EN 60861:2008
(Main)Equipment for monitoring of radionuclides in liquid effluents and surface waters
Equipment for monitoring of radionuclides in liquid effluents and surface waters
Defines technical requirements for equipment for monitoring of alpha-, beta- or gamma-emitting radionuclides in liquid effluents and surface waters, provides general guidance as to the possible detection capability of such equipment and indicates when and where its uses may be practicable.
Einrichtungen zur Überwachung von Radionukliden in flüssigen Ableitungen und Oberflächengewässern
Equipements pour la surveillance des radionucléides dans les effluents liquides et les eaux de surface
Définit les exigences techniques pour les appareils de surveillance des radionucléides émetteurs alpha, bêta ou gamma dans les effluents liquides et dans les eaux de surface. Donne des directives générales sur les aptitudes de tels équipements et indique où et quand ils peuvent être utilisés.
Oprema za spremljanje radionuklidov v odplakah in površinskih vodah (IEC 60861:2006, spremenjen)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2008
Oprema za spremljanje radionuklidov v odplakah in površinskih vodah (IEC
60861:2006, spremenjen)
Equipment for monitoring of radionuclides in liquid effluents and surface waters
Einrichtungen zur Überwachung von Radionukliden in flüssigen Ableitungen und
Oberflächengewässern
Equipements pour la surveillance des radionucléides dans les effluents liquides et les
eaux de surface
Ta slovenski standard je istoveten z: EN 60861:2008
ICS:
13.280 Varstvo pred sevanjem Radiation protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 60861
NORME EUROPÉENNE
March 2008
EUROPÄISCHE NORM
ICS 13.280
English version
Equipment for monitoring of radionuclides
in liquid effluents and surface waters
(IEC 60861:2006, modified)
Equipements pour la surveillance Einrichtungen zur Überwachung von
des radionucléides dans les effluents Radionukliden in flüssigen Ableitungen
liquides et les eaux de surface und Oberflächengewässern
(CEI 60861:2006, modifiée) (IEC 60861:2006, modifiziert)
This European Standard was approved by CENELEC on 2008-02-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60861:2008 E
Foreword
The text of the International Standard IEC 60861:2006, prepared by SC 45B, Radiation
protection instrumentation, of IEC TC 45, Nuclear instrumentation, together with the common
modifications prepared by the Technical Committee CENELEC TC 45B, Radiation protection
instrumentation, was submitted to the formal vote and was approved by CENELEC as
EN 60861 on 2008-02-01.
The following dates were fixed :
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-02-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-02-01
Clauses, subclauses, notes, tables and figures which are additional to those in IEC 60861 are
prefixed “Z”.
Annex ZA has been added by CENELEC.
__________
– 3 – EN 60861:2008
Endorsement notice
The text of International Standard IEC 60861:2006 was approved by CENELEC as a
European Standard with agreed common modifications as given below.
COMMON MODIFICATIONS
1 Scope
In the first sentence of the fourth paragraph replace “continuous monitoring” with
“continuous monitoring (including discrete sequential measurement)”.
In the last sentence of the fourth paragraph replace “extraction and laboratory
analysis” with “extraction followed by laboratory analysis”.
2 Normative references
Add the following:
ISO 11929 (Series) Determination of the detection limit and decision threshold for
ionizing radiation measurements
3 Terms and definitions
3.1 water monitor
Replace the definition with “equipment intended for monitoring of radionuclides in
liquid effluents and surface waters”.
3.3 continuous measurement
Delete the whole definition.
3.5 discrete sequential measurement
Add the following note:
NOTE Z Immediately after collection of the sample the activity of the sample will be measured, during
the time the next sample is collected. The time between taking each sample should be as short as
possible.
3.11 total equivalent window thickness (density thickness)
Replace “medium measured” with “surface of the medium of deposition to be
measured”.
Add at the end of the NOTE “… and the sample container (if any).”
3.16 decision threshold
Replace the first sentence of NOTE 1 with “The decision threshold is the critical
value of a statistical test designed in such a way that the probability of wrongly
rejecting the null hypothesis (H : the physical effect is not present) (error of the first
kind) is equal to a given value α.”.
3.25 sensitivity
Replace the first sentence with “for a given value of the measured quantity, the ratio
of the observed indication to the corresponding conventionally true value of the
measured quantity”.
Add the following note:
NOTE Z This definition is specific to this standard.
5 Equipment design
5.1 Measurement and indication characteristics
5.1.1 Measurement characteristics
Add the following note below the current text:
NOTE Z The decision threshold is calculated according to ISO 11929 series.
