ISO 16796:2022 pdf – Nuclear energy — Determination of Gd 2 O 3 content in gadolinium fuel blends and gadolinium fuel pellets by atomic emission spectrometry using an inductively coupled plasma source (ICP-AES)

ISO 16796:2022 pdf – Nuclear energy — Determination of Gd 2 O 3 content in gadolinium fuel blends and gadolinium fuel pellets by atomic emission spectrometry using an inductively coupled plasma source (ICP-AES).
8.1.7 Dilute to 100 ml with demineralized water. 8.2 Preparation of the powder test samples of Gd 2 O 3 plus UO 2 8.2.1 Weigh 5,0 g of test sample into a beaker, weighed to the nearest 0,001 g. 8.2.2 Prepare the test sample as described in 8.1, steps 8.1.2 through 8.1.7. 8.3 Preparation of pellet standards and test samples 8.3.1 Crush the pellet using a percussion mortar (5.8). 8.3.2 Weigh 5,0 g into a crucible, weighed to the nearest 0,001 g. 8.3.3 Heat the crucible with the test sample in a muffle furnace at 420 °C ± 25 °C minimum for 2 h to 3 h. 8.3.4 Quantitatively transfer the content from the crucible to a glass beaker. Then proceed as described in 8.1, steps 8.1.2 through 8.1.7. 9 Calibration and analysis of test samples 9.1 General Standards as prepared in Clause 7 and 8.1 are used to calibrate the equipment. Calibration standards shall be traceable to the SI and shall bracket the anticipated concentration range for the dissolved test samples being measured. a) In the event that a test sample result is outside of the calibration range: the instrument shall be recalibrated and the measurements repeated; or the test sample dilution scheme shall be adjusted so the concentration of the dissolved test sample is within the calibration range when the measurement is repeated. b) Independence between reference materials used to prepare calibration standards and quality control standards is required. At a minimum, different lots of gadolinium reference material from the same supplier may be used to prepare calibration and quality control standards, however using different suppliers is recommended.
To calibrate the measurement system for powder test samples, the standard solutions prepared in accordance with 8.1 are measured in at least duplicate and the calibration curve produced from the intensity-versus-concentration curve. To calibrate the measurement system for pellet test samples, the standard solutions prepared in accordance with 8.3 are measured in at least duplicate and the calibration curve produced from the intensity-versus-concentration curve. Calibration curves are evaluated using acceptance criteria established by each laboratory, based upon their historical performance; e.g., linear regression fit (R 2 ), slope, and coefficient of error. See example in Annex A. 9.3 Analysis of the test samples and quality control standards The test samples prepared in 8.2 and 8.3 shall be analysed after making the calibration curve. Test samples shall be measured in at least duplicate and spiked test samples should be measured at a defined frequency such as one test sample per batch of ten or fewer similar test samples. To avoid daily correction and achieve the required precision, a new calibration curve is prepared for each batch of test sample determinations. Process blank measurements should be performed periodically to ensure that background levels are in the expected range; however, background corrections are not normally necessary. Quality control (QC) standards shall be prepared and measured in the same manner as test samples. Compare the emission intensities of the test samples and QC standards to the calibration curve and calculate the Gd 2 O 3 concentrations for each of the test samples and QC standards. QC standards shall be used as both opening and closing controls, and should be control charted to monitor measurement and analyst performance. If any of the test samples contain products other than UO 2 and Gd 2 O 3 , the calibration and the instrument control measurements shall be performed using reference material blends having the same matrix as the test samples.
The test samples prepared in 8.2 and 8.3 shall be analysed after making the calibration curve. Test samples shall be measured in at least duplicate and spiked test samples should be measured at a defined frequency such as one test sample per batch of ten or fewer similar test samples. To avoid daily correction and achieve the required precision, a new calibration curve is prepared for each batch of test sample determinations. Process blank measurements should be performed periodically to ensure that background levels are in the expected range; however, background corrections are not normally necessary. Quality control (QC) standards shall be prepared and measured in the same manner as test samples. Compare the emission intensities of the test samples and QC standards to the calibration curve and calculate the Gd 2 O 3 concentrations for each of the test samples and QC standards. QC standards shall be used as both opening and closing controls, and should be control charted to monitor measurement and analyst performance. If any of the test samples contain products other than UO 2 and Gd 2 O 3 , the calibration and the instrument control measurements shall be performed using reference material blends having the same matrix as the test samples.