1、BS ISO 22765:2016Nuclear fuel technology Sintered (U,Pu)O2 pellets Guidance for ceramographic preparation for microstructure examinationBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 22765:2016 BRITISH STANDARDNational forewordThis British Standard is the UK
2、implementation of ISO 22765:2016. 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 be obtained on request to its secretary.This publication does not purport to include all the ne
3、cessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 84761 5 ICS 27.120.30 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standa
4、rd was published under the authority of the Standards Policy and Strategy Committee on 31 December 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 22765:2016 ISO 2016Nuclear fuel technology Sintered (U,Pu)O2pellets Guidance for ceramographic preparation for micr
5、ostructure examinationTechnologie du combustible nuclaire Pastilles (U,Pu)O2frittes Prconisations relatives la prparation cramographique pour examen de la microstructureINTERNATIONAL STANDARDISO22765First edition2016-12-15Reference numberISO 22765:2016(E)BS ISO 22765:2016ISO 22765:2016(E)ii ISO 2016
6、 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll 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 int
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8、rightiso.orgwww.iso.orgBS ISO 22765:2016ISO 22765:2016(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Description . 26 Equipment . 27 Reagents and resin . 28 Operating procedure 38.1 Specimen cutting . 38.2 Resin embedding . 38.3 Rough polishing 38.4 Final
9、polishing . 39 Structure development 49.1 General . 49.2 Development by thermal treatment . 49.3 Development by chemical etching . 49.4 Development by ion etching 5Bibliography 7 ISO 2016 All rights reserved iiiContents PageBS ISO 22765:2016ISO 22765:2016(E)ForewordISO (the International Organizatio
10、n 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 which a technical committee has been established has
11、 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 matters of electrotechnical standardization.The pr
12、ocedures 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. This document was drafted in accordance with the edito
13、rial rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesAttention 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 or all such patent rights. Details of any patent rights iden
14、tified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received. www.iso.org/patentsAny trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the
15、 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 following URL: http:/www.iso.org/iso/foreword.htmlThe committee responsible
16、for this document is ISO/TC 85, Nuclear energy, nuclear technologies, and radiological protection, Subcommittee SC 5, Nuclear installations, processes and technologies.iv ISO 2016 All rights reservedBS ISO 22765:2016INTERNATIONAL STANDARD ISO 22765:2016(E)Nuclear fuel technology Sintered (U,Pu)O2pel
17、lets Guidance for ceramographic preparation for microstructure examination1 ScopeThis document describes the ceramographic procedure used to prepare sintered (U,Pu)O2pellets for qualitative and quantitative examination of the pellet microstructure.The examinations are performed before and after ther
18、mal treatment or chemical etching.They allow observation of any cracks, intra- and intergranular pores or inclusions, and measurement of the grain size, porosity and plutonium homogeneity distribution.The mean grain diameter is measured by one of the classic methods: counting (intercept method), com
19、parison with standard grids or typical images, etc.2The measurement of individual grain sizes requires uniform development of the microstructure over the entire specimen.The plutonium cluster and pore distribution and localization are generally analysed by automatic image analysis systems. The pluto
20、nium distribution is usually revealed by chemical etching but alpha-autoradiography can also be used. The first technique avoids the tendency for autoradiography to exaggerate the size of plutonium-rich clusters due to the distance the alpha particles travel away from the source.2 Normative referenc
21、esThere 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: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online