5.3 Sampling assembly
5.3.1 Sampling and exhaust pipes
Add “radioactive contamination” between “minimize” and “particle traps”.
6 Test procedures
6.5 Test sources
6.5.1 Reference sources
204 137
In the second paragraph delete “ Tl, or Cs,”.
7 Radiation performance tests
7.3 Linearity
7.3.2 Requirements
In the last sentence replace “reference curve” with “reference straight line”.
7.12 Influence of materials in suspension in liquid on activity measurement
7.12.2 Test method
In the second sentence of the first paragraph replace “conductivity of the used
solution shall” with “conductivity of the used solution should”.
– 5 – EN 60861:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
1)
IEC 60038 (mod) 1983 IEC standard voltages HD 472 S1 1989
+ corr. February 2002
A1 1994 A1 1995
+ A2 1997
IEC 60050-393 2003 International Electrotechnical - -
Vocabulary -
Part 393: Nuclear
instrumentation - Physical
phenomena and basic concepts
IEC 60050-394 1995 International Electrotechnical - -
+ A1 1996 Vocabulary -
+ A2 2000 Chapter 394: Nuclear
instrumentation - Instruments
IEC 60068-2-38 1974 Environmental testing - EN 60068-2-38 1999
Part 2: Tests - Test Z/AD:
Composite temperature/humidity
cyclic test
IEC 61000-4-2 1995 Electromagnetic compatibility EN 61000-4-2 1995
A1 1998 (EMC) - A1 1998
A2 2000 Part 4-2: Testing and A2 2001
measurement techniques -
Electrostatic discharge immunity
test
IEC 61000-4-3 2006 Electromagnetic compatibility EN 61000-4-3 2006
(EMC) -
Part 4-3: Testing and
measurement techniques -
Radiated, radio-frequency,
electromagnetic field immunity
test
IEC 61000-4-4 2004 Electromagnetic compatibility EN 61000-4-4 2004
(EMC) -
Part 4-4: Testing and
measurement techniques -
Electrical fast transient/burst
immunity test
IEC 61000-4-5 2005 Electromagnetic compatibility EN 61000-4-5 2006
(EMC) -
Part 4-5: Testing and
measurement techniques -
Surge immunity test
———————
1)
The title of HD 472 S1 is “Nominal voltages for low-voltage public electricity supply systems”.
Publication Year Title EN/HD Year
2)
IEC 61000-4-6 2003 Electromagnetic compatibility 2007
EN 61000-4-6
+ A1 2004 (EMC) - + corr. August 2007
Part 4-6: Testing and
measurement techniques -
Immunity to conducted
disturbances, induced by
radio-frequency fields
IEC 61000-4-11 2004 Electromagnetic compatibility EN 61000-4-11 2004
(EMC) -
Part 4-11: Testing and
measurement techniques -
Voltage dips, short interruptions
and voltage variations immunity
tests
3)
IEC 61000-4-12 1995 Electromagnetic compatibility EN 61000-4-12 1995
A1 2000 (EMC) - A1 2001
Part 4-12: Testing and
measurement techniques -
Oscillatory waves immunity test
4)
IEC 61000-6-4 1997 Electromagnetic compatibility EN 61000-6-4 2001
(mod) (EMC) -
Part 6: Generic standards –
Section 4: Emission standard for
industrial environments
IEC 61010-1 2001 Safety requirements for EN 61010-1 2001
electrical equipment for + corr. June 2002
measurement, control, and
laboratory use -
Part 1: General requirements
IEC 61187 (mod) 1993 Electrical and electronic EN 61187 1994
measuring equipment - + corr. March 1995
Documentation
ISO/IEC Guide 98 1995 Guide to the expression of - -
uncertainty in measurement
(GUM)
ISO 10012 2003 Measurement management EN ISO 10012 2003
systems - Requirements for
measurement processes and
measuring equipment
———————
2)
EN 61000-4-6 includes A1:2004 + A2:2006 to IEC 61000-4-6.
3)
EN 61000-4-12 is superseded by EN 61000-4-18:2007, which is based on IEC 61000-4-18:2006.
4)
EN 61000-6-4 is superseded by EN 61000-6-4:2007, which is based on IEC 61000-6-4:2006.
