On April 15th, 2011, we received an instruction document entitled
"Offsite power supply security of nuclear power stations and
reprocessing plants"* from Nuclear and Industrial Safety Agency of
Ministry of Economy, Trade and Industry (NISA) and afterwards,
pursuant to the document, we checked the status of implementation of
measurements to secure the offsite power supply security and informed
NISA on May 16th.
(Previously announced on April 15th and May 16th, 2011)
We hereby announce that today NISA has informed us that our report is
evaluated as valid.
Since we have also received an instruction document from NISA to
report the status of implementation of measurements to secure the
offsite power supply in Fukushima Daini Nuclear Power Station, considering
the status of the equipment restoration there and implementation of
emergency safety measurements to keep the cold shutdown of the
reactors, we will report it as soon as possible.
We have also received another instruction document** from NISA today,
with regard to seismic measurements at switching stations for the
offsite power supply security. Pursuant to the document, we will check
the contents of the measurements and report to NISA.
*Instruction document
"Offsite power supply security of nuclear power stations and
reprocessing plants (directive)" (April 15th, 2011, NISA No.3)
There was a large blackout within the service area of Tohoku Electric
Power Company due to Miyagiken-oki Earthquake on April 7, 2011.
This accident cast uncertainty about the reliability of power systems,
since it starting from a grounding fault in one part of the power
systems led to the cut of offsite power supply systems to nuclear
power stations and reprocessing facilities (collectively "nuclear
power stations etc."). Therefore, Nuclear and Industrial Safety Agency
(NISA) instructs general electricity utilities to conduct the items
stated below (only 1 and 4 are applicable to processing facilities).
NISA also orders them to report the implementation status by May 16,
2011.
1.Considering that outage in power supply due to earthquake etc. could
affect offsite power supply to nuclear power stations etc., analyze
and evaluate the reliability of power supply in your company's power
systems which could affect power supply to nuclear power stations
etc, and consider measures to improve the reliability further of
power supply to such nuclear power stations (including enforcement
of on site power in nuclear power stations etc.). As for processing
facilities, consider improving equipment within such facilities
which corresponds to the measures above concerning the reliability
of power systems which supplies power to such facilities.
2.In order to improve the reliability of power supply to each unit in
your nuclear power stations, connect all the transmission lines
which are connected to multiple power lines to each unit and enable
power supply.
3.Concerning power line towers of your nuclear power stations,
evaluate seismic adequacy, stabilities of foundation against
earthquakes and depending on the result conduct necessary
countermeasures such as reinforcement work.
4.Concerning electrical facilities such as switchyards of your nuclear
power stations etc., conduct countermeasures such as installing them
indoors and making them watertight to exclude impacts on tsunami.
We may provide the English translation that NISA releases in our press
releases. However, in principle we would advise you to visit the NISA
website for timely and accurate information.