«Safety of Conversion Facilities and Uranium Enrichment Facilities Specific Safety Guide No. SSG-5 IAEA SAFETY RELATED PUBLICATIONS IAEA SAFETY ...»
Safety Guides Safety Guides provide recommendations and guidance on how to comply with the safety requirements, indicating an international consensus that it is necessary to take the measures recommended (or equivalent alternative measures). The Safety Guides present international good practices, and increasingly they reflect best practices, to help users striving to achieve high levels of safety. The recommendations provided in Safety Guides are expressed as ‘should’ statements.
APPLICATION OF THE IAEA SAFETY STANDARDS
The principal users of safety standards in IAEA Member States are regulatory bodies and other relevant national authorities. The IAEA safety standards are also used by co-sponsoring organizations and by many organizations that design, construct and operate nuclear facilities, as well as organizations involved in the use of radiation and radioactive sources.
The IAEA safety standards are applicable, as relevant, throughout the entire lifetime of all facilities and activities — existing and new — utilized for peaceful purposes and to protective actions to reduce existing radiation risks.
They can be used by States as a reference for their national regulations in respect of facilities and activities.
The IAEA’s Statute makes the safety standards binding on the IAEA in relation to its own operations and also on States in relation to IAEA assisted operations.
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International conventions contain requirements similar to those in the IAEA safety standards and make them binding on contracting parties.
The IAEA safety standards, supplemented by international conventions, industry standards and detailed national requirements, establish a consistent basis for protecting people and the environment. There will also be some special aspects of safety that need to be assessed at the national level. For example, many of the IAEA safety standards, in particular those addressing aspects of safety in planning or design, are intended to apply primarily to new facilities and activities. The requirements established in the IAEA safety standards might not be fully met at some existing facilities that were built to earlier standards. The way in which IAEA safety standards are to be applied to such facilities is a decision for individual States.
The scientific considerations underlying the IAEA safety standards provide an objective basis for decisions concerning safety; however, decision makers must also make informed judgements and must determine how best to balance the benefits of an action or an activity against the associated radiation risks and any other detrimental impacts to which it gives rise.
DEVELOPMENT PROCESS FOR THE IAEA SAFETY STANDARDS
FIG. 2. The process for developing a new safety standard or revising an existing standard.
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INTERACTION WITH OTHER INTERNATIONAL ORGANIZATIONS
The findings of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the recommendations of international expert bodies, notably the International Commission on Radiological Protection (ICRP), are taken into account in developing the IAEA safety standards. Some safety standards are developed in cooperation with other bodies in the United Nations system or other specialized agencies, including the Food and Agriculture Organization of the United Nations, the United Nations Environment Programme, the International Labour Organization, the OECD Nuclear Energy Agency, the Pan American Health Organization and the World Health Organization.
INTERPRETATION OF THE TEXT
Safety related terms are to be understood as defined in the IAEA Safety Glossary (see http://www-ns.iaea.org/standards/safety-glossary.htm). Otherwise, words are used with the spellings and meanings assigned to them in the latest edition of The Concise Oxford Dictionary. For Safety Guides, the English version of the text is the authoritative version.
The background and context of each standard in the IAEA Safety Standards Series and its objective, scope and structure are explained in Section 1, Introduction, of each publication.
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1.1. This Safety Guide on the Safety of Conversion Facilities and Uranium Enrichment Facilities makes recommendations on how to meet the requirements established in the Safety Requirements publication on the Safety of Nuclear Fuel Cycle Facilities , and supplements and elaborates on those requirements.
1.2. The safety of conversion facilities and uranium enrichment facilities is ensured by means of their proper siting, design, construction, commissioning, operation including management, and decommissioning. This Safety Guide addresses all these stages in the lifetime of a conversion facility or an enrichment facility, with emphasis placed on design and operation.
1.3. Uranium and waste generated in conversion facilities and enrichment facilities are handled, processed, treated and stored throughout the entire facility.