NORME CEI
INTERNATIONALE
IEC
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
2006-08
Equipements pour la surveillance
des radionucléides dans les effluents liquides
et les eaux de surface
Equipment for monitoring of radionuclides
in liquid effluents and surface waters
IEC 2006 Droits de reproduction réservés Copyright - all rights reserved
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МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue
60861 IEC:2006 – 3 –
CONTENTS
FOREWORD.7
1 Scope.11
2 Normative references .13
3 Terms and definitions .15
4 Classification of equipment.25
5 Equipment design.25
5.1 Measurement and indication characteristics .25
5.2 Reliability .27
5.3 Sampling assembly .27
5.4 Detection assembly .29
5.5 Control assembly.31
5.6 Measurement assembly.31
5.7 Alarm assembly.31
5.8 Indication facilities.33
5.9 Facilities for operational testing.33
5.10 Installation and maintenance facilities .33
5.11 Ambient ionizing radiation protection devices .35
5.12 User safety.35
5.13 Electromagnetic compatibility .35
5.14 Power supply.37
6 Test procedures .37
6.1 General .37
6.2 Tests performed under standard test conditions .37
6.3 Tests performed with variation of influence quantities.39
6.4 Metrological characteristics .39
6.5 Test sources .39
7 Radiation performance tests .41
7.1 Reference response .41
7.2 Sensitivity and relative response of the equipment for a solid source .43
7.3 Linearity .43
7.4 Repeatability of the equipment .45
7.5 Reproducibility of results of measurements .47
7.6 Response time .47
7.7 Uniformity of the protective screens for the beta detector .49
7.8 Overload test.51
7.9 Response to other artificial radionuclides .51
7.10 Response to Rn progeny dissolved in water.51
7.11 Response to ambient gamma radiation.53
7.12 Influence of materials in suspension in liquid on activity measurement .55
8 Liquid circuit performance tests .57
8.1 General .57
8.2 Flow-rate stability .57
8.3 Cleaning efficiency .57
60861 IEC:2006 – 5 –
9 Electrical performance tests .59
9.1 Warm-up time – Detection and measurement assemblies .59
9.2 Power-supply variations .59
9.3 Power-supply transient effects.61
9.4 Alarm-trip stability .61
9.5 Alarm-trip range .61
9.6 Fault alarm .63
10 Environmental performance test .63
10.1 Ambient temperature .63
10.2 Relative humidity.65
10.3 External electromagnetic immunity and electrostatic discharge .65
10.4 Electromagnetic emission.65
11 Type test report .65
12 Certificate.67
13 Operation and maintenance manual .67
Annex A (informative) Guidance for use with radioactive water monitors.77
Annex B (informative) Realization of an artificial effluent for testing .81
Table 1 – Reference and standard test conditions.69
Table 2 – Tests performed under standard test conditions .71
Table 3 – Tests performed with variation of influence quantities.73
Table 4 – Tests of liquid circuit .75
60861 IEC:2006 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EQUIPMENT FOR MONITORING OF RADIONUCLIDES
IN LIQUID EFFLUENTS AND SURFACE WATERS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60861 has been prepared by subcommittee 45B: Radiation
protection instrumentation, of IEC technical committee 45: Nuclear instrumentation.
This second edition cancels and replaces the first edition published in 1987 and the first
edition of IEC 61311 published in 1995.
This edition includes the following significant technical changes with respect to the previous
edition:
a) taking into account of the main technological evolutions, notably the feasibility of
continuous monitoring of alpha radioactivity in liquids;
b) tests of electromagnetic compatibility.
60861 IEC:2006 – 9 –
The text of this standard is based on the following documents:
FDIS Report on voting
45B/499/FDIS 45B/518/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
60861 IEC:2006 – 11 –
EQUIPMENT FOR MONITORING OF RADIONUCLIDES
IN LIQUID EFFLUENTS AND SURFACE WATERS
1 Scope
This International Standard defines technical requirements for equipment for monitoring of
alpha-, beta- or gamma-emitting radionuclides in liquid effluents and surface waters, provides
some general guidance as to the possible detection capability of such equipment and
indicates when and where its uses may be practicable.
NOTE Alpha monitoring in liquids is a possibility that has been demonstrated using a concentration device and
collection of the concentrate in a filter, so this standard may also be applicable to alpha monitoring in liquids.
This standard is applicable to equipment for continuous monitoring of the activity:
– in liquid effluents which could be released in the environment during normal operations;
– in environmental waters.
This standard does not apply to equipment specifically for use in accident conditions that may
require additional capabilities.
This standard is restricted to equipment for continuous monitoring of gross alpha or gross
beta of maximum energy higher than 150 keV or gamma activity in liquid effluent streams and
environmental waters. It does not deal with sample extraction and laboratory analysis.
The object of this standard is to lay down general requirements and give examples of
acceptable methods for equipment to monitor continuously the activity of water.
This International Standard specifies, for the equipment described in the scope, the general
characteristics, general test procedures, radiation, electrical, safety and environmental
characteristics, and the identification and certification of the equipment. Performance
requirements for the safe operation of electrical equipment are provided in IEC 61010-1.
