Contaminated water leakage from a water tank

Print View Posted on: 28 August 2013

Event Date: 19 August 2013 Event Type: Power Reactor
Event Location: Japan, FUKUSHIMA DAIICHI INES Rating: 3 (Provisional)

・Regarding the contaminated water leakage from a water tank in the H4 Tank Area at Fukushima Daiichi NPS that was detected on August 19, radioactivities in the leaked water in the dike were found to be:
- Cesium-134: 4.6×101 Bq/cm3
- Cesium-137: 1.0×102 Bq/cm3
- β emitting radionuclides in total: 8.0×104 Bq/cm3
・The amount of the leaked water is estimated to be approximately 300m3, judging from the decrease of water level in the water tank in question.
・No significant increase in radioactivities was detected in the seawater near the ditch, while high airdose rates were observed in the ditch that flows into the sea.

INES Rating: 3 - Serious incident (Provisional) as per 28 August 2013
Release beyond authorized limits? No
Overexposure of a member of the public? No
Overexposure of a worker? No
Contamination spread within the facility? Yes
Damage to radiological barriers (incl. fuel damage) within the facility? Yes
Degradation of Defence In-Depth Yes
Person injured physically or casualty? No
Is there a continuing problem? No

Masakazu Shima
Nuclear Regulation Authority
toshiyuki_koganeya@nsr.go.jp
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