- Japan’s Atomic Industrial Forum reports work has begun on installing a new spent fuel cooling system for SPF #3 using installed piping for cycling water through an external heat exchanger. It will be very similar to the one now being successfully run on the unit #2 SPF. TEPCO is still trying to devise a SPF cooling system for unit #4 SPF, which was discovered to have badly mangled installed piping located on the demolished refueling deck.
- Final tests of the decontamination system for reactor and turbine building waste waters have have run into another snag. An unexpected leak was found in the new system during final testing. The replacement of a leaking valve on one of the Cesium removal containers will delay the full operation of the system until later today. The system should be operating at full capacity by Saturday, at the latest. Radio-chemical analysis during the test run, using all system components, indicates contamination in the waste waters gets lowered by a factor of 10,000. TEPCO says there is still about 10 days of storage space at the power complex should any other problems emerge.
- TEPCO reports the scale modeling of massive plastic enclosures for reactor buildings 1, 3 & 4 is complete. Actual construction of the the first could start as early as next week. The ~10,000 square meter enclosures are expected to eliminate the potential for future airborne releases from the damaged structures. Unit #2 is not being designated for an enclosure because the outer walls of the building were not demolished by a hydrogen explosion and can be sealed in a less elaborate fashion.
- NHK World tells us TEPCO reports the decontamination system for airborne radioactive isotopes has lowered the concentrations enough to open the access doors to reactor building #2. The airborne concentrations have been reduced by more than 90% inside the structure. However, the decontamination system has had very little impact on the high humidity in the building. They hope opening the access doors will be enough to ventilate the inside air and reduce the moisture levels. TEPCO feels opening the doors will have little radiological impact on the air outside and in the immediate vicinity of the building. There should be no above-limits release beyond the power complex perimeter.
- Some ten of the utility companies in Japan that have nuclear power plants say they will soon be installing “vents” on the roof tops of their outer containment buildings. They say this should allow release of hydrogen build-ups in the (unlikely) event of another massive natural calamity. They don’t want any more refueling deck explosions.
- The Mainichi Shimbun reports the American Nuclear Regulatory Commission (NRC) has finally admitted there were never any dry spent fuel pools at Fukushima Daiichi. The first week of the emergency in March, NRC Chairman Gregory Jaczco insisted one spent fuel pool was dry and another had a level so low that fuel bundles were sticking out of the water. Bill Borchardt, NRC Executive Director of Operations, said the new video footage of unit #4 SPF showed that the pool was never dry, which closed the book on Jaczko’s March speculations. Borchardt called this “extremely good news” and that the situation with #4 SPF “may not have been as serious as was believed.” Commissioner Jaszko has declined commet. He has been under fire for the last week under allegations of misleading the NRC’s staff relative to his trying to close the Commission’s nuclear waste disposal efforts in New Mexico.The NRC also said their initial suggestion that the Japanese widen their evacuation radius to 80 kilometers (50 miles) was based on their belief in SPF #4 being dry. NRC spokesperson Scott Burnell says the Commission still believes their recommendation of a 50 mile evacuation radius is appropriate, but not over the SPF issue. Meanwhile, the NRC is currently investigating existing station blackout regulations in light of what happened at Fukushima. JAIF reports initial findings include (1) not all American plants have met the technological guidelines the NRC has issued related to station blackout, and (2) Fukushima-inspired operator training upgrades for extreme emergencies has not been fully undertaken. The task force working on the project expects to file its formal recommendations by mid-July. The Nuclear Energy Institute (NEI) says the NRC also feels that existing severe accident mitigation systems in America would reduce the effects of a full station blackout.
- Most Japanese news media and JAIF report the “hot spot” situation outside the 20km no-go zone is becoming more intense. Localized evacuations are possible. It makes no sense to evacuate entire communities over high radiation readings limited to a small area. In most cases, the possible evacuations would be specific to a few houses near the hot spots (in some cases only one home each). In all cases, worst-case hot spot exposures have been measured to be just above the 20msv per year emergency standard, which we maintain is not actually risky to anyone when compared to much higher background levels around the world. However, this oft-attacked safety limit for exposure, combined with a general public fear of radiation at any level, makes consideration of localized evacuations politically correct.
- NEI says the sea water decontamination system at Fukushima Daiichi is in full operation. During the test run, zeolite filters removed 20-30% of the radioactive isotope from the waters. NEI adds that TEPCO is attempting to find a way to improve the decontamination factor.
- An Asahi Shimbun article reveals that fear of radiation is creating a new life-style in Fukushima City. More than 200,000 residents have had scans for radiation exposure since March 13. In addition, many people also have their pets get checked out. One person wanted a pet rock checked! Many persons are getting numerous checks, some just for peace of mind and others for business reasons. For example, a City taxi driver gets a “full-body sweep” every day so he can show his patrons a certificate of safety.Some residents were found to have small levels of contamination on skin and clothing between March 13 and March 29. They were asked to shower and have their clothes washed to remove the traces of radioactive dust. Once re-scanned, they were all released with no activity remaining. Since March 29, none of the citizens getting scanned have been contaminated. Regardless, the nine screening stations across Fukushima City perform as many as 500 “sweeps” a day. Asahi says what began as a confirmation of exposure to contamination has become a process to ease people’s fear of radiation.
When we add this to the high sales of portable radiation detection devices across Japan, the City’s decision to have children wear dosimeters at school, and a major upswing in background radiation monitoring points (somewhere between 100 and 1000) across the Prefecture, we see the business of radiation fear in Fukushima City is considerable. The good part of this is that the citizens of Fukushima Prefecture are getting informed about radiation levels around them, possibly creating one of the most detailed background radiation surveys ever recorded. Now that environmental I-131 has decayed to near-zero, Fukushima City is essentially back to natural exposure levels. Will the universities and government of Japan use this opportunity to educate the public about the actual biological effects of ionizing radiation? Only time will tell.