BS IEC 61504:2017 pdf download – Nuclear facilities – Instrumentation and control systems important to safety – Centralized systems for continuous monitoring of radiation and/or levels of radioactivity
For ease of purchasing and fabricating the equipment, the RMS is usually divided into subsystems such as area gamma monitors, airborne effluent monitors, liquid effluent monitors, and process monitors.
All of the above functions are performed by monitors with diverse types of detectors and electronic equipment, leaving to the operator the difficult task of integrating the information presented. It is important to note that, for many anticipated operational occurrences or accidents, no single radiation monitor can provide the definitive picture of the condition of the plant.
An operator uses the indications of an array of monitors to assist in the decision process. Digital technology, using network communication connections and protocols, provides the opportunity to design the centralized system for radiation monitoring to integrate the information provided by the diverse types of monitors and enhance the display capabilities of the RMS. Below are the design requirements in the order they are listed in IEC 61 559-1 as far as possible. For some design topics, this document imposes no additional design requirements beyond those stated in IEC 61 559-1 .
For other design topics, additional requirements are described below. In this clause, the subclause of IEC 61 559-1 is indicated in each subclause header, if an equivalent subclause exists.
4.1.2 General characteristics and lifecycle (IEC 61 559-1 :2009, 4.1 .
1) The centralized systems for radiation monitoring performing functions that are important to safety shall comply with the requirements relating to the characteristics and lifecycle of RMS defined in IEC 62705 and the standards referred in IEC 62705 (e.g. IEC 61 226).
4.1 .3 Safety classification and applicable standards (IEC 61 559-1:2009, 4.1 .
2) The centralized system for radiation monitoring shall be classified according to its suitability to implement I&C functions up to a defined category during the system specification phase as shown in 6.2.3 of IEC 61 51 3:201 1 . According to the category of the function implemented, the following standards shall be applied:
a) System and equipment performing category A functions Any software in the RMS performing category A functions shall be designed and maintained in accordance with IEC 60880. Any HDL-Programmed Device (HPD) in the equipment of RMS performing category A functions shall be designed and maintained in accordance with IEC 62566. Any hardware in RMS performing category A functions and including software or HPD shall be designed and maintained in accordance with IEC 60987.
b) System and equipment performing category B or C functions Any software in RMS performing category B or C functions shall be designed and maintained in accordance with IEC 621 38. Any hardware in RMS performing category B function and including software shall be designed and maintained in accordance with IEC 60987. Hardware in the RMS performing category C function shall be designed, selected and maintained according to the supplier’s requirements.
4.1.4 System architecture and configuration (IEC 61 559-1 :2009, 4.1 .
3) System architecture is the structured relationship between the components of the system. Figure 1 illustrates one example of a typical architecture for a centralized system for radiation monitoring and shows the relationship of this document to other radiation monitoring standards. A number of configurations are acceptable and the figure is not intended to require a specific arrangement of components, communication busses, or interconnections.
The various types of nuclear facilities existing today have different radiation monitoring requirements. RMS functions are therefore plant-specific. A study of the specific RMS functions and design basis shall be performed for each plant and documented accordingly. IAEA safety guide SSG-39 and IEC 61 226 should be used as applicable to guide the development of the design basis. Each RMS function shall be classified according to the guidance of IEC 61 226 and the study for the system configuration shall consider the following conditions:
• Regulations and limits that the RMS shall detect.BS IEC 61504 pdf download.