On June 7, 2011, we received an instruction document*1 from NISA with
regard to anti-earthquake countermeasures of the switchyard etc. with a
view to securing reliability of offsite power supply for Nuclear Power
Stations etc.
Per the instruction document, we compiled a report on the status of the
evaluation regarding the possibility of collapse, damage etc. to the
electrical facilities such as switchyards at our Nuclear Power Station and
reported to NISA on July 7, 2011.
(Previously announced on June 7, 2011 and July 7, 2011)
We received an additional instruction document "Regarding the Seismic
Measures for Switching Yard related to Securing Reliability of External
Power Supply for Nuclear Power Stations, etc. (Additional Directions)"*2
from NISA today.
Per this additional document, we will compile the implementation plan for
evaluation of anti-earthquake resistance etc. at the switchyard etc. of
our Nuclear Power Stations and report to NISA.
END
*1 Instruction document
Regarding the Seismic Measures for Switching Yard related to Securing
Reliability of External Power Supply for Nuclear Power Stations, etc.
(Directions)
(06.07.2011 NA No. 1)
The Nuclear and Industrial Safety Agency ("NISA") received from General
Electricity Utilities, etc., the reports on May 16, 2011 related to NISA's
directions in the 04.15.2011 NA No. 3 dated April 15, 2011 regarding the
securing reliability of external power supply for nuclear power stations
and reprocessing facilities ("NPS, etc."). Today, NISA conducted
evaluation of the subject reports.
In addition, NISA received a report from the Tokyo Electric Power Co. Inc
("TEPCO") on May 23, 2011 regarding the cause for the damage related to
the electric equipment inside and outside Fukushima Dai-ichi Nuclear Power
Station ("NPS") according to the 05.16.2011 NA No. 3 dated May 16, 2011.
According to this report, the circuit breakers, etc., were damaged at the
switching yards related to Units 1 and 2 of the Fukushima Dai-ichi NPS due
to the earthquake.
Considering the above assessments and reports, NISA requests General
Electricity Utilities, etc., to implement the following items from the
perspective of securing reliable external power supply. Moreover, NISA
requests submission of reports regarding the state of implementation for
these measures by July 7, 2011.
Required Items
1. Assess the impact of the possibility for the occurrence of equipment
falling over or damage, etc. causing malfunctions in the electric
equipment of the switching yards, etc. at General Electricity Utilities'
NPS, etc., in consideration of the analysis results of the earthquake
records observed at TEPCO's Fukushima Dai-ichi NPS due to the 2011 Off
the Pacific Coast of Tohoku Earthquake.
As an aside, for these assessments, setting for the seismic force at
each NPS, etc. at the surface level as a standard related to the
switching yards, etc., analyze the stress occurring at the electric
equipment, and evaluate it by comparison with the structural strength
of the subject electric equipment.
2. If by the assessment in above-described 1, it is determined that a
possibility for the occurrence of equipment falling over or damage, etc.
causing malfunctions exists, decide the countermeasures against
earthquakes for the subject electric equipment.
*2 Instruction document
We have provided a Japanese press release version of the instruction
document received from NISA. However, at this time we have reserved the
right to not provide an English version due to potential misunderstandings
that may arise from an inaccurate rendering of the original Japanese text.
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. (will be announced once NISA
announces English version of this instruction document)
