EJ/T 20149.2-2018 Guide for design considerations for hot cell equipment - Part 2: Mechanical drive systems for remote operation English, Anglais, Englisch, Inglés, えいご
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ICS
F
Professional Standard of the People’s Republic of China
EJ/T 20149.2-2018
Guide for design considerations for hot cell equipment - Part 2: Mechanical drive systems for remote operation
热室设备设计导则 第2部分：远程操作用机械驱动系统
(English Translation)
Issue date: 2018-12-28 Implementation date: 2019-03-01
Issued by the Commission of Science, Technology and Industry for National Defense of People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms
4 Quality Assurance Requirements
5 General Requirements
6 Structural Materials
7 Equipment Selection
8 Safety Considerations
9 Other Requirements
Design Guidelines for Hot Cell Equipment - Part 2: Mechanically Driven Systems for Remote Operation
1 Scope
This part specifies guiding principles for the design, selection, quality assurance, installation, operation, and maintenance of mechanically driven systems used in remote operation hot cell environments. The mechanically driven systems referred to in this part include individual components that transmit driving force to hot cell equipment systems, subsystems, assemblies, and other components, as well as complete positioning units and systems that provide position indicators required for driving force and motion monitoring. Specific types include, but are not limited to: drive motors; torque transmission components (such as gears, shafts, couplings, transmission belts, transmission chains, torque limiters, slip clutches, brakes); linear positioning systems (such as lead screws, screw jacks, pneumatic cylinders, hydraulic cylinders, electric actuators); position indicators (such as resolvers, encoders, linear variable differential transformers, limit switches).
This part applies to mechanically driven systems operating under one or more of the following conditions: materials handled or processed pose a significant radiation hazard to personnel or the environment; the equipment service life typically exceeds two years, although equipment with a shorter service life is not excluded; equipment cannot be operated or maintained directly and can only be observed through radiation shielding windows or video observation systems.
2 Normative References
The provisions of the following documents, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrigenda) or revisions do not apply to this standard; however, parties entering into agreements based on this standard are encouraged to investigate the possibility of applying the latest editions. For undated references, the latest edition applies.
GB/T 4960.3 Glossary of nuclear science and technology terms - Part 3: Nuclear fuel and nuclear fuel cycle
GB/T 4960.5 Glossary of nuclear science and technology terms - Radiation protection and safety of radiation sources
EJ/T 20149.1-2018 Design guidelines for hot cell equipment - Part 1: General design guidelines
3 Terms
For the purposes of this part, the terms defined in GB/T 4960.3 and GB/T 4960.5, as well as the following, apply.
3.1
mockup
A full-scale simulation facility that reproduces the physical environment of a radioactive facility using non-radioactive structures, systems, and components. It is used to ensure the performance, installation feasibility, accessibility, operability, visibility, and maintainability of items that will subsequently be installed in a radioactive environment.
3.2
radiation shielding window
An optical transmission component that allows observation of the interior of a hot cell while providing radiation shielding for operators.
4 Quality Assurance Requirements
4.1 Designers, manufacturers, and owners (operating organizations) of hot cell equipment shall have a quality assurance program. The quality assurance program shall be implemented after approval by the regulatory authority.
4.2 The owner (operating organization) shall procure hot cell equipment that meets quality assurance requirements to ensure their remote installation and operation within the hot cell and to guarantee equipment reliability. The design of hot cell equipment shall comply with quality assurance requirements.
4.3 During the design phase, special attention shall be paid to the operational performance and long-term integrity of mechanically driven systems. Problems identified during manufacturing and testing shall be resolved, and design changes shall be formally documented. Equipment lifting and installation procedures shall be carried out under strictly controlled conditions to prevent compromising the operational performance and integrity of the equipment.
4.4 Quality assurance requirements shall be specified for mechanically driven systems and components procured from the market to ensure the assembly, operation, and reliability of hot cell equipment.
5 General Requirements
5.1 For safe and efficient operation, the minimum necessary number of mechanically driven system components shall be arranged within the hot cell. Unnecessary placement of equipment inside the hot cell increases operational and maintenance costs, as well as the final decommissioning and disposal costs of the hot cell equipment. Therefore, before introducing equipment into the hot cell, the necessity of each mechanically driven system for achieving hot cell operation shall be assessed.
5.2 All hot cell equipment shall be handled with great care during transfer and installation to prevent damage from dropping.
5.3 Installation operations shall be carried out according to specified procedures. During installation, lifting of other equipment above and around already installed components should be avoided as much as possible.
5.4 Design shall consider the principles of modularity and standardization to ensure maintainability of the equipment throughout its design life. If necessary, the levels at which equipment components can be disassembled and replaced shall be determined in the early design stage. The optimal level of disassembly and replacement is influenced by factors such as estimated maintenance time, the associated cost of hot cell downtime, personnel radiation exposure, and the cost of disposing of failed components. Fasteners and other components shall adopt standardized designs to reduce the inventory of required maintenance tools. Fastener materials, especially for stainless steel fasteners, shall be carefully selected to prevent galling of threaded pairs.
5.5 Before being installed in the hot cell, hot cell equipment shall be tested and qualified on a mockup.
5.6 The electrical and automatic control instrumentation, as well as reading and alarm instruments for mechanically driven systems, shall be located outside the hot cell whenever possible.
5.7 The selection of structural materials for hot cell equipment shall consider requirements for solid waste management and final disposal.
6 Structural Materials
6.1 Plastics, synthetic rubbers, resins, adhesives, solid-state circuit devices, cable insulation, thermal insulation materials, paints, coatings, and other materials are susceptible to radiation damage and may fail. However, it is impossible to completely exclude the application of these materials and components in a hot cell environment. Their use for specific applications shall be carefully considered, and they shall be retested and qualified under the required service conditions before use.
6.2 When sensitive components are exposed to radiation sources, alpha radiation, beta radiation, and gamma radiation can cause rapid and severe damage. Special consideration shall be given to material selection for equipment potentially exposed to radiation. For materials potentially exposed to chemically corrosive atmospheres such as acids, bases, and strong oxidizing agents, the material's resistance to chemical corrosion shall also be considered.
6.3 For components containing materials susceptible to radiation damage, consideration shall be given to their replacement method, ease of replacement, and/or the use of alternative materials with better radiation resistance.
6.4 Polytetrafluoroethylene (PTFE) ages rapidly in high-radiation environments and should be avoided as much as possible in such environments.
