Zaporizhye Nuclear Power Plant, Ukraine

The 6,000MW Zaporizhye Nuclear Power Plant (NPP), located in Energodar in the south-eastern part of Ukraine, is the biggest nuclear power plant in Europe and the fifth biggest in the world.

It is owned and operated by Ukraine's national nuclear energy generating company Energoatom and is one of the four operational NPPs in the country. It produces around half of the country's nuclear power, which accounts for more than 22% of the total electricity produced in the country.

The plant consists of six pressurised water reactor (PWR) units, each with a gross electrical capacity of 1,000MW, which were commissioned between 1984 and 1995. Unit 3 was shut down on 28 November 2014 and put under repair until 5 December 2014 following a short circuit in the plant's transformer yard.

On 3 December 2014, Energoatom confirmed that it was an electrical fault confined only to the power output section, without affecting the reactor, and that the radiation levels around the plant had remained unchanged.

Zaporizhye NPP details and reactors

Each generating block of the plant consists of a VVER-1000/V-320 reactor, K-1000-60/1500-2 steam turbine and a TWW-1000-4 generator. The Soviet-designed VVER-1000s are pressurised water reactors designed to operate for 30 years.The Zaporizhye nuclear power facility is situated on a 104.7ha site on the banks of the Kakhovka reservoir. The Steppe zone of Ukraine was selected because of available infrastructure at the nearby Zaporozhe Thermal Power Plant, with land unsuitable for agriculture and its distance from foreign territories.

Units 1 and 2 are undergoing a lifetime extension, involving the modernisation of equipment and installation of tension sensors and other advanced safety systems, following the March 2011 Fukushima-Daiichi nuclear disaster.

Zaporizhye spent-fuel dry storage facility

Following the breakup of the USSR, spent-fuel could no longer be transported to Russia and the shortage of free space in the cooling pools demanded a spent-fuel dry storage facility (SFDSF) at the site. Zaporizhye is the first Ukrainian nuclear power plant with VVER type reactors to include a SFDSF.

The spent nuclear fuel from the reactors is stored in cooling pools for four to five years until their residual energy and radioactivity decrease. It is then transferred to the SFDSF.

The storage system can accommodate more than 9,000 spent-fuel assemblies in 380 ventilated storage casks. The facility began operations in August 2004 and 80 casks have already been installed on the site.

Zaporizhye NPP history and technical design

The Council of Ministers of the USSR decided to build a series of nuclear power plants, including the Zaporizhye NPP, in 1978 after the first unit of the Chernobyl NPP began operations.

Zaporizhye NPP's technical design of the first stage, consisting of four units with a combined capacity of 4,000MW, was approved in 1980, and the first unit was commissioned in 1984. The second, third and fourth units were commissioned in 1985, 1986 and 1987 respectively. Meanwhile, the second stage, involving two additional power units with similar reactors, was proposed in 1988 and the fifth unit was commissioned in 1989.

The Chernobyl nuclear disaster prompted the Supreme Council of Ukraine to order a moratorium in 1990 on the construction of new nuclear power units in Ukraine, which led to the suspension of construction work on Unit 6. Severe winters and increasing electricity demand resulted in the lifting of the moratorium, clearing the way for the construction of the Unit 6. The unit was finally grid-connected in 1995, becoming the first nuclear reactor unit in an independent Ukraine.

Contractors involved with the Ukrainian nuclear power plant

Kharkov Scientific Research & Design Institute 'Energoprojekt' (HIEP), Duke Engineering & Services (DE&S) and Sierra Nuclear Corporation (SNC) were involved in the design, construction, testing and operation of the spent-fuel dry storage facility.The VVER-1000 reactors were manufactured by Russian heavy engineering firm Izhorskiye Zavody. Kharkiv turbine plant, now called Turboatom, supplied the 1,000MW steam turbines. Russian engineering company AtomEnergoproekt designed the Zaporizhye nuclear power plant.

HIEP was the general consultant for the design and construction of the facility, while DE&S was responsible for the project development, logistics, construction supervision, licensing, quality assurance, commissioning and maintenance of the systems and equipment. SNC supplied the dry cask storage system for the spent-fuel.

Westinghouse Electric Company was awarded a contract by Energoatom to provide a passive hydrogen control system for Units 1 and 2 to enhance the plant's safety. A contract extension agreement was also signed between the two companies in April 2014 for fuel deliveries to the Ukrainian nuclear power plants through to 2020.

Before the annexation of Crimea, Ukraine depended on Russian nuclear fuel company TVEL for the supply of enriched fuel.