(Corrects corporate structure in paragraphs 1, 4 to show Uranium One not part of Atomredmetzoloto)
* Uranium One mothballs Honeymoon mine in Australia
* Development of the Tanzanian Mkuju River mine may stop
* 50 pct of global production loses money - U1 president
MOSCOW, Nov 13 (Reuters) - The mining arm of Russian state-owned reactor builder and supplier Rosatom, among the world's top three uranium producers, said it would freeze expansion projects in Russia and elsewhere due to low prices.
The price of uranium, used mainly as fuel for nuclear plants, plummeted after the March 2011 meltdown at Japan's Fukushima Daiichi atomic power plant and has shown no signs of recovery.
"We cannot discount the dramatic fall in natural uranium prices, as a result of which over 50 percent of global uranium production is currently loss-making," Vadim Zhivov, chairman of Atomredmetzoloto and president of Uranium One Holding, told Reuters in emailed comments on Wednesday.
"Given the unfavourable market environment, we have decided to freeze expansion projects both in Russia and abroad," Zhivov said.
Rosatom's mining arm comprises Atomredmetzoloto, which controls Russian assets, and Uranium One Holding, which oversees foreign assets.
Uranium One, a Canadian mining firm that Rosatom took private last month, will mothball the Honeymoon mine in uranium-rich South Australia, local media reported this week, citing high costs and unfavourable contracts with Japan's Mitsui .
A company spokesman confirmed on Wednesday that the mine would be put in "care and maintenance" mode.
Zhivov did not specify which of the company's projects had been cancelled, saying the details would be announced later.
Rosatom is also developing the Mkuju River mine in Tanzania and several minor projects in Russia and has plans to expand its Willow Creek project in the U.S. state of Wyoming.
Zhivov said the company was mulling production cuts at some high-cost projects but did not elaborate.
Uranium One, which claims to have the lowest production costs in the industry, said last week it planned to produce 12.5 million pounds of uranium oxide concentrate in 2013 and then reduce output to 12.4 million pounds next year.
November uranium futures on the New York Mercantile exchange closed at $35.85 per pound on Tuesday, compared with $68 per pound before the earthquake and tsunami in Japan.
Uranium One Chief Executive Chris Sattler said in August that low uranium prices would force high-cost mines to close, which could boost prices in the next couple of years as supplies dwindle.. (Reporting by Svetlana Burmistrova and Andrey Kuzmin; Writing by Andrey Kuzmin; Editing by Douglas Busvine and Jane Baird)