ANSI HPS N43.3-2008 For General Radiation Safety C Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources Energies Up to 10 MeV.pdf

1、 ANSI/HPS N43.3-2008 American National Standard For General Radiation Safety Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies Up to 10 MeV Approved: January 2008 American National Standards Institute, Inc. ii Published by Health Physics Society 1313 Dolley Madison Blvd. S

2、uite 402 McLean, VA 22101 Copyright 2008 by the Health Physics Society. All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America iii Abstr

3、act This standard establishes guidance for the design and use of installations that use x-raygenerating devices and sealed gamma-ray sources of energies up to 10 MeV for non-medical purposes. Its main objectives are to keep the exposure of persons to radiation to levels as low as reasonably achievab

4、le (ALARA) and to ensure that no one receives a dose equivalent greater than the maximum permissible dose equivalent. These objectives may be achieved by the use of engineered controls, firm management controls, safe operating procedures, appropriate equipment, and a comprehensive maintenance and su

5、rveillance program. Annexes contain technical information useful for the design of radiation shielding. Key words: Gamma-ray equipment; radiation installations; radiation safety; x-raygenerating devices iv Foreword (This foreword is not a part of American National Standard ANSI/HPS N43.3-2008.) In 1

6、946, the sectional committee of the American Standard Association issued American War Standard Z54.1-1946, “Safety Code for the Industrial Use of X-rays.” Handbook 93 (Z54.1-1963), “Safety Standard for Non-Medical X-ray and Sealed Gamma-Ray Sources,” issued in 1964, was a revision of a part of the w

7、ar standard. These standards provided the necessary guidance for the safe installation and use of penetrating radiation used in industry. The American National Standards Institute Committee N43 examined Z54.1-1963 and determined that a revision was necessary. This task was assigned to Subcommittee N

8、43-5 and the revision was published in 1974 as NBS Handbook 114 (ANSI N543-1974, reaffirmed 1989), “General Safety Standard for Installation Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies up to 10 MeV.” Subcommittee N43-5 began the revision of ANSI N543-1979 in November 1983 and comp

9、leted its work in December 1991. This American National Standard provides guidance for the safe use of x-raygenerating devices and sealed gamma-ray sources with energies up to 10 MeV. Though some principles do not change much over time (for example, time, distance, and shielding), some technologies

10、have changed substantially, warranting a revision of this standard. The last revision of ANSI/HPS N43.3 was in 1993. Since then, there have been considerable changes in the norm regarding dosimetry, radiation detection, and concepts regarding configuration control of hardware and software. This revi

11、sion attempts to address those changes. Perhaps the most substantive changes to be found in this revision are: changes to SI units from conventional special units such as roentgen, updates to references, taking into account the latest information from the international community, acceptance of “radi

12、ation detection instrument” rather than “radiation survey meter” for some entries into an exposure room, discouraging use of continuous alarms unrelated to the need for evacuation, calling for the use of professional health physicists and reliance on their professional judgment, guidance regarding t

13、he use of programmable logic controllers (PLCs), and guidance regarding software configuration control. This standard contains six annexes that are informative and not considered part of this standard. The Accredited Standards Committee N43, on Equipment for Non-Medical Radiation Applications, had t

14、he following personnel at the time it processed and approved this standard: Chairperson Vice Chairperson ABB Industrial Systems, Inc. American Conference of Governmental Industrial Hygienists American Crystallographic Association American Iron and Steel Institute American Public Health Association,

15、Inc. American Society for Nondestructive Testing, Inc. American Society for Testing and Materials Canadian Nuclear Safety Commission Conference of Radiation Control Program Directors Health Physics Society National Council on Radiation Protection 300 and 400 kV constant potential51 Figure D4. Attenu

16、ation in lead of x-rays produced by potentials of 0.5 to 3 MV constant potential .52 Figure D5.Transmission through lead of x-rays produced at 4 to 10 MV .53 Figure D6. Transmission through lead and steel of 6 MV primary x-rays scattered at 90 degrees54 Figure D7. Transmission through iron of x-rays

17、 produced at 4 to 10 MV .55 Figure D8. Attenuation in concrete of x-rays produced by potentials of 50 to 300 kV peak; 400 kV constant potential56 Figure D9. Attenuation in concrete of x-rays produced by potentials of 0.5 to 3 MV constant potential 57 Figure D10. Transmission through concrete of x-ra

