BS ISO 13166-2014 Water quality Uranium isotopes Test method using alpha-spectrometry《水质 铀同位素 采用阿尔法-光谱仪的试验方法》.pdf

1、BSI Standards PublicationBS ISO 13166:2014Water quality Uraniumisotopes Test method usingalpha-spectrometryBS ISO 13166:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 13166:2014.The UK participation in its preparation was entrusted to TechnicalCommittee E

2、H/3/8, Radioactivity measurements methods.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards I

3、nstitution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 75481 4ICS 13.060.60; 13.280Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 March 2014.Ame

4、ndments issued since publicationDate Text affectedBS ISO 13166:2014 ISO 2014Water quality Uranium isotopes Test method using alpha-spectrometryQualit de leau Isotopes de luranium Mthode dessai par spectromtrie alphaINTERNATIONAL STANDARDISO13166First edition2014-03-01Reference numberISO 13166:2014(E

5、)BS ISO 13166:2014ISO 13166:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, o

6、r posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copy

7、rightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 13166:2014ISO 13166:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms, definitions and symbols 14 Principle 25 Chemical reagents and equipment 35.1 General . 35.2 Chemical

8、 reagents 35.3 Equipment . 46 Sampling and samples 46.1 Sampling . 46.2 Sample storage 47 Separation and measurement 57.1 Chemical steps . 57.2 Measurement 58 Expression of results 68.1 Spectrum exploitation 68.2 Calculation of activity concentration . 68.3 Standard uncertainty . 68.4 Decision thres

9、hold . 78.5 Detection limit . 79 Test report . 8Annex A (informative) Chemical separation of uranium . 9Annex B (informative) Preparation of the source by electrodeposition 12Annex C (informative) Preparation of the source by coprecipitation .15Annex D (informative) Occurrence of uranium isotopes 17

10、Bibliography .18BS ISO 13166:2014ISO 13166:2014(E)ForewordISO (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

11、member body interested 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

12、 Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different ty

13、pes of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesAttention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held

14、responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received. www.iso.org/patentsAny trade name used in this document is information given f

15、or the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following UR

16、L: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 3, Radiological methods.iv ISO 2014 All rights reservedBS ISO 13166:2014ISO 13166:2014(E)IntroductionRadioactivity from several naturally occurring and anthropogenic sourc

17、es is present throughout the environment. Thus, water bodies (e.g. surface waters, ground waters, sea waters) can contain radionuclides of natural, human-made, or both origins: Natural radionuclides, including potassium 40, and those originating from the thorium and uranium decay series, in particul

18、ar, radium 226, radium 228, uranium 234, uranium 238, lead 210, can be found in water for natural reasons (e.g. desorption from the soil and wash-off by rain water) or can be released from technological processes involving naturally occurring radioactive materials (e.g. the mining and processing of

19、mineral sands or phosphate fertilizer production and use); Human-made radionuclides, such as transuranium elements (americium, plutonium, neptunium, curium), tritium, carbon 14, strontium 90 and some gamma-emitting radionuclides, can also be found in natural waters as a result of authorized routine

20、releases into the environment in small quantities in the effluent discharged from nuclear fuel cycle facilities. They are also released into the environment following their use in the unsealed form for medical and industrial applications. They are also found in water as a result of past fallout cont

21、amination resulting from the explosion in the atmosphere of nuclear devices and accidents such as those that occurred in Chernobyl and Fukushima .Drinking water may thus contain radionuclides at activity concentrations which could present a risk to human health. In order to assess the quality of dri

22、nking water (including mineral waters and spring waters) with respect to its radionuclide content and to provide guidance on reducing health risks by taking measures to decrease radionuclide activity concentrations, water resources (groundwater, river, lake, sea, etc.) and drinking water are monitor

23、ed for their radioactivity content as recommended by the World Health Organization WHO.An International Standard on a test method for uranium isotope activity concentrations in water samples is justified for a test laboratory carrying out these measurements, required sometimes by national authoritie

24、s, as laboratories may have to obtain a specific accreditation for radionuclide measurement in drinking water samples.Uranium activity concentration can vary according to local geological and climatic characteristics (Annex D).The guidance level for uranium-238 and uranium-234 in drinking water, as

25、recommended by WHO, is 10 and 1 Bq l-1, respectively. The provisional guideline value for the concentration of uranium in drinking water is 30 g l-1based on its chemical toxicity, which is predominant compared with its radiological toxicity.NOTE The guidance level is the activity concentration (roun

26、ded to the nearest order of magnitude) with an intake of 2 l d-1 (litres per day) of drinking water for 1 year, that results in an effective dose of 0,1 mSvyear-1for members of the Public, an effective dose that represents a very low level of risk that is not expected to give rise to any detectable

27、adverse health effect.This International Standard is one of a set of International Standards on test methods dealing with the measurement of the activity concentration of radionuclides in water samples. ISO 2014 All rights reserved vBS ISO 13166:2014BS ISO 13166:2014Water quality Uranium isotopes Te

28、st method using alpha-spectrometryWARNING Persons using this document should be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and he

29、alth practices and to ensure compliance with any national regulatory conditions.IMPORTANT It is absolutely essential that tests conducted according to this document be carried out by suitably trained staff.1 ScopeThis International Standard specifies the conditions for the determination of uranium i

