BS ISO 21484-2017 Nuclear Energy Fuel technology Determination of the O M ratio in MOX pellets by the gravimetric method《核能 燃料技术 采用重量分析法测定MOX芯块的氧金属比》.pdf

1、BS ISO 21484:2017Nuclear Energy Fueltechnology Determinationof the O/M ratio in MOXpellets by the gravimetricmethodBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 21484:2017 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO

2、 21484:2017.The UK participation in its preparation was entrusted to TechnicalCommittee NCE/9, Nuclear fuel cycle technology.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a

3、contract. Users are responsible for its correctapplication. The British Standards Institution 2017. Published by BSI Standards Limited 2017ISBN 978 0 580 84498 0ICS 17.240; 27.120.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published un

4、der the authority of theStandards Policy and Strategy Committee on 28 February 2017.Amendments/Corrigenda issued since publicationDate Text affectedBS ISO 21484:2017 ISO 2017Nuclear Energy Fuel technology Determination of the O/M ratio in MOX pellets by the gravimetric methodnergie nuclaire Technolo

5、gie du combustible Dtermination du rapport O/M dans les pastilles MOX par la mthode gravimtriqueINTERNATIONAL STANDARDISO21484Second edition2017-01Reference numberISO 21484:2017(E)BS ISO 21484:2017ISO 21484:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in Swi

6、tzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be r

7、equested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 21484:2017ISO 21484:2017(E)Foreword iv1 Scope

8、 . 12 Normative references 13 Terms and definitions . 14 Principle 15 Reactions 16 Reagents and materials . 17 Apparatus . 28 Sampling 29 Procedure. 29.1 Preliminary test 29.2 Preparing the crucibles 29.3 Weighing the sample 29.4 Heat treatment cycles . 39.4.1 General 39.4.2 Example 1 . 39.4.3 Examp

9、le 2 . 39.5 Final weighing . 310 Calculation 410.1 Mean atomic mass of oxide after heat treatment 410.2 Calculation of O/M ratio 411 Precision . 411.1 Accuracy 411.2 Precision . 511.3 Sensitivity 512 Test report . 5Bibliography 6 ISO 2017 All rights reserved iiiContents PageBS ISO 21484:2017ISO 2148

10、4:2017(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for w

11、hich a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all

12、 matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. Thi

13、s document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any

14、or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents).Any trade name used in this document is information given for the convenience of u

15、sers and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the followin

16、g URL: www .iso .org/ iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies, and radiological protection, Subcommittee SC 5, Nuclear installations, processes and technologies.This second edition cancels and replaces the first edition (I

17、SO 21484:2008), which has been technically revised.iv ISO 2017 All rights reservedBS ISO 21484:2017INTERNATIONAL STANDARD ISO 21484:2017(E)Nuclear Energy Fuel technology Determination of the O/M ratio in MOX pellets by the gravimetric method1 ScopeThis document describes a method for determining the

18、 Oxygen-to-Metal (O/M) ratio in mixed uranium-plutonium oxide (U,Pu)O2 Xpellets. The parameters given in the following paragraphs are relevant for pellets within a range of O/M ratio corresponding to 1,98 to 2,01. The method described in the document is adapted, with regard to the parameters, if the

19、 expected values of O/M ratio are outside the range.2 Normative referencesThere are no normative references in this document.3 Terms and definitionsNo terms and definitions are listed in this document.ISO and IEC maintain terminological databases for use in standardization at the following addresses

20、: ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp IEC Electropedia: available at h t t p :/ www .electropedia .org/ 4 PrincipleThe (U,Pu)O2 Xsample is submitted to controlled oxidation-reduction under thermodynamic conditions designed to change the O/M ratio to a value of 2,

21、000. The initial stoichiometric deviation, X, is determined from the sample mass difference before and after heat treatment.5 ReactionsThe main reactions are as follows:a) (U,Pu)O2 X x/2O2 (U,Pu)O2,000;b) (U,Pu)O2+x+ xH2 (U,Pu)O2,000+ xH2O.6 Reagents and materialsDuring the analysis, unless otherwis

22、e stated, use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity.6.1 Nitric acid solution, 50 % per volume nitric acid aqueous solution.6.2 Purge gas.6.2.1 Air, a volume fraction of 99,99 % purity grade is recommended.6.2.2 Inert gas, such

23、 as Argon or nitrogen can be used with a recommended volume fraction of 99,99 % purity grade O2 0,000 5 % (5 ppm), H2O 0,000 5 % (5 ppm), N2 0,000 5 % (5 ppm). ISO 2017 All rights reserved 1BS ISO 21484:2017ISO 21484:2017(E)6.2.3 Hydrogen or mixture of hydrogen and inert gas, a volume fraction of 99

24、,99 % purity grade to which water vapour may be added to obtain an oxygen potential (GO) near 420 kJ/mol (100 kcal/mol).7 Apparatus7.1 Furnace, one of the following furnaces can be used.7.1.1 Muffle furnace, controlled up to 950 C, having a device for measuring the temperature and having sweeping po

25、ssibility with various gases.7.1.2 Other furnaces, other furnaces, with same performance can also be used such as Infrared gold image furnace (IR lamp heating).7.2 Crucibles, use platinum or quartz crucibles.7.3 Analytical balance, use an analytical balance with an accuracy of at least 0,1 mg when m

26、uffle furnace is used or at least 0,01 mg if samples are smaller.8 SamplingA representative sample shall be taken from the pellet batch for analysis. If necessary, crush pellets to make smaller samples according to the furnace type or the crucible size.If necessary, care shall be taken to avoid samp

