本文件规定了用热电离质谱法测定硝酸溶液中核材料的同位素和元素铀及钚浓度的方法。 该方法适用于辐照的Magnox和轻水反应堆燃料（沸水反应堆或压水反应堆）、乏燃料后处理厂的最终产品、MOX和铀燃料制造的进料和产品中的铀和钚同位素组成和浓度测量。该方法适用于其他燃料，但如有必要，可对化学分离和尖峰溶液进行调整，以适合每种类型的燃料。

This document specifies a method for the determination of the isotopic and elemental uranium and plutonium concentrations of nuclear materials in nitric acid solutions by thermal-ionization mass spectrometry. The method applies to uranium and plutonium isotope composition and concentration measurement of irradiated Magnox and light water reactor fuels (boiling water reactor or pressurized water reactor), in final products at spent-fuel reprocessing plants, and in feed and products of MOX and uranium fuel fabrication. The method is applicable to other fuels, but the chemical separation and spike solution are, if necessary, adapted to suit each type of fuel.