Pakistan has moved nuclear power from a small experimental role into the centre of its electricity system. Six reactors now operate at two sites, with a combined net capacity of 3,262 megawatts. Four smaller units are located at Chashma in Punjab, while two Generation III reactors operate on the coast near Karachi. Together, the plants supplied more than 22 billion kilowatt-hours to the national transmission system in 2024 and accounted for 18.3% of Pakistan’s electricity mix.
The fleet is also expanding. A fifth unit at Chashma is under construction, adding a further 1,200 MWe of gross capacity. This project continues a long civil nuclear partnership with China, which has supplied reactor technology, fuel, engineering support, and financing. Pakistan’s nuclear program is therefore best understood as a mature operating system with a concentrated foreign partnership, rather than as a collection of isolated plants.
Karachi Changed the Scale of Pakistan’s Nuclear Fleet
Pakistan’s first commercial reactor, KANUPP-1, began operating near Karachi in 1971. The Canadian-designed pressurized heavy-water reactor was small by modern standards and spent its later years operating at reduced power. It closed permanently in August 2021 after 50 years and entered decommissioning.
The site did not disappear with the retirement of the original unit. It was transformed by K-2 and K-3, two Chinese-designed pressurized water reactors with gross capacities of 1,100 MWe each. K-2 entered commercial operation in 2021, followed by K-3 in 2022. The pair now provides almost two-thirds of Pakistan’s gross operating nuclear capacity.
K-2 and K-3 use the ACP1000, or Hualong One, design. The reactors introduced larger unit sizes and Generation III safety features, including passive systems intended to perform important functions without external electrical power or immediate operator action. Their completion changed the national fleet from one dominated by small and medium-sized reactors into one where two large coastal units provide the majority of nuclear generation.
The Karachi site also requires high-capacity transmission, cooling systems, emergency planning, security, fuel logistics, and a skilled workforce. Its proximity to Pakistan’s largest city makes regulatory performance especially important.
Chashma Provides the Operating Backbone
The Chashma Nuclear Power Generating Station near Mianwali is the more established centre of Pakistan’s current reactor program. Its four operating pressurized water reactors entered service between 2000 and 2017. C-1 and C-2 each have gross capacities of 325 MWe, while C-3 and C-4 each provide 340 MWe.
These units are smaller than the Karachi reactors, but their operating performance makes them important sources of steady electricity. In 2024, each Chashma unit generated more than 2,200 GWh, with reported capacity factors ranging from about 80% to more than 90%. Their combined output gives the grid a block of low-carbon generation that is not exposed to daily weather conditions or international fossil-fuel price swings.
Chashma has also allowed the Pakistan Atomic Energy Commission to build capabilities in operations, maintenance, refuelling outages, component supply, and technical services. Repeated expansion at one site preserves an experienced workforce and reuses established transmission, security, and support systems.
Chashma-5 Extends the China-Pakistan Nuclear Partnership
C-5 is the next major step. The unit is listed by the IAEA as a 1,117 MWe net pressurized water reactor, equivalent to 1,200 MWe gross. Its construction will increase the scale of the Chashma site sharply and bring a large Generation III unit into a complex previously built around smaller reactors.
The project reflects the structure of Pakistan’s nuclear supply chain. China has remained the country’s principal external partner because Pakistan is outside the Nuclear Non-Proliferation Treaty and faces restrictions on nuclear trade through the Nuclear Suppliers Group. Most major suppliers do not sell nuclear plants or fuel to Pakistan. China has continued cooperation under agreements that it considers consistent with its earlier commitments.
This concentrated partnership provides reactor designs, project support, financing channels, training, and fuel from a supplier familiar with Pakistan’s institutions. It also creates dependence: enriched fuel is imported from China, and future expansion remains closely tied to Chinese technology and finance.
Nuclear Power Addresses Fuel Risk as Well as Carbon Emissions
Pakistan’s electricity system has long been exposed to imported oil, liquefied natural gas prices, currency pressure, hydrological variation, transmission losses, and the financial weakness of the power sector. Nuclear generation does not solve all of these problems, but it provides a different risk profile.
Nuclear fuel can be stored for long operating cycles, reducing immediate exposure to short-term fossil-fuel price shocks. Continuous generation also supports industrial demand without frequent fuel purchases.
The value is visible in the generation mix. Nuclear power supplied 18.3% of Pakistan’s electricity in 2024, despite representing a smaller share of installed national capacity. High annual output from the six reactors gives nuclear energy a system role comparable to much larger capacity categories that operate less consistently.
However, nuclear construction requires high initial capital spending, long project schedules, and strong institutions. Pakistan’s wider power sector already carries substantial payment arrears and tariff pressure. New reactors must therefore be evaluated not only by their operating cost but also by financing terms, foreign-exchange exposure, construction performance, and the cost of connecting them to the grid.
Regulation, Safeguards, and Waste Management Define the Next Stage
The Pakistan Atomic Energy Commission owns and operates the civilian nuclear fleet, while the Pakistan Nuclear Regulatory Authority is responsible for licensing and oversight. Pakistan’s civilian power reactors are subject to item-specific IAEA safeguards, as are its two research reactors. These arrangements allow the IAEA to verify the peaceful use of safeguarded nuclear material and facilities.
Pakistan’s position outside the NPT continues to shape trade restrictions. Although its civilian reactors are safeguarded, the absence of comprehensive safeguards limits access to the wider international nuclear market.
Waste management is another long-term requirement. Used fuel is stored at reactor sites, initially in pools, and longer-term dry storage has been proposed. Dedicated waste-management centres have also been planned for Karachi and Chashma. As the fleet grows and older reactors move toward retirement, Pakistan will need durable funding, regulation, storage, and decommissioning arrangements rather than project-by-project solutions.
KANUPP-1 is the first major decommissioning test and can provide experience for the eventual retirement of other units.
Pakistan Is Building Depth, Not Just Capacity
Pakistan’s nuclear program now has a clear operating logic. Karachi provides large modern reactors, Chashma provides a long-running multi-unit base, and C-5 extends the fleet with another high-capacity unit. The country has also developed domestic operating and maintenance skills, even though reactor technology and enriched fuel remain closely tied to China.
The most important future question is whether Pakistan can convert this technical continuity into financially sustainable expansion. Nuclear power already makes a significant contribution to electricity supply and limits some exposure to imported fossil fuels. Further growth will depend on project finance, grid investment, regulatory capacity, waste management, and the continued performance of the existing fleet.
C-5 will be the immediate measure of that strategy. If it is completed on schedule and operates reliably, it will strengthen nuclear energy’s position as one of Pakistan’s principal sources of low-carbon baseload electricity. If costs or financing become difficult, the project will also show the limits of expanding a capital-intensive technology inside a financially stressed power system.
