought to hold much fuel debris.

TEPCO used a robot designed to move through cooling water in the vessel.

The survey follows Friday’s release of photographs taken during the previous underwater robotic probe of the same vessel. The robot did not reach the vessel’s bottom during the first probe.

The images show rock-like lumps located near walls of a reactor-supporting structure and various other parts of the vessel.

TEPCO officials say it is very likely the lumps are fuel debris created after nuclear fuel in the reactor melted, mixed with reactor parts, and fell. If confirmed, this would be the first time fuel debris has been found in the No.3 reactor.

Robotic probes have so far failed to provide clear evidence showing the existence and status of fuel debris in other 2 damaged reactors.

Removing the fuel debris is one of the major hurdles to decommissioning the reactors which continues to emit extremely high levels of radiation.

https://www3.nhk.or.jp/nhkworld/en/news/20170722_22/

July 22, 2017 - Posted by dunrenard | Fukushima 2017 | Fuel Debris, Fukushima Daiichi, Melted Fuel, Reactor 3