YOKOTA AIR BASE, Japan — North Korea has been grabbing headlines with expectations of a third nuclear weapons test, but South Korea has been quietly pursing its own atomic goals.

For about two years, South Korea and the United States have been renegotiating a four-decade-old nuclear cooperation agreement set to expire in March 2014. The pact governs what South Korea can and can’t do with nuclear technology and material provided by the U.S.

Any new agreement must conform to the Nuclear Nonproliferation Act of 1978, which tightened restrictions for nuclear trade with countries that did not yet possess atomic bombs. Its intent was to keep enriched uranium from being used in weapons.

The stumbling block in the negotiations at hand, however, is South Korea’s insistence it be given “long-term consent” to enrich uranium and reprocess spent nuclear fuel. Washington wants the current restrictions to stand.

“When the U.S. sends material anywhere, it attaches strings to it,” said Sharon Squassoni, director of the Proliferation Prevention Program at the Center for Strategic and International Studies in Washington.

For example, the U.S. requires its “customers” to receive permission for the transfer of nuclear material or technology to other countries or for enriching uranium and reprocessing spent nuclear fuel. About 60 percent to 70 percent of South Korea’s spent nuclear fuel is of U.S. origin, Squassoni said.

“The key point holding this up is that the South Koreans want programmatic, or long-term, consent to enrich and/or reprocess,” she said.

Billions of dollars of nuclear trade between the two countries could be at risk if the current pact expires. The U.S. is also concerned that such a concession could complicate negotiations with North Korea over nuclear weapons.

To meet the March 2014 deadline, a draft agreement would need to reach Congress by June, Squassoni said.

Talks broke off last fall after a flurry of South Korean media coverage began questioning U.S. restrictions, equating the freedom to reprocess with “nuclear sovereignty,” Squassoni said. She paraphrased the coverage as “Why don’t you trust us? We’re great allies.”

The U.S. government regarded the publicity as a “breach of faith” in negotiating, she said.

South Korean officials complain that the U.S. is treating the country like a “banana republic,” Miles Pomper, a senior researcher at the Monterey Institute of International Studies in California, wrote in the September edition of the Bulletin of the Atomic Scientists.

“They are particularly incensed that Japan, the other main U.S. ally in Asia and also Korea’s former occupier, long ago won U.S. consent to reprocess or enrich U.S.-origin fuel,” Pomper wrote.

The U.S. has been granting “advance long-term consent” to certain countries since the 1980s after some nuclear allies balked at the micromanagement.

But it’s tried to limit long-term consent to countries that don’t already possess enrichment technology, Squassoni said.

“South Korea does not now have enrichment or reprocessing, so the U.S. negotiating position is that we do not give long-term consent to countries that don’t already have it,” she said.

South Korea has said it wants enrichment capability for a number of reasons.

Nuclear power is a growing source of energy and South Korea says it wants to ensure a reliable fuel supply. The nation operates 23 power reactors and expects that number to almost double by 2030, according to Pomper.

Secondly, South Korea believes it needs enrichment to further compete in the nuclear market. In 2009, a South Korea-led consortium won a $20 billion contract to build three reactors in United Arab Emirates — a move that put the country in the big-league atomic business.

South Korea will supply nuclear fuel to the UAE for 15 years, but it relies on outside sources for enriching the uranium.

As a nascent nuclear exporter, South Korea says it needs to provide a full range of services in order to compete with the likes of France’s Areva, Russia’s Rosatom and the U.S.

The Joint Declaration on the Denuclearization of the Korean Peninsula, which North and South signed in 1992, bars both sides from having enrichment and reprocessing facilities.

“Obviously the North Koreans have abrogated that,” Squassoni said. “But from a U.S. perspective, if South Korea develops these capabilities or somehow acquires them, that cannot help any negotiating process with the North Koreans.”

Some observers had expected a way forward would be found once the recent campaign rhetoric about nuclear sovereignty ended. Yet the stalemate remains.

Neither administration wants to politicize the issue, said Seongho Sheen, an assistant professor at the Graduate School of International Studies, Seoul National University.

Nevertheless, Sheen noted, during a visit by U.S. Assistant Secretary of State Kurt Campbell to South Korea in mid-January, President-elect Park Geun-hye said she expected the agreement would be revised.

That could put more unwanted pressure on negotiators from both sides, Sheen said.

The talks did produce an agreement in 2011 to conduct a 10-year study on the technical and economic feasibility of “pyroprocessing,” an experimental method for processing spent fuel.

South Korea says it wants to develop the method to deal with a mounting volume of spent fuel. It touts pyroprocessing’s potential because the separated plutonium, which is the main component in atomic bombs, remains mixed with other elements. That makes it harder to be used in a weapon.

Squassoni dismisses the quest for pyroprocessing to deal with nuclear waste as analogous to “buying an oil refinery to put gas in your car.”

And South Korea won’t likely need enrichment capability because it has assurances of continued fuel for decades from countries such as Australia, Canada, France and the Netherlands, Pomper wrote.

olsonw@pstripes.osd.mil