This post contains a summary of INFCIRC/549 reports by the countries that submit annual civilian plutonium declarations that reflect the status of civilian plutonium stocks as of 31 December 2017. The post will be updated as more states submit their reports.
Japan (INFCIRC/549/Add.1-21) reported owning the total of 47.3 tons of plutonium, 10.6 tons of which is in Japan (the numbers in 2016 were 47.8 tons and 10.7 tons respectively). According to the Status Report on Plutonium Management in Japan - 2017 released in July 2018, out of the 36.7 tons of plutonium abroad, 21.232 tons are in the United Kingdom and 15.486 tons are in France. Japan is currently working on a new approach to plutonium management.
Germany (INFCIRC/549/Add.2-21) reported having no separated plutonium in the country (0.5 tons in 2016). Germany does not report separated plutonium outside of the country. It is believed to be less than 1 ton.
Belgium (INFCIRC/549/Add.3-17) declared no separated plutonium in storage or at reprocessing plants and "less than 50 kg" of separated plutonium in other categories. It reported that it had no foreign plutonium as of 31 December 2017. Belgium also corrected the 2016 report, stating that it had no foreign plutonium as of 31 December 2016 as well, not "less than 50 kg" as it reported at the time.
Switzerland (INFCIRC/549/Add.4-22/Corr.) reported having less than 2 kg of plutonium in the country (in the "located elsewhere" category). The number has not changed since 2016 (it was "less than 50 kg" in 2015).
France (INFCIRC/549/Add.5-22) reported having 80.9 tons of separated unirradiated plutonium in its custody. Of this amount, 15.5 tons belongs to foreign countries. It appears that all that plutonium - 15,486 kg - belongs to Japan. The amount of plutonium owned by France is 65.4 tons.
The United States (INFCIRC/549/Add.6-21) declared 49.4 tons of separated plutonium, of which 4.6 tons are in MOX fuel and 44.8 tons are "held elsewhere" (most of this material is believed to be in weapon components). The numbers have not changed since 31 December 2016.
China has not yet submitted its 2017 report (as of 18 December 2019).
The United Kingdom released information about its plutonium stock on the website of the Office for Nuclear Regulation (later published as INFCIRC/549/Add.8-21). According to the report, as of 31 December 2017 the United Kingdom had the total of 136.1 tons of separated plutonium in the country, of which 23.1 tons belonged to foreign bodies (that includes 21.232 tons of Japan's plutonium). UK own plutonium stock was 113.1 tons.
Russia (INFCIRC/549/Add.9-20) reported owning 59.0 tons of civilian plutonium. This includes 56.7 tons of material in storage, 1.8 tons of plutonium in unirradiated MOX and 0.5 tons of plutonium stored elsewhere. The numbers in 2016 were 54.9, 1.7, and 0.6 tons respectively for the total of 57.2 tons.
In addition to reporting plutonium stocks, some countries also submit data on their civilian HEU:
Germany reported 0.32 tonnes of HEU in research reactor fuel (0.33 tons in 2016), 0.94 tonnes of HEU in irradiated research reactor fuel, and 0.01 tonnes in the category "HEU held elsewhere."
France declared 5190 kg of HEU (4806 kg in 2016), of which 3654 kg (3264 kg) is unirradiated material - 1031 kg (1028 kg) of HEU at fuel fabrication or reprocessing plants, 113 kg (111 kg) at civil reactor sites, 2510 kg (2125 kg) at various research facilities. Also declared are 1536 kg (1593 kg) of irradiated HEU - 134 kg (147 kg) at civil reactor sites and 1402 kg (1394 kg) in other locations. The significant increase of the amount of HEU - an addition of 390 kg of HEU compared to December 2016 - probably reflects the HEU held by Areva/Orano, which manufactures fuel for the German FRM-II reactor. This material is supplied by Russia.
The United Kingdom reported having 1,241 kg of HEU (1,370 kg in 2016). Of this amount, 1,103 kg is unirradiated HEU: 2 kg of unirradiated HEU is stored at the enrichment plants, 329 kg - at fuel fabrication facilities, and 772 kg - at other sites. Irradiated HEU is located at civil reactor sites (5 kg) and other sites (132 kg).