【国外标准】 Standard Test Method for Moisture Analysis of Plutonium Dioxide (PuO2) by Thermogravimetric Mass Spectrometry (TGA-MS)

5.1 This test method is intended for use in quality control laboratories where a quantitative analysis of adsorbed moisture on a PuO2 sample is desired.5.2 The parameters described should be considered as guidelines. They may be altered to suit a particular analysis or type of analyzer, provided the changes are validated by the laboratory and noted in the report.5.3 The quantity of an adsorbed gas on a given PuO2 sample may indicate specific quality or end use performance characteristics. Specific limits on moisture content, for example, are required in cases where PuO2 will be packaged and stored for extended periods of time.1.1 This test method provides necessary information to determine the total amount of moisture (physisorbed and chemisorbed water molecules) in a plutonium dioxide (PuO2) sample using a combination of thermogravimetric and mass spectrometric analyses. This test method is useful when performing analysis in cases where a maximum amount of moisture content in PuO2 samples has been agreed upon by interested parties. For example this method can be used to determine the moisture content of some types of PuO2 packaged to meet the requirements of DOE-STD-3013 (1),2 “Stabilization, Packaging, and Storage of Plutonium-Bearing Materials,” when such PuO2 meets the specifications given in this test method (2).1.2 This test method is applicable to PuO2 samples having the following characteristics: Plutonium mass fraction ≥ 83 % (the plutonium in the sample should be close to stoichiometric PuO2 which is approximately 88 wt% plutonium depending on the isotopic composition of the plutonium, but can have several weight percent impurities), moisture ≤1 %.1.3 The temperature range of test is typically room temperature to greater than 1000 °C. Typically the PuO2 is heated to 1100 °C.1.4 This test method utilizes an inert gas environment (argon, nitrogen, or helium).1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.