ASYNT - AN ADJOINT SYNTHESIS METHOD FOR NEUTRON-IRRADIATION ESTIMATION ON THE VESSELS OF VVER PWR REACTORS/

The new ASYNT method is developed and proposed for neutron fluence cal culations. This method uses the solution of adjoint neutron transport equation for flux/responses evaluation. The evaluation of flux/respons es is reduced to the space and energy integration of the product of 3D adjoint solution and the neutron source distribution, determined by r ealized loading patterns and operational regimes. The adjoint solution does not depend on the neutron source distribution and is obtained on ly once for every surveillance site, response and type of reactor. The application of this method results in separability of azimuthal and a xial dependence in the 3D adjoint solution. That is why the 3D adjoint solution could be synthesised from the 2D and 1D adjoint solutions. T he circular cylinder reactor core presentation of the solution axial d ependence is the only approximation used in the ASYNT method. (C) 1997 Elsevier Science S.A.