As of the beginning of 2025, the global stockpile of weapon-usable fissile materials--about 1,810 metric tons (MT)--included about 1,240 MT of unirradiated highly enriched uranium (HEU) and about 570 MT of separated plutonium. A significant fraction of the global stock of each of these fissile materials is either in nuclear weapons or available for use in weapons. Material is considered not available for weapons when it is either produced outside weapon programs or produced in a weapon program but covered by an obligation, whether by agreement or by national declaration, not to use it in weapons. These estimates have been posted on the IPFM site and published in the "World nuclear forces" chapter of SIPRI Yearbook 2026.

Most of the unirradiated HEU--about 1,100 MT--is in weapons or available for use in weapon programs. The 140 MT of HEU unavailable for weapons includes material reserved for naval and research reactors, US HEU in the downblending queue, as well as an estimated 4 MT of HEU in non-nuclear weapon states. All HEU in non-nuclear weapon states and 3.8 MT of the material in France that it declared civilian are under international safeguards (IAEA and Euratom respectively). The rest of the HEU is not under safeguards or monitoring. This includes the 501 kg of HEU declared by the United Kingdom as civilian, since this material is not under international safeguards.

In contrast with HEU, most of separated plutonium--430 MT out of the total 570 MT--is not available for weapons. This material includes about 47 MT of plutonium owned by non-weapon states (44.4 MT of it by Japan), as well as 116.8 MT and 99.5 MT of plutonium declared as civilian by the United Kingdom and France respectively.

Also in this category is 116.1 MT of separated plutonium out of Russia's total stock. This includes 66.1 MT of material declared as civilian, 25 MT of weapon-origin plutonium that Russia pledged not to use for military purposes as part of the 2010 Plutonium Management and Disposition Agreement, as well as 15 MT of weapon-grade plutonium that is under obligation not to use it in weapons under the US-Russian 1997 agreement on plutonium production reactors.

The US stock of separated plutonium that is not directly available for weapons consists of 49.4 MT of material, most of which is excess material still in weapon components. The estimated 10 MT of reactor-grade plutonium owned by India is not considered directly available for weapons as this material is used in the fuel of India's first breeder reactor. China stopped submitting reports on the status of its civilian plutonium stock after 2016, when it declared having 40.9 kg of material.

Of the 430 MT of plutonium not directly available for weapons, 165 MT is under international safeguards or monitoring. This includes all 47 MT owned by non-nuclear weapon states, 3 MT of US plutonium, and 0.4 MT of India's plutonium under IAEA safeguards. 99.25 MT of French plutonium is under Euratom safeguards.

About 15 MT of Russia's weapon-grade plutonium, separated after 1996, is subject to US monitoring in accordance with the 1997 US-Russian agreement. While it is unlikely that the United States conducts inspections at this time, the agreement apparently remains in force (at least as of 1 January 2025).

Of the estimated 140 MT of plutonium that is in weapons or available for weapons, the largest stocks are those of Russia (about 88 MT) and the United States (38.4 MT). Stocks of other nuclear armed states are much smaller--about 6 MT in France, 3.2 MT in the UK, about 3 MT in China. Other states have less than a metric ton each.

Production of military fissile materials continues in India, which is producing plutonium for weapons and HEU for naval propulsion, Pakistan, which produces plutonium and HEU for weapons, Israel, which is believed to produce plutonium. North Korea has the capability to produce weapon-grade plutonium and highly-enriched uranium.

In the 1990s, the United States and Russia made a commitment not to use some of their weapon-origin and weapon-grade material for weapons and eliminated some of that material. This effort, however, has stalled. Russia formally ended its participation in the Plutonium Management and Disposition Agreement (PMDA) in October 2025. Russia suspended the implementation of this program in 2016 and has been using civilian plutonium to fuel its breeder reactors instead of weapon-grade plutonium as envisioned by PMDA.

The United States terminated the surplus plutonium dilute and dispose program in May 2025 and made the surplus plutonium available to the industry. The United States uses some weapon-origin and weapon-grade HEU in the fuel of naval and research reactors. It also continues to downblend some non-weapon HEU.

