Little progress has been made in sensitive negotiations with the United States on whether to allow Korea to adopt its indigenous technology aimed at reprocessing nuclear fuel in revising a bilateral pact, a senior Seoul official said Monday.

Under a 1974 accord with the U.S., South Korea is banned from enriching uranium or reprocessing spent nuclear fuel. Korea, a major nuclear energy developer, hopes to adopt a so-called pyroprocessing technology in rewriting the pact, which is due to expire in 2014.

The allies have held five rounds of formal negotiations since 2010 to rewrite the 1974 pact, but Washington has not responded to a draft proposal by Seoul to revise the pact since February, the foreign ministry official said.

"We delivered our stance (on revising the nuclear pact) to the U.S. side in February, but a review (by the U.S. side on the stance) has been delayed," the official said on the condition of anonymity.

Asked about how the U.S. side would decide on the request by South Korea to allow it to reprocess spent nuclear fuel, the official replied, "It remains to be seen."

The official, who is familiar with the negotiations, didn't elaborate further, but his remarks raised doubts on whether the allies could conclude the talks by the end of this year.

In the face of growing nuclear waste stockpiles and its ambition to become a global power in the civilian nuclear industry, Korea hopes to adopt pyroprocessing technology, which leaves separated plutonium, the main ingredient in making atomic bombs, mixed with other elements.

South Korea wants the U.S. to allow it to use the new technology because it has to deal with more than 10,000 tons of nuclear waste at storage facilities that are expected to reach capacity in 2016.

But nonproliferation experts say pyroprocessing is not much different from reprocessing, and pyroprocessed plutonium could be quickly turned into weapons-grade material. (Yonhap)