Distribution of Amines and Organic Acids in the Secondary Side of Embalse Nuclear Power Station

Abstract

In this work we summarized the distribution of amines and organic acids generated by the thermal decomposition of morpholine in the secondary side of Embalse NPP. Sampling and analytical procedures to determine the concentration of formic, acetic and glycolic acids, morpholine, ammonia, methylamine, ethanolamine and 2(2-aminoethoxy)ethanol are described. Two sets of samples were collected in March 1995 and October 1996 in the following points: main steam line, composite steam generator blowdown, moisture separator, condensate extraction pump discharge and outlet feed pump. The general trend of the product distribution along the secondary side is similar to that reported for other CANDU NPP. In CNE methylamine and ethanolamine are more abundant than 2(2- aminoethoxy)ethanol due to faster decomposition of morpholine and less oxidizing conditions. Ammonia, and methylamine concentrate in the steam because of the lack of a de-areator. The volatility of ethanolarnine is low and its concentration in the steam generator is high. It could help to neutralize acid conditions in crevices and sludges. The concentration of organic acids in CNE is low as compared with other CANDU NPP, with formic acid being the predominant species. Differences in the relative concentrations of morpholine degradation products as compared to other CANDU NPP are discussed.