Study On Deep Hole Drilling Process Quality Control Of Nuclear Power Steam Generator

Completely solving the quality problem of evaporator deep hole drill is the key to the safe power generation of nuclear power plant.At present,the evaporator manufacturer lacks the analysis of quality data,risk prediction and process control measures in the quality control of deep hole drilling,and there are problems such as low quality qualification rate,high quality cost,and stagnant development of deep hole drilling technology.However,there is little academic research on the quality control of deep hole drilling.According to the process characteristics and quality requirements of deep hole drill for nuclear power evaporator,the research on a more scientific and effective quality control method for deep hole drill has both academic and practical significance.Based on the mechanism of BTA deep hole drilling,PDCA cycle theory of quality control,grey prediction GM(1,1)theoretical model,and support vector regression machine theoretical model,this paper proposes a theoretical model for deep hole drilling quality process control by predicting the size of deep hole drilling to determine the drilling staged quality control objectives;According to the characteristics of deep hole drill,a combined prediction theoretical model is proposed to predict the trend item of deep hole drill size by using the metabolic grey prediction method and the random item of deep hole drill size by using the support vector regression method through theoretical analysis.Then,taking the actual deep hole drilling size detection data of an evaporator manufacturer as an example,the empirical analysis of the two prediction models is carried out to verify the practicability of the combined prediction model.Finally,based on the conclusion of theoretical analysis and empirical analysis,specific measures to improve the quality control of evaporator deep hole drill are proposed,and the actual effect of the improvement is analyzed.The research conclusion of this paper is:(1)At present,the evaporator manufacturer has some deficiencies in the quality data analysis,dynamic risk prediction and control of the deep hole drilling process.The key to improving the quality control of the evaporator deep hole drilling is to strengthen the process control.It is an effective measure to strengthen the process control to make a quality plan before each hole drilling and to break down and formulate phased quality control objectives;(2)The grey support vector regression combination prediction model proposed in this paper can meet the quality prediction requirements of evaporator deep hole drilling,and can be used to scientifically formulate the stage quality control objectives of deep hole drilling process;(3)The quality control mode of deep hole drilling proposed in this paper,which is based on the size prediction model of deep hole drilling to determine the phased quality control objectives and carry out process control,is practical,can analyze and predict the dynamic quality risk of deep hole drilling process,and is conducive to carrying out quality diagnosis in advance,eliminating anomalies,improving the quality qualification rate,and ensuring the absolute safety of nuclear power;It can more scientifically determine the timing of bit replacement,reduce the waste of bit life and the cost of nuclear power manufacturing;It provides data support for the research and development of technologies such as longer life drill bits.The research has great economic and social benefits.