It appears likely South Korea and the U.S. will extend their bilateral nuclear accord for another two years after talks to revise the pact yielded no new ground during their latest negotiations in the U.S. on Thursday.

Seoul and Washington are said to have failed to agree on the sticking point of whether to allow South Korea to reprocess spent nuclear fuel, and agreed instead to an extension of the atomic energy agreement that expires in March.

A South Korean government source says the two sides agreed to work toward a sound and substantial revision on the pact, noting that a final decision has yet to come.

The source added Korean officials returning from Washington will consult with other government agencies before announcing the results of the talks.

Signed in 1974, the atomic energy accord bans South Korea from a proliferation-resistant technology for enriching uranium and reprocessing spent nuclear fuel.