BS ISO 13165-2-2014 Water quality Radium-226 Test method using emanometry《水质 镭226 采用射气测量法的试验方法》.pdf

1、BSI Standards PublicationBS ISO 13165-2:2014Water quality Radium-226Part 2: Test method using emanometryBS ISO 13165-2:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 13165-2:2014.The UK participation in its preparation was entrusted to TechnicalCommittee

2、EH/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

3、Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 75503 3ICS 13.060.60; 17.240Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 April 2014.Am

4、endments issued since publicationDate Text affectedBS ISO 13165-2:2014 ISO 2014Water quality Radium-226 Part 2: Test method using emanometryQualit de leau Radium 226 Partie 2: Mthode dessai par manomtrieINTERNATIONAL STANDARDISO13165-2First edition2014-04-15Reference numberISO 13165-2:2014(E)BS ISO

5、13165-2:2014ISO 13165-2:2014(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, or po

6、sting 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 copyrigh

7、tiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 13165-2:2014ISO 13165-2:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms, definitions and symbols 13.1 Terms and definitions . 13.2 Symbols . 24 Principle 25 Reagents and equ

8、ipment . 35.1 Reagents 35.2 Equipment . 36 Sampling and storage 46.1 Sampling . 46.2 Sample storage 47 Procedures 47.1 Sample preparation 47.2 Measurement conditions 57.3 Counting procedure 58 Quality assurance and quality control programme . 58.1 General . 58.2 Influence parameters 58.3 Instrument

9、verification and calibration 68.4 Method verification . 68.5 Demonstration of analyst capability 69 Expression of results 69.1 Activity concentration of water-soluble 226Ra 69.2 Standard uncertainty of activity concentration 79.3 Limits of the confidence interval . 89.4 Example . 810 Test report . 8

10、Annex A (informative) Decay chains of uranium-238 and thorium-23210Annex B (informative) Bubbler .12Annex C (informative) Glass scintillation cell 14Bibliography .15BS ISO 13165-2:2014ISO 13165-2:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of nat

11、ional standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Interna

12、tional organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intend

13、ed for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.i

14、so.org/directives). Attention 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 responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document wi

15、ll be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expres

16、sions 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 URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 3, R

17、adioactivity measurements.ISO 13165 consists of the following parts, under the general title Water quality Radium-226: Part 1: Test method using liquid scintillation counting Part 2: Test method using emanometryThe following parts are under preparation: Part 3: Test method using coprecipitation and

18、gamma spectrometryiv ISO 2014 All rights reservedBS ISO 13165-2:2014ISO 13165-2:2014(E)IntroductionRadioactivity from several naturally occurring and human-made sources is present throughout the environment. Thus, water bodies (surface waters, ground waters, sea waters) can contain radionuclides of

19、natural and human-made origins:Natural radionuclides, including potassium-40, and those of the thorium and uranium decay series, in particular radium-226, radium-228, uranium-234, uranium-238, and lead-210, can be found in water for natural reasons (e.g. desorption from the soil and wash-off by rain

20、 water) or releases from technological processes involving naturally occurring radioactive materials (e.g. the mining and processing of mineral sands or phosphate fertilizer production and use).Human-made radionuclides such as transuranium elements (americium, plutonium, neptunium, curium), tritium,

21、 carbon-14, strontium-90, and some gamma emitters radionuclides can also be found in natural waters as they can be authorized to be routinely released into the environment in small quantities in the effluent discharge from nuclear fuel cycle facilities and following their use in unsealed form in med

22、icine or industry. They are also found in the water due to the past fallout of the explosion in the atmosphere of nuclear devices and those following the Chernobyl and Fukushima accidents.Drinking water can thus contain radionuclides at activity concentration which could present a risk to human heal

23、th. In order to assess the quality of drinking 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,

24、sea, etc.) and drinking water are monitored for their radioactivity content as recommended by the World Health Organization (WHO).The need of a standard on a test method of radium-226 activity concentrations in water samples is justified for test laboratories carrying out these measurements, require

25、d sometimes by national authorities, as they may have to obtain a specific accreditation for radionuclide measurement in drinking water samples.Radium-226 activity concentration can vary widely according to local geological and climatic characteristics and ranges from 0,001 Bq l1in surface waters up

26、 to 50 Bq l1in natural groundwaters. The guidance level for radium-226 in drinking water as recommended by WHO is 1 Bq l1(see Reference 11).NOTE The guidance level is the activity concentration (rounded to the nearest order of magnitude) with an intake of 2 ld-1of drinking water for 1 year that resu

27、lts in an effective dose of 0,1 mSvy-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 adverse health effect.This International Standard is one of a series on determination of the activity concentration of radio

28、nuclides in water samples. ISO 2014 All rights reserved vBS ISO 13165-2:2014BS ISO 13165-2:2014Water quality Radium-226 Part 2: Test method using emanometryWARNING Persons using this document should be familiar with normal laboratory practice. This document does not purport to address all of the saf

29、ety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.IMPORTANT It is absolutely essential that tests conducted in accordance with this document be carr

30、ied out by suitably qualified staff.1 ScopeThis part of ISO 13165 specifies the determination of radium-226 (226Ra) activity concentration in all types of water by emanometry.The method specified is suitable for the determination of the soluble, suspended, and total 226Ra activity concentration in a

