By Braden Reddall

Dec 12 (Reuters) - NuScale Power LLC, a nuclear technology firm majority-owned by Fluor Corp, said on Thursday it had secured U.S. Department of Energy funding to develop small nuclear reactors just over a year after missing out in a previous award round.

The DoE's cost-sharing program will provide an amount of money that is still to be negotiated out of a $452 million fund aimed at developing small modular reactor (SMR) technology, Fluor said.

The award last year ended up going to Babcock & Wilcox , a well established provider to the U.S. government after years working with nuclear submarines.

John Hopkins, a former Fluor executive in the UK who took over as NuScale's chief executive a year ago, said he viewed the recent addition of Britain's Rolls Royce as a manufacturing partner as a key step in bolstering NuScale's case.

"This past year has been a Herculean effort by people within NuScale and within Fluor," Hopkins said in an interview.

NuScale's 45-megawatt reactor, which can be grouped with others to form a utility-scale plant, would sit in a 5 million-gallon pool of water underground. That means it needs no pumps to inject water to cool it in an emergency - an issue Hopkins said was highlighted by Japan's crippled Fukushima plant.

Cost is also a dominant challenge for nuclear power, 60 percent of the small reactors are built in a factory and therefore easier to finance in increments than the $6 billion minimum for existing reactor designs of 1,000 MW or more.

NuScale and the DoE will now negotiate a deal to formalize the public-private relationship and establish milestones for the five-year funding program. The company will pursue design certification from the U.S. Nuclear Regulatory Commission, and Hopkins said he hoped to have a module working by 2022.

NuScale will match all the federal funds, and Fluor said in a statement that both the company and NuScale were evaluating potential investors and partners for the technology.

U.S. Energy Secretary Ernest Moniz said the department was committed to strengthening nuclear energy's role in the country's "low carbon future."

Friends of the Earth saw the DoE subsidy as evidence that the "imaginary reactors" were uncompetitive in a free market.

"The biggest hurdle will be in securing construction funds and no private money has yet been forthcoming as SMRs are only speculative at this point," said Tom Clements, southeastern nuclear campaign coordinator for Friends of the Earth.

NuScale's design was first developed with DoE cash in 2000, before being refined with Oregon State University backing. The firm secured the patents by giving OSU an equity stake.

Before Fluor stepped in, NuScale found itself on the verge of collapse in 2011 after a key backer, hedge fund manager Francisco Illarramendi, was caught running a Ponzi scheme.