TerraPower, a Bellevue, Wash.-based nuclear energy startup backed by Microsoft chairman Bill Gates, has been raising its profile in recent months. Now the company has just landed $35 million in funding from Charles River Ventures and Khosla Ventures to advance its plans.

TerraPower was born at Intellectual Ventures, a firm headed by former Microsoft Chief Technology Officer Nathan Myhrvold. The startup is seeking to build a new type of nuclear reactor that would use depleted uranium as fuel.

The new funding should help TerraPower to ramp up its activities. Up to now, it's been a small, in-house research effort hosted at Intellectual Ventures.

Charles River Ventures said TerraPower "has grown to nearly 40 full time professionals and 75 technical consultants" with "expertise in nuclear engineering, physics and computer science."

Gates has provided an unspecified amount of funding for TerraPower and has recently been talking up its potential. The Microsoft chairman, who is deeply involved in global health work through his private foundation, has shown a growing interest in nuclear and other energy technologies that could potentially meet the power needs of the world’s poor without contributing to global warming.

Nuclear power, which supplies roughly 20 percent of electricity in the United States, does not produce carbon emissions. The Obama administration has made the construction of new nuclear plants a central plank of its energy plan. But nuclear power remains controversial, associated in the minds of many people with high-profile accidents such as Three Mile Island and Chernobyl.

TerraPower has said it's interested in the global nuclear power market, not just the United States. A report back in March indicated that TerraPower was in talks with Toshiba, of Japan, one of the big players in the nuclear power industry.

Here's more on TerraPower and its traveling-wave reactor concept.

Intellectual Ventures, the firm that spawned TerraPower, has sparked controversy in the technology industry with its business model. The firm has amassed thousands of technology patents, which it licenses to companies — leading some to label it a giant "patent troll."

Lately, Intellectual Ventures has been emphasizing its invention efforts, including TerraPower, a hurricane-suppression system, and a stratoshield to combat global warming.

Interesting side note: Charles River Ventures indicated it is an investor in Intellectual Ventures itself, something I hadn't seen before.

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