To solve a problem wherein a conduit route cannot be appropriately designed due to difficulty in specifying, in a conduit route design stage, the dispersed state of lightning surge current generated in a building and a place where propagation to a weak signal circuit occurs although there is a possibility of the weak signal circuit malfunctioning or failing due to the influence of the lightning surge current generated in the building when a nuclear power plant is struck by lightning.

This analytic evaluation system for conduit route design for evaluating whether there is a possibility of causing malfunction of the weak signal circuit because a conduit route of the weak signal circuit input as design data is influenced by the lightning surge current generated when lightning strikes, is constituted by combining a database 1 storing design data of a structure in the nuclear power plant, an analytic model 2 that can evaluate the dispersed state of the lightning surge current when lightning strikes while reflecting the design data, and an analytic model 3 that can quantitatively evaluate the influence of a current flowing in the structure, upon the weak signal circuit through a conduit.