IEC 60761-5 pdf download.Equipment for continuous monitoring of radioactivity in gaseous effluents
1 Scope and object
This part of IEC 60761 is applicable to equipment intended for the simultaneous, delayed or discrete sequential measurement of tritium in any gaseous form in gaseous effluents dis- charged into the environment. It is applicable to equipment designed to fulfill the following functions: – the measurement of the concentration of tritium in the gaseous effluents at the discharge point and its variation with time; – the actuation of an alarm when a predetermined volumic activity or a predetermined total released radioactivity is exceeded. The equipment may also be used for the determination of the tritium activity discharge over a given period. The object of this standard is to establish specific standard requirements, including technical characteristics and general test conditions and to give examples of acceptable methods for the tritium effluent monitors defined in clause 4. The general requirements, technical characteristics, test procedures, radiation characteristics, electrical, mechanical, safety and environmental characteristics are given in IEC 60761-1. Unless otherwise stated, these requirements apply in this standard.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC 60761. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of IEC 60761 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 60068-2-27:1987, Environmental testing – Part 2: Tests. Test Ea and guidance: Shock IEC 60761-1:2002, Equipment for continuous monitoring of radioactivity in gaseous effluents – Part 1: General requirements IEC 61000 (all parts), Electromagnetic compatibility (EMC) EN 55022:1994, Limits and Methods of Measurement of Radio Disturbance Characteristics of Information Technology Equipment
5 Sampling and detection assembly
5.1 Sampling and exhaust pipes In addition to the general requirements of IEC 60761-1, the following characteristics shall be considered and shall be agreed between manufacturer and purchaser: – the nature of the materials used, paying particular attention to chemical corrosion, electrostatic effects, memory effects, etc.; – the minimum distance between inlet and outlet to avoid recirculation; – the prevention of condensation in the pipe by variation of temperature or pressure; – the ease of decontamination. 5.2 Inlet filter A filter shall be placed in a filter-holder at the sampling circuit inlet to remove any dust and aerosols from the air. In order to maintain the specified performance of the equipment, such a filter shall not trap, or even temporarily, retain tritium. All necessary arrangements shall be made to control the pressure drop in the filter. The system should be designed to allow filter change at a given pressure drop to ensure that an intact filter is in place. 5.3 Ease of decontamination In order to avoid interference with measurements, it is recommended that all necessary arrangements be made to limit the contamination of the detector. In all cases, the detection assembly shall be easy to dismantle, decontaminate and reassemble.5.4 Collection medium If the detection assembly includes an absorbent medium, intended to collect a specific chemical form of tritium, its characteristics, efficiency, retention capacity and delay time constant shall be known for the various radioactive gases of significance in the effluent. The manufacturer shall state how the collection efficiency is influenced by the chemical form of tritium, atmospheric conditions and the presence of chemical products and other gases in sampled air. The manufacturer shall specify the storage conditions of the absorbent medium.