(8/21/2013 New post with two potentially big problems, uploaded.)
As the world's mainstream media and alternative media suddenly rediscover Fukushima I Nuke Plant over the "assumption" by a career bureaucrat at Ministry of Economy, Trade and Industry (whose Agency of Natural Resources and Energy oversees the decommissioning of the plant) that "300 tonnes of highly contaminated [sic] water" may be leaking every day, a real leak of actual waste water with extremely high beta nuclides has been found.
According to TEPCO, who held an ad hoc press conference at noon on August 20, 2013, at least 300 tonnes of waste water after the cesium absorption (by SARRY) and desalination (by Reverse Osmosis Apparatus) has leaked from a huge 1,000-tonne steel tank (or two, they don't know yet), and it is likely that the waste water is STILL LEAKING as TEPCO hasn't been able to identify the location of the leak(s).
Information about the leak, from Jiji Tsushin (8/20/2013), TEPCO's press conference on 8/20/2013 and TEPCO's handout to the press (8/20/2013):
Leak from a group of 1,000-tonne steel tanks (tank is 12 meters in diameter, 11-meter high) in the area H4 which has total 26 tanks. The location is about 500 meters from the embankment.
One of the tanks in this particular group (No.5 in the group I in H4 area, or H4-I-5) was found with the water level that was 3.4-meter lower than before.
Nature of contaminated water: waste water after cesium absorption and desalination (called by TEPCO RO water)
Estimated amount of contaminated water: 300 tonnes (300,000 liters)
Density of radioactive materials (TEPCO's announcement is in Bq/cm3, as it is highly contaminated water; Jiji Tsushin reports the number in Bq/liter):
All-beta including strontium: 80 million Bq/L (80,000 Bq/cm3)
Radioactive cesium: 146,000 Bq/L (146 Bq/cm3)
Most of the leaked waste water went outside the low enclosure built around the tanks. The valve is installed to drain rainwater from the enclosure, and this valve was found "open", as it shouldn't have been.
The water leaked inside the enclosure has been collected (about 4 tonnes as of 12AM on August 20, 2013). The area is being inspected every three hours, but the leak CONTINUES (or TEPCO cannot confirm that the leak has stopped, though the company seems to think it has stopped).
TEPCO hopes to empty the tank No.5 and move the RO waste water into the tanks in the nearby group B, as the tanks in group B is only about 60% full. The rest of the tank in this H4 areas are 97.8% full.
The scale of the leak is one of the largest since the start of the accident (excluding the April 2011 leak of highly contaminated water from the Reactor 2 turbine building basement).
The manufacturer's warranty of the tank is 5 years.
There is a drain nearby that goes to the ocean, but hardly any radioactive materials have been detected from the water (most likely rainwater) in the drain.
Here's how one of the tanks looks like, from the leak in June 2013 from a tank in a different area:
From TEPCO's handout for the press, 8/20/2013 (English labels are by me):