TOKYO, April 25 (Kyodo) — Tokyo Electric Power Co. will equip its idled nuclear reactors with filtered venting systems developed on its own as part of its efforts to swiftly seek their restart, company sources said Thursday.

Japanese utilities are trying to install the system because it will become one of the new safety requirements for reactors from July as a measure to deal with severe accidents, but it is rare to self-develop the system. Other utilities have outsourced the equipment to companies such as heavy electric machinery makers.

By developing the equipment for reactors at the Kashiwazaki-Kariwa plant in Niigata Prefecture, all of which are currently offline, TEPCO aims to shorten the period for the manufacturing and installation of the system to about six months from the usually needed one to two years, while largely curtailing construction costs.

Cutting costs is a key issue for the utility that is struggling to put its business back on track in the face of increasing outlays stemming from the 2011 accident at its Fukushima Daiichi complex.

TEPCO may finish the construction work at the Kashiwazaki-Kariwa plant's boiling water reactor in the summer at the earliest, making it the first reactor in Japan to be equipped with a filtered vent.

Vents with filters can reduce the amount of radioactive substances when pressure needs to be released from reactor containers during emergencies. The Fukushima plant had venting systems but not with radiation-screening filters.

Tokyo Electric Power Services Co., a TEPCO group company, has designed the equipment.

But even if the system is prepared, it is uncertain whether TEPCO will be allowed by the Nuclear Regulation Authority to restart the idled reactors during fiscal 2013 as planned, because concerns linger over geologic faults running beneath the plant.

Japanese utilities are expected to start applying for government permits to put their reactors back online after the new safety requirements take effect in mid-July.

Filtered venting will be an immediate requirement for BWRs, but a five-year moratorium is set for pressurized water reactors because their reactor containers are larger than BWRs.

The two reactors that are currently operating in Japan are both PWRs.