Meanwhile, France explicitly stated that it will use its weapon-origin material that was released during the downsizing of its arsenal in the 1990s to produce new nuclear weapons as necessary.

Note: The difference in the plutonium inventory numbers between the IPFM site and the SIPRI data is due to accounting for the civilian plutonium other than that owned by Japan.

The US Nuclear Regulatory Commission received an export license application XSNM3864 to allow Mirion Industries Corporation to supply radiation detection units to Westinghouse Electric China for use in AP1000 reactors that the company builds there.

The license application specifies that the equipment will include "up to 15 Intermediate Range Core Detectors, each containing up to 6 grams of U-235." The total amount of HEU in the application is 90 g, maximum enrichment is listed as 93.19%, with a U-235 content of 83.87 g.

On 3 June 2026, the leader of North Korea visited a new enrichment facility. According to analysis published by VERTIC, the facility is a new enrichment plant in Yongbyon, described in North Korean media as Nuclear Materials Construction Factory. The IAEA also stated that the layout of the facility shown on photographs is consistent with the building in Yongbyon. The building, in turn, is similar to the enrichment facility in Kangson.

VERTIC estimates that after the addition of this new facility to the existing ones in Yongbyon and Kangson the total enrichment capacity in DPRK reached about 100 tSWU/year (90,900 kgSWU/year in VERTIC's estimate). VERTIC estimates that this corresponds to the capability of producing about 375 kg or weapon-grade HEU a year.

On 26 May 2026, the Ministry of National Defense of the Republic of Korea presented the "Basic Plan for the Development of the Republic of Korea's Nuclear-Powered Submarines" (the press-release in English, translated by Naval News). The document describes the key parameters of the program that aims to build nuclear-powered submarines.

According to the plan, the future submarines will use low-enriched uranium fuel while enabling "long-cycle operation in order to minimize nuclear fuel replacement." The submarines will be developed and built in the Republic of Korea. The first submarine is expected to be launched in the mid-2030s and commissioned into service after the late 2030s.

The document also states that

the Republic of Korea will faithfully fulfill its non-proliferation obligations throughout the entire process of securing and managing low-enriched uranium, the nuclear fuel required for the propulsion system of nuclear-powered submarines, in close communication with the United States.

This language appears to leave open the possibility of acquiring low-enriched uranium from the United States or developing an indigenous enrichment program, potentially also in cooperation with the United States. The two states concluded a cooperation agreement in November 2025 and further discussed potential cooperation on enrichment and reprocessing technologies in January 2026.

Hui Zhang

Satellite images and other accounts suggest that China has started operation of its first 200 MT/year demonstration reprocessing plant, Project I, at the China National Nuclear Corporation (CNNC) Gansu Nuclear Technology Industrial Park in Jinta, Gansu province. Meanwhile, the construction of the second 200 MT/year plant, Project II, at the same site has been completed and would be ready to operate soon, while the third one, Project III, is still under active construction (see Figure 1).

Figure 1: The demonstration reprocessing and MOX facilities at Jinta, Gansu. Satellite image from 2 February 2026 (Coordinates: 40.333750, 98.494167). Credit: SkyFi/Vantor.

China started the construction of its first 200 tons/year demonstration reprocessing plant (Project I) for spent light-water reactor fuel in 2015. Since about 2020, CNNC has begun procuring and installing equipment for the reprocessing lines. At the time, it was expected that Project I would be operational in 2025.

While there have been no official statements or news coverage so far concerning the status of the plant, satellite images and other accounts suggest the first reprocessing plant started operations by mid-2025, maybe as early as late 2024.

The PUREX reprocessing processes need steam for heating chemical mixtures, driving distillation, and dissolving fuel. The demo reprocessing plant seems using the gas-fired steam generation plant with six high stacks for dispersing combustion exhaust, including, for example, water vapor and CO2 (see Figure 2).

Figure 2. Zoom of the Steam Generation Plant shown in Figure 1. The six stacks of the natural gas-fired steam generation plant and their shadows and the steam pipe are clearly shown in the image.