18、ys produced at 4 to 10 MV .58 Figure D11. Transmission through concrete for 6 MV primary x-rays scattered at six different angles.59 ANSI/HPS N43.3-2008 1 For General Radiation Safety Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies up to 10 MeV 1.0 Scope This standard es

19、tablishes guidance for the design and use of installations that use x-raygenerating devices and sealed gamma-ray sources of energies up to 10 MeV for non-medical purposes. Devices that produce photon radiation within this energy range that are merely incidental to use are not included within the sco

20、pe. The standards main objectives are to keep the exposure of persons to radiation to levels as low as reasonably achievable (ALARA) and to ensure that no one receives a dose equivalent greater than the maximum permissible dose equivalent. These objectives may be achieved by the use of engineered co

21、ntrols, firm management controls, safe operating procedures, appropriate equipment, and a comprehensive maintenance and surveillance program. Annexes contain technical information useful for design of radiation shielding. It should be noted that this standard covers a range of radiation sources simi

22、lar to that of ANSI/HPS N43.11, “Safe Operating Practice for Non-Medical X-ray Radiographic and Radio-scopic Equipment.” ANSI/HPS N43.3-2008 is appropriate for use by technical experts for the design of installations and for the establishment of radiation protection programs. It is useful only to a

23、limited extent for day-to-day operation of facilities. It is recommended that ANSI/HPS N43.11 be consulted for routine operational use. Those recommendations containing the word “shall” identify requirements that are necessary to meet the standards of protection in this document. Those using the wor

24、d “should” indicate advisory recommendations that are to be applied when practical. 2.0 Normative References The following standards contain provisions that through reference in this text constitute provisions of this American National Standard. At the time of publication, the editions indicated wer

25、e valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Health Physics Society. 1999. Practice for occupational radiation ex

26、posure records system. ANSI/HPS N13.6-1999. McLean, VA: Health Physics Society. Health Physics Society. 1997. Sealed radioactive sources, classification. ANSI/HPS N43.6-2007. McLean, VA: Health Physics Society. Health Physics Society. 2001. Classification of industrial ionizing radiation gauging dev

27、ices (NBS 129). ANSI/HPS N43.8-2001. McLean, VA: Health Physics Society. U.S. Food and Drug Administration, (FDA). 2006. Cabinet x-ray systems. 21 CFR 1020.40. Washington DC: FDA. 3.0 Definitions The definitions and terms contained in this standard are not intended to embrace all legitimate meanings

28、 of the terms. They are applicable only to the subject treated in this standard. Definitions are provided in this section for clarity and to facilitate a common understanding of the provisions in this standard. These definitions are not intended to supersede similar terms that are defined through ap

29、plicable federal and state regulations. ANSI/HPS N43.3-2008 2 absorbed dose: The energy imparted to matter by ionizing radiation per unit mass of irradiated material. The unit of absorbed dose, in the Systme Internationale (SI), is the joule per kilogram, given the special name gray (Gy) (also commo

30、nly called dose). 1 Gy = 1 J kg1= 100 rad. access panel: Any barrier or panel that is designed to be removed or opened for maintenance or service purposes, permitting access to the interior of the cabinet. accessible area: Any area where the body or a part of the body may be exposed to radiation wit

31、hout necessitating a shutdown of the radiation source. access: Exposure of the body or a part of the body to a particular area. activity (A): The quotient of dN by dt, where dN is the number of spontaneous nuclear transitions or disintegrations that occur in a quantity of a radionuclide in the time

32、interval dt. The SI unit of activity is the becquerel (Bq). 1 Bq = 1 disintegration per second (dps), where 3.7 1010Bq= 1 curie (Ci). air kerma: Kerma (see definition below), where the matter under consideration is air. This unit has replaced the term “exposure” in international technical literature

33、. as low as reasonably achievable (ALARA): Making every reasonable effort to maintain exposures to radiation as far below the dose limits as practical, taking into account the state of technology, the economics of improvements in relation to benefits to health and safety, and other societal and soci

34、oeconomic considerations. attenuation: The reduction of a radiation quantity upon passage of radiation through matter, resulting from all types of interaction with that matter. The radiation quantity may be, for example, the particle fluence rate. becquerel (Bq) The special SI unit of radioactivity,

