1、An American National Standard Published by the American Nuclear Society 555 N. Kensington Ave La Grange Park, IL 60526 ANSI/ANS-18.1-2016 Radioactive Source Term for Normal Operation of Light Water Reactors ANSI/ANS-18.1-2016ANSI/ANS-18.1-2016 American National Standard Radioactive Source Term for N
2、ormal Operation of Light Water Reactors Secretariat American Nuclear Society Prepared by the American Nuclear Society Standards Committee Working Group ANS-18.1 Published by the American Nuclear Society 555 North Kensington Avenue La Grange Park, Illinois 60526 USA Approved November 1, 2016 by the A
3、merican National Standards Institute, Inc. American National Standard ANSI/ANS-18.1-2016 American National Standard Designation of this document as an American National Standard attests that the principles of openness and due process have been followed in the approval procedure and that a consensus
4、of those directly and materially affected by the standard has been achieved. This standard was developed under the procedures of the Standards Committee of the American Nuclear Society; these procedures are accredited by the American National Standards Institute, Inc., as meeting the criteria for Am
5、erican National Standards. The consensus committee that approved the standard was balanced to ensure that competent, concerned, and varied interests have had an opportunity to participate. An American National Standard is intended to aid industry, consumers, governmental agencies, and general intere
6、st groups. Its use is entirely voluntary. The existence of an American National Standard, in and of itself, does not preclude anyone from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. By publication of this standard, the American Nu
7、clear Society does not insure anyone utilizing the standard against liability allegedly arising from or after its use. The content of this standard reflects acceptable practice at the time of its approval and publication. Changes, if any, occurring through developments in the state of the art may be
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9、 the latest issue. The American Nuclear Society accepts no responsibility for interpretations of this standard made by any individual or by any ad hoc group of individuals. Responses to inquiries about requirements, recommendations, and/or permissive statements (i.e., “shall,” “should,” and “may,” r
10、espectively) should be sent to the Scientific Publications and Standards Department at Society Headquarters. Action will be taken to provide appropriate response in accordance with established procedures that ensure consensus. Comments on this standard are encouraged and should be sent to Society He
11、adquarters. Published by the American Nuclear Society 555 North Kensington Avenue La Grange Park, Illinois 60526 USA This document is copyright protected. Copyright 2016 by American Nuclear Society. All rights reserved. Any part of this standard may be quoted. Credit lines should read “Extracted fro
12、m American National Standard ANSI/ANS-18.1-2016 with permission of the publisher, the American Nuclear Society.” Reproduction prohibited under copyright convention unless written permission is granted by the American Nuclear Society. Printed in the United States of America American National Standard
13、 ANSI/ANS-18.1-2016 Inquiry Requests Inquiry Format The American Nuclear Society (ANS) Standards Committee will provide responses to inquiries about requirements, recommendations, and/or permissive statements (i.e., “shall,” “should,” and “may,” respectively) in American National Standards that are
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16、ontacting the ANS Scientific Publications and Standards Department. Inquiry requests shall include the following: (1) the name, company name if applicable, mailing address, and telephone number of the inquirer; (2) reference to the applicable standard edition, section, paragraph, figure, and/or tabl
17、e; (3) the purpose(s) of the inquiry; (4) the inquiry stated in a clear, concise manner; (5) a proposed reply, if the inquirer is in a position to offer one. Inquiries should be addressed to: American Nuclear Society ATTN: Scientific Publications and Standards Department 555 N. Kensington Avenue La
18、Grange Park, IL 60526 or standardsans.org American National Standard ANSI/ANS-18.1-2016 American National Standard ANSI/ANS-18.1-2016 i Foreword (This foreword is not a part of American National Standard, “Radioactive Source Term for Normal Operation of Light Water Reactors,” ANSI/ANS-18.1-2016.) Th
19、e purpose of this standard is to provide a set of typical radionuclide concentrations for estimating the radioactivity in the principal fluid streams of a light water reactor. Some systems will have different concentrations from those indicated in this standard. The values in this standard were thos
20、e judged to be representative concentrations in a light water reactor over its lifetime based upon the data currently available. It is not intended that these data be used as the sole basis for design but be used in environmental reports and elsewhere where expected operating conditions over the lif
21、e of the plant would be appropriate. The data and methodology provided by previous versions of this standard have been incorporated in the GALE computer codes (see Bibliography) used for the calculation of gaseous and liquid effluents from light water reactors. The changes included in this standard
22、should be considered in future updates of these codes. This standard is Revision 3 of American National Standard N237-1976 (ANS-18.1- 1976), “Source Term Specification,” and updates the default activity concentrations and adjustment factors associated with Revision 2 (ANSI/ANS-18.1-1999, “Radioactiv
23、e Source Term for Normal Operation of Light Water Reactors”), based on the latest review of data from operating domestic nuclear power plants as documented in Electric Power Research Institute DRAFT Technical Document, “Technical Bases for Update of the ANSI/ANS-18.1-1999 Standard to Incorporate Con
24、temporary Best-Estimate Radiological Source Terms in Principal Fluid Streams of Light Water Reactors” (October 2015). The values given in this standard will be revised periodically as additional plant operating data become available. This standard does not incorporate the concepts of generating risk
25、-informed insights, performance-based requirements, or a graded approach to quality assurance. The user is advised that one or more of these techniques could enhance the application of this standard. This standard was prepared by the ANS-18.1 Working Group of the American Nuclear Society. The follow
26、ing members contributed to this standard: K. Geelhood (Chair), Pacific Northwest National Laboratory L. Benevides, U.S. Nuclear Regulatory Commission E. Dickson, U.S. Nuclear Regulatory Commission C. Fung Poon, GE Hitachi Nuclear Energy D. Hussey, Electric Power Research Institute M. OConnor, Electr
27、ic Power Research Institute M. Shaver, NuScale Power Inc. T. Lloyd, Westinghouse Electric Company The Large Light Water Reactor the inclusion of radionuclides that could include a significant contribution from external exposure; or the evaluation of the safety of a nuclear facility requiring the ana
28、lyses of the facilities detection of a response to postulated equipment failures or malfunctions. 1.3 Purpose The purpose of this standard is to provide a uniform approach, applicable to light watercooled nuclear power plants, for the determination of expected concentrations in fluid streams. Throug
29、h application of this standard, a common basis for the determination of radioactive source terms for normal operating conditions is established, with the goal of providing a consistent approach for those involved in the design of these facilities. Utilization of this standard is expected to aid the
30、licensing process and the publics understanding of the impact of nuclear power relative to radionuclide concentrations and possible releases to the environment. 2 Definitions 2.1 Shall, should, and may The word “shall” is used to denote a requirement; the word “should” is used to denote a recommenda
31、tion; and the word “may” is used to denote permission, neither a requirement nor a recommendation. American National Standard ANSI/ANS-18.1-2016 2 3 Specifications Parameters that characterize the three types of nuclear steam supply systems are given in Table 1 (BWR), Table 2 (PWR with U-tube steam
32、generators), and Table 3 (PWR with once-through steam generators). The reference plant values are based on typical systems that are sufficiently general to be applicable to most light water reactors. The choice of these parameters is not meant to imply a recommendation of their use in selecting a pl
33、ant design. Figures 1, 2, and 3 present block diagrams of the reference reactor systems and provide the bases for the removal rate equations and adjustment factors. The various radioactive elements that might be present in fluid streams have been divided into six classes, as shown in Table 4. This d
34、ivision was made to facilitate the adjustment procedure. Except for Class 6, these classes are based on the grouping of elements with reasonably similar chemical and physical properties or similar behavior during normal operation. Class 6 includes all other elements that could not be classified read
35、ily in any of the other classes. The following sections describe how this standard is applied to plants that have the parametric values given in Tables 1, 2, and 3 and how to determine radionuclide concentrations if one or more parameters differ from the reference values. 3.1 Specification of radion
36、uclide concentrations for reference plants If the parameters of a plant are the same as those given in Tables 1, 2, or 3, the recommended radionuclide concentrations in Tables 5, 6, and 7 shall be applied. Table 5 radionuclide concentrations shall be applied for reactor coolant for the reference BWR
37、. Table 6 radionuclide concentrations shall be applied for reactor coolant and steam generator fluid for the reference PWR with U-tube steam generators. Table 7 radionuclide concentrations shall be applied for reactor coolant and secondary steam for the reference PWR with once-through steam generato
38、rs. These radionuclide concentrations are based on data obtained from operating nuclear plants. 3.2 Adjustment of the reference plant radionuclide concentrations to a specific plant If any parameter, such as power level, flow rate, or fluid quantity, differs from the values given in Tables 1, 2, or
39、3 (as appropriate), the procedures described in the following paragraphs shall be used to determine the adjustment factors needed to modify the radionuclide concentrations in Tables 5, 6, and 7. Recalculated fluid stream concentrations shall be based on the numerical values provided in Tables 5, 6,
40、and 7, which are given to only one or two significant figures. It is inappropriate to assign a greater accuracy to any fluid stream concentration calculated through the use of the adjustment factors described in this standard. Tables 8 through 12 present the values and equations that shall be used t
41、o determine the adjustment factors for each class of elements. To determine radionuclide concentrations in the principal fluid streams of the plant under study, the concentrations in Tables 5, 6, and 7 shall be multiplied by the appropriate adjustment factors in Tables 10, 11, and 12. Values used in
42、 the determination of adjustment factors are given in Tables 8 and 9. The adjustment factors have been established on the assumption that the specific plant has the same transport and removal paths as the applicable reference plant shown in Figs. 1, 2, and 3. The adjustment factors are based upon the following expression: = ( + ) , where: C is the radionuclide concentration; s is the rate of release to or production of the radionuclide in the system; m is the fluid mass;