The image taken on 11 November 2024 shows some plumes over the top of high stacks (see Figure 3). This is consistent with Chinese accounts that the first demo plant had started operation before mid-2025. It should be noted that unlike vapor coming out of reactor cooling towers, these plumes are not necessarily visible to satellite sensors, in particular during warmer weather. Given that the coldest month in Jinta area is January, the plumes would be easier to see in satellite images taken in winter. The image taken on 26 January 2026 clearly shows plumes over the stacks and some steam coming out of the plant (see Figure 4).

Figure 3. The natural gas-fired steam generation plant near reprocessing and MOX facilities at Jinta, Gansu. Light steam plumes over each stack are visible. Satellite image from 11 November 2024. Credit: Google Earth, Airbus.

Figure 4. The natural gas-fired steam generation plant near reprocessing and MOX facilities at Jinta, Gansu. Long shadows of six stacks and the plumes above the stacks are visible. Steam can also be seen over the plant. Satellite image from 26 January 2026. Credit: SkyFi/Vantor.

Satellite images and commercial bidding and purchase documents show that China started the construction of its second 200 NMT/year demonstration reprocessing plant (Project II) in late 2019. While Project II construction began about four years later than Project I, satellite images from November 2024 show that it was completed at the same time as Project I, suggesting an accelerated construction schedule. This means that Project II could be ready to operate or may be operating already. If that is the case, it would be much earlier than the previously expected date of 2030.

Also, satellite images and other accounts suggest that in 2023 China started construction of a third demonstration reprocessing plant (Project III). Like Projects I and II, Project III probably has the capacity of 200 MT/year of spent light-water reactor fuel. However, one cannot exclude the possibility that Project III could reprocess spent fuel of fast breeder reactors. Based on the experience of Projects I and II, Project III could be commissioned earlier than the previously expected date of 2033.

Moreover, since 2018, CNNC has built a demonstration mixed uranium-plutonium oxide (MOX) fuel fabrication line with a capacity of 20 MT/year at the site. Satellite images show that the construction of this facility was completed by November 2024. The image taken in 2026 shows the completed MOX plant (see Figure 5). It was expected to be commissioned in 2025. However, it is not clear whether the plant has begun operations.

Figure 5. Zoom of the MOX facility shown in Figure 1 (image taken on 2 February 2026). The construction was completed by November 2024. It was expected to be operational in 2025. It is not clear if the facility has begun operations.

This MOX facility is believed to have been built to supply the fuel for China's second CFR-600 breeder reactor, which has been under construction since 2020 and is expected to become operational in 2026. While the fuel for the first CFR-600 reactor, which began operation in 2023, will be supplied by Russia, the second one is likely to use fuel produced domestically. The intergovernmental agreement that covers the cooperation between China and Russia on CFR-600 and related projects appears to include an option of using Russian-origin plutonium, but China may want to use domestic plutonium as well.

If the second CFR-600 uses domestic MOX, and assuming it requires about 5.5 MT of MOX fuel annually (containing about 1 MT of plutonium), the full operation of the first 200 MT/year reprocessing plant (separating about 2 MT of plutonium per year) would cover the CFR's needs twice. With the second reprocessing plant coming online soon, China will quickly accumulate a huge stock of reactor-grade plutonium, at least several times as large as its military stocks of plutonium (about 3 MT).

Moreover, since 2010, China has been producing civilian plutonium at its 50 MT/year pilot plant at Jiuquan complex (Plant 404) at Gansu. In 2017, China submitted its last official report to IAEA and declared having 40.9 kg of separated plutonium as of 31 December 2016. According to one conference report, the pilot plant began operating at the nominal capacity in 2017, which means it has been producing 500 kilograms of plutonium per year since 2017. This means that China may have accumulated about 4-5 MT of reactor-grade plutonium by 2026.

All this shows significant uncertainty about China's plutonium recycling programs. It would be in China's interest to make it more transparent, for example by resuming reporting on its stockpile of civilian plutonium to the IAEA, which was discontinued in 2017.

On 8 May 2026, the US National Nuclear Security Administration announced that it removed all enriched uranium from Venezuela.

