In a test facility with two parallel boiling water reactor fuel assemblies, experiments were carried out with top spray and bottom flooding, simulating loss-of-coolant accident (LOCA) conditions. The flow area restriction, caused by the ballooning of fuel rod cladding within one of the bundles, was provided by blockage plates, which had reductions of 37% in one case and in a second series 70%) of the flow area. Test parameters were system pressure (1, 5, and 10 bars), spray (0.68 and 1.02 m3/h) and flooding rates (1.5, 2, and 3.3 cm/s), power input (520 and 614 kW), and the initial cladding temperature (600 and 800°C at midplane) of the heaters. The test results showed no significant variations from those without blockage, except in the blocked region. An enhancement of heat transfer was observed in a close region downstream from the blockage in cases such as bottom flooding and top spray tests. The results will serve the purpose of code verification for reactor LOCA analysis.