SEOUL, March 18-- The civilian nuclear cooperation accord between South Korea and the United States, which was extended for two more years, took effect on Tuesday, Seoul's foreign ministry said.

The ministry said that the memorandum of understanding which was signed to extend the nuclear energy accord until March 19, 2016, came into force, noting South Korea will make efforts to revise the pact in an advanced and mutually beneficial way.

The treaty, launched in 1973, has banned South Korea from reprocessing spent nuclear fuel and using technology to enrich uranium even for peaceful purposes.

Seoul has demanded an amendment to the nuclear energy accord as its storage facilities for spent fuel from local nuclear power plants are expected to reach full capacity in 2016. The country also cited rising domestic energy requirement and its growing role as a global nuclear power plant exporter.

A series of consultations to abolish the ban have been held since August 2010, but South Korea failed to get a nod from the United States, which is concerned about proliferation.

South Korea has proposed a pyro-processing technology, considered to be less conducive to proliferation, as a solution.