ISO 14850-1-2004 Nuclear energy - Waste-packages activity measurement - Part 1 High-resolution gamma spectrometry in integral mode with open geometry《核能 废弃物包装件的.pdf

1、 Reference numberISO 14850-1:2004(E)ISO 2004INTERNATIONAL STANDARD ISO14850-1First edition2004-05-15Nuclear energy Waste-packages activity measurement Part 1: High-resolution gamma spectrometry in integral mode with open geometry nergie nuclaire Mesurage de lactivit de colis de dchets Partie 1: Spec

2、tromtrie gamma haute rsolution en mode intgral et gomtrie ouverte Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14850-1:2004(E) PDF disclaimer This PDF file may

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5、 parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2004 All rights reserved. Unless ot

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7、ght office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2004 All rights reservedCopyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo

8、 reproduction or networking permitted without license from IHS-,-,-ISO 14850-1:2004(E) ISO 2004 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Terms, definitions and symbols 1 3 Principle . 3 4 Detectors and ancillary equipment . 4 4.1 Mechanical equipment 4 4.2 Detector

9、 and preamplifier. 4 4.3 Amplifier. 5 4.4 Analog-digital converter (ADC) 5 4.5 Multi-channel analyzer (MCA) and data processing system 5 4.6 Background shielding 5 4.7 Collimator. 5 4.8 Gamma ray attenuators 5 5 Calibration 5 5.1 Principle of the calibration. 6 5.2 Calibration apparatus . 7 5.3 Meas

10、urements to be performed 11 5.4 Error estimation of the calibration parameters 12 6 Operating procedure. 13 7 Interpretation of results 13 7.1 Activity . 13 7.2 Uncertainty evaluation 14 7.3 Detection limit . 15 8 Validation of results 16 9 Reporting of results 16 Annex A (informative) Radionuclide

11、transformations Energy and intensity of emissions (ICRP publication 38). 18 Bibliography . 20 Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 14850-1:2004(E) iv IS

12、O 2004 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested

13、in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commi

14、ssion (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technica

15、l committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shal

16、l not be held responsible for identifying any or all such patent rights. ISO 14850-1 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 5, Nuclear fuel technology. ISO 14850 consists of the following parts, under the general title Nuclear energy Waste-packages activity me

17、asurement: Part 1: High-resolution gamma spectrometry in integral mode with open geometry Part 2: Gamma-ray spectrometry using HPGe detectors Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted withou

18、t license from IHS-,-,-ISO 14850-1:2004(E) ISO 2004 All rights reserved vIntroduction Several non destructive methods may be used after calibration to determine the radioactive characteristics of a waste package: gamma spectrometry; passive neutron counting, with or without discrimination of neutron

19、s originating from (,n) reactions; active neutron counting, with detection of neutrons resulting from induced fission reactions (prompt or delayed neutrons). This part of ISO 14850 describes one procedure for measuring the activity contained in waste packages by gamma spectrometry and points out rec

20、ommendations for the calibration of a measurement chain. Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright International Organization for Standardization Repro

21、duced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD ISO 14850-1:2004(E) ISO 2004 All rights reserved 1Nuclear energy Waste-packages activity measurement Part 1: High-resolution gamma spectrometry in integral mo

22、de with open geometry 1 Scope This part of ISO 14850 describes a procedure for measurements of gamma-emitting radionuclide activity in the following homogeneous objects: unconditioned waste, including process waste (filters, control rods, etc.), dismantling waste, etc.; waste conditioned in various

23、matrices (bitumen, hydraulic binder, thermosetting resins, etc.), notably in the form of 100 l, 200 l, 400 l or 800 l drums, and test specimens or samples, (vitrified waste); waste packaged in a container, notably technological waste. It also specifies the calibration of the gamma spectrometry chain

24、 The gamma energies used generally range from 0,05 MeV to 3 MeV. 2 Terms, definitions and symbols For the purposes of this document, the following terms and definitions apply. 2.1 reference source radionuclide sealed in a suitable containment, of which the radioactive characteristics are determined

25、 by comparison with a reference material 2.2 source volume volume in m3taken up by the matrix (or by the waste) in which the activity is distributed 2.3 source weight weight in kg of the matrix in which the activity is distributed 2.4 package object to be characterized, comprising an outer shell (co

26、ntainer or canister) surrounding the (conditioned or unconditioned) source volume 2.5 mockup package consisting of a container and of well-known materials representative of a matrix Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo rep

27、roduction or networking permitted without license from IHS-,-,-ISO 14850-1:2004(E) 2 ISO 2004 All rights reserved2.6 reference package mockup containing reference sources in a well-known configuration 2.7 apparent density of the source ratio of the mass of the source to its volume 2.8 container enve

28、lope of source volume 2.9 matrix structural material immobilizing the radioactivity 2.10 radioprotection-shield material of suitable nature and thickness placed around a package to attenuate the photon emission flux 2.11 gamma ray attenuator material of suitable nature and thickness placed between t

29、he package and detector to attenuate the photon flux 2.12 detector any type of high-purity germanium semiconductor 2.13 efficiency ratio between the number of detected events and the number of emitted gamma photons 2.14 collimator and background shield protective devices for the detector to decrease

30、 background by limitation of the solid angle and gamma background (collimator) and reduction of the ambient background incident (background shielding) 2.15 background noise Benumber of counts in s1recorded at energy e in the background spectrum in the absence of any source, sample or package 2.16 de

31、cision threshold TDvalue (in s1) above which an observed quantity is considered true, within the risk NOTE This limit corresponds the risk of affirming the presence of the true quantity when it is in fact not present. The recommended value of is 2,5 % 2.17 detection limit LDvalue (in Bq) of the meas

32、ured quantity that can be detected with a given probability (1 ), i.e. capable of providing a corrected result exceeding the decision threshold Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted with

33、out license from IHS-,-,-ISO 14850-1:2004(E) ISO 2004 All rights reserved 3NOTE The risk corresponds to the risk of affirming the absence of the true quantity when it is in fact present. The recommended value is 2,5 % 2.18 combined standard uncertainty ucxsum-of-the-squares combination of standard u

34、ncertainties arising from a Type A evaluation (applying statistical methods, expressed as a standard deviation si) and a Type B evaluation (non-statistical methods, expressed as a standard deviation uj): () ()1/ 222c xi jijus u=+2.19 coverage factor k user-defined value, depending on the probability

35、 law, the level of confidence, and the precision of the estimated standard deviation, with k = 1 for standard deviation calculations, and k = 2 for the normal law, for a 95 % confidence level assuming a known standard deviation 2.20 expanded uncertainty product of the standard deviation by the cover

36、age factor, k 3 Principle This part of ISO 14850 describes a non-destructive method implemented using fixed or mobile equipment, which is based on measuring the photon emission rate at different energies by gamma spectrometry: to identify detectable radionuclides in the objects in Clause 1, either b

37、y direct measurement or by using decay schemes; to determine the activity of the identified radionuclides from the counting rates recorded under each total absorption peak, weighted by a calibration factor. The method implies optimization of the equipment parameters, energy calibration and efficienc

38、y calibration (by modelling the transfer function or by fabricating mockups): choice of detector(s), electronic circuitry and shielding; choice of measurement geometry; choice of calibration geometry. The method may be validated: by comparison with destructive examination results on representative s

39、amples; by measurement of reference packages for which the activity, the nature of the radionuclides, the nature of the elements composing the waste and homogeneity are accurately known. Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleN

40、o reproduction or networking permitted without license from IHS-,-,-ISO 14850-1:2004(E) 4 ISO 2004 All rights reserved4 Detectors and ancillary equipment The measuring station usually comprises the following equipment. a) Mechanical equipment: a package-positioning system (rotation, with optional ve

41、rtical movement); a detector-positioning system (vertical, horizontal and distance); a weighing station (optional); a turntable; collimator, background shielding, gamma ray attenuators, b) Detector and signal-processing electronics: a detector and preamplifier; an amplifier; an analog-digital conver

42、ter, a “stand alone” module or a computer interface card, c) Computer with measurement processing and interpretation software. 4.1 Mechanical equipment 4.1.1 Package-positioning system The package-positioning system is designed to support the package to be measured, and to move it in rotation about

43、its vertical axis. It may also allow for vertical moving of the package, and may be equipped with a weighing system. 4.1.2 Detector-positioning system This system carries the detector with its protective shielding, and positions it in elevation and azimuth with respect to the package to be measured.

44、 It may be equipped with a system to determine the relative position of the package with respect to the detector. 4.2 Detector and preamplifier The method covers only high-purity germanium semiconductor detectors. Two types of detectors may be selected depending on the energy of the radionuclides to

45、 be measured: planar or flat coaxial detectors provide better resolution at low energy (below 400 keV), coaxial detectors give higher efficiency at high energies. The semiconductor crystal requires a cryogenic system. The detector signal is collected by a charge sensitive preamplifier; this can be o

46、f either the resistive feedback type, transistor reset type or pulsed optical feedback type depending upon the application. Copyright International Organization for Standardization Reproduced by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS

47、ISO 14850-1:2004(E) ISO 2004 All rights reserved 54.3 Amplifier The amplifier implements Gaussian or triangular pulse shaping with a time constant adjustable from 0,25 s to 15 s. A pileup rejector is generally used, and in some cases the amplifier is equipped with a gated integrator. Various ty

48、pes of amplifiers may be used in conjunction with this method. The choice of an amplifier depends on the other components in the counting system. 4.4 Analog-digital converter (ADC) Two types of ADC converters are used in gamma spectrometry: Wilkinson ADCs, with a variable dead time; counting losses depend on the conversion frequency and the signal amplitude; successive approximation ADCs, with a fixed dead time independent of the signal amplitude. 4.5 Multi-channel analyzer (MCA) and data processing system The analyzer stores the