A comprehensive reliability allocation method, which is applicable to the cases of lack of data in design stage, as well as the complexity of the influence factors and uncertainty of expert evaluation, is presented based on the gray system theory. The key of this method is to modify the weights of influence factors which are associated with expert scoring data by gray correlation analysis before reliability indices are assigned linearly to each subsystem. Based on gray evaluation with 4 levels, the application of this method is illustrated with the reliability allocation of a rotary machine under the consideration that complexity, technical level, importance and environment condition are chosen as influence factors. Compared with the actual faults statistics results, the validity and feasibility of the method is verified.
Based on the problem that existing antivirus software cannot effectively respond to emerging viruses and lacks real-time detection and effective interception of viruses, a class of detection propagation models based on log feature detection of viruses is established based on the classical susceptible-exposed-infected-immune (SEIR) propagation model with the introduction of containment nodes. The experimental results show that the drop rate of infected nodes of this model is increased by 26.45%, 40.68% and 54.24% when the detection rate is taken as 0.5,0.7 and 0.9, respectively, compared with the previous SEIR model. Therefore, the detection propagation model based on the detection of log feature information of viruses can effectively contain and remove the spread of new viruses in the network, and the higher the detection rate, the better the effect.
The equipment performance monitoring program is designed to provide guidance for monitoring the performance of equipment, with an aim to enable engineers to identify hidden hazards as early as possible and take corresponding corrective actions to achieve the purpose of equipment reliability management of nuclear power plant. The nuclear power plant realizes monitoring, control and protection of the whole plant through I&C equipment, by which to ensure the safe, reliable and economic operation of the nuclear power plant. In this paper, a set of performance monitoring program process special for I&C equipment of nuclear power plant is developed. And the RGL system (rod control system and rod position system) of a nuclear power plant is taken as an example to illustrate, analyze and summarize, which lays a foundation for nuclear power plant to carry out equipment reliability management.
With the technological development in the domestic electronic industry and the urgent demand of cost reduction and efficiency improvement in nuclear power plant, the electrical equipment in nuclear power plant has changed from replacing with brand-new equipment regularly or after failure to reusing after aging mitigation. At present, it is very urgent to research the maintenance methods of safety-level electrical equipment. Through the research on the failure mode and influence analysis, vulnerable components and parts, post-repair test and post-repair service life calculation of the safety-level switching power supply module, the maintenance methods are systematically sorted out. Through specific case analysis, the aging of power supply module can be mitigated and the reliability of it can be improved. At the same time, the method can be extended to other safety-level electrical equipment maintenance with one of the characteristics of unavailability of spare parts, high price, and large quantity or reverse demand.
Safety-level system equipment is essential for the nuclear power plant either to complete the reactor emergency shutdown, containment isolation, reactor core cooling and heat emission from containment and reactor, either to prevent large amounts of radioactive substances from being released into the environment, and is also the focus of system equipment reliability management. As the safety-level system equipment has seismic requirements, in this paper, the operating reliability of safety-level I&C system equipment is evaluated and demonstrated, and the general process of reliability evaluation & demonstration is worked out.
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