Solution of the $nd$ scattering problem at the deuteron breakup energy by the boundary condition method

Wave function of three-nucleon system is calculated in the region of configurational space outside of the sphere of radius $R$, taking into account spin and isospin variables. The approximation $R\gg r_0$ where $r_0$ is the range of interaction potential, is used. Potential is taken into account in the approximate way, by means of prescribing the values of logarithmic derivatives of the wave function components. In the approximation considered these values are the same as in the two-body problem. As a result, the wave function is found in the form of the expansion, the coefficients of which are determined from the condition of matching with the linear combination of finite solutions for the region $r\ll R$. These coefficients are not found, but still it is shown that the expansion obtained describes larger set of asymptotic states of the wavefunction.