Reliability prediction and its validation for nuclear power units in service

In this paper a novel method for reliability prediction and validation of nuclear power units in service is proposed. The equivalent availability factor is used to measure the reliability, and the equivalent availability factor deducting planed outage hours from period hours and maintenance factor are used for the measurement of inherent reliability. By statistical analysis of historical reliability data, the statistical maintenance factor and the undetermined parameter in its numerical model can be determined. The numerical model based on the main- tenance factor predicts the equivalent availability factor deducting planed outage hours from period hours, and the planed outage factor can be obtained by using the planned maintenance days. Using these factors, the equivalent availability factor of nuclear power units in the following 3 years can be obtained. Besides, the equivalent availability factor can be predicted by using the historical statistics of planed outage factor and the predicted equivalent avail- ability factor deducting planed outage hours from period hours. The accuracy of the reliability prediction can be evaluated according to the comparison between the predicted and statistical equivalent availability factors. Furthermore, the reliability prediction method is validated using the nuclear power units in North American Electric Reliability Council （NERC） and China. It is found that the relative errors of the predicted equivalent availability factors for nuclear power units of NERC and China are in the range of-2.16% to 5.23% and -2.15% to 3.71%, respectively. The method proposed can effectively predict the reliability index in the following 3 years, thus providing effective reliability management and mainte- nance optimization methods for nuclear power units.

Conceptual Modeling and Simulation Application Analysis of In-service Assessment

Firstly,this paper expounds the conceptual connotation of inservice assessment in the new system,then applies modeling and Simulation in the field of in-service assessment,establishes the conceptual model of inservice assessment and its process,and finally analyzes the application of modeling and simulation in the specific links of in-service assessment.

New Model in Service

China has stepped into the regional aircraft world market with its updating production ability and capacity China’s first homemade next-gen-eration turboprop regional aircraft Modern Ark 600 (MA600) rolled off the production line on June 29 in Xi ’an, capital of Shaanxi Province, marking a milestone in the country’s drive to be one of leading suppliers of passenger airliners with turboprop engines in the world.

Strengthening Steel Joint of Architectural Structure under Loading Condition

Through the comparative analysis of steel plate reinforced, ceramics reinforced and non- reinforced joints under loading condition, the feasibility of strengthening steel joint of architectural structure was studied. By using element birth and death technology simulation of the finite element software ANSYS, it is found that when the reinforced structure is 10 mm in thickness and using steel structure to reinforce the concemed areas, the equivalent stress in concerned regionals reduces by 31.1% compared with that when the structure is not reinforced. When reinforced with ceramics, the equivalent stress in concerned regionals reduces by 24.1% compared with that reinforced with steels; when the reinforced structure is 20 mm in thickness using steels to reinforce the concerned area, the equivalent stress in concerned regionals reduces by 39.4% compared with that when the structure is not reinforced. When using ceramics to reinforce the concerned areas, the eauivalent stress only decreases by 3.7% compared with that reinforced with steels.