[en] Of the start-up tests of ''Fugen'', the specific items are reported in the plant equipemt performance test, plant dynamic characteristic test, chemical and radiation measuring test, overall test, and start-up test. In the plant equipment performance test, 19 items were tested under nuclear heating condition and in loaded state, and it was confirmed that the results satisfied the design performance. In the plant dynamic characteristic test, 13 items were tested under power output condition, and it was confirmed that the results satisfied the design performance. The test is roughly classified into the control characteristic test of the plant control system, transient characteristic test in operation, and transient characteristic test at the time of tripping following a plant failure. Radiochemical and radiation level measuring tests were carried out to obtain the basic data for chemical and radiation management required for smooth plant operation, under atmospheric pressure, nuclear heating and power output conditions. Next, in the final loading test a 100 % electrical output, reactor-related data of about 200 points, turbine-related data of about 70 points and generator-related data of about 70 points were measured and evaluated to ensure that the plant can be safely and continuously operated. Finally, the start-up test program, implementing organization and testing process, the inspection prior to the operation, analytical prediction and data processing, independent inspection and the investigation items during stratup test are described. (Wakatsuki, Y.)