ISO INTERNATIONAL STANDARD 12803 First edition 1997-09-15 Representative sampling of plutonium nitrate solutions for determination of plutonium concentration Echantillonnage représentatif de solutions de nitrate de plutonium en vue de determinerlaconcentrationduplutonium This material is reproduced from Iso documents under International Organization for Standardization (Iso) Copyright, License number IHS/lcc/1996. Not for resale. No part of these ISo documents may be reproduced in any form, electronic retrieval system or otherwise, except as allowed in the copyright law of the country of use, or with the prior written consent of ISo (Case postale 56, 1211 Geneva 20, Switzerland, Fax +41 22 7341o79),IHSortheISOLicensorsmembers. 'So Reference number ISO 12803:1997(E) Copyrightlntematinal Organization for Standadizain No reproduction or networking permitted without license from IHS Not for Resale ISO 12803:1997(E) Foreword IsO (the International Organization for Standardization) is a worldwide 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 closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are 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. ISO/TC 85, Nuclear energy, subcommittee SC 5, Nuclear fuel technoiogy. @ISO1997 Alt 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 Casepostale56·CH-1211Geneve20·Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; 0=isocs; S=central Printed in Switzerland ii No reproduction or networking permtted without license from IHS Not fr Resale ISO 12803:1997(E) INTERNATIONAL STANDARD ISO Representative sampling of plutonium nitrate solutions for determination of plutonium concentration 1 Scope This International Standard describes the basic precautions necessary to ensure that installed tank mixing and sampling systems achieve representative samples from a batch of pure final-product plutonium nitrate solution free from organic compounds and suspended solids, and that the samples remain representative until used. NOTE- WhenthisInternationalStandardisapplied,itcanbeshownthatthedifferencebetweentheplutoniumconcentration 2 Rationale Plutonium processing plants vary in design, process and installation. Therefore standard procedures for sampling of plutonium nitrate storage tanks cannot be established. However, the necessity for representative samples of the tank contentsisabsolutelyfundamentalforaccurateplutoniummeasurement. The chemical and physical properties of plutonium nitrate solutions introduce many factors which can hinder representative sampling. These include: a) storage in shielded tanks for radiation protection, with consequently long sample lines; mixing to avoid stagnant zones; avoid significant density differences within a single tank; d) the possible presence of a second phase, either precipitated plutonium species or organic liquids, which would make totally representative sampling essentially impossible; and high temperature; ) high yieids of radioiytic off-gases, particuiariy at high plutonium-238 or high piutonium(Vi) content, leading to the build-up of gas mixtures under pressure, and the possibility of incorrect voiume measurements; g) high evaporation rates, due to both self-heating and self-radiolysis, especially if mixing is by gas sparging; incorrect volume measureme