To manage the wall thinning of carbon steel piping in nuclear power plants, the utility of Korea has performed thickness inspection for some quantity of pipe components during every refueling outage and determined whe...To manage the wall thinning of carbon steel piping in nuclear power plants, the utility of Korea has performed thickness inspection for some quantity of pipe components during every refueling outage and determined whether repair or replacement after evaluating UT data. Generally used UT thickness data evaluation methods are Band, Blanket, and PTP (Point to Point) methods. Those may not desirable to identify wall thinning on local area caused by erosion. This is because the space between inspecting points of those methods are wide for covering full surface being inspected components. When the evaluation methods are applied to a certain pipe component, unnecessary re-inspection may also be generated even though wall thinning of components does not progress. In those cases, economical loss caused by repeated inspection and problems of maintaining the pipe integrity followed by decreasing the number of newly inspected components may be generated. EPRI (Electric Power Research Institute in USA) has suggested several statistical methods such as FRIEDMAN test method, ANOVA (Analysis of Variance) method, Monte Carlo method, and TPM (Total Point Method) to distinguish whether multiple inspecting components have been thinned or not. This paper presents the NAM (Near Area of Minimum) method developed by KEPCO-E & C for distinguishing whether multiple inspecting components have been thinned or not. In addition, this paper presents the analysis results for multiple inspecting ones over three times based on the NAM method compared with the other methods suggested by EPRI.展开更多
Based on tropical cyclone (TC) data for the period 1949 to 2008 and following the Gumbe-Imethod, Pearson-Ⅲ method and determinacy method, this article estimates the possible minimum centralpressure of TCs affecting s...Based on tropical cyclone (TC) data for the period 1949 to 2008 and following the Gumbe-Imethod, Pearson-Ⅲ method and determinacy method, this article estimates the possible minimum centralpressure of TCs affecting southern Fujian where a nuclear power will be located. Results show that theobserved minimum central pressure of TCs agrees well with the results determined with the methods aboveand there is little difference between them (the minimum central pressure is 867.4 hPa and 868.1 hPa,respectively, in a 1,000-yr return period). Established with the theory of atmospheric dynamics, thedeterminacy method yields a result of 867.28 hPa/1000 years, only a little smaller than the result of theprobability method. Because of randomicity in parameter adjustment with the Pearson-Ⅲ method whereasthe determinacy method is theoretically solid and its estimates are the smallest of the three methods, it istherefore reasonable, for security and conservative concerns, to adopt the result determined with thedeterminacy method as the possible maximum intensity of TC (with the central pressure being 867.28 hPa ina 1,000-yr return period).展开更多
文摘To manage the wall thinning of carbon steel piping in nuclear power plants, the utility of Korea has performed thickness inspection for some quantity of pipe components during every refueling outage and determined whether repair or replacement after evaluating UT data. Generally used UT thickness data evaluation methods are Band, Blanket, and PTP (Point to Point) methods. Those may not desirable to identify wall thinning on local area caused by erosion. This is because the space between inspecting points of those methods are wide for covering full surface being inspected components. When the evaluation methods are applied to a certain pipe component, unnecessary re-inspection may also be generated even though wall thinning of components does not progress. In those cases, economical loss caused by repeated inspection and problems of maintaining the pipe integrity followed by decreasing the number of newly inspected components may be generated. EPRI (Electric Power Research Institute in USA) has suggested several statistical methods such as FRIEDMAN test method, ANOVA (Analysis of Variance) method, Monte Carlo method, and TPM (Total Point Method) to distinguish whether multiple inspecting components have been thinned or not. This paper presents the NAM (Near Area of Minimum) method developed by KEPCO-E & C for distinguishing whether multiple inspecting components have been thinned or not. In addition, this paper presents the analysis results for multiple inspecting ones over three times based on the NAM method compared with the other methods suggested by EPRI.
基金Natural Science Foundation of Fujian Province(2007J0122)Natural Science Foundation of China(90915002)
文摘Based on tropical cyclone (TC) data for the period 1949 to 2008 and following the Gumbe-Imethod, Pearson-Ⅲ method and determinacy method, this article estimates the possible minimum centralpressure of TCs affecting southern Fujian where a nuclear power will be located. Results show that theobserved minimum central pressure of TCs agrees well with the results determined with the methods aboveand there is little difference between them (the minimum central pressure is 867.4 hPa and 868.1 hPa,respectively, in a 1,000-yr return period). Established with the theory of atmospheric dynamics, thedeterminacy method yields a result of 867.28 hPa/1000 years, only a little smaller than the result of theprobability method. Because of randomicity in parameter adjustment with the Pearson-Ⅲ method whereasthe determinacy method is theoretically solid and its estimates are the smallest of the three methods, it istherefore reasonable, for security and conservative concerns, to adopt the result determined with thedeterminacy method as the possible maximum intensity of TC (with the central pressure being 867.28 hPa ina 1,000-yr return period).
