1.1本指南是关于特殊核材料（SNM）监测器及其性能评估的系列指南之一。本系列中的其他部分提供了有关SNM监测、监测器校准和评估方法的信息（请参阅），但指南C 993尤其提供了本指南的大部分基础。厂内性能评估指南的目的是提供一种相对快速的方法 验证 SNM监视器是否按预期执行以检测SNM或替代测试源。 1.2指南C 993指出- 电厂评估是保持SNM监测器处于正确运行状态的计划的一部分，厂内评估可作为常规运行评估，也可用于在监测器校准后验证性能。 1.3本指南基于描述应用和评估SNM监测器的ASTM标准。 ====意义和用途====== SNM监视器是搜索隐藏SNM的有效且不引人注目的手段，设施安全计划使用它们来防止SNM盗窃或未经授权从SNM访问区域移除。 每天使用放射源对监测器进行功能测试，可以确保监测器处于良好的工作状态。对SNM监控器进行频率较低的厂内评估的重要用途是验证监控器是否达到SNM或替代测试源的预期检测概率。 笔记 1-用于厂内评估的SNM测试源通常仅通过保护封装和可能位于源和监测器探测器之间的车辆部件进行屏蔽。然而，评估程序也可以用于验证容器或屏蔽内部SNM的预期检测水平。

1.1 This guide is one of a series on special nuclear material (SNM) monitors and their performance evaluation. Others in the series provide information on SNM monitoring, monitor calibration, and methods of evaluation (see ), but Guide C 993, in particular, provides much of the basis for this guide. The purpose for a guide to in-plant performance evaluation is to provide a comparatively rapid way to verify whether SNM monitors perform as expected for detecting SNM or an alternative test source. 1.2 Guide C 993 points out that in-plant evaluation is one part of a program to keep SNM monitors in proper operating condition and that in-plant evaluation can be used as a routine operational evaluation or can be used to verify performance after a monitor is calibrated. 1.3 This guide is based on ASTM standards that describe applying and evaluating SNM monitors. ====== Significance And Use ====== SNM monitors are an effective and unobtrusive means to search for concealed SNM, and facility security plans use them to prevent SNM theft or unauthorized removal from SNM access areas. Functional testing of monitors on a daily basis with radioactive sources can assure that they are in good working order. The significant use of a less frequent, in-plant evaluation of an SNM monitor is to verify that the monitor achieves an expected probability of detection for an SNM or alternative test source. Note 1—An SNM test source used for in-plant evaluation is normally shielded only by protective encapsulation and the parts of a vehicle that may lie between the source and the monitor’detectors. However, the evaluation procedure could just as well be used to verify an expected level of detection for SNM inside of containers or shields.