1、BSI Standards PublicationBS ISO 21483:2013Determination of solubilityin nitric acid of plutonium inunirradiated mixed oxide fuelpellets (U, Pu) O2BS ISO 21483:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 21483:2013.The UK participation in its preparatio
2、n 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 contract. Users are responsible for its correctapp
3、lication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 76907 8ICS 27.120.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Commi
4、ttee on 31 October 2013.Amendments issued since publicationDate Text affectedBS ISO 21483:2013 ISO 2013Determination of solubility in nitric acid of plutonium in unirradiated mixed oxide fuel pellets (U, Pu) O2Dtermination de la solubilit dans Iacide nitrique du plutonium des pastilles (U, Pu) O2 de
5、 combustibles doxydes mixtes non irradisINTERNATIONAL STANDARDISO21483First edition2013-11-01Reference numberISO 21483:2013(E)BS ISO 21483:2013ISO 21483:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publica
6、tion 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 requested from either ISO at the address below or ISOs member body in the country
7、 of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 21483:2013ISO 21483:2013(E) ISO 2013 All rights reserved iiiContents PageForeword iv1 Scope . 12 Principle 13 Interfe
8、rences 14 Reagents 14.1 Concentrated nitric acid 14.2 Nitric acid high 14.3 Nitric acid low 14.4 Concentrated hydrofluoric acid 14.5 Mixture of acid . 14.6 Sodium hydroxide 25 Apparatus . 25.1 Analytical balance. 25.2 Dissolution apparatus with total reflux condenser . 25.3 Dissolution apparatus wit
9、hout total reflux condenser 25.4 Second dissolution apparatus (polytetrafluoroethylene, PTFE, high density polyethylene, HDPE) 25.5 Filter apparatus 26 Sampling 27 Procedure. 37.1 Preparation of the sample . 37.2 Dissolution procedure 37.3 Treatment of the residue 37.4 Plutonium determination 37.5 R
10、epeat solubility test . 38 Expression of results 48.1 Method of calculation 48.2 Total uncertainty of the Pu measurement . 49 Test report . 4Bibliography 5BS ISO 21483:2013ISO 21483:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standard
11、s 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 the right to be represented on that committee. International organiz
12、ations, 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 procedures used to develop this document and those intended for its fur
13、ther 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 editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesA
14、ttention 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 identified during the development of the document will be in the Introduc
15、tion 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.The committee responsible for this document is ISO/TC 85, Nuclear energy, nuclear technologies
16、 and radiological protection, Subcommittee SC 5, Nuclear fuel cycle.This first edition of ISO 21483 cancels and replaces ISO 12184:1994, which has been technically revised.iv ISO 2013 All rights reservedBS ISO 21483:2013INTERNATIONAL STANDARD ISO 21483:2013(E)Determination of solubility in nitric ac
17、id of plutonium in unirradiated mixed oxide fuel pellets (U, Pu) O21 ScopeThis International Standard specifies an analytical method for determining the solubility in nitric acid of plutonium in pellets of unirradiated mixed oxide fuel (light-water reactor fuels). The results provide information abo
18、ut the expected dissolution behaviour of irradiated pellets under industrial reprocessing conditions. In this aspect, the specific conditions (e.g. time of the test) may vary depending upon the need to match to a specific reprocessors requirements. The test is aimed at determining solubility under e
19、quilibrium conditions rather than the kinetics of dissolution and hence allows for a second dissolution period.2 PrincipleA specified number of mixed oxide pellets of known plutonium content and mass are dissolved in a boiling nitric acid solution. The initial concentration of the nitric acid, the f
20、inal content of U, Pu and the boiling time are carefully controlled. The undissolved residue is then dissolved quantitatively by boiling in a mixture of nitric acid and hydrofluoric acid. The plutonium content of this residue is determined by an appropriate analytical method. The solubility is expre
21、ssed by the ratio of the amount of plutonium dissolved in nitric acid to the amount of plutonium in the sample.3 InterferencesThe dissolution apparatus (Clause 5) and the reagents shall not be contaminated with fluoride, as fluoride can cause an increase in the solubility of the pellets in nitric ac
22、id.4 ReagentsUse only reagents of analytical grade and distilled or demineralised water or water of equivalent purity. Prepare the reagents in compliance with the local laboratory safety instructions.4.1 Concentrated nitric acid = 1,40 g/ml or more4.2 Nitric acid highSolution c(HNO3) = 10 mol/l4.3 N
23、itric acid lowSolution c(HNO3) = 0,5 mol/l.4.4 Concentrated hydrofluoric acid = 1,13 g/ml4.5 Mixture of acidNitric acid, solution c(HNO3) = 14,4 mol/l and hydrofluoric acid, solution c(HF) = 0,05 mol/l. ISO 2013 All rights reserved 1BS ISO 21483:2013ISO 21483:2013(E)4.6 Sodium hydroxideSolution c(Na
24、OH) = 2 mol/l (optional).5 ApparatusUsual laboratory apparatus and, in particular, the following.5.1 Analytical balanceBalance with a 0,1 mg accuracy or better.5.2 Dissolution apparatus with total reflux condenserConsisting of dissolver flask (glass borosilicate or high density polyethylene HDPE are
25、 suitable), heater, total reflux condenser and gas inlet tube. The volume capacity of the flask shall reflect the sample size selected in Clause 6.5.3 Dissolution apparatus without total reflux condenserConsisting of dissolver flask (glass borosilicate or high density polyethylene HDPE are suitable)
