UPDATE 1-Fennovoima says to decide reactor supplier next year

(Recasts with Fennovoima comment)

HELSINKI, Oct 5 (Reuters) - Nuclear consortium Fennovoima said on Friday it had not yet picked a reactor for its nuclear plant in northern Finland, after a paper reported a Fennovoima's boss complementing Toshiba's cooling system over Areva's .

Fennovoima in January received offers from the two companies and it is due to decide next year who will deliver the reactor to its Pyhajoki plant.

"We have not yet made any decision and we are not favouring one over the other as the process is still ongoing," Fennovoima spokeswoman Maira Kettunen said.

Fennovoima's nuclear engineering chief Juhani Hyvarinen was quoted as saying in daily Helsingin Sanomat that " both power plants have a completely electricity-free cooling system, but Toshiba has implemented it slightly better."

One of the lessons of the Fukushima disaster was that two natural disasters could strike at the same time and knock out the electrical supply system of a plant completely, so it could not be cooled down.

The European Union energy commissioner on Thursday urged regulators and operators to act to improve safety at nuclear power plants.

Fennovoima's plant is due to provide cheap energy to its shareholders, including stainless steel maker Outokumpu , retailer Kesko and the local subsidiaries of Swedish metals firm Boliden .

Its biggest single shareholder is German utility E.ON's

Finnish subsidiary, with a 34 percent stake.

(Reporting by Terhi Kinnunen; Editing by Miral Fahmy and David Holmes)

((terhi.kinnunen@thomsonreuters.com)(+358 9 680 50 243)(Reuters Messaging: terhi.kinnunen.thomsonreuters.com@reuters.net))