27、le oxidation during the sampling procedure and the sample preparation. Typical precautions include performing the sampling operation under argon atmosphere, placing the sample in an argon-filled bottle, etc. The laboratory performing the analyses shall establish the procedure.9 Procedure9.1 Prelimin

28、ary testThe balance shall be checked at regular intervals using a standard mass.9.2 Preparing the cruciblesThe crucibles shall be clean and weighed before use. An example of a cleaning procedure that could be used is as follows.a) Clean the crucibles by heating them in nitric acid (6.1) near the boi

29、ling point.b) Rinse thoroughly with deionized water.c) Dry the crucibles in the furnace for 30 min at 150 C under inert atmosphere.d) Allow the crucibles to cool to 35 C in the furnace under inert atmosphere.e) Remove each crucible from the furnace and weigh it to within 0,1 mg or better.f) Record t

30、he crucible mass, m0, in grams.9.3 Weighing the sample9.3.1 Place the sample, sampled as indicated in Clause 8, in an empty crucible.2 ISO 2017 All rights reservedBS ISO 21484:2017ISO 21484:2017(E)9.3.2 Weigh the crucible containing the pellets to within 0,1 mg or better.9.3.3 Record the mass, m1, i

31、n grams of the crucible containing the pellets.9.4 Heat treatment cycles9.4.1 GeneralThe sample shall be heat treated in such a way that the O/M ratio is changed to exactly 2,000. The duration of the oxidation-reduction cycles and the gas flow rates in the furnace shall be optimized according to the

32、 nature of the furnace used, the number of sample pellets measured, the pellet composition, etc.Load the furnace with the crucible containing the sample pellets. Apply the desired heat treatment cycle.9.4.2 Example 19.4.2.1 Under argon sweeping, raise the temperature to 900 C 30 C and hold for 5 min

33、.9.4.2.2 Under air sweeping, maintain the furnace temperature for 1 min to 7 min at 900 C 30 C.9.4.2.3 Under argon sweeping, maintain the furnace temperature for 5 min at 900 C 30C.9.4.2.4 Under argon +5 % to 7 % H2sweeping, maintain the furnace temperature for 8 h to 13 h at 900 C 30 C.9.4.2.5 Unde

34、r argon +5 % to 7 % H2sweeping, shut off the furnace heating and allow the temperature to drop to 35 C.9.4.3 Example 29.4.3.1 Heat the samples for 16 h at 800 C, in an atmosphere comprising a volume fraction of 4 % H2in argon saturated with water at room temperature.9.4.3.2 Cool under dry argon cont

35、aining a volume fraction of 4 % H2.9.5 Final weighing9.5.1 Remove the crucible from the furnace.9.5.2 Weigh the crucible to within 0,1 mg or better.9.5.3 Record the mass, m2, in grams of the crucible after oxidation-reduction heat treatment. ISO 2017 All rights reserved 3BS ISO 21484:2017ISO 21484:2

36、017(E)10 Calculation10.1 Mean atomic mass of oxide after heat treatmentCalculate the mean atomic mass of the oxide after treatment, when O/M = 2,000 exactly, by using Formula (1):mmxmxmxxxxmaPu UAmPu UAmPu UAmO=+()() ()()2 (1)wheremais the mean atomic mass of the oxide of heavy metals;m(Pu) is the m

37、ean atomic mass of plutonium in the oxide;m(U) is the mean atomic mass of uranium in the oxide;m(Am) is the mean atomic mass of americium in the oxide;xPuis the mole fraction in percent of plutonium in the oxide;xUis the mole fraction in percent of uranium in the oxide;xAmis the mole fraction in per

38、cent of americium in the oxide;m(O) is the atomic mass of oxygen (15,999 4);xPu+ xU+ xAm= 100 %.10.2 Calculation of O/M ratioCalculate the O/M ratio by using Formula (2):OMOa=()()()2 0002120,mmmmmm(2)wherem0is the mass of empty crucible, in g;m1is the mass of crucible with test sample before oxidati

39、on-reduction, in g;m2is the mass of crucible with test sample after oxidation-reduction heat treatment, in g;m(O) is the atomic mass of oxygen (15,999 4);mais the mean atomic mass of the oxide of heavy metals.11 Precision11.1 Accuracy30 determinations on stoichiometric mixed oxide pellets containing

40、 approximately 7 % plutonium gave a mean O/M ratio of 2,000.4 ISO 2017 All rights reservedBS ISO 21484:2017ISO 21484:2017(E)11.2 PrecisionThe standard deviation calculated from 30 determinations by two operators on a control sample of stoichiometric mixed oxide pellets containing approximately 7 % p

41、lutonium is better than 0,001.11.3 SensitivityTypically for a 15 g sample a change in weight of 0,5 mg results in a change in O/M ratio of 0,001.12 Test reportThe test report shall contain the following information:a) all information necessary for identification of the sample tested;b) a reference t

42、o this document, i.e ISO 21484:2017;c) the method used;d) the results of the test, including the results of the individual determinations and their mean, calculated as specified in Clause 10;e) any deviations from the procedure specified;f) any unusual features (anomalies) observed during the test;g

43、) the date of the test. ISO 2017 All rights reserved 5BS ISO 21484:2017ISO 21484:2017(E)Bibliography1 ISO 3696, Water for analytical laboratory use Specification and test methods6 ISO 2017 All rights reservedBS ISO 21484:2017BS ISO 21484:2017ISO 21484:2017(E) ISO 2017 All rights reservedICS 27.120.3

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