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, we have compiled the roadmap towards restoration from the
accident and then we updated the progress status of roadmap considering
the current situation, on July 19. Accomplishment of the Step1 target
"Radiation dose is in steady decline" has been confirmed. On November 17,
we updated the further progress.
By bringing the reactors and spent fuel pools to a stable cooling
condition and mitigating the release of radioactive materials, we will
make every effort to enable evacuees to return to their homes and for all
citizens to be able to secure a sound life.
Below is the status of TEPCO's major facilities.
*Underlined are updates from the previous press release.
[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)
*At 9:01 am on December 2, we interrupted the operation of the
alternative cooling in order to replace the inside mesh of the primary
strainer as a countermeasure against the decrease in inhale pressure of
the primary pump for alternative cooling of the spent fuel pool. The
temperature of the spent fuel pool as at the interruption was 18°C and
expected temperature increase was 0.2°C/h (duration of interruption:
approx. 3hours). The water temperature of the spent fuel pool is in a
normal state.
*At 10:25 am on December 2, we adjusted the volume of nitrogen injected
into the Reactor Pressure Vessel from approx. 5m3/h to approx. 10m3/h.
In addition, in order to balance the volume of nitrogen injected into
the Reactor Pressure Vessel and the Primary Containment Vessel of Unit 2
and the volume of exhaust air from gas control system, we adjusted the
volume of exhaust air from gas control system of the Primary Containment
Vessel from approx. 34m3/h to approx. 39m3/h.
*At 10:35 am on December 2, we adjusted water injection volume from
approx. 4.0m3/h to approx. 4.5m3/h since decrease in injection volume
was observed.
*From 12 pm to 2 pm on December 2, we conducted dust sampling at the
opening of Unit 2 reactor building (blow-out panel).
*At 11:13 pm on November 30, the alarm went off at the alternative
cooling system in the Fuel Pool Cooling and Filtering System indicating
that the difference of the flow rate between at the inlet and at the
outlet is large and the system automatically stopped its operation. At
11:34 pm on the same day, no leakage was confirmed by the site
inspection. At 11:00 pm on the same day, the temperature of spent fuel
pool was 22.7 °C and the anticipated temperature increase was 0.3 °C/h. As
there is sufficient buffer, the inspection is scheduled during the
morning of December 1. However, the inspection, the repair work and the
cause analysis is rescheduled to December 2 as it turned out that the
material preparation for such work needs time. On December 2, it was
estimated that air or foreign materials entered the detection line. We
conducted flushing and fulfilled it with clean water and restarted
cooling the spent fuel pool at 1:50pm on the same day. (As at restart
temperature of water was 28.0°C.)
*From 10:10 am to 12 pm on December 2, we conducted dust sampling at the
ventilation equipment filter of Unit 1 reactor building cover.
*From 1 pm to 2 pm on December 2, we conducted dust sampling and measured
air flow at the upper part of the reactor building equipment hatch of
Unit 1.
*From 11 am to 1 pm on December 2, we confirmed leakage at 7 points in
the hose which was used for the water transfer from the desalination
facility to the buffer tank (the leakage was at one or two drops per
second.). Then we made a tentative repair with water stopping tape and
confirmed that the leakage stopped. Since the leaked water was one
treated through decontamination and desalination process and the leaked
amount was so little, there will be no impact on the environment.
*On December 2, we conducted sampling at charcoal filter and particulate
filter of gas control system of Unit 2 Primary Containment Vessel.
·Fukushima Daini Nuclear Power Station:
(Units 1 to 4: shutdown due to the earthquake)
·Kashiwazaki Kariwa Nuclear Power Station: Units 5, 6: under normal
operation
(Units 1 to 4 and 7: outage due to regular inspections)
[Thermal Power Station]
-Power supply has returned to normal and facilities damaged by the
earthquake are now being handled in a timely manner.
[Hydro Power Station]
-Power supply has returned to normal and facilities damaged by the
earthquake are now being handled in a timely manner.
[Impacts on Transmission Facilities]
-Power supply has returned to normal and facilities damaged by the
earthquake are now being handled in a timely manner.
[Impacts on Power Supply and Demand Balance]
This winter, there will be some minus factors such as the regular
inspection of Unit 5 at Kashiwazaki-Kariwa Nuclear Power Station. On the
other hand, there will be several plus factors such as the recovery of the
common thermal power stations which suffered the earthquake. As a result,
we expect to secure 54.9 GW (at the end of December), 54.6 GW (at the end
of January), 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 - 3.4 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 3:00 pm, December 2, 2011) (PDF 375KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress