SMTAG: A code for the sequential analysis of multiple tag gas releases

Abstract

The code SMTAG (Sequential and Multiple TAG Analysis) is used to identify breached reactor components that have released tag gas to the reactor cover gas. Gas tags have been used (Figg et al. 1980 and Lambert 1978) to locate failed fuel pins in both the Fast Flux Test Facility (FFTF) and in the Experimental Breeder Reactor (EBR-2). In the FFTF, other reactor components have been tagged as well, including control assemblies and materials test capsules. The SMTAG code has been used extensively in gas tag analysis. This has resulted in several code enhancements and has been beneficial in learning to use the code effectively. Supporting information for each analysis is provided that is valuable in ensuring that a correct identification is obtained. The relative amounts of various components in a mixed sample are obtained, including the amount of residual gas from previous leakers, fission-product release-to-birth factors, and xenon-hangup. Statistical tests and other comparisons can flag bad or inconsistent measurements or problems in the supporting nuclear data base. The formalism for the code is reviewed here in Section 2.0. Details of the code (including descriptions of the main subroutines) are given in Section 3.0. The use of the code is documented in Section 4.0, along with a discussion of a realistic example. The SMTAG code requires a data base that includes the isotopic amounts of each tag properly corrected for burnup, depletion, and production.