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)
- As finding of accumulated water containing radioactive materials at the
trench between the Process Main Building and the Miscellaneous Solid
Waste Volume Reduction Treatment Building [High Temperature Incinerator
Building] (December 18, 2011), we started the inspection of other
trenches at the site on January 11.
As a result of the inspection made on February 8, the preliminary
results of the nuclide analysis and executed place are as follows:
· Inside the duct for power cables for the Unit 6 water intake
I-131: below the detectible limit, Cs-134: 1.0X10-1 Bq/cm3,
Cs-137: 8.3X10-2 Bq/cm3
· Inside the trench for the Unit 5 and 6 storm drain pipes
I-131: below the detectible limit, Cs-134: 1.7X10-1 Bq/cm3,
Cs-137: 2.5X10-1 Bq/cm3
· Inside the duct for the Unit 5 radioactive fluid pipes
I-131: below the detectible limit, Cs-134: 8.0X10-2 Bq/cm3,
Cs-137: 1.3X10-1 Bq/cm3
· Inside the duct for the Unit 6 main transformer cables
I-131: below the detectible limit, Cs-134: 2.8X10-1 Bq/cm3,
Cs-137: 4.3X10-1 Bq/cm3
· Inside the trench for heavy oil pipes (east of Unit 5)
I-131: below the detectible limit, Cs-134: 2.0X10-1 Bq/cm3,
Cs-137: 2.8X10-1 Bq/cm3
- 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.67.9°C (as
of 5 am on February 9). We will monitor the progress continuously.
* 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
changed the amount of water injection into Unit 2 (from 3:48 am on
February 7 to 6:48 pm on February 8) by conducting a planned shift
beyond the range of operational limitation.
- At 9:47 am February 9, as the amount of water injection decrease, we
adjusted the volume from the feed water system of reactor Unit 2
increased from approx. 6.4 m3/h to approx. 6.8 m3/h, and we continue to
inject water from reactor core spray system approx. 6.8 m3/h.
- At 10:00 am on February 8, we started to transfer the water accumulated
in the basement of Unit 6 Turbine Building to temporary tanks. At 4:00
pm, we stopped the transfer, and at 10:00 am on February 9, we resumed
the transfer.
· 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, February 8, 2012) (PDF 410KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress
