Akkuyu Unit 1 Clears Hydraulic Tests, Moving Closer to Fuel Loading
Rosatom has completed primary-circuit hydraulic testing on Unit 1 of Turkey’s Akkuyu nuclear power plant, clearing the way for hot functional tests, the final major check before nuclear fuel is loaded into the reactor. The milestone, announced by Rosatom director general Alexey Likhachev on October 9, moves Turkey’s first nuclear power station a step closer to supplying electricity before the end of 2026.
What the test checked
Technicians filled the primary circuit with chemically demineralised water and used the plant’s main circulation pumps to raise pressure to 24.5 megapascals, roughly 1.5 times the pressure the reactor will see in normal operation, while bringing the coolant to an initial 135°C. During full-power operation, Akkuyu’s VVER-1200 reactor is designed to run its coolant up to about 330°C at 16 MPa. The test also brought the unit’s automated process control system online for the first time, a system that will monitor and manage reactor operations once the plant is running.
“The safe operation of the entire unit depends on the reliability of the primary circuit,” Likhachev said, confirming that the testing had been completed successfully. Rosatom did not release a specific completion date beyond the October 9 announcement.
Where this fits in the startup sequence
The primary-circuit hydraulic tests followed cold hydraulic tests, which began in June after dummy fuel assemblies were loaded to simulate the reactor core. Those earlier tests checked the leak-tightness of the circuit and flushed the main coolant pipes. With hydraulic testing now done, Akkuyu moves to hot functional tests, which will run the four main circulation pumps at temperatures of at least 260°C to confirm the unit’s systems can handle real operating conditions. Only after hot testing is complete does the plant load actual nuclear fuel and begin the physical startup process.
A long-delayed first for Turkish nuclear power
Akkuyu, being built on Turkey’s Mediterranean coast in Mersin province under a 2010 intergovernmental agreement with Russia, is Turkey’s first nuclear power plant and is being built, owned and operated by Rosatom under a build-own-operate model. Turkey issued the construction licence for Unit 1 in 2018, and nuclear fuel first arrived on site in April 2023. When complete, the plant’s four VVER-1200 units will have a combined capacity of 4,800 MWe, which Rosatom and Turkish officials say will cover roughly 10% of national electricity demand, a trajectory tracked in detail on The Daily Energy’s Akkuyu project tracker. Ankara has repeatedly pushed back the target date for first power from Unit 1 as construction and commissioning milestones slipped; Rosatom’s current guidance points to grid connection before the end of 2026, though the company has not set a firmer date pending the outcome of hot testing and fuel loading.
Rosatom and Turkish authorities are also advancing plans for a second Turkish nuclear plant at Sinop and have discussed a possible third site in the Thrace region with Chinese partners, alongside a separate agreement with the United States to study nine small modular and next-generation reactor designs for domestic deployment by 2050.
Why it matters for Turkey’s energy mix
Turkey currently imports the bulk of the natural gas and coal it burns for power, and Akkuyu is central to Ankara’s strategy for cutting that import bill while diversifying away from gas-fired generation. A successful hot-test campaign and fuel loading this autumn would put Unit 1 on track to become the country’s first operating reactor, a milestone that has already slipped several years past its original 2023 target date tied to the centenary of the Turkish republic. It would also arrive as other new nuclear newcomers move through similar late-stage testing, including China’s newly grid-connected Tianwan 7 reactor.
Sources
World Nuclear News, “Hydraulic tests completed at Turkey’s Akkuyu 1,” October 9, 2026, for test details, pressure/temperature figures and the Likhachev quote. Atommedia.online (Rosatom press materials) for background on the cold hydraulic test phase and commissioning sequence. World Nuclear News, “Akkuyu 1 set for next stage of pre-commissioning activities,” for construction licence and fuel delivery history.
Illustrative image. Photo: Rosatom Digital Press Office/АО «Аккую Нуклеар», CC BY 4.0, via Wikimedia Commons — source
