Material unaccounted for

rdf:langString Material unaccounted for

rdf:langString Material unaccounted for (MUF), in the context of nuclear material, refers to any discrepancy between a nuclear-weapons state's physical inventory of nuclear material, and the book inventory. The difference can be either a positive discrepancy (an apparent gain of material) or a negative discrepancy (an apparent loss of material). Nuclear accounting discrepancies are commonplace and inevitable due to the problem of accurately measuring nuclear materials. This problem of inaccurate measurement provides a potential loophole for diversion of nuclear materials for weapons production. In a large plant, even a tiny percentage of the annual through-put of nuclear material will suffice to build one or more nuclear weapons. MUF is a term used within , the organisational and physical tests used in the monitoring of fissile material and the detection of any impermissible removal. An associated term is limit of error for the material unaccounted for (LEMUF), meaning the associated statistical limits of error possible for the MUF. In a civilian context, MUF is also sometimes referred to as the inventory difference (ID). A 2014 report by the United States Army War College's Strategic Studies Institute states that although the quantity of MUF globally is unknown, it is "significant." They add that "U.S. nuclear weapons MUF alone is pegged at nearly six tons—i.e., enough to fashion at least 800 low-tech, multi-kiloton bombs," with Russian MUF numbers assumed to be as large. "As for Chinese, Indian, Pakistani, Israeli, and North Korean MUF figures, though, we have only a general idea of what they might be […] The civilian production of nuclear weapons-usable plutonium in the United States, United Kingdom (UK), Japan, France, and India also is a worry. We know that specific accounting losses in the case of civilian plutonium reprocessing and fuel making in the UK and Japan have been significant—measured in scores of bombs worth. What they might be elsewhere, again, is unknown."