1、Designation: E 944 08Standard Guide forApplication of Neutron Spectrum Adjustment Methods inReactor Surveillance, E 706 (IIA)1This standard is issued under the fixed designation E 944; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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 the analysis and interpretation of thephysics dosimetry for Light Water Reactor (LWR)
3、surveillanceprograms. The main purpose is the application of adjustmentmethods to determine best estimates of neutron damage expo-sure parameters and their uncertainties.1.2 This guide is also applicable to irradiation damagestudies in research reactors.1.3 This standard does not purport to address
4、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:2E 170 Terminology
5、Relating to Radiation Measurementsand DosimetryE 262 Test Method for Determining Thermal Neutron Re-action and Fluence Rates by Radioactivation TechniquesE 263 Test Method for Measuring Fast-Neutron ReactionRates by Radioactivation of IronE 264 Test Method for Measuring Fast-Neutron ReactionRates by
6、 Radioactivation of NickelE 265 Test Method for Measuring Reaction Rates andFast-Neutron Fluences by Radioactivation of Sulfur-32E 266 Test Method for Measuring Fast-Neutron ReactionRates by Radioactivation of AluminumE 343 Test Method for Measuring Reaction Rates byAnaly-sis of Molybdenum-99 Radioa
7、ctivity From Fission Dosim-eters3E 393 Test Method for Measuring Reaction Rates byAnaly-sis of Barium-140 From Fission DosimetersE 481 Test Method for Measuring Neutron Fluence Ratesby Radioactivation of Cobalt and SilverE 482 Guide for Application of Neutron Transport Methodsfor Reactor Vessel Surv
8、eillance, E706 (IID)E 523 Test Method for Measuring Fast-Neutron ReactionRates by Radioactivation of CopperE 526 Test Method for Measuring Fast-Neutron ReactionRates by Radioactivation of TitaniumE 693 Practice for Characterizing Neutron Exposures inIron and Low Alloy Steels in Terms of Displacement
9、s PerAtom (DPA), E 706(ID)E 704 Test Method for Measuring Reaction Rates by Ra-dioactivation of Uranium-238E 705 Test Method for Measuring Reaction Rates by Ra-dioactivation of Neptunium-237E 706 Master Matrix for Light-Water Reactor PressureVessel Surveillance Standards, E 706(0)E 844 Guide for Sen
10、sor Set Design and Irradiation forReactor Surveillance, E 706(IIC)E 853 Practice for Analysis and Interpretation of Light-Water Reactor Surveillance Results, E706(IA)E 854 Test Method for Application and Analysis of SolidState Track Recorder (SSTR) Monitors for Reactor Sur-veillance, E706(IIIB)E 910
11、 Test Method for Application and Analysis of HeliumAccumulation Fluence Monitors for Reactor Vessel Sur-veillance, E706 (IIIC)E 1005 Test Method for Application and Analysis of Radio-metric Monitors for Reactor Vessel Surveillance, E706(IIIA)E 1018 Guide for Application of ASTM Evaluated CrossSectio
12、n Data File, Matrix E 706 (IIB)E 2005 Guide for Benchmark Testing of Reactor Dosimetryin Standard and Reference Neutron FieldsE 2006 Guide for Benchmark Testing of Light Water Reac-tor Calculations2.2 Nuclear Regulatory Commission Documents:41This guide is under the jurisdiction of ASTM Committee E1
13、0 on NuclearTechnology and Applications and is the direct responsibility of SubcommitteeE10.05 on Nuclear Radiation Metrology. A brief overview of Guide E 944 appearsin Master Matrix E 706 in 5.3.1(IIA).Current edition approved Nov. 1, 2008. Published January 2009. Originallyapproved in 1983. Last p
14、revious edition approved in 2002 as E 944 02.2For 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.3Withdrawn. The
15、last approved version of this historical standard is referencedon www.astm.org.4Available from Superintendents of Documents, U. S. Government PrintingOffice, Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NUREG/
16、CR-1861 PCA Experiments and Blind TestNUREG/CR-2222 Theory and Practice of General Adjust-ment and Model Fitting ProceduresNUREG/CR-3318 LWR Pressure Vessel Surveillance Do-simetry Improvement Program: PCA Experiments, BlindTest, and Physics-Dosimetry Support for the PSF Experi-mentNUREG/CR-3319 LWR
17、 Power Reactor SurveillancePhysics-Dosimetry Data Base CompendiumNUREG/CR-5049 Pressure Vessel Fluence Analysis andNeutron Dosimetry2.3 Electric Power Research Institute:5EPRI NP-2188 Development and Demonstration of an Ad-vanced Methodology for LWR Dosimetry Applications2.4 Government Document:4NBS
18、IR 853151 Compendium of Benchmark NeutronFields for Reactor Dosimetry3. Significance and Use3.1 Adjustment methods provide a means for combining theresults of neutron transport calculations with neutron dosimetrymeasurements (see Test Method E 1005 and NUREG/CR-5049) in order to obtain optimal estim
