ISO INTERNATIONAL STANDARD 12795 First edition 2004-08-01 Nuclear fuel technology Uranium dioxide powder and pellets - Determination of uranium and oxygen/uranium ratio by gravimetric method with impurity correction Technologiedu combustiblenucléaire-Dioxyded'uranium en poudresetenpastillesDeterminationdelateneurenuraniumetdu rapport oxygene/uranium en utilisant la méthode gravimétrique avec correction des impuretés Reference number ISO 12795:2004(E) ISO @ ISO 2004 ISO12795:2004(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In accepts no liability in this area Adobeis atrademarkofAdobeSystems Incorporated. the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ? ISO2004 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either isO at the address below or IsO's memberbody in the country of the requester. ISO copyright office Case postale 56.CH-1211Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland ii ISO 2004-All rights reserved ISO 12795:2004(E) Contents Page Foreword 1 Scope. 2 Principle. 3 Reactions.. 4 Reagents . 5 Apparatus. 6 Sampling and samples 7 Procedures... 7.1 Calibration... 7.2 Determination. 8 Expression of results.. 8.1 Methodof calculationandformulae 8.2 Precision and accuracy.. 9 Test report. Bibliography Iso2004-All rights reserved ili ISO12795:2004(E) Foreword IsO (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 non-governmental, in liaison with isO, also take part in the work. isoO collaborates closely with the InternationalElectrotechnicalCommission(iEC)onallmattersofelectrotechnicalstandardization. International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2 The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an 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 or all such patent rights. ISO 12795 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 5, Nuclear fueltechnology iv @ ISO 2004 - All rights reserved INTERNATIONAL STANDARD ISO 12795:2004(E) Nuclear fuel technology Uranium dioxide powder and pellets Determination of uranium and oxygen/uranium ratio by gravimetric method with impurity correction 1 Scope This International Standard specifies a method of determining the mass fraction of uranium and the oxygen-to- uranium atomic ratio in hyperstoichiometric uranium dioxide (UO2+x) powders and pellets. This International Standard is used for the determination of the U mass fraction and the O/U-ratio of nuclear grade uranium dioxide. The precision and accuracy stated in 8.2 are valid, if the total amount of impurities in the sample does not exceed the figures given in 8.2. An impurity correction in the U mass fraction and the O/U-ratio determination should be performed, if the amount of total impurities in oxide form exceeds 1 500 μg per gram of sample. Lower impurity levels influence the O/U-ratio by less than 0,000 5 and can be neglected. The non-volatile impurities shall be determined by an appropriate technique, and the correction applied. If the tota