Characterizing difficult-to-measure radionuclides in low level waste using the computer codes 3R-STAT and SF-STAT

This paper discusses the application of the computer codes, 3R-STAT and SF-STAT, in low level waste characterization programs to determine the concentrations and quantities of the difficult-to-measure radionuclides in low level waste shipped for disposal. The radionuclides addressed by the use of these two computer codes includes: l-129 and Tc-99, Sr-90, and the transuranic radionuclides. This paper discusses the analytical models used in the codes and the justification for the models in determining the release quantities of l-129 and Tc-99, and the scaling factors for Sr-90 and the transuranic radionuclides. The validation of the computer codes is discussed as an alternative to costly and potentially less accurate sampling and measurement programs. Recent experience with the application of the two computer codes in the Italian low level waste program to characterize all of the waste which was generated by the Italian nuclear plants and which is currently is storage at the nuclear sites is discussed