From NEI’s Japan Earthquake launch page:
Fukushima Daiichi Water Filtration System Testing Continues
- Tokyo Electric Power Co. is working to restart full-scale tests of the water filtration system it will use to decontaminate and recycle radioactive water that has flooded the basements of buildings at the Fukushima Daiichi nuclear energy facility. The system went into full operation on Friday but was shut down after five hours when radiation levels rose more quickly than anticipated in the part of the system that removes oil and sludge. TEPCO may add more equipment to remove oil or lower the water flow rate through the system. Cooling water injections into reactors 1, 2 and 3 are accumulating in the building basements at the rate of 500 tons per day, and could overflow in about a week if the decontamination system is not functional by then.
- TEPCO was able to open an entrance to the damaged reactor 2 building to lower high humidity levels without causing an increase in overall radiation levels at the site. The company has been filtering radioactive materials from the air inside the reactor building prior to opening the entrance. The move to lower humidity in the reactor building from near 100 percent levels will allow workers to enter the building to begin repair tasks, including calibrating a reactor water level gauge and ultimately restoring recirculating coolant.
- TEPCO has begun refilling an equipment storage pool on the top floor of reactor 4 after discovering that the water level in that pool had dropped to a third of its capacity, exposing activated metal equipment and causing higher levels of radiation inside the building. Submerging the equipment again should lower worker exposure to radiation, the company said.
- Mike Weightman, who led an International Atomic Energy Agency team to Japan March 24-June 1, leads a review of the agency's preliminary assessment of the accident at Fukushima Daiichi at the IAEA's Ministerial Conference on Nuclear Safety that began in Vienna today and continues throughout the week. Weightman is chief nuclear inspector and head of the United Kingdom's Health and Safety Executive's Nuclear Directorate. Also speaking are IAEA Director General Yukiya Amano; NRC Chairman Gregory Jaczko; and Banri Kaieda, Japan's minister for economy and industry. The Japanese government's official report also is expected to be heard at the conference. Attendees also will consider the IAEA's role in assessing member countries' nuclear safety frameworks, and could recommend a global framework for emergency preparedness.
- The Japanese Nuclear Safety Commission has decided on a short-term policy to begin managing radioactive waste materials from the cleanup of the damaged Fukushima Daiichi site. Applicable "clearance levels" for the reuse of contaminated materials should be those already applicable in existing guidance, the commission stated. The commission also said that the radiation dose to residents near future temporary waste storage or disposal facilities, and for workers at incineration or waste treatment facilities, should not exceed 100 millirem per year (1 mSv/year). The Japanese Ministry of the Environment is discussing how to dispose of radioactive waste generated from the cleanup of the Fukushima Daiichi plant site.
- The Associated Press has published two pieces of a series of four articles criticizing various aspects of nuclear plant safety. NEI is preparing media responses to the series.