Turkey's Akkuyu 1 passes primary-circuit pressure tests; hot tests come next

Victoria Shinder12 October 2026, 08:282 min read

Hydraulic tests of the primary circuit at unit 1 of the Akkuyu nuclear power plant in southern Turkey have been completed, World Nuclear News reported on 9 October, citing Rosatom. The step clears the way for hot functional tests, the last major test series before nuclear fuel is loaded.

What was tested. The primary circuit — the reactor vessel, the main circulation pumps, the steam generators, the pressuriser and the main pipework connecting them — was filled with chemically demineralised water and pressurised to 24.5 MPa, about one and a half times the reactor's normal operating pressure of roughly 16 MPa. Water temperature at the initial stage reached 135°C. Pressure and temperature were produced by the unit's own main circulation pumps, and control-room staff monitored equipment and piping through the plant's automated process control system, which was put into operation during the tests.

Where this sits in commissioning. The cold tests began in June, after dummy fuel was loaded. Their purpose is to confirm that safety-relevant components are installed correctly, that the primary circuit is leak-tight, and to clean the main circulation pipes; it is also the first time the reactor systems run together with auxiliary systems. Hot functional tests follow, checking equipment under operating conditions, including all four main circulation pumps at 260°C or more. Both cold and hot tests take place before fuel loading. Rosatom's director general Alexey Likhachev called the result confirmation of the quality of installation and welding and "another step towards the unit's physical startup".

The project and its schedule. Akkuyu, in Mersin province, is Turkey's first nuclear plant: four VVER-1200 reactors, 4,800 MWe in total, built by Rosatom under a build-own-operate model — the Russian side owns and runs the plant and sells the power. Once complete it is expected to cover about 10% of Turkey's electricity. The construction licence for unit 1 was issued in 2018, and fuel arrived on site in April 2023. The 2010 intergovernmental agreement aimed for unit 1 to be commissioned within seven years of all permits; the current aim is for it to start supplying the Turkish grid by the end of 2026, which leaves under three months for hot tests, fuel loading, physical startup and first power.

Turkey also plans a second plant at Sinop and has held talks with China about a third.

Source: World Nuclear News, 9 October 2026 — https://www.world-nuclear-news.org/articles/hydraulic-tests-completed-at-turkeys-akkuyu-1