[en] This paper presents the results of a semiscale Mod-1 blowdown heat transfer test conducted to supply thermal-hydraulic data concerning the fluid phenomena that occur during a small break LOCA. The small break, although more likely to occur than a large break, does not appear from the test results to be as severe a LOCA as the large break. Results of the semiscale test add significantly to the scant data base available on small break loss-of-coolant experiments. (author)