Use of on-line atomic absorption in a power plant environment

Westinghouse has been conducting a program to upgrade the purity of primary-loop cooling water in pressurized water reactor (PWR) nuclear power plants, and a method was needed to measure cationic impurities such as calcium, magnesium, and aluminum in the 0 to 10-ppb range. After examination of alternative methods, a Perkin-Elmer Model 5000 flameless atomic absorption (AA) unit with and AS-40 autosampler was selected and tested on line in a nonlaboratory, auxiliary building area of an operating nuclear power plant. Electrical isolation, dust and dirt protection, supplemental system cooling, and sample preconditioning all had to be provided to enable what is essentially a laboratory instrument to function in the more hostile plant environment. Some problems arose in the electronics of the spectrometer portion of the instrument, such as loss of preprogram instruction, multiple false readings, and loss of averaging functions. These problems were not of major proportions, however, and the system was able to track contamination levels through plant shutdown for refueling and consistently monitor impurities in the sub-parts-per-billion range. It has been shown that with new automated flameless AA systems, high-quality analyses can be obtained on line and without the need of a highly trained spectroscopist as an operator