19、ates for neutron damageexposure parameters with assigned uncertainties. The inclusionof measurements reduces the uncertainties for these parametervalues and provides a test for the consistency between mea-surements and calculations and between different measure-ments (see 3.3.3). This does not, howe
20、ver, imply that thestandards for measurements and calculations of the input datacan be lowered; the results of any adjustment procedure can beonly as reliable as are the input data.3.2 Input Data and Definitions:3.2.1 The symbols introduced in this section will be usedthroughout the guide.3.2.2 Dosi
21、metry measurements are given as a set of reactionrates (or equivalent) denoted by the following symbols:ai, i 5 1,2, . (1)These data are, at present, obtained primarily from radio-metric dosimeters, but other types of sensors may be included(see 4.1).3.2.3 The neutron spectrum (see Terminology E 170
22、)atthedosimeter location, fluence or fluence rate F(E) as a functionof neutron energy E, is obtained by appropriate neutronicscalculations (neutron transport using the methods of discreteordinates or Monte Carlo, see Guide E 482). The results of thecalculation are customarily given in the form of k
23、groupfluences or fluence rates.Fj5*EjEj11F E!dE, j 5 1,2, . k (2)where:Ejand Ej+1are the lower and upper bounds for the j-th energygroup, respectively.3.2.4 The reaction cross sections of the dosimetry sensorsare obtained from an evaluated cross section file. The crosssection for the i-th reaction a
24、s a function of energy E will bedenoted by the following:siE!, i 5 1,2, . (3)Used in connection with the group fluences, Eq 2, are thecalculated group-averaged cross sections sij. These values aredefined through the following equation:sij5*EjEj11FE!siE!dE/Fj(4)i 5 1,2, . . n;j 5 1,2, . k3.2.5 Uncert
25、ainty information in the form of variances andcovariances must be provided for all input data. Appropriatecorrections must be made if the uncertainties are due to biasproducing effects (for example, effects of photo reactions).3.3 Summary of the Procedures:3.3.1 An adjustment algorithm modifies the
26、set of input dataas defined in 3.2 in the following manner (adjusted quantitiesare indicated by a tilde, for example, i):i5 ai1Dai(5)FE! 5FE! 1DFE! (6)or for group fluence ratesFj5Fj1DFj(7)siE! 5siE! 1DsiE!, (8)or for group-averaged cross sectionssij5sij1Dsij(9)The adjusted quantities must satisfy t
27、he following condi-tions:i5*0FE!siE!dE, i 5 1,2, . n (10)or in the form of group fluence ratesi5(j 5 1ksijFj, i 5 1,2, . n (11)Since the number of equations in Eq 11 is much smaller thanthe number of adjustments, there exists no unique solution tothe problem unless it is further restricted. The math
28、ematicalalgorithm in current adjustment codes are intended to make theadjustments as small as possible relative to the uncertainties ofthe corresponding input data. The more recent codes likeSTAYSL, FERRET, LEPRICON, and LSL-M2 (see Table 1)are based explicitly on the statistical principles such as“
29、Maximum Likelihood Principle” or “Bayes Theorem,” whichare generalizations of the well-known least squares principle.Using variances and correlations of the input fluence, dosim-etry, and cross section data (see 4.1.1, 4.2.2, and 4.3.3), eventhe older codes, notably SAND-II and CRYSTAL BALL, canbe i
30、nterpreted as application of the least squares principlealthough the statistical assumptions are not spelled out explic-itly (see Table 1). A detailed discussion of the mathematicalderivations can be found in NUREG/CR-2222 and EPRINP-2188.3.3.1.1 An important problem in reactor surveillance is thede
31、termination of neutron fluence inside the pressure vessel wall5Available from the Electric Power Research Institute, P. O. Box 10412, PaloAlto, CA 94303.E944082at locations which are not accessible to dosimetry. Estimatesfor exposure parameter values at these locations can beobtained from adjustment
32、 codes which adjust fluences simul-taneously at more than one location when the cross correlationsbetween fluences at different locations are given. LEPRICONhas provisions for the estimation of cross correlations forfluences and simultaneous adjustment. LSL-M2 also allowssimultaneous adjustment, but
33、 cross correlations must be given.3.3.2 The adjusted data i, etc., are, for any specific algo-rithm, unique functions of the input variables. Thus, uncertain-ties (variances and covariances) for the adjusted parameterscan, in principle, be calculated by propagation the uncertaintiesfor the input dat
34、a. Linearization may be used before calculatingthe uncertainties of the output data if the adjusted data arenonlinear functions of the input data.3.3.2.1 The algorithms of the adjustment codes tend todecrease the variances of the adjusted data compared to thecorresponding input values. The linear le