30、sotope activity concentration in samples of environmental water (including sea waters) using alpha-spectrometry and 232U as a yield tracer. A chemical separation is required to separate and purify uranium from a test portion of the sample.Plutonium isotopes can interfere, if present, with detectable

31、 activities in the sample.The detection limit for measurement of a test portion of about 500 ml is approximately 5 mBq l1with a counting time of about 200 000 s.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for i

32、ts application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3696, Water for analytical laboratory use Specification and test methodsISO 5667-1, Water quality Sampling Part 1: Guidan

33、ce on the design of sampling programmes and sampling techniquesISO 5667-3, Water quality Sampling Part 3: Preservation and handling of water samplesISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measurements of io

34、nizing radiation Fundamentals and applicationISO/IEC 17025, General requirements for the competence of testing and calibration laboratoriesISO 80000-10, Quantities and units Part 10: Atomic and nuclear physics3 Terms, definitions and symbolsFor the purposes of this document, the terms, definitions,

35、and symbols given in ISO 80000-10 and ISO 11929 and the following apply.INTERNATIONAL STANDARD ISO 13166:2014(E) ISO 2014 All rights reserved 1BS ISO 13166:2014ISO 13166:2014(E)Table 1 Symbols and definitionsSymbol DefinitionA activity of 232U tracer added, in becquerels, at the date of measurementc

36、Aactivity concentration of 238U or 235U or 234U, in becquerels per litrecA*decision threshold, in becquerels per litrecA#detection limit, in becquerels per litrecAcAtrianglerighttriangleleft,lower and upper limits of the confidence interval, in becquerels per litreR total measurement yieldr0, r0Tbac

37、kground count rate per second for the uranium analytes and tracer in the respective regions of interest (ROI) of the blank sample spectrumRcchemical yieldrg, rgTgross count rate per second for the uranium analytes and tracer in the respective regions of interest (ROI) of the test sample spectrumt0ba

38、ckground counting time, in secondstgsample counting time, in secondsU expanded uncertainty, calculated by U = ku(cA) with k = 1, 2 , in becquerels per litreu(cA) standard uncertainty associated with the measurement result; in becquerels per litreV volume of test sample, in litres counting efficiency

39、4 PrincipleThe test sample is mixed with an aliquot of 232U tracer, followed by equilibration of the sample prior to analysis. After a valence cycle to adjust the oxidation states, chemical isolation of uranium is achieved by a concentration step (e.g. a precipitation) followed by a specific separat

40、ion step (e.g. using ion exchange chromatography).Thorium-230, 226Ra and 228Th can be present in water and can interfere with the counting of uranium isotopes if no chemical separation is carried out to remove these radionuclides from the test portion.The measured thin source is prepared by electrod

41、eposition or coprecipitation and mesured by alpha-spectrometry using a grid chamber or a semiconductor-type apparatus. Measurements rely on the interaction of alpha-particles with the detecting medium. This interaction creates a charge, which is amplified and output as a voltage pulse proportional t

42、o the deposited energy of the incoming alpha-particle.The electric pulse from the detector is analysed by the electronic systems. Data analysis software provides a spectrum, in which the number of pulses (counts) recorded in each energy interval is shown.The analysis of the count rates in the uraniu

43、m isotopes alpha-energy windows allows the determination of the test sample activity concentration for uranium-238, uranium-235 and uranium-234, after correcting for the blank count rate, volume of the test sample and the total measurement yield (chemical yield and detection efficiency).The chemical

44、 yield and detection efficiency are not necessarily determined separately, but are determined together by measuring the total measurement yield from the net count rate of 232U, added as a chemical yield tracer.In order to quantify any potential interference coming from the reagents, a blank sample i

45、s prepared in the same way as the test sample. This blank sample is prepared using a reference water.2 ISO 2014 All rights reservedBS ISO 13166:2014ISO 13166:2014(E)For quality control, in order to quantify potential impurities in the tracer solution, another blank sample shall be prepared with addi

46、tion of tracer.The radioactive characteristics of the main uranium isotopes are given in Table 2 (References 78).Table 2Uranium iso-topeHalf-life yearsMain emission energy keVIntensity %232 70,6 ( 1,1)5 263,48 30,65 320,24 69,1233 159,1 ( 0,2) 1034 783,5 13,24 824,2 84,3234 2,455 ( 0,006) 1054 722,4

47、 28,424 774,6 71,37235 704 ( 1) 1064 366,1 18,84 397,8 57,194 414,9 3.01236 23,43 ( 0,06) 1064 445 26,14 494 73,8238 4,468( 0.005) 1094 151 22,334 198 77,54With a spectral resolution (FWHM full-width half-maximum height) of around 20 keV in best cases, alpha-spectrometry cannot easily resolve 233U a

48、nd 234U, nor 235U and 236U, due to the similarity in their respective emission energies; however, 233U and 236U are not normally encountered in environmental samples.5 Chemical reagents and equipment5.1 GeneralThe chemical reagents and equipment used for chemical treatment and preparation of the sou

49、rce are described in Annexes A to C, which give various alternatives. Where there are options, at least one of the options presented shall be used.Use only reagents of recognized analytical grade.5.2 Chemical reagents5.2.1 Laboratory water, used as a blank, as free as possible of chemical or radioactive impurities (e.g. uranium isotopes), complying with ISO 3696, grade 3.Fresh rainwater is an example of water with a very low uranium activity concentration. The uranium activity concentrat