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.
* 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. 3.0m3/h, core spray system: approx. 6.0m3/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 25, the temperature of the lower part of
the RPV (top of the lower head)(135°) : approx. 45.2 °C
(Reference)
· At 5:00 am on February 25, the temperature of the lower part of
the RPV (top of the lower head)(270°) : approx. 39.5 °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.
- At 10:15 am on February 25, following arrangement had done as the
amount of water injected to reactor of Unit 1 & 2 decreased
Unit 1: the water injection volume from the core spray system changed
from approx.1.6m3/h to approx. 2.0m3/h (the reactor feed
water system stays the same: approx.4.5m3/h)
Unit 2: the water injection volume from the reactor feed water system
changed from approx.2.6 m3/h to approx. 3.0m3/h (the core
spray system stays the same: approx.6.0m3/h)
- At 10:20 am on February 25, we started the accumulated water from the
basement of Turbine building of Unit 1 to the basement of Turbine
building of Unit 2.
- On February 23, we conducted gas sampling survey of the PCV gas
control system of Unit 3 and confirmed that Xenon 135 was below the
detection limit (9.4 x 10-2Bq/cm3) at the inlet of the system and
also below 1 Bq/cm3 that is a threshold of recriticality.
· Fukushima Daini Nuclear Power Station:
Units 1 to 4: shutdown due to the earthquake
- At 5:19 pm on February 24,, to change the residual heat removal
system (RHR) B line of Unit 4 to A line, we suspended operation of B
line and at 5:24 pm on the same day, we restarted line A.
· 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 11:30 am on February 25, 2012) (PDF 452KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress