Sigh. TEPCO never learns. The first press conference was held yesterday morning (over in Japan); 6 hours had already passed since the accident but they didn't have any information other than the photo. The information had to wait until the evening press conference, more than 12 hours after the accident: that the contaminated water also leaked.
Information from TEPCO's evening press conference on July 10:
The water treatment system was restarted at 5:40PM, about 12 hours after the leak was found.
50 liters of liquid that leaked was both the chemical to be used in the coprecipitation unit AND the contaminated water. It was mostly the contaminated water.
Density of contamination: 5,500 becquerels/cubic centimeter of radioactive cesium.
The PVC coupler that connected the metal pipe and the hose cracked, causing the leak.
Connecting a metal pipe with a PVC hose by a PVC coupler was not a normal practice.
The PVC coupler has been replaced with a metal coupler.
It's not known whether TEPCO also replaced the similar connections in AREVA's unit.
I'll post when more details become available on TEPCO's site.
The photo is from Asahi Shinbun, the new and improved joint, but still looking awkward: