1、 ANSI/HPS N43.7-2007 American National Standard Safe Design and Use of Self-Contained, Dry Source Storage Irradiators (Category I) Approved: August 2007 American National Standards Institute, Inc. ii Published by Health Physics Society 1313 Dolley Madison Blvd. Suite 402 McLean, VA 22101 Copyright 2
2、007 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 ANSI/HPS N43.7-2007 iii The Subcommittee N43-3
3、.4 responsible for the development of American National Standard N433.1-1977 (R-1989) consisted of the following members: Carl Brastrup Elmer Eisenhower Doug Collins Eric Ridout Eric Curnow, chairman Al Tapert Frank Davis Dudley Woodard George Dietz The Subcommittee N43.7 responsible for the develop
4、ment of American National Standard ANSI/HPS N43.7-2007 included the following members: Pete Baker John Jankovich Eric Beers, chairman Jack Ransohoff Rod Chu JL Shepherd Floyd Hamiter Mark Smith Ralph Jacobs Jon Young This standard was consensus balloted and approved on 20 October 2005 by the America
5、n National Standards Committee, N43, on Equipment for Non-Medical Radiation Applications. At the time of balloting, the N43 Committee had the following membership: Chairperson Vice Chairperson ABB Industrial Systems, Inc. Alliance of American Insurers American Automobile Manufacturers Association Am
6、erican Conference of Governmental Industrial Hygienists American Crystallographic Association American Insurance Services Group American Iron and Steel Institute American Public Health Association, Inc. American Society for Nondestructive Testing, Inc. American Society for Testing and Materials Cana
7、dian Nuclear Safety Commission Conference of Radiation Control Program Directors Health Physics Society National Council on Radiation Protection therefore, it is essential to establish basic criteria to ensure a high standard of radiation safety in the design and use of irradiators, but in a way tha
8、t does not unnecessarily restrict the logical use and growth of radionuclide applications. This standard sets forth basic safety standards recommended in irradiator design and use. Its use by regulatory authorities, relative to the review of radionuclide applications, is encouraged. This standard is
9、 an industry consensus and does not take precedence over applicable federal or state regulations. Because of the variety of designs, four general categories of irradiators have been established to facilitate preparation of standards. Separate standards establish the criteria to be used in the design
10、, fabrication, installation, use, and maintenance for each irradiator category. The categories are as follows: Category I: Self-contained, dry source storage irradiators (American National Standard ANSI/HPS N43.7). An irradiator in which the sealed source is completely contained in a dry container c
11、onstructed of solid materials, the sealed source is shielded at all times, and human access to the sealed source and the volume undergoing irradiation is not physically possible in its designed configuration. Category II: Panoramic, dry source storage irradiator (American National Standard ANSI/HPS
12、N43.10). A controlled human access irradiator in which the sealed source is contained in a dry container constructed of solid materials, and the sealed source is fully shielded when not in use; the sealed source is exposed within a radiation volume that is maintained inaccessible during use by an en
13、try control system. Category III: Self-contained, wet source storage irradiator (American National Standard ANSI/HPS N43.15). An irradiator in which the sealed source is contained in a storage pool (usually containing water), the sealed source is shielded at all times, and human access to the sealed
14、 source and the volume undergoing irradiation is physically restricted in its designed configuration and proper mode of use. Category IV: Panoramic, wet source storage irradiator (American National Standard ANSI/HPS N43.10). A controlled human access irradiator in which the sealed source is containe
15、d in a storage pool ANSI/HPS N43.7-2007 vii (usually containing water) and the sealed source is fully shielded when not in use; the sealed source is exposed within a radiation volume that is maintained inaccessible during use by an entry control system. ANSI/HPS N43.7-2007 1 Safe Design and Use of S
16、elf-Contained, Dry Source Storage Irradiators (Category I) 1.0 Scope This standard applies to self-contained, dry source storage irradiators (Category I) that contain sealed gamma- or beta-emitting sources for the irradiation of objects or materials. The standard establishes criteria to be used in t
17、he proper design, fabrication, installation, use, and maintenance of these irradiators that will ensure a high degree of radiation safety. This standard applies to irradiator designs produced after the date of this publication. This standard is not a substitute for regulations. Nothing in this stand