26、, heater, condenser and gas washer bottle. The volume capacity of the flask shall reflect the sample size selected in Clause 6.5.4 Second dissolution apparatus (polytetrafluoroethylene, PTFE, high density polyeth-ylene, HDPE)For the dissolution with nitric acid/hydrofluoric acid mixture. This second
27、 dissolution is carried out with total reflux condenser (Clause 5).5.5 Filter apparatusApparatus consisting of a vacuum funnel and a nitric-acid-resistant filter of a pore size less or equal to 1 micron (e.g. nitrocellulose or polycarbonate membrane filter 1 m).6 SamplingThe sample size shall be lar
28、ge enough to be representative of the lot, both whole and broken pellets are acceptable for this test. The minimum sample size could be chosen as a function of the pellet composition and the laboratorys detection limit. In any way, the minimum size must be equal or greater than 1 pellet.2 ISO 2013 A
29、ll rights reservedBS ISO 21483:2013ISO 21483:2013(E)7 Procedure7.1 Preparation of the sampleWeigh the pellets and transfer quantitatively into the dissolver flask (5.2 and 5.3). In order to reach a heavy metal concentration of around 1 mol/l, the total volume V, in litres, of nitric acid solution (4
30、.2) to be used is given byVmcM= wherem is the sum of the mass of uranium and plutonium in the sample in grams,M is the average atomic weights of the metals, in grams per mole;c is the concentration of the uranium and plutonium in the solution, in moles per litre (c = 1 mol/l). This value corresponds
31、 to the practice of the “reprocessing dissolution of spent fuel”.7.2 Dissolution procedureIntroduce the calculated volume of nitric acid solution (4.2) into the flask containing the sample pellets. Boil the contents of the flask under reflux for the specified period (examples are 10 h and 18 h). The
32、 time required for the solubility test is dependent upon the commercial contract and agreed with the commercial customer. Boiling shall begin within 30 min. Cooling to below around 50 C should be ended within 30 min. To avoid a delay in cooling, compressed air may be passed through the solution. The
33、 arising nitrous vapour may be trapped in a gas washer bottle filled with sodium hydroxide solution (4.6)7.3 Treatment of the residueQuantitatively transfer the solution and the undissolved residue into the filter apparatus and filter the solution using the vacuum funnel. Thoroughly rinse the residu
34、e on the filter with nitric acid solution (4.3)If the filtered residue is seen to contain fragments of pellets, this may be indicative of a problem with the manufacture of MOX material. Repeat the test using a tared filter to weigh the residue (7.5).Place the filter and the residue in a dissolver fl
35、ask (5.4) and add around 25 ml of the nitric acid/hydrofluoric acid (4.5). Heat the acid to its boiling point and pursue ebullition under reflux until the residue is completely dissolved and at least during 2,5 h.In general, after this duration, no residue still remains with HNO3/HF dissolution. If
36、residue still remains, then it is possible to add hydrofluoric acid (0,05 mol/l) in order to obtain total dissolution.7.4 Plutonium determinationMake up the solution resulting from the treatment of the undissolved residue to a known volume or known mass. Take samples and analyse their plutonium cont
37、ent by a suitable method. The method shall have an uncertainty of 20 % or lower, even in the presence of higher level impurities contained in the dissolved material. The spectrophotometry method described in ISO 9463 is adequate. Other methods like mass spectrometry (TIMS or ICPMS) can also be used.
38、7.5 Repeat solubility testIf visible pellet fragments are observed in the residue of the first dissolution test (7.2), perform a new test on a fresh sample. For this test, the test duration (up to 18 h), concentration of nitric acid (up to 10 mol/l) ISO 2013 All rights reserved 3BS ISO 21483:2013ISO
39、 21483:2013(E)and U+Pu concentration (0,9 mol/l) shall be defined before carrying out the test. The conditions of each test and its results should be reported.8 Expression of results8.1 Method of calculationThe plutonium solubility, L, expressed as mass fraction in percent, is calculated according t
40、he following equation:L = 1-mmWPu21 100 wherem1is the mass of the sample, in grams;m2is the mass of plutonium in the residue, in grams;WPuis the mass fraction of the plutonium in the sample.8.2 Total uncertainty of the Pu measurementThe total uncertainty is dependent upon the mass fraction of the pl
41、utonium WPuand of the analytical method used to determine the plutonium content in the residue. Typically, for a material with a mass fraction greater than 5 % and a sample size of at least 6 g, a total uncertainty of 20 % can be achieved.9 Test reportThe test report shall include the following info
42、rmation:a) a reference to this International Standard;b) date and place of the test carried out;c) identification and mass of the sample;d) the reference of the analytical method used;e) the method of calculation of the results including the boiling time;f) the results and their units;g) any unusual
43、 features observed during the test;h) potential increasing of dissolution time;i) any operation regarded as optional.4 ISO 2013 All rights reservedBS ISO 21483:2013ISO 21483:2013(E)Bibliography1 ISO 9463, Nuclear energy Nuclear fuel technology Determination of plutonium in nitric acid solutions by s
44、pectrophotometry ISO 2013 All rights reserved 5BS ISO 21483:2013ISO 21483:2013(E) ISO 2013 All rights reservedICS 27.120.30Price based on 5 pagesThis page deliberately left blankBSI is the national body responsible for preparing British Standards and other standards-related publications, information
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