Nuclear powered ship, which has advantages of voyage capability with a high power level, are directly or indirectly influenced by ship motions or sea wave. Although the effect of ship motions or sea wave on the reactor system is important in designing or operation of marine reactor, the data obtained from the prototype marine reactor are not many in the open literature. Mutsu conducted the experimental voyage in order to obtain the data concerning the effect of ship motions and sea wave on the reactor system. The behavior of reactor system were analyzed by the data of wave height, ship motions and turbine load in the case of the experiments in ship maneuvering and straight cruising against swell. The response of reactor power and water levels in the steam generator and the pressurizer to the wave, ship motions or maneuvering were revealed in the present paper.
