Monday 11 November 2013

Start of Decommissioning

Later this month work will start on removing the fuel assemblies in Reactor 4 at Fukushima Daiichi. The building was badly damaged in the hydrogen explosion and you may remember the scare at one time about nuclear fallout if the roof caved in. Well, all the debris has been removed and a brand new building constructed above and alongside the unit. 

There are 1,331 spent fuel assemblies and 202 unused ones being kept cool in a pool above the reactor. The plan is to lift each one out by crane, insert into a special container and transport to a different storage pool 100 metres away. This work, which marks the beginning of decommissioning proper, will take until the end of next year.

According to the local paper (Fukushima Minpo 10 November 2013), radiation on the 5th Floor is  0.1 - 0.13 mSv/hour. 36 people will work in 6 groups with each group working about two hours a day. The maximum exposure allowed for each worker is 0.8 mSv per day. That sounds a lot to me - most people don't want more than 1 mSv in a year! I hope they're well protected.

The two biggest problems in decommissioning Fukushima Daiichi will be removing the melted fuel in reactors 1 to 3, and ensuring there are enough skilled people over the next 30 to 40 years to do the work. Tepco has just announced a raft of measures to improve working conditions. The current 10,000 yen allowance per day (on top of normal pay) is to be doubled to 20,000 yen (200 US$, 126 GBP) per day. Next, the area where full-face masks don't have to be worn is to be increased to two thirds of the site as a result of decontamination. The masks are cumbersome - workers can't communicate with each other easily - and this may have contributed to work errors in the past. New facilities - an 8-storey rest house for 1,200 workers and a cafeteria to provide 3,000 meals  - are also to be built on site. But they won't be ready for over a year. In the meantime, conditions are pretty cramped.

The local evening news showed Bobby Charlton (former football star who helped England win the World Cup in 1966) visiting J-village, which used to be the national youth soccer training centre. He said what an immaculate pitch it used to be and was obviously shocked to see it covered in pre-fabs for the workers at Fukushima Daiichi. He pledged British help in reinstating it.

The national news was full of pictures of the typhoon and tsunami-like flooding in the Philippines. My heart goes out to those people.

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