ASTM_E_2006_-_10.pdf

Designation:E200610Standard Guide forBenchmark Testing of Light Water Reactor Calculations1This standard is issued under the fixed designation E2006;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers general approaches for benchmarkingneutron transport calculations in light water reactor systems.Acompanion guide(Guide E2005)covers use of benchmarkfields for testing neutron transport calculations and crosssections in well controlled environments.This guide coversexperimental benchmarking of neutron fluence calculations(orcalculations of other exposure parameters such as dpa)in morecomplex geometries relevant to reactor surveillance.Particularsections of the guide discuss:the use of well-characterizedbenchmark neutron fields to provide an indication of theaccuracy of the calculational methods and nuclear data whenapplied to typical cases;and the use of plant specific measure-ments to indicate bias in individual plant calculations.Use ofthese two benchmark techniques will serve to limit plant-specific calculational uncertainty,and,when combined withanalytical uncertainty estimates for the calculations,will pro-vide uncertainty estimates for reactor fluences with a higherdegree of confidence.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E261 Practice for Determining Neutron Fluence,FluenceRate,and Spectra by Radioactivation TechniquesE262 Test Method for Determining Thermal Neutron Reac-tion Rates and Thermal Neutron Fluence Rates by Radio-activation TechniquesE706 Master Matrix for Light-Water Reactor Pressure VesselSurveillance Standards,E 706(0)(Withdrawn 2011)3E844 Guide for Sensor Set Design and Irradiation forReactor Surveillance,E 706(IIC)E944 Guide for Application of Neutron Spectrum Adjust-ment Methods in Reactor Surveillance,E 706(IIA)E1018 Guide for Application of ASTM Evaluated CrossSection Data File,Matrix E706(IIB)E2005 Guide for Benchmark Testing of Reactor Dosimetryin Standard and Reference Neutron Fields3.Significance and Use3.1 This guide deals with the difficult problem of bench-marking neutron transport calculations carried out to determinefluences for plant specific reactor geometries.The calculationsare necessary for fluence determination in locations importantfor material radiation damage estimation and which are notaccessible to measurement.The most important application ofsuch calculations is the estimation of fluence within the reactorvessel of operating power plants to provide accurate estimatesof the irradiation embrittlement of the base and weld metal inthe vessel.The benchmark procedure must not only prove thatcalculations give reasonable results but that their uncertaintiesare propagated with due regard to the sensitivities of thedifferent input parameters used in the transport calculations.Benchmarking is achieved by building up data bases ofbenchmark experiments that have different influences on un-certainty propagation.For example,fission spectra are thefundamental data bases which control propagation of crosssection uncertainties,while such physics-dosimetry experi-ments as vessel wall mockups,where measurements are madewithin a simulated reactor vessel wall,control error propaga-tion associated with geometrical and methods approximationsin the transport calculations.This guide describes generalprocedures for using neutron fields with known characteristicsto corroborate the calculational methodology and nuclear dataused to derive neutron field information from measurements ofneutron sensor response.3.2 The bases for benchmark field referencing are usuallyirradiations performed in standard neutron fields with well-known energy spectra and intensities.There are,however,less1This test method is under the jurisdiction of ASTM Committee E10 on NuclearTechnology and Applicationsand is the direct responsibility of SubcommitteeE10.05 on Nuclear Radiation Metrology.Current edition approved Oct.1,2010.Published October 2010.Originallyapproved in 1999.Last previous edition approved in 2005 as E2006-05.DOI:10.1520/E2006-10.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 well kn