1、ANSI/ANS-8.14-2004use of soluble neutronabsorbers in nuclearfacilities outside reactorsANSI/ANS-8.14-2004REAFFIRMED June 29, 2016ANSI/ANS-8.14-2004 (R2016)November 16, 2011 ANSI/ANS-8.14-2004 (R2011) This standard has been reviewed and reaffirmed with the recognition that it may reference other stan
2、dards and documents that may have been superseded or withdrawn. The requirements of this document will be met by using the version of the standards and documents referenced herein. It is the responsibility of the user to review each of the references and to determine whether the use of the original
3、references or more recent versions is appropriate for the facility. Variations from the standards and documents referenced in this standard should be evaluated and documented. This standard does not necessarily reflect recent industry initiatives for risk informed decision-making or a graded approac
4、h to quality assurance. Users should consider the use of these industry initiatives in the application of this standard. ANSI/ANS-8.14-2004American National StandardUse of Soluble NeutronAbsorbers in NuclearFacilities Outside ReactorsSecretariatAmerican Nuclear SocietyPrepared by theAmerican Nuclear
5、 SocietyStandards CommitteeWorking Group ANS-8.14Published by theAmerican Nuclear Society555 North Kensington AvenueLa Grange Park, Illinois 60526 USAApproved May 25, 2004by theAmerican National Standards Institute, Inc.AmericanNationalStandardDesignation of this document as an American National Sta
6、ndard attests thatthe principles of openness and due process have been followed in the approvalprocedure and that a consensus of those directly and materially affected bythe standard has been achieved.This standard was developed under procedures of the Standards Committee ofthe American Nuclear Soci
7、ety; these procedures are accredited by the Amer-ican National Standards Institute, Inc., as meeting the criteria for AmericanNational Standards. The consensus committee that approved the standardwas balanced to ensure that competent, concerned, and varied interests havehad an opportunity to partici
8、pate.An American National Standard is intended to aid industry, consumers, gov-ernmental agencies, and general interest groups. Its use is entirely voluntary.The existence of an American National Standard, in and of itself, does notpreclude anyone from manufacturing, marketing, purchasing, or using
9、prod-ucts, processes, or procedures not conforming to the standard.By publication of this standard, the American Nuclear Society does not insureanyone utilizing the standard against liability allegedly arising from or afterits use. The content of this standard reflects acceptable practice at the tim
10、e ofits approval and publication. Changes, if any, occurring through developmentsin the state of the art, may be considered at the time that the standard issubjected to periodic review. It may be reaffirmed, revised, or withdrawn atany time in accordance with established procedures. Users of this st
11、andardare cautioned to determine the validity of copies in their possession and toestablish that they are of the latest issue.The American Nuclear Society accepts no responsibility for interpretations ofthis standard made by any individual or by any ad hoc group of individuals.Requests for interpret
12、ation should be sent to the Standards Department atSociety Headquarters. Action will be taken to provide appropriate response inaccordance with established procedures that ensure consensus on theinterpretation.Comments on this standard are encouraged and should be sent to SocietyHeadquarters.Publish
13、ed byAmerican Nuclear Society555 North Kensington AvenueLa Grange Park, Illinois 60526 USACopyright 2004 by American Nuclear Society. All rights reserved.Any part of this standard may be quoted. Credit lines should read “Extracted fromAmerican National Standard ANSI0ANS-8.14-2004 with permission of
14、the publisher,the American Nuclear Society.” Reproduction prohibited under copyright conventionunless written permission is granted by the American Nuclear Society.Printed in the United States of AmericaForewordThis foreword is not part of American National Standard “Use of Soluble NeutronAbsorbers
15、in Nuclear Facilities Outside Reactors,” ANSI0ANS-8.14-2004!This standard provides guidance for the use of soluble neutron absorbers forprocess and handling operations in which solutions of neutron absorbers areused for criticality control. This standard supplements the provisions for “Nu-clear Crit
16、icality Safety in Operations with Fissionable Materials Outside Reac-tors,” ANSI0ANS-8.1-1998, in providing more detailed guidance for the use ofsoluble neutron absorbers. Soluble neutron absorbers can be used as a primarymeans of criticality safety control or as defense in depth to provide an addit
17、ionalsafety margin and as such make the safety of the system more robust. As withany parameter controlled for criticality safety, and particularly important withsoluble neutron absorbers, one must ensure that the controlled parameter ismaintained within the range that has been shown by experiment or
18、 evaluation tomaintain subcriticality.This standard prepared by Working Group ANS-8.14 was composed of the fol-lowing members:T. A. Reilly Chairman!, Westinghouse Safety Management Solutions, LLCR. D. Carter Past Chairman!, IndividualL. J. Berg, U.S. Nuclear Regulatory CommissionA. S. Garcia, U.S. D
19、epartment of Energy, IdahoR. A. Knief, XE CorporationR. C. McBroom, U.S. Department of Energy, Oak Ridge Operations OfficeL. M. Montierth, Idaho National Engineering and Environmental LaboratoryJ. A. Morman, Argonne National LaboratoryV. L. Risner, USECS. K. Skiles, NuclearSafety AssociatesR. E. Wil
20、son, U.S. Department of Energy, Rocky Flats Environmental Technology SiteThis standard was prepared under the guidance of Subcommittee 8, FissionableMaterials Outside Reactors, of the American Nuclear Society. Subcommittee 8 atthe time of initial ballot was composed of the following members:T. P. Mc
21、Laughlin Chairman!, Los Alamos National LaboratoryJ. A. Schlesser Secretary!, Westinghouse Safety Management Solutions, LLCF. M. Alcorn, IndividualE. D. Clayton, IndividualA. S. Garcia, U.S. Department of Energy, IdahoN. Harris, BNFLC. M. Hopper, Oak Ridge National LaboratoryR. Kiyose, IndividualR.
22、A. Libby, Pacific Northwest National LaboratoryD. A. Reed, Oak Ridge National LaboratoryT. A. Reilly, Westinghouse Safety Management Solutions, LLCH. Toffer, Fluor Federal ServicesG. E. Whitesides, IndividualConsensus Committee N16, Nuclear Criticality Safety, was composed of thefollowing members at
23、 the time of approval:C. M. Hopper Chairman!, Oak Ridge National LaboratoryR. A. Knief Vice-Chairman!, XE CorporationG. H. Bidinger, IndividualR. D. Busch, University of New MexicoM. S. Chatterton, U.S. Nuclear Regulatory CommissionH. L. Dodds, Jr., University of TennesseeR. S. Eby, American Institu
24、te of Chemical EngineersC. D. Manning, Framatome ANPB. McLeod, Institute of Nuclear Materials ManagementS. P. Murray, Health Physics SocietyiH. C. Paxton, IndividualR. L. Reed, Westinghouse Safety Management Solutions, LLCB. M. Rothleder, U.S. Department of EnergyF. W. Sanders, IndividualD. R. Smith
25、, IndividualR. G. Taylor, IndividualJ. T. Thomas, IndividualR. M. Westfall, Oak Ridge National LaboratoryiiContentsSection Page1 Introduction . 12 Scope . 13 Definitions 13.1 Limitations 13.2 Shall, Should, May . 13.3 Glossary of Terms 14 Administrative Requirements and Guidance . 24.1 Neutron Absor
26、ber Selection . 24.2 System Design and System Modifications 24.3 Criticality Safety Evaluations . 24.4 Quality Control Program 34.5 Facility Operation with Soluble Absorbers 35 References 3 iii Use of Soluble Neutron Absorbers inNuclear Facilities Outside Reactors1 IntroductionGuidance for criticali
27、ty control in process andhandling operations with fissile material is pre-sented in American National Standard “Nu-clear Criticality Safety in Operations withFissionable Materials Outside Reactors,” ANSI0ANS-8.1-1998 1#.1!However, for solutions thesingle parameter subcritical limits on unit mass,vol
28、ume, concentration, and geometricdimen-sions can be highly restrictive. Significantlylarger limits are possible if soluble neutron ab-sorbers2!are present in such solutions.ANSI0ANS-8.1-1998 provides general guidancefor the use of soluble neutron absorbers for crit-icality accident prevention. This
29、standard3!pro-vides specificguidance for the use of solubleneutron absorbers for criticality control. Expe-rience has shown that operations involving theuse of such absorbers can be performed both safelyand economically. When soluble neutron absorb-ers are present, but are not required for nuclearcr
30、iticality safety, their use is outside the scope ofthis standard. Separate standards have been de-veloped to address specific applications of neu-tron absorbers. Examples areAmerican NationalStandard “Use of Borosilicate-Glass RaschigRings as a NeutronAbsorber in Solutions of Fis-sile Material,”ANSI
31、0ANS-8.5-19962#andAmer-ican National Standard “Use of Fixed NeutronAbsorbers in Nuclear Facilities Outside Reac-tors,” ANSI0ANS-8.21-1995 3#.2 ScopeThis standard provides guidance for the use ofsoluble neutron absorbers for criticality con-trol. This standard addresses neutron absorberselection, sys
32、tem design and modifications,safety evaluations, and quality control programs.3 Definitions3.1 LimitationsThe definitions given below and in Sec. 3.3,“Glossary of Terms,” are of a restricted naturefor the purpose of this standard. Other special-ized terms are defined in Glossary of Terms inNuclear S
33、cience and Technology 4# and “Glos-sary of Nuclear Criticality Terms” 5#.3.2 Shall, should, and mayThe word “shall”is used to denote a require-ment; the word “should”is used to denote arecommendation; and the word “may”is usedto denote permission, neither a requirementnor a recommendation. To confor
34、m to this stan-dard, all operations shall be performed in ac-cordance with its requirements but notnecessarily with its recommendations. Whenrecommendations are not implemented, justi-fication shall be documented.3.3 Glossary of termsneutron absorber: A neutron-capture mat-erial4!; also referred to
35、as a neutron poison.nuclear criticality safety: Protection againstthe consequences of a criticality accident, pref-erably by prevention of the accident.soluble neutron absorber: Any neutron poi-son easily dispersed inliquid, solution, or1!Numbers in brackets refer to corresponding numbers in Section
36、 5, “References.”2!Strictly speaking, absorption is defined as “the neutron induced reaction including fission where the neutronceases to exist as a free particle.” Capture is “neutron absorption not leading to fission or other production.”However, by nuclear criticality safety convention, use of th
37、e terms absorption or absorber in the sense of thisstandard denotes the capture process.3!The current standard, ANSI0ANS-8.14-2004, is herein referred to as “this standard.”4!As applied in nuclear criticality safety, absorber implies nonfission absorption that is capture. See alsofootnote 2 above.!1
38、suspension, used specifically to reduce the re-activity of a system and for which reactivitycredit is taken in the nuclear criticality safetyevaluation of the system.validation: A process to demonstrate that theanalytical methods used to compute the ef-fectiveness of the neutron absorber systemsfor
39、criticality control meet predeterminedrequirements.verification: The establishment of confir-mation of the truth or accuracy of a fact byinvestigation, comparison with a standard, orreference to the facts.4 Administrative requirementsand guidanceRequirements and guidance for the use of sol-uble neut
40、ron absorbers as a criticality safetycontrol are grouped under five topics: solubleneutron absorber selection, system design andmodification, safety evaluations, quality con-trol program, and facility operations with sol-uble absorbers.4.1 Neutron absorber selection4.1.1 Selection of a soluble neutr
41、on absorbershall include assessment of the operating en-vironment and of the chemical compatibilityof the neutron absorber with the process forwhich it is to be used. Consideration shallbe given to the solubility of the neutronabsorber and to materials and conditionse.g., temperature and pressure! t
42、hat couldcause precipitation or plateout of the neutronabsorber.4.1.2 The soluble neutron absorber shall main-tain its minimum required neutron absorptioncapability during its intended operating life.4.1.3 Selection of a soluble neutron absorbershall include an assessment of the absorbereffectivenes
43、s under credible conditions of neu-tron moderation and reflection.4.1.4 Selection of a neutron absorber shall in-clude evaluation of radiation effects e.g., de-pletion by neutron absorption, radiolysis! overits operating life.4.1.5 Selection of a soluble neutron absorbershall include evaluation of t
44、he requirements ofoperations and of fissile material accountability.4.1.6 Selection of a soluble neutron absorbershould include evaluation of the requirementsof other safety disciplines.4.2 System design andsystem modificationsThe following system design requirements andrecommendations shall apply t
45、o both systemdesign and system modifications.4.2.1 For the range evaluated as subcritical,the system design shall prevent inadvertentconcentration of fissile solution and removal ordilution of the neutron absorber.4.2.2 For the range evaluated as subcritical,the system design shall account for poten
46、tialdegradation of the neutron absorber and thechemicals used to dissolve or stabilize the neu-tron absorber.4.2.3 The design of the system equipment in-corporating soluble neutron absorbers shouldincorporate human factors engineering prac-tices for preparation, use, and control of theneutron absorb
47、er.4.2.4 The system design shall consider theneed for inspection, sampling, and verificationof the adequacy of the neutron absorbing capa-bility prior to use and during the operationallifetime of the neutron absorber.4.2.5 Ameans of verification shall be providedto determine that the system design,
48、safety, andoperating requirements are met for all opera-tions that utilize soluble neutron absorbers.4.3 Criticality safety evaluations4.3.1 Evaluations shall include allowances foruncertainties in the neutron absorber concen-tration, distribution, and neutronic propertiesi.e., accuracy of neutron c
49、ross-section values!.4.3.2 Evaluations shall include considerationof equipment design tolerances, chemical reac-tion tolerances, material substitutions, geom-etry changes, modeling assumptions, processvariables, neutron absorber isotopicdistribu-tion, and relevant uncertainties.American National Standard ANSI0ANS-8.14-200424.3.3 Evaluations shall consider the potentialfor neutron absorber degradation in the nor-mal operating environment due to physical orchemical actions and solution compositionchanges.4.3.4 Evaluations shall consider the effect onnuclear criticality s
