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Lead-based reactor nuclear power has the advantages of inherent safety, compact size, light weight, long service life, and high efficiency, and it is widely applied to advanced marine equipment, unmanned underwater vehicles, and deep-sea space stations for energy and power purposes. Conducting research on lead-based reactor marine nuclear power is key to the technological innovation of energy and power for marine equipment in China. This study clarifies the application scenarios and development demands of marine nuclear power, summarizes the development status of lead-based reactor nuclear power from the aspects of technical characteristics, representative applications, and research status, and analyzes corresponding key technologies including nuclear fuel and cladding materials, key components in the primary loop, coolant processes and oxygen control, and advanced power generation technologies. Moreover, the study explores the development challenges for lead-based reactor marine nuclear power and proposes there feasible technical routes: low-temperature lead-based reactor marine nuclear power, high-temperature and high-efficiency lead-based reactor marine nuclear power, and integrated natural-circulation lead-based reactor marine nuclear power. Furthermore, we propose the following suggestions to promote the leapfrog development of marine nuclear power in China:(1) strengthening research and development (R&D) of specialized technologies for the lead-based reactor marine nuclear power and accelerating the deployment of demonstrative projects; (2) incorporating lead-based reactors into the country's major energy strategies and creating a standards system; (3) establishing national joint R&D centers and creating new models for technological innovation and industrial development.

ObjectivesThis study explores the use of a nonlinear adaptive inertia weight particle swarm optimization (PSO) algorithm to realize the optimal design of the path and arrangement of pipelines in the nuclear power primary loop systems of ships. MethodsAccording to the pipeline layout design characteristics, the constraints, evaluation functions and spatial model of the primary loop system are established. Based on the number of pipeline nodes, a new fixed-length coding method for the PSO algorithm is proposed, along with a direction guidance mechanism. As the standard PSO algorithm has such shortcomings as a slow convergence speed and susceptibility to falling into the local optimal solution, an improved nonlinear adaptive inertia weight PSO algorithm supplemented by a linearly changing learning factor is proposed. The improved PSO algorithm is combined with a co-evolutionary algorithm to form a co-evolutionary PSO algorithm for solving branch pipeline problems. The improved algorithm is then applied to the pipeline layout optimization problem of the nuclear power primary loop systems of ships. ResultsThe simulation results show that the convergence speed of the proposed algorithm is increased by 40% –50% compared with that of the standard algorithm. The improved algorithm can not only obtain higher quality pipeline layouts, but also solve the problem in which the standard PSO algorithm can easily fall into the local optimal solution. Conclusions The results of this study can provide useful references for the pipeline layout optimization of the nuclear power primary loop systems of ships.

[Objectives] The purpose of this paper is to solve the main steam pipeline whipping protection problem from a ship's steam generator(SG) to the cabin wall.[Methods] Therefore, a finite element model of the inverted L-shaped pipeline and U-bolts is established using LS-DYNA software to simulate the collision dynamic process. Under two layout schemes,the stress-strain distribution and restraint rejection force time history curves of the U-bolts are analyzed.[Results] In collisions caused by the imaginary welding seam break of the SG oblique steam exit,the horizontal pipeline displacement is even greater than the vertical,requiring the installation of another group of U-bolts to restrain lateral pipeline movement. With regard to such limiting factors as cabin spatial dimensions and seam break collision protection for the right-angle elbow at both ends,one set of 45-degree obliquely installed U-bolts located at the inverted L-shaped pipeline elbow can replace two sets of horizontally and vertically installed U-bolts.[Conclusions] The results of this study can have guiding significance for the whipping protection design of the main nuclear power steam pipelines of ships.

Floating nuclear power plants are affected by sea wind and waves, which will produce various forms of movement, and cause changes in the thermal and hydraulic characteristics of the reactor core and threaten the safety of reactor operation. In response to the R&D and design requirements of floating nuclear power plants, the research progress on the thermal-hydraulic characteristics of reactors under ocean conditions in China are reviewed in this paper. The emphasis is put on flow heat transfer, bubble behavior, flow instability, and critical heat flux under ocean conditions. Research progresses as well as the issues that need to be focused on in the future research are discussed in detail.

• Using compressed air as energy to deal with LOCA of marine nuclear power plant. • Coordinated control of safety injection system with IFCU. • Safety injection model of marine nuclear power plant is established and simulated. In case of a large or medium LOCA accident of marine nuclear power plant, the loop pressure drops rapidly. In case of power failure of the whole ship at this time, the active safety injection system will lose its function because the safety injection pump needs AC power, and the core is at risk of melting. A passive marine safety injection system based on high-pressure compressed gas is designed for the superposition of large and medium LOCA accidents and the whole ship's power failure accidents, including the safety injection subsystem of medium and low pressure and the safety injection subsystem of recirculation. The energy required for safety injection is provided by the potential energy of compressed gas, the pressure head is provided by the technology of gas-liquid booster pump, and the collection signals and valves are controlled by the technology of intelligent fluid control unit with small power consumption. The power supply used in the system is provided by DC 24 V battery. The mathematical and physical models of accumulator, gas storage tank, gas-liquid booster pump, reactor body and its pipeline are established for the designed passive safety injection system. The operation and safety characteristics of medium pressure safety injection, low pressure safety injection and recycling safety injection under LOCA accident conditions are simulated. The safety injection time and flow rate of three safety injection pressures are simulated by medium pressure safety injection, the safety injection time and peak temperature are simulated by low pressure safety injection, and the pressure and system temperature are simulated by recirculation safety injection. The simulation results show that the marine passive safety injection system designed under LOCA accident conditions can meet the requirements of core cooling. [ABSTRACT FROM AUTHOR]

Li, W. and Yu, H., 2020. Radiation solution method of marine nuclear power plant based on 3D neutron transport equation. In: Yang, Y.; Mi, C.; Zhao, L., and Lam, S. (eds.), Global Topics and New Trends in Coastal Research: Port, Coastal and Ocean Engineering. Journal of Coastal Research, Special Issue No. 103, pp. 535–538. Coconut Creek (Florida), ISSN 0749-0208. With the wide application of nuclear energy in marine nuclear power plant, the nuclear safety analysis of marine nuclear power reactor has become inevitable, and has been gradually concerned. Radiation safety criterion is an important index of safety analysis of nuclear power plant. Because of the characteristics of the reactor, its radiation protection management has higher and more strict requirements, which makes strengthening radiation protection become an important task of the reactor. The radiation solution method of marine nuclear power plant based on 3D neutron transport equation is proposed. Firstly, the program mathematical model of dose field analysis of marine nuclear power reactor cabin is constructed to obtain the radiation dose field of marine nuclear power reactor cabin. Then, based on the obtained nuclear radiation measurement field information, the radiation solution of the marine nuclear power plant is realized by the discrete solution method based on the 3D neutron transport equation. It is verified that the method has high accuracy and credibility for radiation calculation of an offshore nuclear power plant. [ABSTRACT FROM AUTHOR]