BS ISO 19226:2017 INTERNATIONAL ISO STANDARD 19226 First edition 2017-11-30 Nuclear energy - Determination of neutron fluence and displacement per atom (dpa) in reactor vessel and internals Energie nucleaire - Determination de la fluence neutronique et du déplacement par atome (dpa) dans la cuve et les internes du réacteur Reference number ISO 19226:2017(E) OSI @ IS0 2017 BS ISO 19226:2017 IS0 19226:2017(E) COPYRIGHT PROTECTED DOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form writtenpermission.Permission canberequestedfromeitherIsOattheaddressbelow orIso'smemberbodyinthecountryof the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii @ IS0 2017 - All rights reserved BS ISO 19226:2017 IS0 19226:2017(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. ..1 2 Normative references ..1 3 Terms and definitions ..1 4 Transport theory calculational models .3 4.1 General .3 4.1.1 Output requirements. .3 4.1.2 Methodology: transport calculations with fixed sources. .3 4.2 Transport calculation 4 4.2.1 Input data 4 4.2.2 Discrete ordinates (SN) method .4 4.2.3 Monte Carlo transport method. 4 4.2.4 Adjoint fluence calculations ..5 4.3 Validation of neutron fluence calculational values 5 4.4 Determination of calculational uncertainties .5 5 Reactor pressure vessel neutron dosimetry measurements .6 5.1 Introduction .6 5.2 General requirements for reactor vessel neutron metrology .6 5.3 Stable-product neutron dosimeters . 5.4 Dosimeter response parameters 7 5.5 Uncertainty estimates and measurement validation in standard neutron fields 7 6 Comparison of calculations with measurements .8 6.1 Introduction .8 6.2 Direct comparison of calculated activities with measured sensor activities .8 6.3 Comparison of calculated rates with measured average full-power reaction rates 8 6.4 Comparison of the calculations against measurements using least-squares methods ..8 7 Determination of the best-estimate fluence .9 8 Calculational methods for dpa and gas production 8.1 Displacements per atom (dpa) 9 8.2 Gas production 9 Bibliography 11 @ IS0 2017 - All rights reserved ii