Detail of EJ/T 1180-2005

Introduction of EJ/T 1180-2005

Design Criteria for Installed Radiation Monitoring System in PWR Nuclear Power Plant Buildings 1 Scope This standard specifies the function and composition of installed radiation monitoring system in PWR nuclear power plant buildings, arrangement radiation monitoring point and the classification and requirements of measuring channel. This standard is applicable to the design for installed radiation monitoring system in PWR nuclear power plant buildings. This standard is not applicable to the design for controlled area access monitoring system and personal dose monitoring system. 2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent modification to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of these documents is applicable. For undated references, the latest edition of the normative document is applicable to this standard. GB/T 8993 "Environmental Conditions and Testing Procedures for Nuclear Instrumentation" GB/T 12727 "Qualification of Electrical Items of the Safety Systems for Nuclear Power Generating Stations" GB/T 13625 "Seismic Qualification of Electrical Equipment of the Safety System for Nuclear Power Plants" GB/T 15474 "Safety Classification of Instrumentation and Control Systems and Their Electrical Equipment of Nuclear Power Plants" GB/T 15475 "Classification of Quality Assurance for Instrumentation and Control System and Their Electrical Equipment of Nuclear Power Plants" 3 Terms and Definitions 3.1 Area radiation monitoring It is used for continuously monitoring the radiation dose rate and air activity concentration of a certain installed area in nuclear power plants. 3.2 Effluents monitoring It is used for continuously monitoring the radioactive activity of effluents in nuclear power plants. The effluents include gas and liquid effluents, and the gas effluent generally refers to aerosol, iodine and inert gases. 3.3 Safety barrier monitoring In nuclear power plants, the safety barrier refers to fuel element jacket, reactor coolant bearing boundary and containment. The safety barrier monitoring is used for monitoring the integrity of these three barriers (leakage situation). 3.4 Process monitoring It is used for supervising the working state of certain important system and equipment in nuclear power plants utilizing the monitoring process media or the change of certain position radioactivity level. And the process monitoring includes safety barrier monitoring. 3.5 Single failure It refers to a kind of random failure resulting in a certain component not implementing the intended function. All kinds of secondary failures caused by single random event shall be taken as the constituent of single failure. 3.6 Single failure criteria It means that the equipment combination for implementing the same measurement mission can maintain the planned function when single random failure occurs to any part in it. 3.7 Physical separation The physical separation shall include: a) Geometric separation, such as distance and direction; b) Appropriate barrier separation; c) Combination of above 3.8 Function separation It refers to all kinds of methods that make the function of a certain circuit or system free from the influence of another circuit or system. 3.9 Electrical separation It refers to the loop that there is no electricity among component, equipment, channel or system. 3.10 Independent equipment It refers to the equipment that is independent and has two following characteristics: a) The capacity for implementing the required function is free from the influence of other equipment operation or failure; b) The capacity for implementing the function is free from the influence of the consequence caused by functionated supposed initial incident. 4 Function of Radiation Monitoring System The installed radiation monitoring system in PWR nuclear power plant buildings (hereinafter referred as monitoring system) shall be provided with three following functions at least. 4.1 Area Radiation Monitoring The monitoring system shall truly monitor and indicate the radiation level and radioactive air contamination level of each important area, and guarantee the power plant staff free from unnecessary radiation exposure. The monitoring system shall also provide the radiation level information of each important area in power plant for radiation protection personnel, technical support personnel and radiation emergency personnel. This information may be used for analyzing, searching and judging the possible fault by relevant personnel so as to promptly handle the fault and guarantee the safe operation of nuclear power plants.

Contents of EJ/T 1180-2005

Foreword I 1 Scope 2 Normative References 3 Terms and Definitions 4 Function of Radiation Monitoring System 4.1 Area Radiation Monitoring 4.2 Effluents Monitoring 4.3 Process Monitoring 5 Monitoring System Composition and Measuring Channel Classification 6 Arrangement of Radiation Monitoring Equipment 6.1 General Principles 6.2 Arrangement of Area Gamma Radiation Monitoring Point 6.3 Arrangement of Air activity Concentration Monitoring Points 6.4 Arrangement of Effluents Monitoring Points 6.5 Arrangement of Process Monitoring Points 7 Requirements of Measuring Channel 7.1 General Requirements 7.2 Safety Class of Measuring Channel 7.3 Seismic Classification of Measuring Channel 7.4 Quality Assurance Classification of Measuring Channel 7.5 Quality Appraisal Classification of Channel 8 Applicable Standards of Each Measuring Channel Instrument Annex A (Informative) Main Measuring Channels of Radiation Monitoring System in Ling Ao Nuclear Power Plants Annex B (Informative) Applicable Standards of Radiation Monitoring System Instrument