At around 12:30pm, May 11, 2011, employees who had been conducting vertical
shaft obstruction work, confirmed water flowing into the pit (a vertical
shaft made of concrete) via power cable pipe lines.
Together with investigating the possible leakage of water including
radioactive materials to the outside of the boundary, at around 4:05 pm, we
confirmed that the water outflows out of the pit into the sea.
Thereafter, we inserted cloths into the pipes that lead to the pit and put
some concrete in it and at 6:45pm, we confirmed the outflow had stopped.
(Previously announced on May 11, 2011)
Following this event occurrence, on the same day, TEPCO received verbal
instruction from Nuclear and Industrial Safety Agency, Ministry of Economy,
Trade and Industry (NISA).
- To confirm an impact to the ocean
- To immediately conduct water stoppage measures
- To immediately identify the route of the inflow/outflow and the situation
and report to NISA
TEPCO compiled preventive measures and countermeasures to prevent
scattering to the outside of harbor, in addition to the condition of
inflow/outflow routes and the impact on the ocean as instructed. On May
20th, we reported them to NISA.
(Previously announced on May 21, 2011)
TEPCO, yesterday, received the instruction documents from NISA "Regarding
the countermeasure report against water outflow including radioactive
materials to the outside from Unit 3 of Fukushima Daiichi Nuclear Power
Station (instruction)"*. Hereafter, following this instruction, TEPCO will
promptly take response and summarize that matters, and report them to NISA.
*Regarding the countermeasure report against water outflow including
radioactive materials to the outside from Unit 3 of Fukushima Daiichi
Nuclear Power Station (instruction)
[May 23rd, 2011 NISA No.2]
On May 20th, 2011, NISA received a countermeasure report from TEPCO against
water including radioactive materials (hereafter called "contaminated water")
to the outside from around the intake canal of Unit3 of Fukushima Daiichi
Nuclear Power Station.
On the report, as countermeasures to prevention of recurrence, obstructing
the shaft, putting some sandbags inside the intake canal, implementing
circulating purification system, etc. will be implemented.
Nuclear and Industrial Safety Agency (hereafter called "NISA"), in addition
to countermeasures TEPCO reported, would like TEPCO to implement below
actions by each due date in order to enhance countermeasures against
prevention of recurrence of contaminated water outflow at the site.
1.On TEPCO's report, although 27 points of vertical shafts, which lead to
seawater piping trench will be obstructed using concrete etc by the end
of June, 2011, we would like TEPCO to investigate the status of vertical
shafts and seawalls (cracks of quay etc.), which is not confirmed the
status yet. For such points that it cannot deny the possibility of water
outflow, the countermeasure to prevent water outflow must be planned by
June 1st, 2011.
2.On TEPCO's report, continuous monitoring of seawater inside/outside of
harbor at the site and enhancing monitoring system as same as Unit 2 for
analyzing seawater inside of the silt fence at Unit 1, Unit 3 and Unit 4
will be implemented. We would like TEPCO, in addition to the above
measures, if TEPCO confirms significant increase of density of
radioactive materials based on the result of monitoring inside the harbor,
immediately conducts visual investigation etc and if some water outflows
are confirmed, TEPCO takes proper implementation to stop the water
outflows. Also, the results must be reported to NISA.
3.Accumulated contaminated water should be property reduced and to lower
the possibility of occurrence of water outflow, conduct investigation to
a maximum extent regarding the status of accumulated water inside the
facility. The storage and disposal plan for contaminated water must be
reported to NISA by June 1st, 2011.
