A former nuclear power plant engineer Yuzo Uehara posted the following tweets on March 24th.
Proposal 240323: Radiation exposure decreases to 1/10 inside of a building for sure. A culvert (imagine a tunnel) made of metal containers or concrete would be good. Installing lead etc. on the walls would be more effective for reducing radiation. Not only inside of a culvert but also its back side has very good blocking effect. It’s better to install it at the nuclear power plant site.
Proposal 2403242: TV report said that workers extending cables had radiation exposure. If the culvert method, I proposed, had been applied, I think it could have been prevented from happening. Because it’s an emergency situation, safety is fundamental. If a small and compact culvert were installed inside the buildings, it allows us to put workers and equipment in place appropriately, and makes shifting easy. Giving reassurance is a fundamental of safety.
Proposal 2403244: During the work inside the high radiation buildings, radiation management is key. Install small and compact culverts every 10m and make them the accessing path as well as a equipment yard. Cure plastic sheets inside and install awnings with lead sheets outside. Inside the culvert, the air is sent through the pipeline to keep positive pressure. This is the radiation management during the work. Setup makes the work quicker.