June 12, 2019
Measure twice, cut once.
Work to remove the highly contaminated units 1-2 vent tower at Fukushima Daiichi took an unfortunate turn last month. The cutting rig had been tested at one of the research facilities and was determined ready to use. When the equipment was assembled on site and work was to commence, it was discovered the crane and cutting rig could not be lifted high enough to place it in the vent tower stack.
With the work now on hold, contractors involved tried to determine what went wrong. Three issues were found that created the cascading error.
The cables that attach the cutting rig to the crane were longer in real life than they were in the on paper design. This caused the cutting rig to sit 3 meters too low.
The crane being used on site was slightly different than what was assumed on paper, this impacted the height the rig could be lifted to.
The engineering survey of the site and ensuing blueprints incorrectly interpreted the total height of the tower by 1 meter. This was due to portions of the base and attachment of the vent tower on site being miscalculated. The base of the tower is obscured by concrete slabs and other shielding put in place after the extent of the dangerous radiation in the tower was better understood.
The solution to part of the problem is to position the crane closer to the tower. This requires the addition of gravel fill to the area to provide the crane a elevated area to sit upon.
The series of miscalculations will cause the work to cut down the vent tower to be delayed until late July 2019.
Read more: simply Info