ISO INTERNATIONAL STANDARD 18315 First edition 2018-11 Nuclear energy Guidance to the evaluation of measurement uncertainties of impurity in uranium solution by linear regression analysis Energie nucleaire - Lignes directrices pour I'evaluation des incertitudes de mesure des impuretes en solution d'uraniumpar analysederegression linéaire Referencenumber ISO18315:2018(E) ISO @IS02018 IS018315:2018(E) COPYRIGHTPROTECTEDDOCUMENT @ISO2018 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 orIso's memberbody in the countryof therequester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone:+41227490111 Fax:+4122749 09 47 Email: copyright@iso.org Website: www.iso.org Published in Switzerland ii @ IS0 2018 - All rights reserved IS018315:2018(E) Contents Page Foreword ..iv 1 Scope. .1 2 Normativereferences 3 Terms and definitions 4 Principle .3 5 Uncertainty evaluation ..4 5.1 Regression line fitting .4 5.2 Adequacycheckoffittedregressionline .5 5.3 Combined uncertainty. .5 5.4 Effectivedegreesoffreedom. .6 5.5 Expanded uncertainty 7 6 Reflection of reference solutionuncertainties inevaluation ..7 7 Bias correction. .7 8 Uncertaintyevaluation report ..7 AnnexA (informative)Practicalexampleofuncertaintyevaluation .9 Annex B (informative)Flowchart of uncertainty evaluation process ..13 Annex C (informative) Non-uniform variances and weighting method .15 Bibliography .18 @ IS0 2018 -All rights reserved iii