NEW YORK (CNNMoney.com) -- John McCain's call for a big push into nuclear power can certainly be met - if the country is willing to pay more for power and tolerate the safety risks.

Earlier this week McCain, the presumptive Republican nominee for president, said he wants to build 45 more nuclear power plants to make the country more energy independent. That would add significantly to the nation's current fleet of 104 active plants, which produce about 20% of the nation's power.

The advantages to nuclear power are primarily two-fold: It doesn't emit greenhouse gases, and it is a reliable form of electricity produced from uranium - a fairly abundant domestic resource.

McCain and others have been touting nuclear energy as a possible replacement for foreign oil, if and when the country shifted to electric cars.

The utility industry is behind the construction of more nuclear plants.

"We have been saying for years that we have to not only preserve our current fleet [of nuclear plants], but enlarge it significantly," said Jim Owen, a spokesman for the Edison Electric Institute.

Obstacles to nuclear power

But the utility industry has not brought a new nuclear plant online since 1984.

Regulatory hurdles and public opposition to nuclear plants following the partial meltdown at Three Mile Island in 1979 are often cited for the freeze in new plants. Yet what almost everyone cites as the main obstacle now is cost: Nuclear power is just plain expensive.

It costs between $6 billion to $8 billion to build a new nuclear reactor, according to Steve Kerekes, a spokesman for the Nuclear Energy Institute. That's about four times the cost of building a new similar-sized coal plant.

If McCain wants 45 new plants, he'll have to provide the utility industry with some incentives to take on this huge up front expense.

These could come in the form of low-interest loans, laws restricting greenhouse gases (which would make coal more expensive) or the construction of a long-promised facility to handle the waste.

"The cost of building them is immense," said Peter Tertzakian, chief energy economist at ARC Financial, a Calgary-based private equity firm. "The commitment has got to be long term."

While the costs to build a nuclear plant are high, fueling it with uranium is relatively cheap.

Over the long term, nuclear power is thought to be competitive with other forms of power generation.

The total costs to produce nuclear and wind power are expected to run about 7 cents per kilowatt hour in 2015, according to projections by the U.S. Energy Information Administration. Coal and natural gas are thought to cost just a penny less, mostly due to the rising price of fossil fuels.

And, as the Edison Institute's Owen points out, in a world facing greenhouse gas restrictions and using ever more power, "the cost of whatever we are going to do is going to be big."

The safety controversy

If the cost issue is overcome, there is still the safety issue.

"Nuclear is [not] all that clean," the environmental group Greenpeace writes on its Web site. "You still have to mine the uranium used in the reactors - and mining is a dirty, polluting process. And you have to store the nuclear waste somewhere - waste that can be around for centuries, sitting in a storage facility somewhere, susceptible to leaks."

The government has long planned to build a long-term waste storage facility at Nevada's Yucca Mountain. But people that live nearby are unsurprisingly opposed to the idea, and construction has been held up for years.

In the meantime, radioactive waste is stored on-site at nuclear plants. The Nuclear Energy Institute's Kerekes says the total amount is small - all the waste produced from decades of nuclear power would fill up a football field to the depth of 20 feet.

And Kerekes said the licensing process at Yucca Mountain - which by congressional decree couldn't handle much more than the current waste but, Kerekes said, could be expanded to take several times that amount - will take about four years to complete.

He wasn't sure if that would lead to construction, but with Nevada Democrat Harry Reid currently running the show in the Senate, chances of that happening don't look good.

"The proposed Yucca Mountain nuclear waste dump is never going to open," said Reid in a statement on his Web site.

"I have successfully fought against the proposal to store nuclear waste in Nevada for over two decades because it threatened the health and safety of Nevadans and people across our nation."

Some also question nuclear plants' vulnerability, especially in an age fraught with terrorist concerns.

To illustrate this point, the Web site of environmental group Greenpeace begins its discussion on nuclear power with a photo of two reactors painted with a red bull's-eye.

The industry says that nuclear technology has gotten much safer since the days of Three Mile Island and the Chernobyl disaster, and the government says security has greatly improved since Sept. 11.

Statistics from security tests done in the 1990s were not reassuring.

Of the 81 security tests done between 1991 and August 2001, nearly half turned up lapses that could lead to core damage and probable radioactive release, according to the U.S. Nuclear Regulatory Commission.

Kerekes said those tests were designed to turn up failures, and they are now corrected.

Backing that contention, the Nuclear Regulatory Commmission said security tests done in 2007 showed a much safer system. While over half of the 199 tests showed some sort of minor problem, only five turned up what the agency called issues of "low to moderate security significance."

Many people say other countries have run safe nuclear programs for decades.

McCain is also confident nuclear plants pose little danger, telling the New York Times recently they are "safe, efficient, inexpensive and obviously a vital ingredient in the future of the economy of our nation and in our mission to eliminate over time our dependence on foreign oil."

Still, that may not be reassuring to communities where these plants get built.

"Everyone's OK with it, until they find out one's going in their backyard," said Tertzakian.