Standard Guide for Design of Equipment for Processing Nuclear and Radioactive Materials

Importancia y uso:

4.1 Equipment operability and long-term integrity are concerns that originate during the design and fabrication sequences. Such concerns can only be addressed or are most efficiently addressed during one or the other of these stages. Equipment operability and integrity can be compromised during handling and installation sequences. For this reason, the subject equipment should be handled and installed under closely controlled and supervised conditions.

4.2 This guide is intended as a supplement to other standards, and to federal and state regulations, codes, and criteria applicable to the design of equipment intended for this use.

4.3 This guide is intended to be generic and to apply to a wide range of equipment types and configurations.

4.4 The term equipment is used herein in a generic sense. See 3.2.6 for the definition.

4.5 This service imposes stringent requirements on the quality and the integrity of the equipment, as follows:

4.5.1 Leak tightness is required. This implies containment of liquids at all times, and retention of vapors and gases by means of vessel design, or through means of engineered provisions or operational procedures, or both, that ensure the retention, collection, and treatment of vapors and off-gases when the vessel cannot be fabricated or operated with an air-tight vessel configuration. Radioactive materials must be contained.

4.5.2 Equipment must be capable of withstanding rigorous chemical cleaning and decontamination procedures.

4.5.3 Equipment must be designed and fabricated to remain dimensionally stable throughout its life cycle.

4.5.4 Close fabrication tolerances are required to set nozzles and other datum points in known positions.

4.5.5 Fabrication materials must be resistant to radiation damage, or materials subject to such damage must be shielded or placed so as to be readily replaceable.

4.5.6 Smooth surface finishes are required. Irregularities that hide and retain radioactive particulates or other adherent contamination must be eliminated.

4.5.7 Equipment must be capable of being operated virtually unattended, unseen, and trouble-free over long periods.

4.6 It is assumed that the radiation hazards, combined with the need for confinement and containment, will necessitate a shielded enclosure cell equipped for some degree of remote handling and processing capability in the transuranic materials handling, processing, or machining operations (see 1.2.2).

4.7 Equipment intended for use in the processing and incorporation of radioactive wastes in host composites or matrices may operate at high temperatures and pressures and may require engineered provisions for the removal of large heat loads under normal and emergency conditions. The chemical corrosion and erosion conditions encountered in these processes tend to be extremely severe, placing emphasis on design for containment integrity.

4.8 Maintenance records from the plant or from a plant having a similar processing mission may be available for reference. If available and accessible, these records may offer valuable insight with regard to the causes, frequency, and type of failure experienced for the type and class of equipment being designed and engineered.

4.9 The constraints cited herein are intended to help the engineer establish conditions aimed toward the following:

4.9.1 Enhancing radioactive materials containment integrity,

4.9.2 Minimizing the loss of in-process materials or the spread of hazardous radioactive contaminants,

4.9.3 Minimizing equipment blemishes or faults that promote the adherence or retention of radiation sources,

4.9.4 Facilitating the ease and safety of decontamination and maintenance sequences, and

4.9.5 Reducing the failure frequency rate for all types and classes of equipment used in this service.

4.10 Exclusions: 

4.10.1 In general, this guide is not intended to apply when the conditions set forth in 1.2.1 are irrelevant to the design of equipment or systems.

4.10.2 Given the conditioned exceptions set forth in 4.10.3, this guide is not intended to apply to the following:

4.10.2.1 Operations—Operation of equipment or facilities.

4.10.2.2 Uranium Ore Mining—Equipment or facilities associated with the mining of uranium ore.

4.10.2.3 Uranium/Plutonium/Heavy or Reactive Metals Processing Equipment—Equipment for the processing, machining and handling of uranium, plutonium, or other trans-uranic materials in metallic or other forms such as solutions, slurries, powders, or pellets when the radiation exposure levels are minimal, or when such operations are carried out in hoods or glove boxes and do not require massive radiation shield walls or enclosures. (See 1.2.2.)

4.10.2.4 Laboratory/Research and Development/Semiworks Equipment—Equipment for the above named facilities. The use of this guide in an unrestricted manner would result in equipment that is over-designed and costly for the above service conditions. (See qualification in 4.10.3.)

4.10.2.5 Ancillary and Support Services—Equipment and facilities designed for ancillary and service facilities that are located and installed outside shield walls, in spaces that are directly accessible for purposes of operation, maintenance and repair. (Note, however, the exception stated in 1.2.3.)

4.10.2.6 Nuclear (Fission) Reactors and Auxiliaries Thereof—Design of nuclear fission reactor vessels and auxiliary components and systems used in, or associated with, power reactor facilities or to nuclear reactors and auxiliaries intended for any other use or purpose. This guide does not apply to any equipment item or complex where the primary equipment design considerations include the dissipation of fission heat, or where the removal of radioactive decay heat loads resulting from reactor shutdown is a necessity, or both. (See qualification in 4.10.3.)

4.10.2.7 Decommissioning—Decommissioning of equipment. (See qualification in 4.10.3.)

4.10.2.8 Nuclear Criticality Safety—Design for nuclear criticality safety. (See qualification in 4.10.3.)

4.10.3 Given the foregoing non-applicability statement, this guide may be selectively applied to laboratory, research and development, and semi-works equipment when equipment integrity, materials containment, and the need for ease of cleaning are prime design considerations, where it is deemed essential to safety, or when it is otherwise justifiable. Also, many of the design criteria, guidelines, and caveats set forth herein will have applicability to certain equipment items and auxiliaries to be found in a reactor facility environment. Guidance provided herein relative to equipment features and provisions that minimize the retention of radioactive contamination in any form, and that facilitate cleanup and decontamination, will generally satisfy the potential need for equipment cleanup associated with the eventual decommissioning and disposal of the equipment. Specific guidance is provided in instances where design, fabrication, or integrity considerations are essential to the preservation of conditions or dimensions necessary to meet pre-determined and specified nuclear safety requirements.

Subcomité:

C26.09

Referida por:

C1725-17R22, C1062-23, C1533-15R22, C1554-18R23, C1661-23

Volúmen:

12.01

Número ICS:

27.120.30 (Fissile materials and nuclear fuel technology)

Palabras clave:

design; equipment; nuclear materials; processing;