The study of Alkanolamines in PWR secondary cooing system

• Main Authors: Fang, Chieh, 方傑
• Other Authors: Kuo Yang-Ming
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/99296220647257598758

碩士 === 中國文化大學 === 應用化學研究所 === 86 === Abstract The secondary coolant system of nuclear pressurizedwater reactor(PWR) includes the following subsystems or components:steam generator(SG), main steam line( MSL),high pressure turbine(HPTB), moisture separator reheater( MSR), low pressure turbine(LPTB) and condensed water system( CWS), condensed polisher dimineralizer, feed water system (FWS) etc. From MSL to turbine, there are steam/liquid coexisted regions; the other subsystems belong to single liquid phase. The water treatment or water chemistry control of PWR secondary coolant system additional with ammonia and hydrazine for all volatile treatment, since 1970 thismethod had been emphasis for most PWRs all over the world. This treatment indicates that injection of ammonia and hydrazine before final feed water keeping the pH(25℃) in the range of 8.8~10.0(the lower range 8.8~9.2 for the copper containing plants; the higher range 9.2~10.0 for the ferrous containing plants). However, owing to the higher volatility of ammonia in the steam/liquid coexisted regions causes the pH ofliquid phase decreased to lower Value where local corrosion mainly erosion-corrosion happened. Therey,the new concept of adopting the alkanolamines having the property "Basicity in higher and volatility in lower than of ammonia" instead of ammonia as water treatment reagents after 1990. This concept is expected to get the optional condition for secondary water chemistry of PWR. In this thesis, four alkanolamines including ethanolamine(ETA), morpholine(MH), 3-methoxyl propylamine(MPA), 2-ammino-2-methylpropylamine (AMP) were selected for the study of reacting with nuclear grade ion exchange resins(Dowex, Amberlite, Purolite, Ionac) that expect to find out the best amine having the lowest selectivity coefficient with ion exchan resins i.e. lowest consumption may achieve good cost/benefit effect. The study of volatility in the secondary water condition at 300℃,1400psig was performed also that expects to find out the best amine having the lowest volatility. The conclusion results of these studies were that the best potential alkanolaminewere ETA and MH. The analytical methods for alkanolamine were investigated. It was found that the ion chromatography(IC) and total organic carbon determination(TOC) were the advanced handling, availiable methods.Keywords: alkanolamines, ion exchange resins, volatility, total organic carbon, ion chromatography.