For the export of nuclear materials (NM), the NSG guidelines require governmental assurance from the importing State that the NM will be used for peaceful purposes, safeguards and physical protection will be applied, and prior consent will be obtained for retransfer. By providing this assurance, the importing State (recipient) is responsible for fulfilling the obligations required by the exporting States (supplier). If the Nuclear Cooperation Agreement (NCA) has been concluded between the supplier and recipient, it may be replaced by implementing the procedures under the NCA. In the case of NM subject to this obligation, continuous management at the national level is required because prior consent from the supplier may be required for retransfer to a third party under the assurance or may be subject to annual reporting. The obligation swaps are the exchange of obligations of NM without the physical movement of it. Since the physical movement of NM is costly and risky, its obligations are often exchanged for commercial reasons. The basis for obligation swaps is the fungibility and equivalence of NM. The fungibility allows that the inventories of NM need not physically identify the particular NM originally obligated but identify an equivalent quantity of the same isotopic composition. In addition, under the principle of equivalence, even if NM loses its unique physical properties, it can be exchanged by another obligated or nonobligated NM. That is, the principles of equivalence and proportionality allow the comparison of quantities of uranium in different forms. Therefore, it is theoretically possible not only to exchange obligations between NM in same physical form, but also different physical forms of same composition (with the same enrichment), e.g., UO2 powder and its pellets. In U.S., it appears that there are obligation swaps of NM between different enrichment levels, but according to the NCA and its Administrative Arrangement between ROK and U.S., Canada and Australia, the principle of fungibility and equivalence shall not be used to reduce the quality of a quantity of NM. In other words, swaps between NM of different enrichment levels are not allowed under the NCA and AA. However, according to the Supplementary Arrangement between ROK and Canada, the replacement of NM by lower quality NM may only occur where the two States so decide following consultation. The U.S., Canada, and Australia, which are major suppliers of NMs, allow internal obligation swaps within the U.S. and the EU through NCA. The NCA between ROK and these countries does not address whether internal swaps are possible. Since governmental assurance does not impose restrictions on swaps, it can be considered if necessary. Although there is no actual practice of obligation swaps in ROK, research will be necessary regarding the extent to which swaps in ROK should be allowed and the need for government approval or permission.

A bilateral Nuclear Cooperation Agreement (NCA) should define what is subject to the agreement and when. Nuclear Materials (NM) are the subject of NCA with almost all countries, and the definition used in these agreements is borrowed from Article 20 of the IAEA Charter. The IAEA’s definition of NM as consisting of special fissionable material and source material and describes the types of material each contains. In order to control the export of NM under national laws and implement NCA, not only the types of NM but also quantitative criteria are required. This is because controlling small quantities of NM is impossible, unnecessary, and would create excessive administrative burdens. For this reason, the NSG guidelines establish a quantitative threshold of NM requiring control. Nevertheless, no quantitative thresholds have been agreed upon for NM subject to a NCA. Whether NM transferred is subject to the NCA is primarily a matter for the supplier states to determine. The supplier states make the decision based on quantitative criteria defined in their own export control laws. ROK identifies NM that require export licenses by reflecting the same criteria as the NSG guidelines in Foreign Trade Laws and its Notifications. Less than 500 kg of Natural Uranium, 1,000 kg of Depleted Uranium, 1,000 kg of Thorium, and 50 effective grams of special fissionable materials do not require an export license and is therefore not subject to NCA. In the US, the quantitative threshold for requiring an export license is different from that of ROK. For example, special fissionable materials that are not Pu are required if the individual shipment exceed 1 effective gram or 100 effective grams per year. The difference in the quantitative thresholds for NM between the two countries mean that the same item may be subject to NCA under US standards, but not under ROK’s. For example, the export of 8 grams of highly enriched uranium (93%) contained in a neutron detector would not be subject to the NCA in ROK, but would be considered NM subject to a NCA and required a special license in the US. Of course, in order to ensure the application of safeguards and physical protection to all NM transferred between the two countries, the agreement may not include a quantitative threshold for NM. However, the absence of such a threshold can lead to different conclusions by the two countries on the same item and make it challenging to control retransfers. The definition of quantitative standards will be necessary in the supplementary administrative arrangement for the practical control and management of NM subject to the NCA.