Gerhard Bart

Evaluation of the Radial Distribution of Gadolinium Isotopes in Nuclear Fuel Pins by Secondary Ion Mass Spectrometry (SIMS)

Secondary Ion Mass Spectrometry (SIMS) is a suitable technique to evaluate the relative isotopie Gd distribution across fuel pellets. It is faster and provides greater lateral resolution than microdrilling techniques. Measurements on polished fuel cross sections with G d 2 0 3 contents of 3 and 7 wt%, an in i t i a l 2 3 5 U enrichment of about 3.5 % and burnup values between 2 and 6 GWd/tM were performed. In spite of cracked and porous surfaces, repeated measurements on the same sample lay within a span of less than 15% (relative), provided that the residual isotopie abundances were greater than ca. 1%. The major disadvantage of the SIMS technique is the limitation concerning quantitative analysis. In this work, SIMS data have been normalized by radiochemical and mass spectrometric analysis of adjacent samples.

Experience in SIMS surface analysis of radioactive waste glasses

Abstract In order to predict the long term corrosion behaviour of high level radioactive vitrified waste under repository conditions, surface analytical tools play an important role. The paper describes the experience gained with a shielded secondary ion mass spectrometer in active glass surface analysis. To improve on the qualitative character of in depth profile data, relative sensitivity factors are applied and an internal elemental standard of known surface concentration is used to quantify the profile concentration results.

Measurement of carbon distribution in nuclear fuel pin cladding specimens by means of a secondary ion mass spectrometer

Abstract Cladding carburization during irradiation of advanced mixed uranium plutonium carbide fast breeder reactor fuel is possibly a life limiting fuel pin factor. The quantitative assessment of such clad carbon embrittlement is difficult to perform by electron microprobe analysis because of sample surface contamination, and due to the very low energy of the carbon Kα X-ray transition. The work presented here describes a method developed at the Swiss Federal Institute for Reactor Research (EIR) to use shielded secondary ion mass spectrometry (SIMS) as an accurate tool to determine radial distribution profiles of carbon in radioactive stainless steel fuel pin cladding. Compared with nuclear microprobe analysis (NMA) [1], which is also an accurate method for carbon analysis, the SIMS method distinguishes itself by its versatility for simultaneous determination of additional impurities.

Surface Film Characterization of Corroded HLW Glass Specimens

In a joint Japanese, Swedish, Swiss HLW glass characterization programme, interactions of real waste glass specimens with possible burial system components are studied. The report describes the glass surface analytical work performed at the Swiss Federal Institute for Reactor Research (EIR) during the first completed phase of the programme.