From the examination, it was quantitatively shown that there is no suitable power source other than a nuclear-powered engine to meet the power demand. From these reasons, an undersea-navigating observation ship, with SCRS installed and capable of navigating in the Arctic Ocean as the main survey area, in the sub-Arctic sea area, and under stormy conditions, has been in the process of design and investigation. This selection would be reasonable so that it will be easy to obtain general comprehension of the need in relation to global environmental problems that are focused on problems on a whole earth scale that need to be solved in the near future. A conceptual image of the undersea-navigating observation ship with SCR installed (displacement weight of 500 tons) is shown in Fig. 10.3.
Fig. 10.3 Undersea Navigation Observation Ship Equipped with SCRs
10.2 Research and Development by Ship Research Institute2)
Following related work in 1997, a project titled “Studies related to the application of the system reliability analysis method GO-FLOW” aimed at establishing element technology for reliability analysis of the reactor facility to begin with the marine reactor. A reactor accident sequence identification function was examined, and an accident propagation simulator was developed. In “Studies on improvement of reliability of power supply facilities of a nuclear-powered ship,” extraction of the self-sequence, which is a problem in evaluating safety, was developed for a fire in which measures to avoid simultaneous failures are considered to be insufficient. In “Studies on numerical simulation of the thermal hydrostatic behavior of a marine reactor,” a secondary non-stationary thermal hydrostatic analysis code was developed in order to simulate the effect of flow fluctuations derived from the ship motion on the capacity for removing decay heat from the core. In the field of the radiation shielding, the performance of high-performance shielding material was evaluated, as was safe transportation of returned radioactive wastes; a high-performance liquid shielding material was developed, and a ceramic-type, multi-function shielding material was then developed. In addition, the effect of vertical motion on the natural-circulation cooling system was studied, and studies were implemented on utilization technology of the human integral function to the reactor plant and an autonomous, decentralized cooperative function monitoring system.
10.3 Research and Development by Other Institutes
Tokyo University of Mercantile Marine completed a study of flashing and condensation of high-pressure saturated water within the water-filled containment, as generated in a small loss-of-coolant accident of the DRX and SCR (joint study with SRI)3), and a study of the flashing hammer phenomenon caused when high-pressure saturated water contacts cold water (joint study with JAERI)4). Kobe University of Mercantile Marine successively completed studies on the “thermal now” phenomenon of the passive safety system of a marine reactor (joint study with Kyoto University), and on dynamic characteristics and control of a marine reactor.
