GB 27742-2011Active concentration for material not requiring radiological regulation (English PDF)

Foreword

are mandatory, the rest are recommended.

This Standard is formulated by referring to IAEA safety guide “Application of the Concepts of Exclusion, Exemption and Clearance” (No. RS-G-1.7), and combining the actual situations in China.

The Appendix A of this Standard is informative, the Appendix B is nominative. This Standard was proposed by National Nuclear Corporation.

This Standard shall be administered by National Standardization Technical Committee of Nuclear Energy (SAC/TC 58).

Main drafter of this Standard: Xia Yihua.

1 Scope

This Standard specifies the active concentration for material not requiring radiological regulation (hereinafter referred to as regulation-exempted concentration).

This Standard applies to activities such as production operation, trade, landfill or recycle of large amount (more than 1 ton) material. However, it does not apply to the following conditions:

- Food, water, animal feed and any substances used in food or animal feed;

- Radon in the air (optimized action level of radon concentration in the air is shown in

- Material in transporting (managed according to transportation standard);

- Radioactive residues in the environment (including field soil) .

2 Normative references

however, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.

3 Terms and definitions

The following terms and definitions apply to this Standard.

The collective term of substances and materials, including large amount of solid raw materials, auxiliary materials or materials intend to be deposed involved in the activities such as production operation, trade, recycle and landfill disposal.

The radionuclides that is naturally existed in the earth with significant amount. It mainly refers to the native radionuclides 235U, 238U, 232Th and theirs decay daughter.

situations that can not control the irradiation size and possibility through implementing the requirements of this Standard, such as the irradiation caused by 40K in human body and the cosmic ray reaching to the earth's surface.

The practice and the source in practice that comply with the specified exemption requirements and levels, and they are exempted from regulatory requirements after agreed by the regulatory authorities.

items that have been approved to practice according to regulations.

The metal of which the pollution concentration is equal to or less than the clearance Chinastandards.org level specified in the relevant national standards, is used as raw materials after approval and melting; or the concrete of which the pollution concentration is equal to or less than the clearance level specified in the relevant national standards, is used as building materials after approval and mixing.

4 Determination basis of regulation‐exempted concentration

5 Regulation‐exempted concentration value

regulation-exempted concentration value of natural radionuclides is shown in Chinastandards.org Table B.1.

regulation-exempted concentration value of artificial radionuclides is shown in Table B.2.

6 Application of regulation‐exempted concentration

7 Verification of meeting regulation‐exempted concentration values

activity concentration to representative samples, it shall establish and adopt qualified verification process for activity concentration value. 7.2 Under the premise of ensuring that the active concentration for material shall not exceed the regulation-exempted concentration value of this Standard, it can adopt some indirect methods, including conducting on-site screening and measurement of Chinastandards.org γ dose rate of radioactive-contaminated materials, the method of determining the relationship between the different nuclides content according to appropriate derivation, the method of inquiring traceable information (including their origin and source) about material, and other indirect verification methods acceptable by the regulatory authorities. relationship between its γ radioactivity level and the content of different nuclides is clear, it is very convenient to adopt on-site screen of γ dose rate. It shall under the premise of ensuring that the active concentration in the material does not exceed the level listed in Table B.1 and Table B.2, or other levels required by regulatory authorities - USE the relationship (with sufficient safety margin) BETWEEN the active concentration in material determined by experiment and calculation AND γ external irradiation dose to determine the screen level of γ dose rate under certain measurement conditions. And CONDUCT on-site screen of γ dose rate. It is no necessary to conduct active concentration analysis to the material under screen level of γ dose rate. When screening results indicate that it is necessary to conduct active concentration analysis, or it is necessary to conduct sampling for concentration analysis to meet quality assurance requirements, it can conduct sampling to material according to relevant quality assurance requirements of sampling, and SEND to the laboratory to perform active concentration analysis. 7.4 Regulatory authorities shall verify the sampling and measurement methods, the quality assurance requirements of instrument configuration and verification adopted 7.5 Before conducting the measurement of material, it shall classify different kinds of materials, so as to let the composition and sources of same kind of material remain close. When conducting direct measurement or sample concentration analysis, tit shall ensure the representativeness of measurement condition and sampling samples. 7. […]

Appendix A The irradiation scenarios, ways, main relevant parameters considered when deriving regulation-exempted concentration for artificial

heap in melting plant; Inhaled internal irradiation in melting plant;

Residents near the public place built by polluted materials 1-year-old ~ 2-year-old children Place external irradiation;

Root transfer factor (ft) Not applicable Not applicable Annual ingested amount (q) g/a or kg/a Dose coefficient (einh) µSv/Bq Workers Children (1-year-old~2-year-old) Adults Children ar-old) Elements Reality Low probability Elements Reality Low probability Chinastandards.org Elements Reality Low probability Elements Reality Low probability Chinastandards.org

Appendix B Regulation-exempted concentration value

Note 1: Natural radionuclides, refer to any nuclide in the decay chain of which the mother nucleus is 238U, 235U and 232TH, and in permanent balance. That is, it includes the first-of-chain natural radionuclides 238U, 235U and 232TH in the material, and segmented-chain’s first-of-chain nuclide 225Ra, and every decay daughter nuclide in their decay chain.

“normally” in this area, and any additional concentration value brought by activities.

Note 3: For active concentration of natural 40K in the material, it is not regulated.

Note: * means the half life is less than one day.