[en] This report presents the experimental data of RUN 928 conducted at the ROSA-III test facility. The facility is a volumetrically scaled (1/424) simulator for a BWR/6 with the electrically heated core, the break simulator and the scaled ECCS(emergency core cooling system). RUN 928 was a 50 % split break test at the recirculation pump suction line with an assumption of HPCS diegel generator failure and conducted as one of the break configuration sensitivity tests. A long throat nozzle was used for a break plane. A peak cladding temperature (PCT) of 888 K was reached at 198 s after a break during the reflooding phase. Whole core was completely quenched by ECCS, and the effectiveness of ECCS was confirmed. The primary test results of RUN 928 are compared in this report with those of RUN 916, which was a 50 % split break test with an orifice as the break plane. The initiation of core dryout in RUN 928 was slightly later than that in RUN 916 because of the smaller subcooled break flow rate. Duration of core dryourt was, however, almost the same between the two tests. PCT in RUN 928 was 29 K lower than that in RUN 916. (author)