In connection with the loss of offsite power source at Higashi-dori
Nuclear Power Station of Tohoku Electric Power Company, which was caused
by Earthquake Off the Coast of Miyagi Prefecture on April 7th, 2011, we
received an order*1 from Nuclear and Industrial Agency to apply for
approval of modification on Safety Regulations on Nuclear Reactor
Facilities*2. We applied to Ministry of Economy, Trade and Industry for
approval of modification on Safety Regulations on Nuclear Reactor
Facilities of Kashiwazaki-Kariwa Nuclear Power Station on April 21st.
In accordance with the amendment of the interpretation of ministry
ordinance about restrictions on plant operation, being "there must be two
operable emergency generators during cold shutdown and fuel replacement",
we modify the description as per attached regarding the restrictions on
plant operation in the safety regulations which are associated with
non-operated diesel generators for emergency.
(Previously announced on April 21st, 2011)
The application of modification on Safety Regulations on Nuclear Reactor
Facilities of Kashiwazaki-Kariwa Nuclear Power Station was approved by
Minister of Economy, Trade and Industry today.
Attachment: Comparison chart for amendment of safety regulations on
nuclear reactor facilities for Kashiwazaki-Kariwa Nuclear
Power Station(PDF 134KB)
*1 The order issued on April 9th, 2011, is as below.
"Regarding interpretation of safety regulations on emergency generating
facilities: an order"(April 9, 2011)
The Earthquake Off the Coast of Miyagi Prefecture occurred on April 7,
2011 and Higashi-dori Nuclear Power Station of Tohoku Electric Power
Company lost the offsite power and emergency generating facilities started
up to maintain the power source. Although the offsite power has been
restored, emergency generating facilities shut down due to some troubles.
Thus, it was reported as a failure to secure the restriction of operation
regulated in the safety regulations.
Amongst the matters on operation of nuclear reactors facilities in the
safety regulations stipulated in such as Article 16.7 of the current
"Rules on the Installation and Operation of Commercial Power Reactors"
(No. 77 of Ordinance of Ministry of International Trade and Industry, of
Showa 53 (of 1978)), the interpretation on restriction of operation
requires one emergency generating facility operable for each nuclear
reactor in the condition of cold shutdown such as during regular
inspections and fuel replacement (which includes the cases of storing
spent fuels in spent fuel pools). However, in consideration of the
accident of Fukushima Daiichi Nuclear Power Station caused by Tsunami
induced by Tohoku-Chihou-Taiheiyo-oki Earthquake, 2011, it is extremely
important to secure power source. Therefore, the interpretation was
amended to require two emergency generating facilities operable which
connect to necessary emergency alternate-current high-voltage bus line for
each nuclear reactor (when power stations have more than one nuclear
reactor, they can count the number of emergency generating facilities of
other units which are connected to the necessary emergency alternate-
current high-voltage bus line.)
As a result, it is required to immediately take actions for emergency
safety measures, ordered on March 30, including securing power supply cars,
fire fighting engines, fire fighting hose and others and also is required
to immediately implement amendment of safety regulations of "Rules on the
Installation and Operation of Commercial Power Reactors", which fulfils
the above interpretation and also is one of the safety measures for
emergency, by April 28 of this year.
*2 Safety Regulations on Nuclear Reactor Facilities
In accordance with Act on the Regulation of Nuclear Source Material,
Nuclear Fuel Material and Reactors, Paragraph 1, Article 37, the business
operator shall draw it up and apply for government's approval. It provides
overall operation on overall security activities in regard to operation of
power plant, fuel management and radiation dose management.
