[en] The purpose of this report is to present the RELAP4/MOD6 model developed to study small break transient tests in LOFT. This 19 volume model was based directly on the more detailed 53 node and 29 node models currently in use. Comparisons between LOFT model predictions and data taken from Semiscale Test S-02-6 were completed to show that the model adequately handles small break hydraulic phenomena. A communicative break model based on this small break model was developed and a comparison was made between the two. While the communicative break calculations showed a slower transient, the phenomena seen were basically identical. Therefore, a plant modification to LOFT was not recommended