Over the last week, workers have confronted another leaking tank, a partial shutdown of nitrogen injection equipment and a glitch in a water treatment system at Fukushima Daiichi.
Recent developments related to the Tokyo Electric Power Co. plant blacked out following Japan's 2011 earthquake and tsunami include:
Another Tank Leaks
As TEPCO contends with storms dumping rain onto the contaminated site, the company reported that radioactive water might have reached the ocean after leaking from the top of a tank. Tank farms at the plant are surrounded by low dikes to confine potential leaks to the immediate area, but those structures have effectively created ponds around the base of the tanks during heavy rains. A worker spotted the leak Wednesday after crews pumped accumulated rainwater into the tanks. According to a TEPCO release, an adjacent inspection scaffolding allowed contaminated water to travel outside the dike and into a ditch that drains to the sea. TEPCO officials quoted by Jiji Press estimated 430 liters of contaminated water with beta-ray emitting contaminants measured at 580,000 becquerels per liter escaped the dike. The tanks had been topped off with rainwater, and Japanese media reported the cover of the leaking tank had not been closed properly.
Nitrogen Injection Partially Shut Down By Mistake
Part of the nitrogen-injection system put in place to prevent hydrogen explosions at the damaged units briefly went offline Tuesday. A nitrogen separating apparatus stopped at about 10:46 a.m., TEPCO reported, while an identical piece of equipment continued to provide nitrogen to the reactors and another was in standby. A worker had hit the separator's stop button by mistake, according to a TEPCO release, and the equipment was restarted that afternoon.
Overlooked Debris Shuts Down ALPS
A reduced flow from a tank prompted the shutdown Sept. 27 of part of the ALPS system to remove multiple nuclides from water at the plant. Upon inspection, TEPCO reported, workers found a rubber pad from the foot of a ladder blocking the bottom of the tank. It was removed, and the system resumed a hot test run Monday.