1 Scope
This standard specifies the basic regulations for the general clearance levels of materials contaminated with radionuclides and acceptable levels of to-be-released sites with radioactive substance residuals.
This standard is applicable to any material (article) contaminated with radionuclides controlled by the audit and management, site with radioactive substance residuals, as well as building and equipment therein.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document referred to applies.
GB 13367-92 Principles for the exemption of radiation sources and practices from regulatory control
GB 14500-2003 Regulations for radioactive waste management
GB 17567-1998 Clearance levels for recycle and reuse of steel and aluminum from nuclear facilities
GB 18871-2002 Basic Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources
HJ53-2000 Interim regulation for acceptable levels of residual radionuclides in soil of site considered for release
3 Terms and Definitions
The following terms and definitions apply in this standard.
3.1 Radioactive waste
Radioactive waste, referred to as waste in this standard, refers to the waste expected not to be reused from the practice or intervention (regardless of physical form), including radioactive substances or substances contaminated by radioactive substances; the activity or activity concentration is greater than the clearance level specified by the audit and management department.
Extremely-low radioactive waste refers to a great deal of wastes generated in the process of nuclear facility decommissioning and environment regulation, with low radioactivity level but slightly higher than the clearance level. Exemption waste refers to the waste less than the clearance level and exempted from the control of audit and management.
3.2 Decommissioning
Decommissioning is the management and technology activity adopted for the long-term safety of the public and the environment after the expiration and service of nuclear facilities. The purpose of decommissioning is to realize unrestricted/restricted release or use of sites and/or facilities.
3.3 Recycle and reuse
Metal materials in the materials with contamination level lower than or equal to the clearance level specified by the audit and management department can be recycled as the raw materials after examination, approval and smelting; surface-contaminated metal materials and equipments can be cleared and reused after examination and approval, if their surface contamination levels are lower than or equal to the surface contamination clearance levels given by the standard.
3.4 Dose constraint
It refers to a kind of predetermined constraint of personal dose for source, which is relevant with source, and is used as the constraint condition of protection and safety optimization for considered source. For occupational exposure, the dose constraint is a kind of personal dose value related to source, which is used for restricting selection range considered in optimization process. For public exposure, the dose constraint is the upper bound of annual dose received by member of the public from plan running of one controlled source. Exposure referred to in dose constraint is the sum of annual dose received by any critical group through all exposure pathways in the anticipated operation process of controlled source. Dose constraint for each source shall guarantee that the sum of dose received by any critical group from all controlled sources within the dose limit. For medical exposure, except the protection optimization of radiated medical research personnel or personnel taking care of radiated patient (except worker), the dose constraint value shall be deemed as guidance level.
3.5 Exemptions
It refers that the practice and source in practice meet specified exemption requirement or level by confirmation and are exempted from implementation and management according to the requirements of radiation work after agreed by the audit and management department. Typical exemption sources include such low-activity sources in scientific research as tracing source, calibration source and some consumer goods with a small amount of radioactivity. During the process of clearance, the exemption principle expansion shall be applied to the recycled and reused materials as well as landfill-disposed extremely-low radioactive wastes.
