MOSCOW, July 16 (RIA Novosti) - Russian state nuclear fuel producer Tvel has won a tender to supply enriched uranium to power plants in Slovakia up to 2015,  a source from Slovak power utility Slovenske Elektrarne said on Wednesday.

"Tvel will sign a contract to supply fuel to five existing reactors at two Slovak nuclear plants - Mohovce and Bohunice - where VVER-440 reactors are operating, and for two reactors being built at the Mohovce plant," the source told RIA Novosti.

Slovenske Elektrarne's press service refused to comment on the issue before the official tender results are announced. "It is our company culture that we never disclose information about procurement processes until contracts are officially signed," the spokesman told RIA Novosti.  

U.S.-based Westinghouse Electric Company also participated in the tender.

TVEL has 14 nuclear fuel producing subsidiaries in Russia. Every sixth nuclear reactor in the world is powered by TVEL-made fuel. The corporation meets the nuclear fuel demand of 73 reactors in Russia and 13 countries, including Ukraine, Bulgaria, the Czech Republic, Slovakia, Hungary, Finland, Armenia, Lithuania and China.

Britain joined the list of TVEL's customers under a contract signed in May 2007.

Commenting on TVEL's success in the Slovak tender, Russia nuclear power agency Rosatom said the company would supply Slovakia with new-generation fuel, with enhanced features.

"At present, the fuel has a five-year cycle, which will increase to six years in the near future," a Rosatom official said. "Therefore, the fuel efficiency at [Slovak] reactors will improve significantly."