Book Description

An integrated sampling and gamma ray spectrometry system has been developed for analysis of TRIGA reactor primary cooling water. A microcomputer controls pumps and valves using BASIC and assembly language programs to pump 300 ml liquid samples into a reference geometry surrounding a Ge(Li) detector. Gamma ray spectra are acquired by a multichannel buffer and are analyzed by a software sequence executed on an IBM PC XT. After analysis the sample can be routed to holding containers or a waste container, depending on a user-selected option. The system is also configured as an on-line coolant monitor, using a Nal(Tl) detector to measure the gross gamma ray activity in the primary line in conjunction with a binary counting chip read under software control. When the gross count rate exceeds a user-selected threshold, a sample is automatically tapped from the primary line, its gamma ray spectrum is analyzed, and an analysis report is printed. The sampling system was used to remove sequential samples of coolant from the TRIGA primary system at hourly intervals during one megawatt operation. Neutron activation production terms for AlAr, 56Mn and 2ANa were determined. An overnight analysis of the AlAr, 56Mn and 24Na were determined. An overnight analysis of the primary coolant was also performed to determine the analytical sensitivity of the system using long spectral acquisition times. Finally, the autoanalysis software was used to automatically obtain and analyze a coolant sample, while storing a second sample in a holding container. The holding container sample was analyzed using a separate detector system to independently verify the activity reported during the autoanalysis.