The Armenian government’s decision to prolong the service life of the Armenian NPP until 2026, has been agreed by the European Union (EU) as part of the Comprehensive and Enhanced Partnership Agreement (CEPA), signed last November, Armenian Energy Minister Artur Grigoryan said on 25 May. The news comes despite repeated requests from the EU for the closure of the plant. CEPA will come into force after all 28 EU member states and Armenia ratify it.
The two-unit Armenian NPP was built in the 1970s but was closed following a devastating earthquake in 1988. One of its two VVER 440-V230 light-water reactors (Metsamor 2) was recommissioned with Russian assistance in 1995 in the face of severe energy shortages. The plant currently generates some 35% of Armenia's electricity.
In the long term, the Armenian authorities plan to build a new nuclear plant to replace the ageing facility, but the project has been delayed for financial reasons, and the government decided in March 2014 to extend the plant’s service life to 2026. The service life extension is supported by a Russian state loan of $270m and $30m in grants.
Upgrade scope
Work has already begun and is expected to be completed before the end of 2019 or 2020, after which the projected service life of the station will be extended until 2027. The main contractor for overhauling the station is Rusatom Service, part of the Russian state nuclear corporation Rosatom.
Metsamor 2 comprises a reactor and two turbo-units. In April turbo unit No 4 (turbine, generator, main transformer) was stopped for partial modernisation (replacement of condensers, separators). This work was undertaken by Russian company Atomenergoremont, which has the necessary equipment, labour and material resources, as well as a mostly positive experience of doing such job, plant director Movses Vardanyan told Ria Novosti. On 1 June the reactor and the turbine unit No 3 will be shut down. It is planned to upgrade the high and low-pressure cylinders of turbine 3, and to replace generator 3, current leads, main transformer 3, and auxiliary systems equipment. On 1 August, the unit will be restarted with a partially modernised turbo system 4. The work undertaken in 2018 is expected to result in a 10% increase in output as a result of the increased efficiency of the turbine units, without any increase in fuel consumption. After a major overhaul, from 2020, the plant will be able to produce 10-12% more electricity, Vardanyan noted.
Vardanyan said the work planned for 2019 “will be the most stressful”, and would include the most complicated work on upgrading the safety systems. The aim is to significantly increase in the initial design level of the station's safety. This will involve modernising nine major safety systems, and replacing elements of control and management systems. As the work cannot be completed during a regular repair outage, and the reactor will be shut down for four months (from 1 June to 1 October) in 2019. The power unit will be fully operational by 1 December 2019.
The work is being carried out in two stages. The first stage included a comprehensive survey of the equipment. Some 70,000 items were inspected involving more than 5000 pieces of equipment, to assess the residual life of unchangeable and non-renewable components (reactor plant equipment, main buildings and structures). Schedules for repair, modernisation and replacement of the remaining equipment were drawn up.
Because Metsamor 2 has a first-generation VVER-440 (seismic resistant modification V-270) reactor, the General Designer of the nuclear plant (IAE), the Chief Designer of the NPP (OKB Gidropress) and other specialised organisations had to be involved in the work on a comprehensive survey. These organisations were involved in extending the lifetime of similar power units (Novovoronezh and Kola in Russia as well as VVER reactors in the Czech Republic, Slovakia, Hungary, and Finland).
Significant progress has also been made on the second stage of the programme: agreements have been concluded and are being implemented for the design and supply of necessary equipment and for work to modernise and replace some systems. New generators are being manufactured by OJSC Power Machines from St. Petersburg according to NPP-2006 standards. Because output will increase by several hundred gigawatt hours a year, the plant management expects to recoup the cost of the generators in two or three years. Currently, the average annual production of electricity, depending on the duration of outages, is 2.3-2.5TWh. In 2021, after completion of the extension work, the annual production of electricity is expected to be 3.0-3.3TWh.
"And we can extend the term of the station for more than ten years, said Vahram Petrosyan, director of the Armatom Research Institute for Operation of Nuclear Power Plants. “Work for longer life extension periods is already underway at the Kola and Novovoronezh NPPs in Russia, at the Paks NPP in Hungary."
Intergovernmental agreements with Russia stipulate the extension as operation until September 2026. However, Vardanyan noted that as a result of upgrades and equipment, “we will effectively get an updated turbine department, the service life of which is 30 years. So what happens after 2026 is entirely dependent on justifying the residual life of the non-replaceable equipment (reactor plant equipment). Based on the experience of similar power units with VVER-440 reactors, the project design reserve is enough to operate the reactor plants for a total up to 50-60 years. Any such decision will be made by the Armenian government taking into account technical, economic, energy, and political factors.”
Possible new unit
As to a replacement nuclear plant, Vardanyan said the search for “an acceptable medium power project for Armenia, preferably with a VVER reactor” given the long operator experience with such power units. However power units with VVER-1000 or VVER-1200 and would put a strain on the Armenian power grid which has a capacity of about 2500MWe. Life extension of the existing power unit “will give us enough time to make the most balanced and justified decision in this respect”. Having spent $300m modernising the unit will result in an energy-generating facility that can be operated for another 20-25 years according to its technical parameters. “Ignoring such an opportunity does not look like the best solution.”
Photo: Metsamor NPP