Conversion facilities and enrichment facilities may process or use large amounts of hazardous chemicals, which can be toxic, corrosive, combustible and/or explosive. The conversion process and the enrichment process rely to a large extent on operator intervention and administrative controls to ensure safety, in addition to active and passive engineered safety measures. A significant potential hazard associated with these facilities is a loss of the means of confinement resulting in a release of uranium hexafluoride (UF6) and hazardous chemicals such as hydrofluoric acid (HF) and fluorine (F2). In addition, for enrichment facilities and conversion facilities that process uranium with a 235U concentration of more than 1%, criticality can also be a significant hazard.
1.4. The objective of this Safety Guide is to provide recommendations that, in the light of experience in States and the present state of technology, should be followed to ensure safety for all stages in the lifetime of a conversion facility or a uranium enrichment facility. These recommendations specify actions, conditions or procedures necessary for meeting the requirements established in Ref. . This Safety Guide is intended to be of use to designers, operating organizations and regulators for ensuring the safety of conversion facilities and enrichment facilities.
1.5. The safety requirements applicable to fuel cycle facilities (i.e. facilities for uranium ore processing and refining, conversion, enrichment, fabrication of fuel including mixed oxide fuel, storage and reprocessing of spent fuel, associated conditioning and storage of waste, and facilities for the related research and development) are established in Ref. . The requirements applicable specifically to conversion facilities and enrichment facilities are established in Appendix III of Ref. . This Safety Guide provides recommendations on meeting the requirements established in Sections 5–10 and in Appendix III of Ref. .
1.6. This Safety Guide deals specifically with the handling, processing and storage of depleted, natural and low enriched uranium (LEU) that has a 235U concentration of no more than 6%, which could be derived from natural, high enriched, depleted or reprocessed uranium. In conversion facilities for the conversion of uranium concentrate to UF6, several different conversion processes are currently used throughout the world on a large industrial scale. At present enrichment facilities use either the gaseous diffusion process or the gas centrifuge process.
1.7. The implementation of other safety requirements, such as those on the legal and governmental framework and regulatory supervision (e.g. requirements for the authorization process, regulatory inspection and regulatory enforcement) as established in Ref.  and those on the management system and the verification of safety (e.g. requirements for the management system and for safety culture) as established in Ref. , is not addressed in this Safety Guide. Recommendations on meeting the requirements for the management system and for the verification of safety are provided in Ref. .
1.8. Sections 3–8 of this publication provide recommendations on radiation protection measures for meeting the safety requirements established in the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (Ref. ). The recommendations in the present Safety Guide supplement the recommendations on occupational radiation protection provided in Ref. .
1.9. The typical process routes of conversion facilities and enrichment facilities are shown in schematic diagrams in Annexes I and II (see also Ref. ).
1.10. This Safety Guide consists of eight sections and four annexes. Section 2 provides the general safety recommendations for a conversion facility or an enrichment facility. Section 3 describes the safety aspects to be considered in the evaluation and selection of a site to avoid or minimize any environmental impact of operations. Section 4 deals with safety in the design stage; it provides recommendations on safety analysis for operational states and accident conditions and discusses the safety aspects of radioactive waste management in the conversion facility or enrichment facility and other design considerations. Section 5 addresses the safety aspects in the construction stage. Section 6 discusses safety considerations in commissioning. Section 7 deals with safety in the stage of operation of the facility: it provides recommendations on the management of operation, maintenance and periodic testing, control of modifications, criticality control, radiation protection, industrial safety, the management of waste and effluents, and emergency planning and preparedness. Section 8 provides recommendations on meeting the safety requirements for the decommissioning of a conversion facility or an enrichment facility. Annexes I and II show the typical process routes for a conversion facility and an enrichment facility. Annexes III and IV provide examples of structures, systems and components important to safety and operational limits and conditions grouped in accordance with process areas, for conversion facilities and enrichment facilities, respectively.
2. GENERAL SAFETY RECOMMENDATIONS
2.1. In conversion facilities and enrichment facilities, large amounts of uranium
compounds are present in a dispersible form: