ISO INTERNATIONAL STANDARD 16117 First edition 2013-10-01 Nuclear criticality safety Estimation of the number of fissions of a postulated criticality accident Sécurite de criticité nucleaire - Evaluation du nombre de fissions en cas d'un hypothétique accident de criticité Reference number IS0 16117:2013(E) LSO IS02013 HS under Not for Resale IS0 16117:2013(E) COPYRIGHTPROTECTEDDOCUMENT ISO2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or 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 @ IS0 2013 - All rights reserved No reproductic networking permited without license from IHS Not for Resale IS0 16117:2013(E) Contents Page Foreword ..iv Introduction. 1 Scope. .1 2 Terms and definitions ..1 3 General principles ..2 4 Fissions number estimate .3 4.1 General .3 4.2 Inputdata. .3 4.3 Use of simplified models. .3 4.4 Use of calculation tools 4 Annex A (informative) Flow diagram of a criticality accident analysis(from Is0 27467:2009) ...5 Annex B (informative) Characteristics of criticality accidents that occurred during process operation .7 Annex C (informative) Experimental results ..12 Annex D (informative) Simplified formulae ..18 Bibliography .24 iii se with IS thout license from IHS Not for Resale