31、ll types of water with soluble 226Ra activity concentrations greater than 0,02 Bq l1.In water containing high activity concentrations of 228Th, interference from 220Rn decay products can lead to overestimation of measured levels (see Figure A.2).2 Normative referencesThe following documents, in whol

32、e or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 5667-3, Water quality Sampling Part

33、3: Preservation and handling of water samplesISO/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 symbols3.1 Terms and definitionsFor the purposes of this document,

34、 the terms and definitions in ISO 80000-10 and the following apply.3.1.1reference measurement standardmeasurement standard designated for the calibration of other measurement standards for quantities of a given kind in a given organization or at a given location3.1.2working measurement standardmeasu

35、rement standard that is used routinely to calibrate or verify measuring instruments or measuring systemsNote 1 to entry: A working measurement standard can be used as a solution of known activity concentration obtained by precise dilution or dissolution of a reference standard.INTERNATIONAL STANDARD

36、 ISO 13165-2:2014(E) ISO 2014 All rights reserved 1BS ISO 13165-2:2014ISO 13165-2:2014(E)3.2 SymbolsFor the purposes of this document, the symbols in ISO 80000-10 and the following apply.cA226Ra activity concentration in water, in becquerel per litrecAdecision threshold, in becquerel per litrecA#det

37、ection limit, in becquerel per litreccAAtrianglerighttriangleleft, lower and upper limits of the confidence interval, in becquerel per litrefacorrection factor for ingrowth of 222Rn in the bubbler, dimensionlessfdcorrection factor for the decay of 222Rn in the detection volume, dimensionlessn number

38、 of counting cyclennumber of alpha-emitters present in the cell per becquerel of radon after a waiting time period between the filling time and the counting time of the cell (n is approximately 3 at a waiting time of 3 h for 1 Bq of radon)N0number of background countsN number of gross countstccounti

39、ng time (common to N, N0), in secondstitime of the different steps of the measurement procedure, i = 0,1 and 2U expanded uncertainty calculated by U = ku(cA) with k = 2u(cA) standard uncertainty associated with the measurement resultV volume of the test sample, in litretotal efficiency including deg

40、assing efficiency and counting efficiency of the system for a count carried out with a radioactive equilibrium between 222Rn and its short-lived decay products, in pulses per second per becquerel decay constant of the 222Rn, per second4 PrincipleThis test method is based on the emanation and scintil

41、lation counting of 222Rn, a gaseous daughter product of 226Ra, from a solution (see Reference 6).The measurement of 226Ra activity concentration in water is carried out following two separate steps, the sample preparation followed by the measurement of the test sample.Preparation consists of: dissol

42、ution when total or particulate radium is to be assayed; filtration when soluble radium is to be measured.It is followed by pre-concentration, if necessary, and an accumulation of decay products without an initial separation.2 ISO 2014 All rights reservedBS ISO 13165-2:2014ISO 13165-2:2014(E)After f

43、iltration and acidification, the test sample is placed in a bubbler (see Figure B.1) and stored for ingrowth of 222Rn.After a suitable ingrowth period, the radon gas is removed from the solution by purging with the radon-free gas and transferring it to a scintillation cell, whose internal surface is

44、 coated with silver-activated zinc sulfide, ZnS(Ag) (see Figure C.1)(see Reference 8).The alpha-particles produced by the decay of 222Rn and its short-lived decay products (218Po, 214Po) transfer their energy as they pass through the scintillation medium. As they return to their ground state, the ex

45、citation electrons in the scintillation medium emit photons from the ZnS(Ag) coating that can be detected by a photomultiplier (PMT). The photomultiplier converts the photons into electrical pulses that are then counted. The pulse count is directly proportional to the activity concentration of radon

46、 and its decay products present in the scintillation cell.The soluble 226Ra activity concentration is calculated, taking into account the known steady state between 226Ra and 222Rn after transferring 222Rn into a scintillation cell.Given its high power of emanation, radon can also escape from partic

47、les suspended in water. In the case of the analysis of raw water, it is therefore advisable to dissolve the particulate fraction (see Reference 7).5 Reagents and equipment5.1 ReagentsUnless otherwise stated, use only reagents of recognized analytical grade and distilled or demineralized water or wat

48、er of equivalent purity and no undesirable radioactivity.5.1.1 Concentrated nitric acid solution, HNO3.5.1.2 Dilute nitric acid solution, less than or equal to 100 g l1, with no alpha-radioactivity.5.1.3 Reference solution of 226Ra.5.1.4 Cellulose ester filter, 0,45 m porosity.5.1.5 Hydrochloric aci

49、d solution, if the particulate fraction of 226Ra requires dissolution.5.2 EquipmentUsual laboratory equipment and, in particular, the following.5.2.1 Hotplates.5.2.2 Needles, length of approximately 30 mm, diameter of approximately 1,5 mm.5.2.3 Bubblers, minimum volume of 125 ml with two (poly)tetrafluoroethylene needle valves (see Figure B.1).5.2.4 Specialized solid-state scintillation detection set, equipped with a photomultiplier.5.2.5 Manometer, to measure pressure.5.2.6 Flat-bottomed glass scintillation ce