GB/T 7165.4-2008 in English

《GB/T 7165.4-2008气态排出流（放射性）活度连续监测设备 第4部分：放射性碘监测仪的特殊要求》由TC30（全国核仪器仪表标准化技术委员会）归口，TC30SC3（全国核仪器仪表标准化技术委员会辐射防护仪器分会）执行，主管部门为国家标准化管理委员会。
GB/T7165的本部分适用于针对所有形式放射性碘的同时、延时或顺序测量的设备。当对排出流进行取样测量时,附着在气溶胶上的碘一般由前置过滤器进行采集,然后在实验室进行单独分析,以提供完整的测量。
放射性碘监测仪应具有下列功能:
---测量气态排出流中碘和碘化合物的体积活度以及排放的放射性碘的总活度;
---当碘或碘化合物的放射性活度浓度或总活度超过预置阈值时,启动报警信号。
这类设备会测量到气态排出流中存在的其他放射性核素的活度,其中包括天然放射性核素。对其他核素的甄别在测量低水平的放射性碘时非常重要。
在烟囱或通风管道中,本部分既考虑了利用活性炭来作为碘的取样介质,又考虑了对碘的直接测量。
本部分的目的是规定第4章所列碘监测仪的特定标准要求,包括技术特性和一般试验条件,并给出可行方法的实例。
GB/T7165.1-2005中规定了这类设备的一般要求、技术特性、试验方法、辐射特性、电气特性、机械特性、安全特性和环境特性。除非另有说明,这些要求均适用于本部分。

This part of GB/T 7165 is applicable to equipment intended for the simultaneous, delayed or discrete sequential measurement of radioactive iodine in all forms. When the effluent is sampled for measurement, iodine bound on aerosols is generally collected on a prefilter which shall be analyzed separately in a laboratory to provide a complete measurement.
It is applicable to equipment designed to fulfill the following functions:
——The measurement of the volumic activity of iodine and compounds of radioactive iodine in gaseous effluents or of the released iodine total activity;
——The actuation of an alarm signal when either a predetermined concentration or a predetermined total released activity due to iodine or its compounds is exceeded.
This equipment is intended for measurement over a wide range of activity in the presence of other radionuclides in the gaseous effluent, including naturally occurring radioactive nuclides. Discrimination against other radionuclides can be important in measuring low levels of radioactive iodine.
This part considers both the use of iodine collection media such as activated charcoal and the direct measurement of iodine in stacks or ventilation ducts.
The object of this part is to lay down specific standard requirements, including technical characteristics and general test conditions, and to give examples of acceptable methods for iodine monitors as defined in Chapter4.
The general requirements, technical characteristics, test procedures, radiation characteristics, electrical, mechanical, safety and environmental characteristics are given in GB/T 7165.1-2005. Unless otherwise stated, these requirements apply in this part.

Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Classification of iodine monitors
5 Sampling and Detection Assembly (where applicable)
6 Check source
7 Expression of Measurement
8 Response to Other Ionizing Radiations
9 Discrimination against Natural Activity
10 Standard Test Conditions
11 Tests Performed with Variation of the Influence Quantities
12 Reference and Special Sources
13 Radiation Performance Test
14 Tests of the Air Circuit
15 Type Test Report and Certificate