Akkuyu’s First Reactor Clears Containment Test, Nears 2026 Startup

Turkey’s first nuclear power plant has cleared one of the final engineering hurdles before fuel loading, as the operator of the Akkuyu plant confirmed that the inner containment building of Unit 1 has passed its strength and leak-tightness tests. The eight-day test campaign, completed this week, pushes the Russian-built project a step closer to a long-delayed goal: putting electricity from Turkey’s first reactor onto the national grid before the end of 2026.

Akkuyu Nuclear JSC, the Rosatom subsidiary that owns and operates the plant under a build-own-operate agreement with Ankara, said engineers raised the air pressure inside Unit 1’s containment structure to 0.46 megapascals — equivalent to a load of about 47 tonnes on every square metre of the containment surface — before stepping the pressure back down in stages, including to below atmospheric level. Leak-tightness was checked at both the elevated and the reduced pressure points.

What the test confirms

The containment building is the last physical barrier between a reactor core and the outside environment, so regulators and operators treat its pressure integrity as a non-negotiable precondition for loading fuel. “The results confirm the high quality of the containment construction work,” Akkuyu Nuclear CEO Sergei Butckikh said, adding that the plant can now move to the next stage of pre-startup commissioning, according to World Nuclear News, which first reported the test results on November 13.

That next stage covers cold and hot functional testing of the reactor plant. Cold functional tests are designed to verify the leak-tightness of the primary circuit — the loop that will carry radioactive coolant once the reactor is running — while hot functional tests check how systems behave under operating temperatures and pressures before fuel is loaded. Akkuyu Nuclear has not given an exact date for fuel loading.

A multi-year build nearing its payoff

Akkuyu’s Unit 1 has been under construction since 2018, when Turkey’s nuclear regulator issued the construction licence. Nuclear fuel assemblies were delivered to the site in April 2023, and a commissioning permit followed in December 2023, authorising the start-up and set-up processes that have continued through this year. In late October, Akkuyu Nuclear reported that hydraulic strength tests on the unit’s secondary circuit equipment — the systems on the non-radioactive side of the steam cycle — had also been completed successfully, one of several milestones that have fallen into place in the run-up to this week’s containment test.

The plant itself is bigger than Unit 1 alone. Rosatom is building four VVER-1200 pressurised water reactors at the Akkuyu site in Mersin province, with a combined capacity of 4,800 megawatts. Work on the other three units is running in parallel: first concrete for Unit 4 was poured in July 2022, and concrete work on that unit’s turbine foundation was completed in early November. Once all four units are operating, Akkuyu is expected to meet roughly 10% of Turkey’s electricity demand.

Why Ankara is watching the schedule closely

Turkey imports the large majority of the oil and gas it consumes, and successive governments have cited that exposure as a strategic vulnerability. Akkuyu sits at the centre of the country’s response: Ankara has set out a $500 billion energy investment plan aimed at cutting import dependence by 2040, and it has lined up additional nuclear capacity beyond Akkuyu, including a financing arrangement with South Korea for further reactor projects. Turkey was also among the 39 countries that used the COP31 summit to back a global pledge to triple nuclear capacity by 2050, a sign of how central atomic power has become to the country’s energy diplomacy.

Akkuyu is built and financed under a build-own-operate model unusual in the nuclear industry: Rosatom owns the plant outright and sells the power it generates to Turkey under a long-term pricing agreement, rather than Turkey financing construction directly. That structure has let Ankara add roughly 4.8 GW of low-carbon, dispatchable capacity without taking on the project’s construction risk directly, though it also means Turkey’s long-term exposure to a single foreign state-owned operator for a strategic share of its power supply.

What comes next

With the containment tests behind it, Unit 1 moves into cold and hot functional testing — steps that typically take weeks to a few months at comparable VVER-1200 projects before fuel loading can begin. Turkish officials have repeatedly pointed to the end of 2026 as the target for Unit 1 to start supplying power to the grid; the pace of the remaining commissioning steps over the coming weeks will show whether that timeline holds.

Sources

• World Nuclear News, “Strength and leak tests completed for Akkuyu 1 containment,” November 13, 2026 — test parameters, CEO quote, commissioning sequence. world-nuclear-news.org
• Akkuyu Nuclear JSC, project news, November 2026 — operator statement on test results. akkuyu.com
• World Nuclear News, “Hydraulic tests completed at Turkey’s Akkuyu 1,” October 2026 — secondary circuit test background.
• Istanbul Ticaret Gazetesi and Mersin Portal, November 12, 2026 — independent Turkish-language reporting on the same test results.

Illustrative image. Photo: Rosatom Digital Press Office/АО «Аккую Нуклеар», CC BY 4.0, via Wikimedia Commons — source