PRAGUE, Nov 3 (Reuters) - Three companies have placed preliminary bids to build up to five nuclear reactors for Czech power firm CEZ in what is expected to be the country's biggest-ever procurement deal, CEZ said on Tuesday.

Chief Executive Martin Roman confirmed that Russia's Atomstroyexport, the Westinghouse Electric unit of Toshiba Corp and France's Areva were the only bidders.

'We can confirm that no one else has bid apart from firms that declared they would bid,' Roman said.

CEZ is expected to draw a shortlist early next year for the deal which analysts say may be worth around 500 billion crowns ($27.93 billion).

(Reporting by Jan Korselt, writing by Jan Lopatka, Editing by Michael Kahn) ($1=17.90 Czech Crown) Keywords: CEZ NUCLEAR/

(prague.newsroom@thomsonreuters.com; Reuters Messaging: jan.lopatka.reuters.com@reuters.net; +420-224 190 474)

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