Friday, September 4 2020 13:15

ArmInfo. An installation for the reduction annealing (heat treatment) of the reactor vessel metal was delivered to the Armenian NPP. The plant will be prepared  for the final part of the work on extending the service life, which  will take place in 2021 - the reactor will be annealed, which will  return it to its original state by 80-85%.

Reactor annealing is the most effective way to restore the  physicomechanical properties of the reactor vessel metal, which  change during operation under the influence of constant radiation  exposure. The reactor vessel is the "heart" of the power unit, and it  is its resource that determines the period of the station's operation  extension.

The body is annealed with complete unloading of fuel assemblies (FA)  into the spent fuel pool. This is necessary for inspection of the  vessel and installation of the annealing unit inside the reactor  vessel. Using an annealing unit, the reactor vessel is heated to a  temperature of 475 degrees, kept at this temperature for several  days, after which it slowly cools down. The structure of the metal  restores its properties, which increases its service life.

The procedure will be carried out by several organizations, each of  which is responsible for its own area of work. The technology has  been developed and the necessary calculations are being made by the  National Research Center "Kurchatov Institute", OKB "GIDROPRESS" and  TsNIIKM "Prometey", and the enterprises - "Atomenergoremont" and  "TsNIITMASH" will perform work at the station itself.

For the first time, the technology of the reduction annealing of the  reactor pressure vessel metal was applied in 1987 at the third power  unit of the Novovoronezh NPP. Now this procedure is being carried out  at all stations where the service life is being extended. Reduction  annealing has already been carried out at VVER-440 reactors of such  nuclear power plants as Kola NPP (Russia), Rovno NPP (Ukraine),  Kozloduy NPP (Bulgaria) and Loviisa NPP (Finland).

Let us remind that recently the Armenian NPP after scheduled  preventive maintenance was connected to the country's energy system.  For the fifth year now, the Armenian NPP has been combining scheduled  preventive maintenance with the implementation of a program to extend  the life of the second power unit of the plant. A budget loan of 63.2  billion drams (about $ 130 million) will be provided to complete the  station's program. For the implementation of the program, Armenia  previously attracted a loan of $ 270 million from the Russian  Federation and a grant of $ 30 million, and as of today the residual  resource of these funds was $ 107 million. For objective and  subjective reasons, it was not possible to agree with Russian  partners on this residual resource. For this reason, a decision was  made to attract a budgetary loan of 63 billion drams. In 2020, the  Armenian NPP will receive 18.7 billion drams from these funds, in  2021 - 31.5 billion drams and in 2022 - 13 billion drams. The  maturity of each tranche is 12 years, of which the first 2 years will  be concessional. The interest rate will be equivalent to the interest  rate of the borrowed funds of the Russian Federation raised earlier.  The loan is provided without collateral. The Ministry of Finance of  the country will issue government treasury bonds under the program.  Within the framework of the project, it is also envisaged to form an  interdepartmental tender commission, which will carry out all tender  procedures and monitor the process of implementing the program.