ASYNT — An adjoint synthesis method for neutron irradiation estimation on the vessels of VVER/PWR reactors Original Research Article

The new ASYNT method is developed and proposed for neutron fluence calculations. This method uses the solution of adjoint neutron transport equation for flux/responses evaluation. The evaluation of flux/responses is reduced to the space and energy integration of the product of 3D adjoint solution and the neutron source distribution, determined by realized loading patterns and operational regimes. The adjoint solution does not depend on the neutron source distribution and is obtained only once for every surveillance site, response and type of reactor. The application of this method results in separability of azimuthal and axial dependence in the 3D adjoint solution. That is why the 3D adjoint solution could be synthesised from the 2D and 1D adjoint solutions. The circular cylinder reactor core presentation of the solution axial dependence is the only approximation used in the ASYNT method.