Putting Akkuyu on firm foundations

The project is being developed by Akkuyu Nuclear JSC, a subsidiary of Russian state nuclear corporation Rosatom, as part of a 2010 intergovernmental framework agreement between Russia and Turkey. Once complete, the station will comprise four 1200 MWe VVER-1200 reactors, the reference units being those at Novovoronezh II, where the first reactor has been in operation since 2017 and the second is under commissioning.

The aim is to complete the first reactor at Akkuyu in 2023 – the same year the Republic of Turkey celebrates its 100th anniversary. This schedule is “very ambitious,” admits Mikhail Cherdantsev, deputy director for construction works at Akkuyu, but the project will be able to benefit from experience elsewhere. Cherdantsev, for example, has been at Akkuyu since 2014, bringing experience as former head of design for Novovoronezh II and from another export project at Bushehr in Iran. Also, Rosenergoatom, Russia’s nuclear power plant operator, is acting as a consultant for the Turkish project, bringing invaluable experience from new-build projects in Russia, particularly the reference units at Novovoronezh II.

While the goal of 2023 remains “possible,” the official target in the intergovernmental agreement is reactor start-up seven years after receipt of the construction licence. This means Akkuyu 1 should be commissioned no later than March 2025, with the remaining three units expected to follow at yearly intervals.

The specific features of the Turkish site, such as its geographic location and climatic conditions mean that there are slight differences from the reference units at Novovoronezh in Russia. For example, on the conventional side, the service water supply system for Akkuyu will involve the use of desalination complexes, and cooling will be from the sea rather than large evaporative cooling towers.

The VVER-1200 design incorporates both active and passive safety systems and includes a “wide range of design, engineering and organisational measures” to address source events, root causes and consequences of a Fukushima type accident.

Passive heat removal systems, for example, ensure core cooling for at least 72 hours, including during blackout. The design also incorporates hydrogen recombiners to prevent the formation of explosive hydrogen inside the containment, and includes a “core catcher”.

To withstand potential tsunamis and floods the plant is being built at +10.5m above sea level. It is also designed to withstand wind speeds up to 56 m/s, aircraft impact with a velocity of 200 m/s, external explosion, abnormal snow and ice loads, and earthquakes – a particular concern in Turkey – with extensive seismic surveying of the site. Seismic resistance remains under close attention and control of the Turkish Atomic Energy Authority (TAEK) and the IAEA, which, along with other organisations, have completed more than ten site inspections.

Atomenergomash is supplying the reactor pressure vessel, reactor coolant pumps, and steam generators for Akkuyu along with the core catcher, which is expected to be the first unit 1 component to arrive on site, in June. The conventional island equipment for Akkuyu is being supplied by AAEM, a joint venture between Atomenergomash (part of Rosatom) and General Electric (which took over Alstom’s steam turbine activities in 2015). Under a 2017 subcontract AAEM will design and supply Arabelle half speed steam turbines, Gigatop generators, moisture separator reheaters and condensers, with deliveries scheduled for 2021-2024.

In addition to being Turkey’s first nuclear plant (after about 50 years of deliberation), Akkuyu is the world’s first nuclear project to be implemented on a BOO (build–own–operate) scheme. This investment model will see Russia finance, manage the project and act as the reactor operator.

As part of the intergovernmental agreement, a 15-year power purchase agreement is in place with the Turkish Electricity Trade and Contract Corporation (TETAS) which guarantees the purchase of 70% power generated from the first two units at Akkuyu and 30% from the third and fourth units. Electricity will be purchased for 12.35¢/kWh, with the remaining electricity to be sold in the open market by the producer.

Rosatom may sell a stake of up to 49% to other parties who wish to invest in the project, and says that negotiations with potential investors are “in progress”.

The Akkuyu plant and the BOO model could become the benchmark for future Russian export projects.

Akkuyu is just one of an impressively large number of nuclear projects that Rosatom is currently working on – 36 overseas and six in Russia, according to its website.

These include the world’s only floating nuclear power plant, the Akademik Lomonosov (pictured below), scheduled to be deployed during 2019 to provide heat and power to the Pevek region in the far north, replacing the aged Bilibino (nuclear) and Chaunsk plants.