These safety requirements and corresponding tests are applicable if the manufacturer wants
to, or is required to, label its equipment with the appropriate safety mark (for example, CE,
UL, etc.).
This standard is applicable to water monitors intended to fulfil the following functions:
– measurement of the volumetric activity or count rate (see 5.1.2) due to radionuclides in
the liquid and its variation with time;
– actuation of an alarm when a limit value of volumetric activity or count rate in water is
exceeded.
Annex A gives some guidance for use with radioactive water monitors.
60861 IEC:2006 – 13 –
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60038:1983, IEC standard voltages
Amendment 1 (1994)
Amendment 2 (1997)
IEC 60050-393:2003, International Electrotechnical Vocabulary (IEV) – Part 393: Nuclear
instrumentation – Physical phenomena and basic concepts
IEC 60050-394:1995, International Electrotechnical Vocabulary (IEV) – Chapter 394: Nuclear
instrumentation – Instruments
Amendment 1 (1996)
Amendment 2 (2000)
IEC 60068-2-38:1974, Basic environmental testing procedures – Part 2-38: Tests − Test Z/AD:
Composite temperature/humidity cyclic test
IEC 61000-4-2:2001 Electromagnetic compatibility (EMC) − Part 4-2: Testing and measure-
ment techniques – Electrostatic discharge immunity test
Amendment 1 (1998)
Amendment 2 (2000)
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measure-
ment techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measure-
ment techniques – Surge immunity test
IEC 61000-4-6:2004, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measure-
ment techniques – Immunity to conducted disturbances, induced by radio-frequency fields
Amendment 1 (2004)
IEC 61000-4-11:2004, Electromagnetic compatibility (EMC) – Part 4-11: Testing and measure-
ment techniques – Voltage dips, short interruptions and voltage variations immunity tests
IEC 61000-4-12:1995, Electromagnetic compatibility (EMC) – Part 4-12: Testing and measure-
ment techniques – Oscillatory waves immunity test
Amendment 1 (2000)
IEC 61000-6-4:1997, Electromagnetic compatibility (EMC) – Part 6: Generic standards –
Section 4: Emission standard for industrial environments
———————
There exists a consolidated edition 6.2 (2002) including edition 6.0 and its amendments 1 and 2.
There exists a consolidated edition 1.2 (2001) including edition 1.0 and its amendments 1 and 2.
There exists a consolidated edition 2.1 (2004) including edition 2.0 and its amendment 1.
There exists a consolidated edition 1.1 (2001) including edition 1.0 and its amendment 1.
60861 IEC:2006 – 15 –
IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 1: General requirements.
IEC 61187:1993, Electrical and electronic measuring equipment – Documentation
ISO Guide to the expression of uncertainty in measurement (GUM), 1995.
ISO 10012:2003, Measurement management systems – Requirements for measurement
processes and measuring equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions concerning detection and
measurement of ionizing radiation and nuclear instrumentation given in IEC 60050-393 and
IEC 60050-394, as well as the following, apply.
3.1
water monitor
equipment intended for radioactivity monitoring in liquid effluents discharged into the
environment and into environmental waters
3.2
activity monitoring
different ways of monitoring:
Monitors with sampling,
simultaneous measurement,
discrete sequential measurement,
Monitors without sampling
direct measurement
3.3
continuous measurement
simultaneous and discrete sequential measurement
3.4
simultaneous measurement
measurement of a sample taken at the same time as the sample is collected
NOTE Measurements carried out with the detector in contact with the liquid (beta detector) or inside it (gamma
detector) are considered as a simultaneous measurement.
3.5
discrete sequential measurement
measurement of a sample that is undertaken separately from collection of the sample with a
short collection time separated by a short delay from the time of measurement
3.6
direct measurement
measurement, without sampling, with the detector immersed in liquid flow or adjacent to the
duct where the liquid is flowing
3.7
sampling assembly
assembly for collecting a representative sample
60861 IEC:2006 – 17 –
3.8
detection assembly
assembly used for measuring the activity. The detection assembly includes one or more
radiation detectors
3.9
measurement assembly
assemblies and function units designed to measure quantities connected with ionizing
radiation (activity, volumetric activity, etc.)
