On the determination of 36Cl and 129I in solid materials from nuclear decommissioning activities

Investigating the 36Cl memory effect in pyrolysis of solid samples from nuclear decommissioning activities

“…The analysis method applied in this work to measure 36 Cl was based on a three-step procedure (see Fig. 1) developed in our earlier work for 36 Cl and 129 I determination [16]. This is a procedure involving (1) pyrolysis of solid samples in a Fig.…”

“…Therefore, a shorter protocol (about 3 h 30 min) was used when analysing inorganic samples (white sand or concrete), whilst a longer heating protocol (about 5 h 30 min) was used in the analysis of graphite samples in order to avoid uncontrolled pyrolysis possibly leading to spontaneous explosions due to the higher carbon content. As described in the earlier work Llopart Babot et al [16], the pyrolysis procedure in combination with a radiochemical separation and LSC measurement was selected to determine 36 Cl in decommissioning samples where low activities are expected. The amount of 36 Cl expected in real samples was 50 mBq g −1 to 4 Bq g −1 [38], and therefore we decided to perform our tests mainly with a spike of 4 Bq 36 Cl using 1 g concrete blank samples.…”

“…Several procedures for the analysis of 36 Cl in decommissioning wastes have been reported in the literature [7,8,[13][14][15][16]. Pyrolysis has been widely reported for sample preparation of chlorine-containing solid samples because a closed system is needed for collecting chlorine due to its high volatility [17][18][19].…”

“…Techniques such as Liquid Scintillation Counting (LSC) or acceleration mass spectrometry (AMS) have been described for the quantification of 36 Cl activity concentrations [20][21][22][23][24][25]. In our previous work [16], a residual 36 Cl signal was frequently observed in procedural blank samples measured after having measured 36 Cl-spiked samples. A memory effect with 36 Cl was also reported as being an issue in AMS due to attachment of chlorine to the ion source [26][27][28].…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…Llopart-Babot et al investigated combined measurement of 36 Cl and 129 I in concrete and graphite from a Belgian reactor undergoing decommissioning. 200 Pyrolysis was combined with chemical separation, with nal measurement by liquid scintillation counting. Recovery through the procedure was assessed by determining stable Cl and I using ion chromatography and ICP-MS, respectively.…”