On May 16, 2011, we received an instruction* from Nuclear and Industrial
Safety Agency (NISA) of Ministry of Economy, Trade and Industry titled
"Countermeasures based on a report on records of damage situation of power
facilities inside and outside of Fukushima Daiichi Nuclear Power Station
(instruction)"
Thereafter we put together the contents in a report on the result of
investigation of causes that brought about damage situation of power
facilities inside and outside of Fukushima Daiichi Nuclear Power Station
and those why protective devices of transmission lines worked and electric
transmission was suspended (Countermeasures in the future are included in
the result). We submitted the report to NISA on May 23.
(Previously announced on May 17 and May 24, 2011)
And we have organized a report with the result of seismic analysis based
on presumption of seismic waveform from data of observation points located
near the power station about the causes that brought about damage
situation of power facilities inside and outside of the Power Station. We
submitted the report to NISA on Jan 19, 2012.
(Previously announced on Jan 19, 2012)
We assumed the causes that the steel towers collapsed by the collapse of
fill inside of Fukushima Daiichi Nuclear Power Station in the report to
NISA on May 23, 2011. Subsequently, we have examined an investigation or
analysis about a cause of the collapse of fill still more.
We announce we submitted the report to NISA today.
END
○ Attachment(The attachment file will be posted later.)
Report on countermeasures based on a report on records of damage
situation to power facilities inside and outside of Fukushima Daiichi
Nuclear Power Station (instruction)
* Countermeasures based on a report on records of damage to power
facilities inside and outside of Fukushima Daiichi Nuclear Power Station
(NPS) (instruction)
2011.05.16 NISA no. 7
Today on May 16, with regard to collection of a report pursuant to the
provisions of Article106, paragraph 3 of the Electricity Business Act
(Act No. 170 of 1964), we received a report from your company on damage
situation of power facilities, electric transmission to NPS and
restoration situation of off-site power by urgent measures inside and
outside of NPS since the occurrence of the Tohoku-Chihou-Taiheiyou-Oki
Earthquake (Earthquake).
We, Nuclear and Industrial Safety Agency (NISA), determine we have to make
clear causes that brought about damage situation of power facilities
inside and outside of NPS in the report and those why protective device of
transmission lines worked and electric transmission was suspended in order
to utilize study to further enhance reliability of power supply to nuclear
power stations.
Hence, we request that you report the following items to us by May 23,
2011.
Required Items
1. Results of determination why the following items and other electric
facilities inside and outside of NPS have caused damage situation since
Earthquake occurred; especially, you should analyze whether damage
situation was caused by Earthquake or the tsunami by operation records
including those just after the earthquake occurred and accident records in
nuclear reactor facilities stipulated in paragraph 1 of Article 7 of Order
on Installation and Operation of Nuclear Reactors for Commercial Power
Generation (Order No.77 of Ministry of International Trade and Industry of
1978) regarding the current accident at NPS in accordance with the
provisions of Article 67, paragraph 1 of Act on Regulation of Nuclear
Source Material, Nuclear Fuel Material and Reactors (Act No. 166 of 1957)
by records in the report and Nuclear No.1 on April 24, 2011 dated on April
25, 2011.
○ Fukushima Daiichi Nuclear Power Station
· Causes why power receiving circuit breakers and disconnecting switches
were damaged
· Causes of troubles on electric wires connecting Toden Genshiryoku Line
· Causes of collapse of a high tension tower of Yonomori Line No.27
· Causes why regular and emergent power distribution panels were damaged
○Shin Fukushima Electric Power Substation
· Causes why major transformers were damaged
· Causes why circuit breakers were damaged
· Causes why disconnecting switches were damaged
· Causes why instrument transformers were damaged
· Causes why current transformers were damaged
2. Results of determination why protective devices of the following
transmission lines worked and electric transmission was suspended
○ Fukushima Daiichi Nuclear Power Station
· Okuma Line No.1
○ Shin Fukushima Electric Power Substation
· Okuma Line No.2, 3 and 4
· Yonomori Line No. 1 and 2