טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentDrofin Dmitry
SubjectAssessment of a Method to Measure Radioactive Content
in Drinking Water
DepartmentDepartment of Quality Assurance and Reliability
Supervisor Dr. Phineas Dickstein


Abstract

Water is one of main sources of human exposure to ionizing radiation despite the fact that the level of radioactivity in natural water is usually low. Radio nuclides in a human body may be harmful depending on the concentration of the isotopes, their type, their activities and their corresponding half-lives. The International Commission on Radiological Protection (ICRP) recommended limits of committed effective doses and maximum acceptable concentrations (MACs) for radio nuclides in drinking water were derived accordingly.

A variety of measurement methods serves to control the radio nuclides content in public water sources, differing in sensitivity, complexity and cost of application. In this experimental work, conducted at the Counting Laboratory of the Soreq Nuclear Research Center (NRC), the co-precipitation procedure was used to prepare samples of water for the measurement of their radio nuclides content. The water for this study was provided by Mekorot, The Israel Water Authority, from wells located at the Negev district.

The analyses of the accumulated experimental data revealed an effect of the Total Dissolved Solids (TDS) values on the corresponding number of counts from the samples. This may be due to self absorption in the co-precipitated layer. An empirical correction function for the TDS effect is presented in this work. The analyses pointed out the experimental and procedural conditions required to allow an acceptable level of sensitivity and accuracy in terms of the Minimum Detectable Activity, to ensure that the water under inspection meets the standard.