18、ard relieves persons from complying with applicable federal and state requirements governing the use of these irraditors or devices. 2.0 Definitions Accessible surface: that surface of the irradiator to which human access is possible without the use of tools or without penetration of the structural
19、radiation shield. Authorized personnel (authorized person): those individuals authorized by the pertinent regulatory or controlling authority to: a. operate the irradiator, b. perform periodic contamination detection tests on the irradiator, c. install, maintain, and service the irradiator, and d. c
20、ontrol access to the irradiator. Capsule: protective envelope used for prevention of leakage of radioactive material from a sealed source. Contaminated material: any material or object other than a sealed source that contains a radioactive substance (or substances) in average concentration or total
21、quantity in excess of the limits established by the pertinent regulatory or controlling authority. Depleted uranium: uranium material in which the isotope 235U is less than 0.711 weight percent of the total uranium present. Encasement: material that completely covers or encloses the primary shieldin
22、g material; this does not include cosmetic shells or cabinets. Interlock: see Safety interlock. Irradiate mode: status of an irradiator during which the sample volume or material is intentionally being irradiated. Irradiator: device or facility that contains and uses sealed sources for the irradiati
23、on of objects or materials (see Self-contained dry source storage irradiator). Leak test: see Radioactive contamination tests. Licensee: individual or organization to whom the pertinent regulatory authority has issued a license or other document authorizing receipt, possession, and use of an irradia
24、tor. Manufacturer: individual or organization that controls the design, fabrication, registration, and/or distribution of the irradiator or device. Operator: authorized person who controls the use of an irradiator. Primary shielding: the material integral to the design of the irradiator that has as
25、its primary function the attenuation of radiation emitted by the sealed source(s) to acceptable levels. Quality assurance: all those planned and systematic actions necessary to provide adequate confidence that an irradiator will perform satisfactorily in service. Quality control: those quality assur
26、ance actions that provide a means to control, measure, and document the characteristics of an item and/or process to established requirements. Radioactive contamination tests: tests designed to measure any removable radioactive material that may be present on or in the irradiator for the purpose of
27、indicating possible release of radioactive material from the sealed source; also referred to as leak tests. ANSI/HPS N43.7-2007 2 Restricted area: that region around the irradiator to which human access is controlled for radiation safety purposes. Safety interlock: a fail-safe device for precluding
28、exposure of an individual to radiation or other hazards. Safety-related service: any service work that could affect the radiation safety of an irradiator, such as bypassing of the radiation safety interlocks; modification to the shielding that could result in radiation levels in excess of those spec
29、ified in Section 5 of this standard; or source loading, replenishment, removal, and redistribution. Sample load/unload mode: status of an irradiator during which the samples are added to or removed from the sample volume. Sealed source: radioactive source sealed in a capsule or having a bonded cover
30、, the capsule or cover being strong enough to prevent contact with and dispersion of radioactive material under the conditions of use and wear for which it was designed. Self-contained dry source storage irradiator: an irradiator in which the sealed source(s) is completely contained in a dry contain
31、er constructed of solid materials, the sealed source(s) is shielded at all times, and human access to the sealed source(s) and the volume(s) undergoing irradiation is not physically possible in its design configuration. Shall: indicates a recommendation that is necessary to meet the standards of pro
32、tection of this document. Should: indicates an advisory recommendation that is to be applied when practicable. Source: see Sealed source. Source holder: that component of the irradiator into which the source is positioned, including any retaining screws, pins, clips, etc. Source transport container:
33、 Container specifically designed and licensed by the pertinent regulatory or controlling authority to transport sealed sources. Storage mode: status of an irradiator during which the sample volume or material is not being irradiated. Transient mode: status of an irradiator during which the sample vo
