- #3 spent fuel pool (SPF) has cooled to a nominal temperature of ~40 oC within 24 hours of new system operation. This in much quicker than TEPCO predicted, similar to what happened with the new #2 SPF cooling system when it began to operate several weeks ago. NHK World should be commended for making this good news public.
- JAIF says the waste water circulation system is in full operation. The weak piping that has been springing leaks has been replaced with stronger materials. Plus, the operating procedures have been upgraded to insure there will be no more components incorrectly positioned. The system has been working as designed since Saturday, and enough water has been decontaminated to provide all reactor vessel injections. TEPCO reports the start-up and testing problems over the past two weeks were due to a “lack of preparation” and pressure to rush through operational testing on a system comprised entirely of foreign-made components.
- Saturday, a robot began operation to remove debris from the interior of #3 reactor building. JAIF reports the robot has been working very well. On Sunday, a second robot was sent inside and measured the rad levels in the areas the first robot had cleared, and TEPCO says the rad levels were lower than before the cleaning.
- Asahi Shimbun reports a 362 ft. long levee has been build to protect unit #3 and 4 from another tsunami. The levee is built out of tarps and netting filled with large rocks. The top of the levee sits more than 14 meters above the shoreline, at low tide.
TEPCO added something quite disconcerting…this levee is the first such sea-side tsunami protection for units #3&4! These units sit about 10 meters above the sea level, so they thought they didn’t need additional tsunami protection. Further, the new levee is estimated to protect the units from an 8 meter tsunami, at high tide, spawned by an earthquake of 8 on the Richter scale. The 8 meter tsunami was the design basis for the plant prior to March 11. In other words, units #3&4 may not have met design basis criteria for tsunami! If NISA was aware of this and let them operate the plants anyway, they are a very poor regulatory body. If NISA didn’t know, then TEPCO should have their operating license revoked!
- A Japan Times article says Tsuruga unit #1 reactor containment does not have an over-pressure venting system. Of the 30 Mark I containments in Japan on Boiling Water Reactor systems, this is the only one lacking the venting technology. Japan Atomic Power Company says they did not install such a system because the did not believe it was needed for Tsuruga #1. If this article is correct, it demonstrates that compliance with safety regulations in Japan is a matter of individual utility discretion. Regulatory compliance should be mandatory, not discretionary.
- NHK World reports Japan’s Ministry of Science has surveyed more than 400 locations within 20 kilometers of Fukushima Daiichi and found contamination levels lower on asphalt pavements than on open fields and in forests. This is because asphalt is much less porous than soil which let rains wash away some of the deposited contamination. This survey also allows us to see what the actual contamination levels are across the “no-go” zone within 20 kilometers of the damaged power station. As we expected, the highest levels are located in areas that were downwind of the plant between March 15 and March 21, the period of high airborne releases when the winds were blowing inland. The highest reading reported is from an unpaved road near Tamioka Town (~10 km distance) at a bit less than 40 microsieverts per hour. These first 400 monitoring locations are mostly within the probable high concentration pathway northwest of the power plants. The Ministry plans to monitor 3,400 locations from across the entire no-go region by August. The first series of readings will be taken in spots expected to have the highest readings, like roadside ditches, gardens and other run-off collection areas. Hopefully, locations found to have radiation levels below 3.8 microsieverts per hour will be re-opened to residents.
- TEPCO has released their first actual pictures of unit #4 spent fuel pool, taken June 29.
The water level is obviously below the top of the pool, but it seems there are still several meters of water above the stored fuel bundles (marked by the blue Cherenkov effect). At 82 oC, we can readily see the steam wafting from the hot water in the pool. We now know the source of the “white smoke” occasionally seen coming from the destroyed unit #4 refueling deck.
- World Nuclear Association (WNA) reports a possible reason for why unit #2 reactor building did not have a hydrogen explosion like the other three units. WNA says operators opened a “blow-out panel” which allowed hydrogen to stay below an explosive concentration. We have not found this information anywhere else, but WNA has been quite reliable. As such, this report immediately opens questions relative to units #3&4. Did they also have blow-out panels? If they did, why weren’t they opened after unit #1 blew its roof off?
On the nuclear waste front, University of Tokyo reports they have found substantial deposits of rare earth elements in the mud on the floor of the central Pacific, which might rid Japan’s hi-tech industry of reliance on foreign supplies. However, there is a plethora of rare earths to be found in old spent nuclear fuel bundles (See “Nuclear Waste : Is It?”) which can do the same thing. Recycling spent fuel cells allows 95% of the matrix to be re-used as reactor fuel, and the remaining fission products (the true nuclear waste) is super-rich in rare earths which lose their radioactivity in less than 50 years. Why is no-one making plans to utilize this method of gaining a very valuable resource?
Rare earths are essential in the production of many hi-tech products and computer components. China currently has a virtual corner on the rare earth market, with America a distant second. Tokyo University’s discovery makes it possible for nations to dredge up the precious minerals from deep sea mud in international waters. However, the rare-earth-rich sea floors are between 3,500 and 6,000 meters below the surface of the Pacific. A daunting depth, indeed. It would be cheaper and easier to process rare earths from spent fuel, vice dredging the mud 2 to 3 miles under the sea. Plus, recycling spent fuel would effectively solve the nuclear waste issue.