22、browsing platform: available at http:/www.iso.org/obp4 PrincipleThe ceramographic preparation of (U,Pu)O2pellets involves two steps: specimen polishing, after embedding or not the specimen in a specific resin; thermal treatment or chemical etching to reveal the specimen microstructure. ISO 2016 All
23、rights reserved 1BS ISO 22765:2016ISO 22765:2016(E)5 DescriptionThe procedure comprises the following operations: cutting the specimen; resin embedding; rough polishing; final polishing; thermal treatment or chemical etching.The resin embedding operation may precede the specimen cutting operation. R
24、esin embedding may be skipped when a mechanical device is used to hold the specimen during cutting and polishing. Thus, it is preferable to cut the pellet before embedding it.6 EquipmentThe equipment shall be installed in an environment capable of monitoring specimen containment throughout the opera
25、ting sequence.6.1 Diamond-impregnated metallography disk cutting machine with a cooling system.6.2 Automatic polishing machine, preferably with a system for exerting constant pressure on the test specimen.6.3 Resin preparation equipment (spoons, spatulas, PVC containers, mould).6.4 Labware for etchi
26、ng.6.5 Ultrasonic specimen cleaning tank (optional).6.6 Optical microscope or binocular capable of at least 10.6.7 Programmable furnace, able to reach a temperature of about 1 600 C under argon gas sweeping.6.8 Engraving pen.7 Reagents and resin7.1 Resin to be determined by the user, for example: li
27、quid epoxy resin mixed with a suitable proportion of activator from the same manufacturer, curing generally occurs within 24 h at room temperature; polyester resin; curing occurs in 1 h.7.2 Acid aqueous solution for the chemical etching (e.g. chrome oxide and hydrofluoric acid).7.3 Demineralised wat
28、er, complying with ISO 36961.7.4 Alcohol.2 ISO 2016 All rights reservedBS ISO 22765:2016ISO 22765:2016(E)8 Operating procedure8.1 Specimen cuttingThe pellet is cut using a diamond-impregnated metallography disk-cutting machine with a cooling system, along the selected axis (longitudinal or axial).Af
29、ter cutting, the specimen is cleaned in alcohol or demineralised water. An ultrasonic cleaning tank may be used.8.2 Resin embeddingPrior to rough and final polishing, the cut specimen is embedded in resin. Therefore, the half pellet is put inside a mould with the cut face against the mould bottom.Th
30、e prepared resin, with potentially a colouring in order to distinguish the pellet Pu content, is then poured inside the mould.After the required time (e.g. around 30 min to 60 min), the embedding pellet can be removed from the mould.Then, the identification number of the pellet sample can be graved
31、with the engraver pen on the resin.The mould should be cleaned in order to reuse it.8.3 Rough polishingThe resin-embedded specimens shall be, at first, rough-polished to eliminate any resin traces on the surface and ensure flatness. This may be done using a multi-stage process.An example is describe
32、d below: P180 (82 m) abrasive disk (for specimens embedded in resin after cutting): time as necessary to reach the surface flush with the resin; P400 (35 m) abrasive disk: 30 s to 1 min; P800 (22 m) abrasive disk: 30 s to 1 min; P1200 (15 m) abrasive disk: 30 s to 1 min;Rough polishing is performed
33、on a polishing machine with an air pressure of 100 kPa to 150 kPa, and at a rotation speed of 70 r/min to 270 r/min.The specimen is thoroughly cleaned in alcohol between each step and after completion of the rough polishing operation. The cleaning may be done in an ultrasonic tank.8.4 Final polishin
34、gAn example is described below.The polishing operation is performed using a series of woven satin disks after injecting a diamond-paste with a grain size of 1 m to 6 m. Polishing is carried out for about 20 min on a polishing machine with an air pressure of 100 kPa to 200 kPa.The specimen is thoroug
35、hly cleaned in alcohol and dried in air after polishing. The cleaning may be done in an ultrasonic tank. The polished surfaces should be mirror finished and free of scratches.The polishing quality is checked by observing the specimen under a microscope or a binocular. ISO 2016 All rights reserved 3B
