Siemens started talks with Rosatom last month after saying it would sell its 34 percent stake in a nuclear reactor building venture with France’s Areva SA.

After last month’s talks,  Russian Prime Minister Vladimir Putin signaled support for a deal, suggesting that a Russian-German joint venture could target the growing world market for commercial nuclear energy.

Rosatom and Munich-based Siemens, Europe’s largest engineering corporation, said they will now negotiate the terms and conditions of their planned cooperation. The aim is to have a final agreement by May.

There will be about 400 new nuclear plants worldwide by 2030, involving investment of more than 1 trillion euros ($1.3 trillion), according to a forecast the companies cited.

The memorandum of understanding foresees Russia’s Rosatom holding 50 percent plus one share of the joint venture, which would "push ahead with further development of Russian pressurized water reactor technology," the joint statement said.

"The joint venture may take up business opportunities along the entire nuclear conversion chain from fuel fabrication to decommissioning of nuclear power plants," it added.

In remarks reported by Rosatom’s website, Rosatom Chief Sergei Kiriyenko said: "In a fully fledged partnership with Siemens, we want to become the world market leader in nuclear power business.”

"I am looking forward to soon making the next successful steps in our negotiations," he said.

Siemens CEO Peter Loescher said he sees an opportunity "to enlarge our footprint in nuclear business with a very strong and experienced partner," Rosatom reported.

Siemens brings to the table expertise in areas such as turbines, generators and operating systems. The German industrial conglomerate wants to gain exposure to Rosatom’s involvement in the whole nuclear fuel chain.

The venture will face stiff competition from Westinghouse, sold in 2006 by the UK government to Toshiba, General Electric of the US, and Areva.

German officials have signalled their support for Siemens’ nuclear ambitions, in spite of Berlin’s decision to phase out nuclear power. In contrast, Russia has backed plans to build 26 new nuclear power plants in the next 12 years.

Siemens has long ties with Russia and has worked with Rosatom on several projects since the 1990s. Both companies are involved in the construction of a nuclear power plant in Bulgaria.

Russia in recent years has pushed hard to break into the worldwide civilian nuclear energy market, which has long been dominated by the United States.