35、 where 1 Bq = 1 spontaneous nuclear transition (disintegration) per second (dps), 3.7 1010Bq= 1 curie (Ci). cabinet x-ray system1: An x-ray system with the x-ray tube installed in an enclosure which, independently of existing architectural structures except the floor on which it may be placed, is in

36、tended to contain at least that portion of a material being irradiated, provide radiation attenuation, and exclude personnel from its interior during generation of x-radiation. Included are all x-ray systems designed primarily for the inspection of carry-on baggage at airline, railroad, and bus term

37、inals, and in similar facilities. An x-ray tube used within a shielded part of a building, or x-raygenerating device that may temporarily or occasionally incorporate portable shielding is not considered to be a cabinet x-ray system. collimator: A device used to limit the size, shape, and direction o

38、f the primary beam. controlled area: A specified area in which access of personnel to radiation or radioactive material is controlled. A controlled area should be under the supervision of a person who has knowledge of the appropriate radiation protection practices, including pertinent regulations, a

39、nd who has responsibility for applying them. curie (Ci): The conventional special unit of activity. One curie equals exactly 3.7 1010Bq. dose equivalent (H): The product of Q and D at a point in tissue, where D is the absorbed dose and Q is the quality factor at that point (ICRU 1998): H = QD The un

40、it of dose equivalent is the joule per kilogram (J kg1) with the special name sievert (Sv), where 1 Sv = 100 rem. For radiation protection purposes in this standard, the dose equivalent in Sv may be considered numerically equivalent to the absorbed dose in Gy (1 rem 1 rad 1 R). Unless otherwise spec

41、ified, “dose equivalent” may also be assumed for the purposes of this standard to be equivalent to Hp(10), individual dose equivalent, penetrating, at a depth of 10 mm in tissue (deep dose equivalent). See the note under the definition of exposure. exposure (X): A measure of the ionization produced

42、in air by x or gamma radiation of 1Controlled under 21 CFR 1020.40. ANSI/HPS N43.3-2008 3 energies less than or equal to 3 MeV. It is the sum of the electrical charges of all of the ions of one sign produced in air when all electrons liberated by photons in a volume element of air are completely sto

43、pped in the air, divided by the mass of the air in the volume element. The SI unit of exposure is coulomb per kilogram (C kg1). The conventional special name for exposure is the roentgen (R), where 1 R = 2.58 104C kg1. Though the conversion is slightly dependent on photon energy, for the purposes of

44、 this Standard, an exposure of 100 R corresponds to an air kerma of approximately 0.878 Gy (1 R 0.878 rad in air). Note: “exposure” is also used colloquially to express contact with a radiation field. Its use as either the technical term above or in the more conversational sense should be obvious by

45、 context. exposure area: Any controlled area in which an actively used radiation source or x-ray production target may be present. exposure rate: Exposure per unit time. In the case of a pulsed x-raygenerating device, the exposure rate is considered to be the time-weighted average over a full cycle,

46、 not an instantaneous rate. fail-safe design: A design in which failures of indicators or safety components that can be reasonably anticipated result in a condition in which personnel are safe from exposure to radiation. For example: (a) if a light indicating “x-rays on” fails, the production of x-r

47、ays shall be prevented, or (b) if a shutter status indicator fails, the shutter shall close. gray (Gy): The special SI name given to the unit of absorbed dose. 1 Gy = 1 J kg1= 100 rad. half-value layer (HVL), half-value thickness (HVT): The thickness of a specified substance which, when introduced i

48、nto a beam of radiation, reduces the exposure rate at the reference point by one-half. high radiation area: Any area, accessible to individuals, in which radiation levels could result in an individual receiving a deep dose equivalent in excess of 0.001 Sv (0.1 rem) in one hour at 30 cm from the radi

49、ation source or from any surface that the radiation penetrates. installation: A radiation source, with its associated equipment, and the space in which it is located (see section 4, Classes of Installations). interlock: An electromechanical device that automatically precludes access to an area of radiation hazard either by preventing entry or by automatically removing the radiation hazard ionizing radiation: Any electromagnetic or particulate radiation capable or producing ions, directly or indirectly, by interaction with matter, inc