In light of the situation concerning the damages at Fukushima Daiichi
Nuclear Power Station due to the Tohoku-Chihou-Taiheiyou-Oki Earthquake
that occurred on March 11th 2011, TEPCO has begun implementing emergency
countermeasures to prevent damages to the reactor core and spent fuel,
suppress discharges of radioactive materials and restore the cooling
function of the reactor facility. This is all being done under the
assumption that all three functions (Availability of all facilities that
supply AC power, reactor cooling by seawater, and spent fuel pool cooling)
were simultaneously failed when the tsunami struck.
We received an Order(*) from the Minister of Economy, Trade and Industry
that requires the enforcement of emergency countermeasures for further
safety at the Nuclear Power Station. Based on this, in addition to
emergency safety countermeasures at Kashiwazaki Kariwa, we organized a
report regarding the prevention of flooding by tsunamis, and further
countermeasure plans to restore safety which was submitted to the Ministry
of Economy, Trade and Industry (METI) on April 21st, 2011.
(Announced on 21st April 2011)
After the submission of the report, some errors were pointed out to us by
the Nuclear and Industrial Safety Agency (NISA). In response, we amended
the errors and re-submitted the report to the Minister of Economy, Trade
and Industry today.
<Amended part>
Emergency countermeasures for safety at Kashiwazaki Kariwa Nuclear Power
Station (implementation report)
The data of the maximum load and others in Units 6 and 7 in "Attachment 4-
(3) 1. a. Function of Alternative Water Injection to Reactors and Spent
Fuel Pools" have been amended. (Please see attachments for details)
We seek the continuous cooperation and support from the ministries and
local communities, and via tight communication, we intend to focus all of
our efforts towards the stabilization of Fukushima Daiichi Nuclear Power
Station.
If we identify any points that should be reflected into the Tsunami
countermeasures at Kashiwazaki Kariwa Nuclear Power Station during the
process of analysis and evaluation of the cause(s) of the accident, we
will take swift action to have them incorporated.
Attachment 1: Attachment 4-(3)
1. a. Function of Alternative Water Injection to Reactors and Spent Fuel
Pools (after revision) (PDF 14.3KB)
Attachment 2: Attachment 4-(3)
1. a. Function of Alternative Water Injection to Reactors and Spent Fuel
Pools (before revision) (PDF 14.1KB)
*Order:
"Implementation of emergency safety measures of other nuclear power
stations based on the accidents at Fukushima Daiichi & Fukushima Daini
Nuclear Power Stations (Order)"
(NISA no.7 on March 28, 2011)
The accident at Fukushima Daiichi Nuclear Power Station caused by the
tsunami that struck immediately following the Tohoku-Chihou-Taiheiyou-Oki
Earthquake resulted in a nuclear disaster of unprecedented portions in
Japan. Currently, TEPCO and relevant authorities such as national and local
governments have come together to prevent the outspread of this nuclear
disaster and repair the damages.
NISA has garnered all of its resources to continuously tackle the many
challenges this accident is posing and through analysis and evaluation is
working to gain a thorough and overall understanding of the many factors
that comprise the accident including the generating mechanism of the
tsunami. The causes of the accident will be clarified and drastic measures
will be taken.
On the other hand, it would appear that large tsunamis of this scale
triggered by huge earthquakes like the one that struck on March 11th do
not occur frequently, but may cause a serious damage to a nuclear power
station. In consideration of this matter, as a start and based on currently
understood factors, emergency safety measures that will enable the
suppression of the discharge of radioactive materials and the restoration
of the reactor facility's cooling function in the event that the power
supply function is failed due to a tsunami should be taken for those
nuclear power stations besides Fukushima Daiichi Nuclear Power Station and
Fukushima Daini Nuclear Power Station. Furthermore, NISA must confirm via
examinations etcetera that the creation and implementation of these
emergency safety measures are conducted appropriately by the electric
power suppliers. If this is done, then we should be able to prevent
reactor damages leading to the occurrence of a nuclear disaster in the
event that the power supply function is failed by a tsunami.
Therefore, according to the regulations on operation maintenance for
operation systems for the maintenance of a reactor facility in the event
of a tsunami and the installation of an actual generation reactor after
revision which requires the maintenance of security regulations and
operation regulations, we request immediate permission to work on the
following emergency safety measures and report the implementation status
of these emergency safety measures.
Notes:
For emergency safety measures, the following countermeasures to prevent a
damage to the reactor core and spent fuel, suppress discharge of
radioactive materials and restore the cooling function of the reactor
facility should be taken even if the three functions such as the functions
of all facilities that supply AC power, the functions of all facilities
that cool the reactor facility and the function of all facilities that
cool the spent fuel pool by seawater are failed by the tsunami.
Furthermore, security regulation should be maintained according to the
revision of the regulations concerning installation of the actual
generation reactor and operations, and the approval of the revision of
the security regulations should be applied.
1. Implementation of emergency inspection
Implementation of an emergency inspection of equipment and facilities to
prepare for an emergency response in the event of a tsunami
2. Implementation of the review and training of the emergency response plan
Implementation of the review and training of an emergency response plan
that assumes that the functions of all facilities that supply AC power,
the functions of all facilities that cool the reactor facility and the
functions of all facilities that cool the spent fuel pool by seawater
have been failed.
3. Securing of power source in emergency situations
Securing of a backup power source which can supply necessary power agilely
in case any power sources in the nuclear power station are lost and
alternate emergency power sources cannot be secured
4. Securing of a definitive heat removal function in emergency situations
Preparation of restoration countermeasures of an agile heat removal
function that assumes loss of the seawater system facility or its function
5. Securing the cooling of the spent fuel pool in emergency situations
Implementation of countermeasures to supply cooling water agilely in case
the cooling of spent fuel pool and normal water supply to the spent fuel
pool in the nuclear power station inadvertently stop.
6. Implementation of immediate countermeasures taken in consideration of
the configuration of each nuclear power station