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 R
oadmap 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)
- Since 9:50 am on February 10, we have conducted the work to add
flowmeters to the nitrogen injection line at the side of Primary
Containment Vessel of Unit 3 in order to improve the reliability of
nitrogen injection activity. During this period, due to this work, we
suspended the nitrogen injection task temporarily (*). At 10:55 am on the
same day, we started operation to inject nitrogen and at 11:24 am, we
complete the series of the operation.
* In the Chapter 12 of Nuclear Reactor Facilities Security Regulation
"The Way of Ensuring Mid-term Security", as the treatments like
"Operational limitation" or "Measures required in case of not
satisfying the operational limitation" are determined, it is supposed
the operator act per the required measures if it fails to satisfy the
operational limitation. This time, to implement maintenance works, we
have suspended the work of nitrogen injection at the side of Primary
Containment Vessel of Unit 3 by conducting a planned shift beyond the
range of operational limitation (from 9:50 am to 11:30 on February 10).
- From February 2, tendency of temperature rise at the bottom of PCV has
been observed. While we increased the water injection to the reactor and
have been monitoring the trend of the temperature, it is still high
around 70°C. On February 6, we sampled the gas by the gas control system
of Unit 2 Primary Containment Vessel. The density of Xenon 135 at the
entrance of the system was below the detection limit. Since it is below
1Bq/cm3, which is the threshold for judging re-criticality, we confirmed
the reactor didn't go re-critical, however, in order to avoid the
possibility of going re-critical being increased as a result of the water
density in the reactor being increased by rapid injection of cold water
is increased, we injected the boric acid into the reactor as a safety
countermeasure from 0:19 am to 3:20 am on February 7, which was before
we increased the volume of the water injection. At 4:24 am on the same
day, we changed the amount of the core spray system injection water from
3.7m3/h to 6.7m3/h (the amount of the continuing feed water system
injection is 6.8m3/h). Currently, the temperature is approx.68.0°C (as of
11 am on February 10). We will monitor the progress continuously.
- At 8:39 on February 10, 2012, because it has been observed that the
amount of treatment flow of the second Cesium adsorption apparatus
gradually, we suspended temporarily the operation of the apparatus. At
2:19 pm on the same day, we started those instruments, and at 2:32 pm
the rated flow was achieved (approx. 35m2).
- At 2:43 pm on February 10, we started to transfer accumulated water from
underground floor of turbine building of Unit 2 to centralized radiation
waste treatment facility (Miscellaneous Solid Waste Volume Reduction
Treatment Building [High Temperature Incinerator Building]).
- At 1:28 pm on February 10, we started injection of hydrazine to the spent
fuel pool of Unit 4 trough the circulating cooling system.
· 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 3:00 pm on February10, 2012) (PDF 670KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress
