A method was developed for the analysis of a once-through steam generator that is based on a multinode movable boundary formulation and an accurate description of the departure from nucleate boiling boundary. In the development of this method, a liquid-metal reactor steam generator was used as a reference design. To evaluate its performance, the Energy Technology Engineering Center steam generator shutdown experiment in the once-through mode was analyzed. Also, the predictions of this method were compared with those of another steam generator code. These analyses showed that the predictions of this methodology agree very well with the experimental measurements and the predictions of the other code. The maximum difference between the temperatures predicted by this model and measurements was ∼5 K.