35、ast squares adjustmentcodes yield estimates for the output data with minimumvariances, that is, the “best” unbiased estimates. This is theprimary reason for using these adjustment procedures.3.3.3 Properly designed adjustment methods provide meansto detect inconsistencies in the input data which man
36、ifestthemselves through adjustments that are larger than the corre-sponding uncertainties or through large values of chi-square, orboth. (See NUREG/CR-3318 and NUREG/CR-3319.) Anydetection of inconsistencies should be documented, and outputdata obtained from inconsistent input should not be used. Al
37、linput data should be carefully reviewed whenever inconsisten-cies are found, and efforts should be made to resolve theinconsistencies as stated below.3.3.3.1 Input data should be carefully investigated for evi-dence of gross errors or biases if large adjustments arerequired. Note that the erroneous
38、 data may not be the ones thatTABLE 1 Available Unfolding CodesProgram Solution MethodCode AvailableFromRefer-encesCommentsSAND-II semi-iterative RSICC Prog. No. CCC-112, CCC-619, PSR-3451Acontains trial spectra library. No output uncertainties in theoriginal code, but modified Monte Carlo code prov
39、ides outputuncertainties (2, 3, 4)SPECTRA statistical, linear estimation RSICC Prog. No. CCC-1085, 6 minimizes deviation in magnitude, no output uncertainties.IUNFLD/UNFOLDstatistical, linear estimation 7 constrained weighted linear least squares code using B-splinebasic functions. No output uncerta
40、inties.WINDOWS statistical, linear estimation, linearprogrammingRSICC Prog. No. PSR-136, 1618 minimizes shape deviation, determines upper and lower boundsfor integral parameter and contribution of foils to bounds andestimates. No statistical output uncertainty.RADAK,SENSAKstatistical, linear estimat
41、ion RSICC Prog. No. PSR-1229, 10,11,12 RADAK is a general adjustment code not restricted to spectrumadjustment.STAYSL statistical linear estimation RSICC Prog. No. PSR-11313 permits use of full or partial correlation uncertainty data foractivation and cross section data.NEUPAC(J1) statistical, linea
42、r estimation RSICC Prog. No. PSR-17714, 15 permits use of full covariance data and includes routine ofsensitivity analysis.FERRET statistical, least squares with log normala priori distributionsRSICC Prog. No. PSR-1452, 3 flexible input options allow the inclusion of both differential andintegral me
43、asurements. Cross sections and multiple spectra maybe simultaneously adjusted. FERRET is a general adjustmentcode not restricted to spectrum adjustments.LEPRICON statistical, generalized linear leastsquares with normal a priori and aposteriori distributionsRSICC Prog. No. PSR-27716, 17, 18 simultane
44、ous adjustment of absolute spectra at up to twodosimetry locations and one pressure vessel location. Combinesintegral and differential data with built-in uncertainties. Providesreduced adjusted pressure vessel group fluence covariancesusing built-in sensitivity database.LSL-M2 statistical, least squ
45、ares, with log normala priori and a posteriori distributionsRSICC Prog. No.PSR-23319 simultaneous adjustment of several spectra. Providescovariances for adjusted integral parameters. Dosimetry cross-section file included.UMG Statistical, maximum entropy with outputuncertatintiesRSICC Prog. No.PSR-52
46、920, 21 Two components. MAXED is a maximum entropy code. GRAVEL(22) is an iterative code.NMF-90 Statistical, least squares IAEA NDS 23, 24 Several components, STAYNL, X333, and MIEKE. Distributed byIAEA as part of the REAL-84 interlaboratory exercise onspectrum adjustment (25).GMA Statistical, gener
47、al least squares RSICC Prog. No.PSR-36726 Simultaneous evaluation with differential and integral data,primarily used for cross-section evaluation but extensible tospectrum adjustments.AThe boldface numbers in parentheses refer to the list of references appended to this guide.E944083required the larg
48、est adjustment; thus, it is necessary to reviewall input data. Data of dubious validity may be eliminated ifproper corrections cannot be determined. Any elimination ofdata must be documented and reasons stated which areindependent of the adjustment procedure. Inconsistent datamay also be omitted if
49、they contribute little to the output underinvestigation.3.3.3.2 Inconsistencies may also be caused by input vari-ances which are too small. The assignment of uncertainties tothe input data should, therefore, be reviewed to determinewhether the assumed precision and bias for the experimentaland calculational data may be unrealistic. If so, variances maybe increased, but reasons for doing so should be documented.Note that in statistically based adjustment methods, listed inTable 1 the output uncertainties are determined only by theinput uncertainties and are
