Due to the Tohoku-Chihou-Taiheiyou-Oki Earthquake which occurred on March
11, 2011, TEPCO's facilities including our nuclear power stations have
been severely damaged. We deeply apologize for the anxiety and
inconvenience caused.
With regard to the accident at Fukushima Daiichi Nuclear Power Station, on
April 17, 2011, we have compiled the roadmap towards restoration from the
accident and on July 19 we accomplished the Step1 target "Radiation dose
is in steady decline". Then on December 16 we confirmed the accomplishment
of the Step 2 target "Release of radioactive materials is under control
and radiation doses are being significantly held down".
In addition, on December 21, 2011, we have compiled the "Mid-to-long-Term
Roadmap toward the Decommissioning of Fukushima Daiichi Nuclear Power
Units 1-4, TEPCO".
In addition to the maintenance of the plant's stable condition, we will
implement Mid-to-Long Term countermeasures towards the decommissioning of
Fukushima Daiichi Nuclear Power Units 1-4 to enable evacuees to return to
their homes as soon as possible and reduce the anxiety of the people in
Fukushima and the whole nation as soon as possible.
Below is the status of TEPCO's major facilities.
* The updates are underlined.
[Nuclear Power Station]
·Fukushima Daiichi Nuclear Power Station: Unit 1 to 3: shut down due to
the earthquake:
(Units 4 to 6: outage due to regular inspections before the earthquake)
- With regard to the water injection volume for Unit 2 reactor, which was
increased with temperature figure raising, we have gradually adjusted
it to the original volume before temperature increasing (Feed water
system: approx. 3.0㎥/h, core spray system: approx. 6.0㎥/h). During
our observing the plant parameter after the decreasing the flow rate of
feed water system on February 22, we found that one thermometer in the
lower part of the RPV indicated the different movement from others.
From 0:21 pm to 2:48 pm on February 23, we investigated the concerned
device. As the result of the measurement of DC resistance, we found no
breaking wire and availability of the thermometer. But we confirmed
that the DC resistance of it became higher than the previous
measurement test data. We will evaluate the soundness of the concerned
device and examine correspondence in future. We make sure no
re-criticality state because there were no significant changes at the
monitoring post and as the result of the sampling for the Gas Control
System of the Unit 2, we confirmed that the concentration of Xe-135 was
below the detectible limit.
·At 5:00 am on February 26, the temperature of the lower part of the
RPV (top of the lower head 135°) : approx. 44.7 °C
(Reference)
·At 5:00 am on February 26, the temperature of the lower part of the
RPV (top of the lower head 270°) : approx. 40.3 °C
- At 8:30 am Today (Feb. 25), Tepco worker and partner companies'worker
found water leakage at welded part of piping at B line of 2nd Cesium
adsorption apparatus(SARRY) placed on the 1st floor in Miscellaneous
Solid Waste Volume Reduction Treatment Building (High Temperature
Incinerator Building) of Fukushima Daiichi Nuclear Power Station. The
leakage is just a drop per second and the amount of water leaked is
approx. 10 litters (2m x 5m x 1mm). Those leaked water are stayed in
barrier in the building and it did not leaked to out of the building.
At 10:44 am, we stopped operation of SARRY and closed valve positioned
in the upstream of leaked point to prevent further leakage of the water.
We confirmed that the leakage was stopped at 11:10 am. Surface
radiation is approx. 4-5mSv/h (2mSv/h in the back ground). We will
sample the leaked water and analyze the radioactivity concentration.
The treatment of accumulated water is not affected by suspending the
SARRY, and there is a lot of purified water that there is no effect
injecting water to the reactor.
The result of nuclide analysis for leaked water is as follows:
I-131: Below detection limit, Cs-134: 1.3 x 105 Bq/㎤, Cs-137: 1.8 x
105 Bq/㎤
After that, per the reimplementation of remotely controlling 2nd Cesium
absorption apparatus (B line), where a water leakage was found, we have
activated the system A line since 6:41 pm. At 6:44 pm, the water flow
amount reached 20 ㎥/h and we stably started treating the accumulated
water. At 8:35 am on February 26, to replace the said duct and filter
of the apparatus B line, we shutdown A line of the apparatus.
- At 10:20 am on February 25, we started transfer of the accumulated
water from the basement of Unit 1 Turbine Building to that of Unit 2
Turbine Building. At 9:44 am on February 26, the transfer stopped
·Fukushima Daini Nuclear Power Station:
Units 1 to 4: shutdown due to the earthquake
·Kashiwazaki Kariwa Nuclear Power Station:
Units 6: under normal operation
(Units 1 to 5 and 7: outage due to regular inspections)
[Thermal Power Station]
·Power supply has returned to normal and the facilities damaged by the
earthquake are now being handled in a timely manner.
[Hydro Power Station]
·Power supply has returned to normal and the facilities damaged by the
earthquake are now being handled in a timely manner.
[Impacts on Transmission Facilities]
·Power supply has returned to normal and the facilities damaged by the
earthquake are now being handled in a timely manner.
[Impacts on Power Supply and Demand Balance]
This winter, there are some minus factors such as the regular inspection
of Unit 5 at Kashiwazaki-Kariwa Nuclear Power Station. On the other hand,
there are several plus factors such as the recovery of the common thermal
power stations which suffered the earthquake. As a result, we expect to
secure 53.7 GW (at the end of February) supply power.
Compared to the maximum demand in the last winter, which is 51.5 GW, we
will have 2.2 GW generation reserve margin.
We expect to maintain stable power supply this winter. However, as there
remains possibilities of unplanned shutdowns at our power stations and
growth in the demand according to the rapid change in the temperature, we
would like to ask your reasonable effort to save electricity.
We will continue to make our efforts to maintain stable operation and
maintenance of the power facilities in order to "prevent in principle" the
planned blackouts and secure power supply.
Appendix: Past Progress (As of 10:00 am on February 26, 2012) (PDF 455KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress