|Types of facilities|
Around 19:20 on 20 April 2016, TEPCO found that RO-concentrated water was leaking from a heat-insulating material of transfer piping to G-6 tank area.
Extent of soil contaminated by leakage was about 30 cm × 30 cm.
The leak was stopped after shut down of transferring RO-concentrated water.
The place concerned is approximately 70 meters away from the nearest drainage, and the possibility of flowing into the ocean is ruled out, so there is no impact on the environment.
The maximum amount of leakage estimated by TEPCO is 2.7 litres.
On March 11, 2016, Kakrapar-1 was operating at 220 MWe. At about 0852 hrs, primary containment (pump room) pressure high alarm appeared in control room. Both fast acting reactor shutdown systems and liquid poison injection system actuated automatically and brought the reactor to long term sub-critical state. Emergency Core Cooling System (ECCS) actuated as per design and provided cooling to the core.
As per the established procedure, plant emergency was declared at 0910 hrs.
Shutdown cooling loop was taken in service and primary coolant temperature was brought to 45 °C.
On 21st August 2015, ASN was informed by EDF of the accidental exposure of a worker from an EDF contractor to a dose of ionising radiation exceeding the regulation limit.
On 18th August, during the check carried out prior to exiting the limited access area, contamination was detected on the worker’s chin. He had been carrying out maintenance work in preparation for the hydrotesting of an exchanger on the chemical and volume control system in the reactor 4 safeguard auxiliaries building in the Le Blayais NPP.
On 29 May, 2015, TEPCO found that contaminated water being transferred to turbine building of unit 3 from 1000 tons notch tank was leaking from the cracked pressure hose.
TEPCO stopped the inappropriate transfer of contaminated water.
The estimated volume of the leaked water is approximately 7 m3.
Although the leaked water flowed into the drainage which led to the port there has been no significant change in radioactivity of the ocean that raises any concern about influence to health and the environment.
TEPCO found that leakages of water accumulated in the dikes due to rainfall in 4 areas storing contaminated water at Fukushima Daiichi NPS between 9 and 14 September 2015.
The dikes are installed in order to prevent contaminated water from spreading in case a leakage from the tanks would occur.
On 2 October, 2013, TEPCO found a water dropping from around the top plate of B area (south) tank (No.5 tank at Group A in B area), in where treated water from the desalination apparatus is stored, at Fukushima Daiichi NPS.
The leaked water was not only dropping inside the dike, but also dropping to outside of the dike at B area (south) via the scaffold installed around the tank for inspection.
Because it cannot be denied that the water leaked from the top plate of the tank flowed into the drainage channel via the side ditch nearby, and leaked into the sea, TEPCO performed water-stop measures
Approximately 11 m3 amount of water leakage occurred from a
pipe joint of desalination system (reverse osmosis membrane, RO-3) inside the temporary warehouse on 9 October, 2013.
The water has retained in the dike installed in the warehouse.
The radioactivity concentration of the leakage water was 34kBq/cm3 by totall beta nuclides.
Out of eleven workers who were working in the warehouse, six workers had radioactive material on their bodies, and five workers had no radioactive material on their bodies.
On 6 February,2014, TEPCO found that the water treated by Simplified Active Water Retrieve and Recovery System (SARRY, cesium removal facility) and Reverse Osmosis Desalination Facility (RO) was leaking from the flange of water pressure measuring instrument equipped to the water pipe in which the water was running to the reactors unit 1 to 3 for their cooling.
The leaked water was flowing into the underground nearly under the water pressure measuring instrument.
The water leakage from the flange was stopped by means of closing the valve attached between the flange and the water pipe.
At 23:25 (Japan time) on 19 February, 2014, TEPCO found that water was leaking from the upper part of Tank C-1 in H-6 Tank Area, which has stored the water that was condensed by RO (reverse osmosis desalination facility) after the treatment by SARRY (cesium removal facility), to the dike surrounding H-6 Tank Area and to the outside of the dike through the rainwater drainpipe running from the upper part of Tank C-1 to the ground surface beyond the dike.
At 05:40 (Japan time) on 20 February, 2014, TEPCO succeeded in stopping the water leakage by means of closing the valves installed between Tank
The Central Waste Building at Fukushima Daiichi NPS has been currently used as a storage facility for contaminated water from the Nuclear Reactor Buildings Unit 1 to 4.
On 11 April, 2014, TEPCO found that the level of contaminated water in the Central Waste Building unnaturally fell down although the contaminated water was not transferred to other places, and on
13 April, 2014, it was found by TEPCO that some contaminated water in the Central Waste Building was transferred to the Incineration Building, which has been prepared as an emergency storage facility for contaminated water.