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)
- As accumulated water containing radioactive materials was found in the
trench between Process Main Building and Miscellaneous Solid Waste Volume
Reduction Treatment Building (High Temperature Incinerator Building) in
Centralized Radiation Waste Treatment Facility (December 18, 2011),
inspection of other trenches in the site was commenced from January 11.
As a result of inspection on February 10, location where accumulated
water was found and results of nuclide analysis (preliminary result) are
shown below;
· Unit 6, inside of seawater pipe duct (SW system)
I-131:Below detection limit (ND), Cs-134:2.1x10-1Bq/cm3,
Cs-137:3.4x10-1Bq/cm3
· Unit 5, inside of seawater pipe duct (SW system)
I-131:ND, Cs-134:1.4x10-1Bq/cm3, Cs-137:1.5x10-1Bq/cm3
· No6, inside of trench for diesel fuel pipe
I-131:ND, Cs-134:2.5x10-1Bq/cm3, Cs-137:3.7x10-1Bq/cm3
· Unit 6, inside of pipe duct (b/w pump room and MG set build.)
I-131:ND, Cs-134:1.1x10-1Bq/cm3, Cs-137:2.0x10-1Bq/cm3
· Unit 6, inside of seawater pipe duct (North side, emergency line)
I-131:ND, Cs-134:ND, Cs-137:1.2x10-1Bq/cm3
· Unit 6, inside of seawater pipe duct (South side, emergency line)
I-131:ND, Cs-134:1.4x10-1Bq/cm3, Cs-137:2.0x10-1Bq/cm3
- At 1:28 pm on February 10, injection of hydrazine started through the
circulating piping line into the spent fuel pool of Unit 4. Stopped on
3:05 pm on the same day.
- At 10:00 am on February 10, started transfer of accumulated water in the
underground of turbine building of Unit 6 to temporary storage tank.
Stopped on 4:00 pm on the same day.
- 8:45 am on February 10, started transfer of accumulated water from site
banker building to process main building in the centralized waste
treatment facility. Stopped on 4:39 pm on the same day.
- 6:20 pm on February 10, as decrease of water injection rate into reactor
of Unit 2 was observed, adjustment was made from approx.6.3m3/h to
approx. 6.8m3/h for feed water system and from approx. 6.6m3/h to approx.
6.7m3/h for core spraying system.
- 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.68.5°C (as of
5 am on February 11). We will monitor the progress continuously.
· 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 February11, 2012) (PDF 673KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress