Andrey Dementiev
Department Head, Life Extension, Modernization and Planning Department for Nuclear Power Plants
ROSENERGOATOM Group OJSC
Extending the operating life of existing nuclear power stations is a cost effective investment for the preservation of their generating capacities. In addition to the construction of NPP’s, extending the life of existing nuclear power stations has become an important trend in the development of the nuclear power industry. Currently, a programme to this end is in effect in Russia.
When the 30 year life span was originally estimated in the 1950’s and 60’s, no actual performance data was available on wear and tear and lifespan issues. With the experience gained in the operation of the nuclear power stations, we can now reassess the potential lifespan of the equipment and power generating units. Moreover, the financial outlay for obtaining the ROSTEKHNADZOR licences for equipment that has had its life extended is significantly less than the expenses required for the construction of new power generating units.
To date, life extension works have been carried out on 14 power generating units, with a total capacity of 7 362 mW. By January 1, 2010, power generating units with extended operating life generated roughly 158 billion of kWh of electric power, which is comparable with the annual output of all nuclear power stations in Russia.
Fig. 1: Scenario for retiring the generating capacities of nuclear power stations in Russia
In compliance with federal regulations concerning nuclear power use, life extension works will be carried out in two stages. The first stage includes developing the project itself; multipurpose surveys, evaluating the safety of the power generating unit, assessing the cost effectiveness of life extension works, operating life and design development. The second stage is the actual project implementation, which includes evaluating the remaining residual life of the non-replaceable equipment, the modernisation of equipment with the aim of improving safety in the power generating units, replacing the equipment with no service life left, preparing the safety documentation for the rehabilitated equipment (detailed assessment of safety) and also, arrangements for the issue of ROSTEKHNADZOR licenses for the extended operation life time. The life extension project is carried out in close cooperation with world renowned scientific and design organisations such as the Experimental Design Bureau GIDROPRESS, the Kurchatov Institute, NIKIET (Power Engineering Research and Design Institute), VNIIPIET (Russian National Design and Scientific Research Institute of Complex Power Technology), Physics of Power Engineering Institute, CNIITMASH (Central Scientific Research Institute of Engineering Technology), VNIIAES (Russian National Scientific Research Institute for the Operation of Nuclear Power Stations), among others.
As a result of large-scale modernisation, the safety level of the 14 power generating units with extended operating life has significantly increased and have achieved targets recommended by International Atomic Energy Agency (IAEA) for nuclear power stations.(Pic 2).
Fig. 2: Modernisation within the framework of tidal power stations; results & probability of severe damage to active zone
Following feasibility studies carried out after the life extension works, the 14 power generating units have been approved for an additional period of 15 years. According to current knowledge and requirements, the additional 15-year operating life of the power generating units is based on the remaining life of critical components (pressurised water reactor body and graphite stack).
When evaluating the cost effectiveness life of extension projects for NPP’s, it is plain to see the ROI. Assessing the projects to date, investments made into the modernization and rehabilitation of NPP’s are not only very cost effective, but a great option in terms continued safety, the most important factor in any part of the nuclear industry.
The duration of the additional operating life is the key indicator when determining the cost effectiveness of the power generating unit life extension programs. When taking everything into account, an economically feasible extension time is from 15 to 30 years and is determined for each specific case on the basis of technical and economical factors.
The operating life of five power generating units in the following 2nd generation nuclear power station will be extended for between 15 and 30 years: No 4 of the Leningradsky (High Power-Pressure Tube-Reactor-1000), No 5 of Novo-Voronezhsky (Pressurised Water Reactor -1000), No 3 of Beloyarsky (Fast-Neutron Reactor-600), No 3 of Kolsky (Pressurised Water Reactor-440), No 1 of Smolensky (High Power-Pressure Tube-Reactor-1000). Preparation works will also be carried out on another six power generating units.
Regarding experience exchange on the life extension of power generating units, ROSENERGOATOM Group works in cooperation with foreign partners such as NAEK ENERGOATOM Ukraine, the KOZLODUY Nuclear Power Station in Bulgaria, EDF (France) and operating organisations in Czech Republic, Slovakia, Spain, etc. Cooperation with foreign companies also takes place during project implementation – equipment from foreign manufacturers, including Ukraine, Germany, Croatia and other countries, is used.
In addition to these life extension projects, other measures such as the improvement of reactor thermal output have been carried out. Such measures provided for an increase in capacity of 1800 mW from 2007 to 2009.
As of today, based on test results carried out during experimental production, the following power generating units have increased capacity: No 2, 3 and 4 of Balakovskaya and No 1 of Rostovskaya nuclear power stations – 104% of the nominal capacity, unit No 1 of Kurskaya nuclear power station – 105 % of the nominal capacity.
We are planning to switch the following power generating units to experimental production at an increased level of capacity by the end of 2010: No 3 and 4 of Kolskaya nuclear power station, No 1 of Balakovskaya nuclear power station and No 3 of Kalininskaya nuclear power station, unit No 2 of Kurskaya power station and unit No 2 of Leningradskaya power station.
The Kurchatov Institute and VNIIAES (Russian National Scientific Research Institute for the Operation of Nuclear Power Stations) evaluated the capacity for the VVR1000. The possibility, and indeed economic viability of a capacity increase, up to 110% from current output (reference – unit No 4 at the Balakovskaya nuclear power station) will also be used in the development of new nuclear power station designs. These upgrades are planned for between 2010 – 2014.
The activities we are carrying out to extend the operating life of Russia’s existing Nuclear Power
Plants and the subsequent increase in power production provides for a number of additional opportunities in the development of the whole industry, and indeed makes a considerable contribution into the Nuclear Renaissance.
