UPDATE 1-Ontario puts new nuclear reactor program on hold

* Ontario suspends bid process for Darlington reactors

* Says received three proposals, only AECL met guidelines (Adds details)

TORONTO, June 29 (Reuters) - The Canadian province of Ontario said on Monday it is suspending a program to build a new nuclear power plant at it Darlington nuclear facility due to uncertainty about the future of reactor builder Atomic Energy Corp Ltd.

The Ontario government said that only AECL, which is owned by the Canadian federal government, met the requirements of its plan to build two reactors at the Darlington site, east of Toronto, by 2018.

"Concern about pricing and uncertainty regarding the company's future prevented Ontario from continuing with the procurement at this time," provincial Energy Minister George Smitherman said in a release.

As well as AECL, Ontario also received proposals for the new reactors from French group Areva SA (CEPFi.PA) and Westinghouse Electric Co, which is owned by Toshiba Corp (6502.T) and Shaw Group Inc SGR.N.

In late May, Canada's federal government said it planned to seek buyers for AECL as part of an asset sale to wrestle down its record budget deficit.

The Ontario government launched the procurement process in March 2008 to build a two unit nuclear power plant at Darlington.

($1=$1.15 Canadian) (Reporting by Scott Anderson; editing by Peter Galloway)