Update #25: July 4, 2011
At NHK July 4th, we learn that the decontamination/cooling water circulation system ran as expected for only a day.
The article quoted yesterday said: "Tokyo Electric Power Company said the system no longer requires fresh water input…Previously, the system required 2 to 3 tons of fresh water per hour." Water flow decreased slowly for almost 12 hours, before injections of fresh water began. TEPCO speculates the pipes were clogged with "some kind of debris". Stay tuned.
Water flow falls at No.1 reactor, but restored
"The volume of cooling water flowing into the No.1 reactor of the Fukushima Daiichi nuclear plant fell on Monday, forcing workers to inject additional water…." Monday, July 04, 2011 17:29 +0900 (JST)
More on yesterday's leak at Unit 5 also. I've included the picture of the "leak" below. This is not a drip, drip, drip leak, as you can see, more a large spray of sea water. The leak was described as 12 in long by 3 inches wide yesterday. So the hose must be a minimum 8 inch diameter hose ((25 inch circumference).
Yesterday's TEPCO speculated the leak was caused "because the pleated flexible tube was constantly moved by tides and had come under hydraulic pressure". Of course that explanation made little sense since the water-filled hose would always be "under hydraulic pressure." Today's story says the hose failed because it was bent at an acute angle. If you look carefully at the picture, you can see the hose is draped over a metal frame and certainly is not bent at less than a 90° angle (the definition of "acute"). I imagine the real problem is the flexible hose needs to be properly supported, not just draped about, or that th hoses are not rated for the pressure from the the pumps. We can only hope the flexible hoses containing radioactive water are properly supported. . .never mind, "not bent at acute angles".
Hoses at Fukushima to be checked