【国外标准】 Standard Practice for Sampling Special Nuclear Materials in Multi-Container Lots (Withdrawn 2012)

Plans for sampling and analysis of nuclear material are designed with two purposes in mind: the first is related to material accountability and the second to material specifications. For the accounting of special nuclear material, sampling and analysis plans should be established to determine the quantity of special nuclear material held in inventory, shipped between buyers and sellers, or discarded. Likewise, material specification requires the determination of the quantity of nuclear material present. Inevitably there is uncertainty associated with such measurements. This practice presents a tool for developing sampling plans that control the random error component of this uncertainty. Precision and accuracy statements are highly desirable, if not required, to qualify measurement methods. This practice relates to“ precision” that is generally a statement on the random error component of uncertainty. 1.1 This practice provides an aid in designing a sampling and analysis plan for the purpose of minimizing random error in the measurement of the amount of nuclear material in a lot consisting of several containers. The problem addressed is the selection of the number of containers to be sampled, the number of samples to be taken from each sampled container, and the number of aliquot analyses to be performed on each sample. 1.2 This practice provides examples for application as well as the necessary development for understanding the statistics involved. The uniqueness of most situations does not allow presentation of step-by-step procedures for designing sampling plans. It is recommended that a statistician experienced in materials sampling be consulted when developing such plans. 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.