ISO INTERNATIONAL STANDARD 11311 First edition 2011-07-01 Nuclear criticality safety Critical values for homogeneous plutonium-uranium oxide fuel mixtures outside of reactors Sureté-criticité - Valeurs critiques pour oxydes mixtes homogenes de plutonium et d'uranium hors reacteurs Reference number ISO 11311:2011(E) @ ISO 2011 y IHS under ted without license from IHS Not for Resale ISO 11311:2011(E) COPYRIGHTPROTECTEDDOCUMENT @ ISO2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, IsO's member body in the country of the requester. ISO copyright office Case postale 56 : CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland @ ISO 2011 - All rights reserved etworking permitted without license from IHS Not for Resale ISO 11311:2011(E) Contents Page Foreword Introductior 1 Scope 2 Normative references. 3 Terms and definitions 4 Reference systems concerned by this International Standard 4.1 Reference fissile media. 4.2 Moderation conditions. 4.3 Geometricalmodels 4.4 Reflecting conditions 5 Critical values 5.1 Presentation of the results. 5.2 Requirements.... 6 Subcritical limits and margin of safety .. Annex A (informative) Reference fissile media.. AnnexB(informative)Criticalityschemesusedforthecalculations Annex C (normative) Critical dimensions for a water reflection of 3o cm .. AnnexD(normative)Criticaldimensionsforawaterreflectionof2,5cm. Annex E (normative) Critical parameters for a water reflection of 30 cm.. 11 Annex F (normative) Critical parameters for a water reflection of 2,5 cm .. 2 Bibliography. CopyrightInternational OganzaonSandardizaloghtsreserved ii nse from IHS Not for Resale