ISO INTERNATIONAL STANDARD 9279 First edition 1992-03-01 Uranium dioxide pellets - Determination of density and total porosity -- Mercury displacement method Pastilles de dioxyde d'uranium - Determination de la masse volumique et de la porosite totale - Methode de deplacement du mercure Referencenumber ISO 9279:1992(E) Provided by IHS underlicense with ISo Noreproductionornetworking permited withoutlicensefromIHS Not for Resale ISO 9279:1992(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 which a technical committee has been established has the right to be represented on that committee.International organizations,govern- mental and non-governmental, in liaison with iso, also take part in the work. iso collaborates closely with the International Electrotechnical Commission(lEC)onallmattersofelectrotechnicalstandardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75%of the member bodies casting a vote. International Standard isO9279 was prepared by Technical Committee IsO/TC 85, Nuclear energy, Sub-Committee SC 5, Nuclear fuel tech- nology. CISO1992 All rights reserved. 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 the publisher. International Organization for Standardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland Tnational Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale ISO 9279:1992(E) INTERNATIONAL STANDARD Uranium dioxide pellets -- Determination of density and total porosity - Mercury displacement method Scope 3.4 Thermometer, for measuring the temperature 1 of mercury to the nearest 0.1 K. This International Standard describes a method for determining the density andtotal porosity of 4 Procedure sintered UO2 pellets. The method can be applied to other bodies, for example green pellets, UO2-PuO2 SAFETY PRECAUTIONS-- Standard precautions and UO2-Gd,Os pellets, and also to irradiated ma- shall be observed when handling uranium dioxide terial in hot cells. Fractured pleces of a pellet can samples and mercury. also betested.The mass ofthe specimen should not be less than about 1 g. 4.1 Calibration Principle The calibration of the balance shall be checked periodically according to the control plan which de- The method is based on the determination of the fines frequency and acceptable range. pellet volume by displacement of mercury which does not penetrate the open pores due to its surface 4.2s Sample preparation and determination of tension. The density and the total porosity are de- its mass termined by this volume and the mass of the pellet. 4.2.1 Wash the pellet or the pieces of a pellet in 3Apparatus acetone followed by ethanol. 3.1 Mercury pycnometer, consisting of two cham- 4.2.2 Dry the sample for 1 h in a vacuum of ap- bers and a mercury collection flask. The flanges of proximately 10 Pa. these components of the glass apparatus are sealed with vacuum grease.(See figure1.) 4.2.3 Determine the mass (m) of the sample to the nearest 0.1 mg. The sample should occupy at least 10 % of the vol- ume of chamber ll (see figure 1). 4.3 Determination of the vold volume of The purity of the mercury shall be at least 99.99 % chamber ll (see figure 1) NOTE1 Excessive use of grease should be avoided to 4.3.1 Fill chamber I with sufficient mercury to ex- prevent errors when the joint is separated for welghing. ceed the volume of chamber ll. Determine the mass (m',) of chamber I filled with mercury, to the nearest 3.2 Vacuum system, capable of reaching a vacuum 0,1 mg. of atleast1Pa. 4.3.2 Ass