Iran could ruin Bulgarian hopes to sell a reactor it will receive from Russian company Atomstroyexport, Russian daily Kommersant quotes experts as saying.

The comment comes days after Bulgaria was ordered to pay EUR 550 M to Rosatom's subsidiary Atomstroyexport over the abandoned plan for the construction of a nuclear power plant in Belene, on the Danube river.

Sofia says it is looking into options to sell to a third country the equipment already produced for Belene, which it will receive after paying off the sum.

In theory, reactors made for Belene could be used in the expansion of the Bushehr Nuclear Power Plant, a project Moscow and Tehran have already agreed to renew. The Islamic Republic has resorted to such a step once, when the first unit of Bushehr was built with used German equipment purchased back in the Shah's times.

While Rosatom has declined to comment on the issue, a source whose background is related to the nuclear industry has told Kommersant it is only the Iranians who could purchase the reactors, but they are "tough negotiators" and would only like to obtain the equipment at prices much beyond market levels.

The source, while arguing the Belene reactor could be integrated into Bushehr-2, says the latter move might result in corrections in the project on behalf of Atomstroyexport that might affect the final price tag offered to the Iranian side.