A chain of assumptions and leaving it to subcontractors．．．TEPCO “We didn’t check it ourselves”．．．Why did the mistake happen when removing debris from Fukushima Daiichi？
0001@Old Man Friends Club ★.Sep. 6, 2024 (Fri) 14:48:38.10ID:Ih/NynDH9
On the 5th, Tokyo Electric Power Company (TEPCO) released the results of its investigation into the cause of the delay in the operation to collect trace amounts of melted nuclear fuel (debris) at the No. 2 reactor at the Fukushima Daiichi Nuclear Power Plant due to a mistake. The company said that workers rushed to make preparations under high radiation levels and failed to notice their mistake due to their assumptions. This exposed TEPCO’s attitude of leaving the work to subcontractors, with no TEPCO employees on site, and sloppy management that failed to detect mistakes during inspections. Tokyo Electric Power Company has indicated that it plans to begin sampling as early as next week, after taking measures to prevent recurrence. (Arai Mutsuyoshi, Yamashita Hazuki) ◆ “A chain of assumptions” and “leaving it to subcontractors” The mistake was made in the pipe (approximately 1.5 meters long, 16 centimeters in diameter, and weighing approximately 95 kilograms) used to push the fishing rod-style device for collecting debris into the containment vessel. When working to connect five pipes with a cable, the first pipe was mistakenly connected to the fourth. According to TEPCO, all five cables are almost identical in appearance, but some have different specifications, such as whether or not they have screw holes, and if they are connected in the wrong order, they may not be able to be pushed in halfway. On July 27, workers inside the No. 2 reactor building carried a pipe to the front of the equipment. At that time, a pipe was left behind in the temporary storage area. When connecting on the 28th, they realized they were missing, so they connected as the fourth on the 29th. The pipe I forgot was the first one, but I thought it was the second one, so I decided it would be okay to connect it to the fourth one. A chain of assumptions began. The factors cited as contributing factors were high radiation levels at the site, which meant workers could not stay there for long, so they rushed the work, and they also did not check properly, so they did not notice the mistake and assumed that they were doing it correctly. The worker was wearing full-face masks and heavy protective clothing and overlooked the numbers on the pipes indicating the connection order. Furthermore, the person in charge at Mitsubishi Heavy Industries, the general contractor in charge of the site, falsely reported to TEPCO that “preparation was completed on the 28th.” TEPCO did not have any employees present at the site, and the order in which the pipes were connected was not included in the inspection items, so it did not check and therefore did not notice the mistake. TEPCO’s Akira Ono, head of decommissioning the plant, said, “Our foresight was lacking. “We need to give broader consideration to safety and reliability in the future,” he said in a remorseful statement. [Omitted] ◆ “TEPCO’s involvement was weak” Troubles and mistakes continue According to TEPCO, about 5,000 people are involved in the decommissioning work at Fukushima Daiichi every day. Of these, approximately 1,000 are TEPCO employees. The core of the work on site is carried out by approximately 4,000 general contractors and subcontractors. TEPCO employees will mainly be checking the progress and dangers of the work. However, management of the work was lax, and troubles continued, including one in October last year when a worker at a multi-nuclide removal facility for contaminated water was doused in cleaning waste liquid and exposed to unexpected radiation. Continue reading in the Tokyo Shimbun, September 6, 2024, 6:00 a.m.
>>7 Since the client, TEPCO, received false reports, there’s nothing they can do Since the client usually isn’t on-site The general contractor, Mitsubishi, ultimately bears all responsibility But the primary contractor was the one that actually led the work, so that was probably the right choice.
The outcome would have been the same even if TEPCO had been there. It would have been better if the ordering party or the person in charge had been there. A commentator said earlier that if they had been on TV the mistake wouldn’t have happened, but I don’t think that’s true.
I’m not sure if they even have a responsible attitude towards cleaning up after themselves. It’s a serious matter, so they need to do multiple checks properly. It’s a mess like this even before the contents have been taken out, so it’s not surprising that anything could happen.
Don’t run away just because you don’t want to get exposed to radiation. You don’t show your face on the job site, so the subcontractors don’t feel nervous.
This is the corporate culture of today’s large companies.
Even in general contractors’ construction and plant work, they leave it up to the subcontractors to do their own inspections, and even leave the benchmarks (the xy axis base points that serve as the standard for buildings and equipment) to the contractors. If corners are cut in places that will be hidden by the finishing work, it can no longer be checked. General contractors have always insisted on having the ability to do construction because they have been inspecting and checking, but now they’re not doing so well.
Comments