ISO INTERNATIONAL STANDARD 11482 First edition 1993-12-15 Guidelines for plutonium dioxide (PuO2) sampling in a nuclear reprocessing plant Lignes directrices pour I'échantillonnage du dioxyde de plutonium (PuO2) dans une usine de retraitement ISO Reference number 1SO 11482:1993(E) ISO 11482:1993(E) Foreword Iso(theInternational 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 which 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 closelywith theInternational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 11482 was prepared by Technical Committee ISO/TC 85, Nuclear energy. Subcommittee SC 5. Nuclear fuel technology. AnnexesAandBofthisInternationalStandardareforinformationonly ISO1993 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 · CH-1211 Geneve 20 · Switzerland Printed in Switzerland ii INTERNATIONALSTANDARD ISO ISO11482:1993(E) Guidelines for plutonium dioxide (PuO2) sampling in a nuclear reprocessing plant Scope onthe dewpoint of the airorof theventilation gas; This International Standard gives guidelines to ensure that the homogenization and the sampling system on the air (gas) pressure within the glove box; supply representative samples from a batch of on the operating conditions; plutoniumoxideandtoensurethatthesaidsample remains representative until aliquoting. Possible mass -ontheprevioushistoryoftheplutoniumoxide. change of the sample duringtransportand storage is also considered. Ingloveboxes supplied with dry air or drygas like These guidelines apply to PuO2 powder with a spe- Ar or N2 (- 65 °C dew point) with a depression cific surface area lower than 25 m'ig. of 30 mm water and with 10 air changes per hour, the kinetics of mass increase are slow. They de- pend on: General the initial concentration of volatile impurities The methods and installations used in reprocessing which is defined as being the mass loss after plantsvaryconsiderablyand it is impossibletoestab heating in a furnace for1h at 135C lish standardized procedures for the homogenization and the sampling systems. the specific surface area. Because of the physico-chemical properties of the For a specific surface area of 7 m?/g and an initial plutonium oxide, numerous factors can yield samples concentration of volatile impurities of 0 % on which are not representative of the batch. Special at- leaving the oxalate calcining furnace, the oxide tention should be given to the following: gains mass at a rate of about 0,015 % per 24 h. a The processing line between the homogenizer C) Under the operating conditions which have just and the packing station, as well as the sampling been described, the mass increase is negligible line shall be completely emptied between the when the initial concentration of volatile impurities preparation of batches so as to avoid one batch is less than 0,3 %. Mass losses are observed contaminating the following one. during the calcining of the sample; they become larger as the initial concentration of volatile im- b) The chemical composition of plutonium oxide purities increases. For an initial volatile impurity powders is prone to change with time: according concentration of 0,67 %, a mass loss of 0,37 % is toitsphysical stateandtheconditionsunder observed in 2