36、S ISO 22765:2016ISO 22765:2016(E)The pellets prepared in this way are suitable for examinations such as porosity measurements, and overall ceramographic examinations to reveal cracking.9 Structure development9.1 GeneralTo determine the grain size, the structure should first be revealed by thermal tr
37、eatment or chemical etching. Chemical etching can also be used to reveal the distribution of plutonium clusters. An alternative, to reveal the distribution of plutonium clusters, can be the alpha-autoradiography.9.2 Development by thermal treatmentAfter cutting, the sample is not embedded, but place
38、d into a mechanical device. Then, the half pellet placed in the mechanical device is polished. The polishing operation prior to the thermal treatment may be done using a multi-stage process.An example is described below.Rough polishingRough polishing is performed on a polishing machine with an air p
39、ressure of 100 kPa to 150 kPa, and at a rotation speed of 70 r/min to 270 r/min. P180 (82 m) abrasive disk (for specimens embedded in resin after cutting): time as necessary to reach the surface flush with the resin P400 (35 m) abrasive disk: 30 s to 1 min P800 (22 m) abrasive disk: 30 s to 1 min P1
40、200 (15 m) abrasive disk: 30 s to 1 minThe specimen is thoroughly cleaned (ultrasonically or not) in alcohol between each step and after completion of the rough polishing operation.Final polishing (see 8.4)Furnace sequenceThe sample is introduced into the furnace after dismounting from the mechanica
41、l device.Thermal treatment can be carried out under various conditions. An example is described below: heating rate: 283 C/h; fixed temperature level: 1 600 C; duration: 6 h; scavenging with argon throughout the cycle.The conditions are chosen to suit the furnace characteristics, the presence of oth
42、er gases, gas flow and the duration of the cycle.9.3 Development by chemical etchingThe specimens are immersed for 30 s to 1 min in a reactive mixture, then rinsed in water and dried in air.4 ISO 2016 All rights reservedBS ISO 22765:2016ISO 22765:2016(E)Chemical etching involves a large number of va
43、riables. The operator determines the nature of the reagent and the duration of the etching operation according to the pellet composition (Pu content, etc.) and the results obtained.Examples: room-temperature etching; distilled water: 96 ml; chromium oxide Cr2O3: 20 g; mass fraction of 40 % hydrofluo
44、ric acid: 48 ml; etching time: 25 s to 1 min; hot etching: 70 C: distilled water: 24 ml; saturated ammonium difluoride solution: 1 ml; sulfuric acid (s.g. 1,84): 1 ml; etching time: 1 min to 5 min.9.4 Development by ion etchingThe specimen is set in a chamber of the ion etching device. An example of
45、 the device is shown in Figure 1.After evacuating air by rotary and diffusion pumps, argon gas is introduced into the chamber. Argon ions are sputtered onto the surface of the specimen by ion gun for about 10 min. The operator determines the duration of the etching operation according to the pellet
46、composition (Pu content, etc.) and according to the results obtained. ISO 2016 All rights reserved 5BS ISO 22765:2016ISO 22765:2016(E)Key1 sample loader2 etching chamber3 glove box4 ion gun5 argon gas inlet6 observation window7 oil mist filter8 rotary pump9 diffusion pumpaMovement of sample loader w
47、hen closing and opening.Figure 1 Ion etching device6 ISO 2016 All rights reservedBS ISO 22765:2016ISO 22765:2016(E)Bibliography1 ISO 3696, Water for analytical laboratory use Specification and test method2 ASTM E112, Standard test method for determining average grain size ISO 2016 All rights reserve
48、d 7BS ISO 22765:2016ISO 22765:2016(E) ISO 2016 All rights reservedICS 27.120.30Price based on 7 pagesThis page deliberately left blankBSI is the national body responsible for preparing British Standards and other standards-related publications, information and services.BSI is incorporated by Royal C
49、harter. British Standards and other standardization products are published by BSI Standards Limited.British Standards Institution (BSI)About usWe bring together business, industry, government, consumers, innovators and others to shape their combined experience and expertise into standards -based solutions.The knowledge embodied in our standards has been carefully assembled in a dependable format and refined through our open consultation process. Organization
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