Improvised Fukushima water decontamination system fails at first ‘skid’
By arevamirpal::laprimavera
18 June 2011 According to TEPCO’s handout for the press for June 18, TEPCO stopped the entire water processing system manually when the surface radiation at the “skid” for removing oil and technetium exceeded 4 millisievert/hour, the limit set for replacing the zeolite cylinders (which TEPCO calls “vessel”) inside the skid. That “skid” contains 4 cylinders filled with SMZ (surfactant modified zeolite) to absorb oil and technetium. (The system diagram by TEPCO is provided after the break, with English labels added by me.) The cause for the high radiation at the oil-technetium skid wasn’t given in the handout, but in the press conference TEPCO listed the following as potential cause:
- The radiation measurement device picked up the radiation from the pipe that transports highly contaminated water to the system; or
- The water contained extremely radioactive sludge; or
- The water contained too much seawater for the system to handle. […]
#Fukushima I Nuke Plant: Kurion’s System Was Stopped At the Very First “Skid”
By Hiroshi Ishizuka and Naoya Kon
19 June 2011 Just five hours after Tokyo Electric Power Co. started normal operation of equipment to purify highly radioactive water at the Fukushima No. 1 nuclear power plant, the system had to be switched off at dawn on June 18 because of higher than expected radioactivity around the unit. The water decontamination process is important to the utility’s plans to regain control at the stricken plant because it offers a way of dealing with the approximately 110,000 tons of radioactive water that has accumulated in turbine buildings and elsewhere on the site. Heavy rain is threatening to make that water overflow. The failure of the system also compromises plans for “cyclic injection” of cooling water into the stricken nuclear reactors, which would allow fuel rods to be cooled on a sustainable basis by reusing contaminated water. That process was originally scheduled to start June 18 but will have to be put back, TEPCO said. Company officials said they did not know what caused the high levels of radioactivity near the purification equipment and did not know when it would be back in operation. […] But starting full operation of the system would make cleaning of the devices difficult. The interior of the pipes and containers would be contaminated by high levels of radioactivity, making repairs hazardous. Any overhaul would require full decontamination, further delaying the process. Normal operation of the equipment would also produce 2,000 cubic meters of highly radioactive sludge by the end of the year, which would have to be stored in tanks on the site. No decision has been made on how to process it. […]
