Several methodological attempts were made to assess the potential impact of a planned wind turbine on the operational work of weather radar. International recommendations for co-location have been established and incorporated in many countries. The main point of these recommendations states that the location of a wind turbine any part of which reaches RLOS (Radar Line Of Sight) requires the analysis of its impact on radar performance. The growing number of applications for the technical assessment of planned wind farms demand the use of a simple method of calculation for the first step of the authorization process. A typical wind turbine consist of several metallic parts. Based on the assumption that only moving, metallic parts of a turbine cause echoes indelible by standard filtering used in radar signal preprocessing, a method of preliminary evaluation of such maximum potential clutters was developed. The method takes into account how great a part of turbine is really illuminated by a radar beam and for this part calculates a RCS (Radar Cross Section) and its equivalent radar reflectivity. A very detailed description of the model is given in this article in order for it to be easy to implement in any calculation system. Discussion of the influence of the main simplifications assumed in this model, as well as a comparison of the theoretical results with example data in operational mode of radar work, are included in this article.