According to the NNSA report, the removal of the material was first discussed during the visit of DOE Secretary Wright to Venezuela in February 2026. The operation involved NNSA's Office of Defense Nuclear Nonproliferation (DNN), US Department of State personnel in Washington and Caracas, and experts from the United Kingdom, the Venezuelan Ministry of Science and Technology, and the International Atomic Energy Agency (IAEA). The material was transferred to the Savannah River Site in the United States.

The removed material is 13.5 kg of uranium "enriched to just above 20%" contained in spent fuel of the RV-1 research reactor at the Venezuelan Institute for Scientific Research (IVIC). The reactor was shut down in 1991.

According to the information released by the US Global Threat Reduction Initiative (GTRI) program in 2015, the United States removed 54 spent fuel assemblies from Venezuela in October 1998 and 2 spent fuel assemblies in November 1999. These assemblies contained US-origin material.

The fuel assemblies removed in this shipment contained HEU supplied by the United Kingdom.

The Belgian Nuclear Research Centre SCK•CEN requested approval from the Federal Agency for Nuclear Control (FANC) to begin operations of its BR2 research reactor with LEU fuel.

The reactor so far has been using HEU fuel with 93% enrichment. The material has been supplied by the United States. The most recent export license to ship the material to Belgium was approved in May 2023. At the time, the material was supplied as fuel assemblies manufactured by U.S. company Babcock & Wilcox.

According to SCK•CEN, three LEU fuel elements were tested in the reactor in 2023. (World Nuclear News reports that three Lead Test Assemblies were delivered in 2025).) If approved, the LEU fuel would be manufactured by French company Framatome.

On 7 April 2026 the Indian government announced that the Prototype Fast Breeder Reactor (PFBR) reached criticality. The 500 MWe reactor is located at Kalpakkam.

Reactor construction began over 20 years ago, in 2004, with a plan to begin operation in 2010 but it has experienced recurring delays. In March 2024 the operator began loading fuel in the reactor. In August 2025 the Department of Atomic Energy announced that the criticality would be achieved in March 2026.

In 2026, India's Parliamentary Standing Committee on Science and Technology, Environment, Forests and Climate Change noted that the cost of the breeder reactor project was now estimated to be over twice the initial planned cost: ₹8,181 crore, compared with an original cost of estimate of ₹3,492 crore. (In purchasing power parity terms, the costs are $3.9 billion and $1.7 billion.)

The Committee also noted that 'fast reactor fuel cycle facility' (FRFCF) to reprocess the breeder's spent fuel was originally to be ready to operate in 2014 but it was now expected to be commissioned in December 2029.

The lengthy delays and cost escalations of the PFBR are illustrative of challenges faced by fast breeder reactors elsewhere. For background on the troubled history and operating experiences worldwide of breeder reactors, see the IPFM report Fast Breeder Reactor Programs: History and Status.

BWX Technologies announced its intent to apply to the US Nuclear Regulatory Commission for a license to build a new enrichment facility. The new plant will be built adjacent to the BWXT Nuclear Fuel Services (NFS) facility in Erwin, TN. The plant is expected to begin operations in 2035.

The company reported that this facility will support the $1.5 billion contract it received in September 2025 as part of a DoE program launched in 2024.

The technology for the facility will be developed at the center BWXT established in Oak Ridge, TN and will be based on the research under the Domestic Uranium Enrichment Centrifuge Experiment (DUECE) that has been carried out at the Oak Ridge National Laboratory since 2016.

On 2 April 2026, Urenco USA announced the completion of the first phase of the expansion plan that it unveiled in 2023. The fourth new centrifuge cascade began operations on 30 March 2026, bringing the total newly installed capacity to 350 tSWU/year (the first three cascades became operational in May, September, and December 2025).

After this phase of expansion, the capacity of the plant in Eunice is estimated to be 4,650 tSWU/year.

According to Urenco USA, another 350 tSWU/year of capacity will be added in 2026-2027. The company also plans to add another 2,100 tSWU/year in the future. [UPDATE: The plan to add 2,100 tSWU/y was announced in June 2026]

If this plan is completed, it would bring the total capacity to 7,100 tSWU/year. The original plan envisioned that the total capacity of the facility would reach 5,700 tSWU/year.