Study On The Mooring Design And Impacts Of Nuclear Power Platform Of Ice Zone

In recent years,with the global energy development becoming more and more saturated and the energy supply becoming intense,the rich oil and gas resources in the Arctic have attracted the attention of the whole world,obviously,the development prospect is very broad.At the same time,offshore oil exploitation is faced with the rapid decline of associated gas volume and the great increase of fuel demand in offshore oil field,the conventional selfgeneration mode needs a lot of fuel,while nuclear energy as a clean energy,it's also efficient and environmentally friendly,the use of seawater for cooling will also greatly reduce the operating cost of nuclear power.Therefore,the establishment of offshore floating nuclear power station in the polar region is an economic and effective way to develop Arctic petroleum resources and solve energy supply problems.However,under the extreme sea condition of the Arctic,the energy supply for offshore resource development is severely limited due to the freezing and poor natural conditions all the year round,so it is of great significance to design a new offshore nuclear platform with cold resistance,ice load resistance,wind and wave resistance.In this regard,this paper mainly studies the following aspects:1)According to the main functions and external environmental conditions of the platform in the ice area,the basic form of it and the preliminary layout of the mooring system are determined,and the characteristics of the semi-taut mooring system adopted in this paper are analyzed,which not only reduces the radiation range,but also the mooring loads and the costs.Then,based on the API criterion,the design criteria and process of mooring system are proposed.2)Different from the previous studies,due to the particularity of the operating sea conditions,in this paper,the ice load is also considered except wind,wave and current loads,and an ice discrete element model is constructed to simulate the interaction process between sea ice and marine mooring structures.At the same time,the influence of different ice parameters and the coupled motion response of platform and mooring on the ice load are studied.3)On this basis,the overall performance evaluation of the initial mooring system is carried out: firstly,an iterative algorithm for dynamic response analysis of mooring system is established by MATLAB software,which accurately simulates the real-time static configuration and tension distribution of mooring lines,and is verified by comparison with AQWA results.Combined with the secondary development function of AQWA,the hydrodynamic calculation and time-domain coupling analysis are carried out for the platform and mooring system in the ice age and no ice age,the motion response of the platform under different environmental loads is studied for checking the mooring system preliminarily.4)In consideration of the basic design process of mooring system,the sensitivity of the basic mooring parameters is studied,analyzing the general rules and doing more with the mooring system optimization according to the function and stability requirements of nuclear power platform.Finally,a semi-taut mooring scheme which meets the requirements of the criterion greatly is proposed,and apparently,it has better performance.5)Finally,based on T-N curve method,rain flow counting method and miner fatigue cumulative damage theory,the fatigue damage assessments of the final mooring scheme during the ice season and ice-free season are carried out.Now,the overall design process of the mooring system is completed,and the results are expected to provide references for the longterm safety assessment of mooring system in the subsequent practical projects.