With the trouble-prone Monju fast-breeder reactor set to be scrapped and nuclear materials piling up, Japan's policy on reprocessing atomic fuel is becoming increasingly uncertain.

According to a U.S. government source, the administration of President Barack Obama has had discussions on the "comprehensive advance consent" that the U.S.-Japan nuclear cooperation agreement provided for 28 years ago.

Comprehensive advance consent is a special privilege under which Japan is the only country without nuclear weapons that is allowed to reprocess spent nuclear fuel from the U.S.