34、lume or source is in transition between the storage and the irradiate mode. Unrestricted area: any region to which human access is not controlled for radiation safety purposes. 3.0 General Considerations 3.1 Health Warning The nature, severity, and duration of the effects of radiation exposure depen
35、d, among other factors, on the dose and type of radiation, rate of exposure, portion of the body exposed, and individual sensitivity. In irradiators, ozone is produced by radiolysis. Although this gas may be harmful to health, the exposure levels are not typically significant with Category I irradia
36、tors. 3.2 Radiation Protection Criteria Recommendations for limits on individual equivalent dose from ionizing radiation are established by national and international authorities such as the National Council on Radiation Protection and Measurements (NCRP) 1 and the International Commission on Radiol
37、ogical Protection (ICRP) 2. Operational limits for irradiators should follow the recommendations set forth in the current reports of the NCRP and the ICRP. These recommendations are expressed in terms of a maximum equivalent dose, either as effective dose or the equivalent dose to portions of the bo
38、dy. Regulations pertaining to dose limits have been promulgated by the U.S. Nuclear Regulatory Commission 3, the U.S. Department of Energy 4, or state regulatory or controlling authorities. Personnel doses resulting from irradiator operations shall be maintained as low as reasonably achievable (ALAR
39、A). Maximum allowable personnel doses from irradiator operations shall follow the applicable requirements of Title 10, Code of Federal Regulations, Part 20, Subpart C for ANSI/HPS N43.7-2007 3 occupationally exposed individuals and Subpart D for individual members of the public. For U.S. Department
40、of Energy occupationally exposed individuals the requirements of Title 10, Code of Federal Regulations, Part 835 apply. 3.3 Achieving Safe Operation The safety of an irradiator depends mainly on its design, construction, installation, and proper operation and maintenance or servicing. Responsibility
41、 for the safe design of the irradiator interlocks, controls, primary shielding, and so forth, lies with the manufacturer. The irradiator shall be designed and constructed by qualified personnel and be approved by the pertinent regulatory or controlling authority. Because operators usually have the c
42、losest association with particular irradiators, functional responsibility for safe operation is generally theirs. Operator training, knowledge, experience, and competence will establish the degree of safety associated with operation of the irradiator. Safe operation of the irradiator requires thorou
43、gh understanding by personnel of why and how it functions. This is particularly important when safety-related services such as installation, inspection, and repair of interlocks or source replenishment are performed. These activities shall be performed by or under the supervision of personnel who un
44、derstand the design and construction of the irradiator and its safety components and who will restore all safety components to their operational design condition upon completion of servicing. Each intended use of the irradiator (i.e., irradiation of different products) shall be evaluated prior to us
45、e to ensure that safety of the irradiator is not compromised. 4.0 Sealed Sources 4.1 General All sealed sources shall be authorized under the appropriate regulatory criteria for use in the irradiator. For general sealed source requirements, refer to ANSI/HPS N43.6 5, Sealed Radioactive Sources, Clas
46、sification. Sealed sources should be at least doubly encapsulated. 4.2 Performance Requirements and Classification Using the ANSI/HPS N43.6 5 or International Standard ISO 2919 6 sealed source performance classification system, sources used in Category I irradiators shall have a minimum performance
47、classification of either C43323 or E43323, and, for transportation within the United States, shall follow the applicable requirements of Title 10, Code of Federal Regulations, Part 71 and Title 49, Code of Federal Regulations, Chapter I, Subchapter C, Hazardous Materials Regulations. If applicable,
48、the sealed source bend test described in ANSI/HPS N43.10 7 should be considered. 4.3 Certification and Documentation The source manufacturer or supplier shall maintain records relating to the sealed source(s) and provide certification that the sealed sources meet the relevant requirements. This information may be required to meet licensing and transport requirements. The records shall include the following: a. Model number and identification number of the source(s), date of measurement, absolute activity of the primary radionuclide on the date of measurement, and the activity
