Development of ToSPACE for Pipe Wall Thinning Management in Nuclear Power Plants

Abstract

A number of piping components in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, SPE (Solid Particle Erosion), LDIE (Liquid Droplet Impingement Erosion), etc. Those mechanisms may lead to thinning, leak, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 of USA in 1986 and in Mihama unit 3 of Japan in 1994, the pipe wall thinning management has emerged as one of the most important issues in nuclear power plants. To manage the pipe wall thinning in the secondary system, Korea has used a foreign program since 1996. As using the foreign country's program for long term, it was necessary to improve from the perspective of the users. Accordingly, KEPCO-E & C has started to develop the 3D-based pipe wall thinning management program (ToSPACE, Total Solution for Piping And Component Engineering management) from eight years ago, and the development was successful. This paper describes the major functions included in ToSPACE program, such as 3D-based DB (Database) buildup, development of FAC and erosion evaluation theories, UT (Ultra-sonic Test) data reliability analysis, field connection with 3D, automatic establishment of long-term inspection plan, etc. ToS-PACE program was developed to allow site engineers performing the selection of inspection quantity at each refueling outage, UT data reliability analysis, UT evaluation, determination of next inspection timing, identification of the inspecting and replacing components in 3D drawings, etc., to access easily.

Cause Analysis for Wall Thinning of Small-Bore Piping in Nuclear Power Plant by ToSPACE, FLUENT and Theoretical Evaluation

“…The causes of thinning were analyzed using the thermal hydraulic analysis function of ToSPACE [4]. The scope of modelling for performing thermal hydraulic analysis is from the two pipes in front of the orifice and valve to the thinned location connected to the header pipe as shown in Figure 1.…”

Estimation of Elbow Wall Thinning Using Ensemble-Averaged Mel-Spectrogram with ResNet-like Architecture

“…Pipe wall thinning due to high-temperature and high-pressure flow is a kind of failure in nuclear power plants, and several serious incidents due to wall thinning were reported in 1986 and 2004 [ 1 , 2 , 3 ]. Since the pipe wall thinning phenomenon by flow accelerated corrosion (FAC) poses a threat to safety, major countries have developed codes to predict pipe wall thinning [ 4 , 5 , 6 ]. Reliable analysis and decisions for the inspection are made according to the codes to prevent pipe rupture.…”

Comparison between FAC Analysis Result Using ToSPACE & CHECWORKS Programs and Experimental Result

“…ToSPACE includes the ability to predict the wall thinning caused by FAC, LDIE, Cavitation, Flashing, and SPE at once. In addition, it includes the capabilities of sensitivity analysis, 3D DB construction, inspection data reliability analysis, UT data evaluation, and long-term inspection plans which are utilized for the pipe wall thinning management works at plant site [4].…”