3.10
alarm assembly
assembly that will initiate an audible or visible alarm in the event of an alarm threshold being
breached or in case of fault of the equipment
3.11
total equivalent window thickness (density thickness)
thickness, generally expressed in mass per unit area (mg/cm ), which a particle emitted
normally from the medium measured traverses to reach the sensitive volume of the detector
NOTE This thickness includes the distance covered in liquid or air plus the thickness of the entry window of the
detector. This may include any screen or coating over the detector for protection against the liquid effluent
3.12
coefficient of variation
ratio V of the standard deviation s to the arithmetic mean x of a set of n measurements x
i
given by the following formula:
n
s 11
V== xx−
()
∑ i
xx n − 1
i=1
3.13
relative intrinsic error
relative error of indication of a piece of equipment or an assembly with respect to a quantity
when subjected to a specified reference quantity under specified reference conditions
expressed as
ν −ν
c
e =
i
ν
c
where
ν is the indicated value of a quantity;
ν is the conventionally true value of the quantity at the point of measurement
c
3.14
uncertainty of measurement
parameter associated with the result of a measurement that characterizes the dispersion of
the values that could reasonably be attributed to the measurand
NOTE 1 The parameter may be, for example, a standard deviation (or a given multiple of it) or the half-width of an
interval having a stated level of confidence.
NOTE 2 Uncertainty of measurement comprises, in general, many components. Some of these components may
be evaluated from statistical distribution of the result of series of measurements and can be characterized by
experimental standard deviation. The other components, which can also be characterized by standard deviation,
are evaluated from assumed probability distributions based on experience or other information.
60861 IEC:2006 – 19 –
NOTE 3 It is understood that the result of the measurement is the best estimate of the value of the measurand
and that all components of uncertainty, including those arising from systematic effects, such as components
associated with corrections and reference standards, contribute to the dispersion.
3.15
coverage factor
k
numerical factor, k, used as a multiplier of the combined standard uncertainty in order to
obtain an expanded uncertainty
3.16
decision threshold
fixed value of the decision quantity by which, when exceeded by the result of an actual
measurement of a measurand quantifying a physical effect, one decides that the physical
effect is present
NOTE 1 The statistical test is designed in such a way that the probability of wrongly rejecting the hypothesis
(error of the first kind) is equal to a given value α. For this standard, α equals 5 % and the decision threshold (DT)
is calculated using the following general formula:
DT = 1,64 2var()b = 2,32 s()b
where
s is the experimental standard deviation of the background.
NOTE 2 For equipment given an indication in terms of count rate the standard deviation used may be the
estimated standard deviation of the background count rate,u , given by the following formula, instead of the
(b)
experimental standard deviation, s:
b
u =
(b)
t
where
b is the count rate due to the background (counts/second);
t is the time of measurement (in seconds).
3.17
decision quantity
random variable for the decision whether the physical effect to be measured is present or not
3.18
effective range of measurement
range of values of the quantity to be measured over which the performance of a piece of
equipment or an assembly meets the requirements of its specifications
3.19
dynamic range
quotient of the signal from the maximum measurable indication of a quantity to the signal from
the decision threshold of that quantity
3.20
response time
time required after a step variation in the measured quantity for the output signal variation to
reach a given percentage for the first time, usually from 10 % to 90 %, of its final value
3.21
volumetric activity
quotient of the measured activity by the total volume of the sample
NOTE This quantity is expressed in becquerel per cubic metre (Bq/m ).
60861 IEC:2006 – 21 –
3.22
surface emission rate of solid sources
number of particles of a given type above a given energy emerging from the front face of the
source per unit time
3.23
conventionally true value (of a quantity)
best estimate of the value of a quantity used for a given purpose
NOTE A conventionally true value is, in general, regarded as sufficiently close to the true value for the difference
to be insignificant for the given purpose. For example, a value determined from a primary or a secondary standard
or by a reference instrument, may be taken as the conventionally true value.
3.24
reference response
ratio, under standard test conditions, given by the relation
A
v
R =
ref
A
vc
where
A is the value of the volumetric activity indicated by the equipment or assembly under test;
v
A is the conventionally true value of the volumetric activity measured
vc
3.25
sensitivity
for a given value of the measured quantity, ratio of the variation of the observed variable to
the corresponding variation of the measured quantity
I − B
S =
A
c
where
I is the indicated value in presence of the radioactive source measured;
B is the indicated value of the background;
A is the conventionally true value of the activity, the volumetric activity, or surface emission
c
rate of the source.
3.26
relative response
value calculated, during type testing, equal to the ratio between the reference response (or
the reference sensitivity) of the equipment for a liquid source and the sensitivity of the same
equipment for a solid source
NOTE The relative response allows for the determination of the reference response (or the reference sensitivity)
of all identical equipment that the equipment type tested from the measurement or the sensitivity for solid source.
3.27
repeatability (of a measuring instrument)
ability of a measuring instrument to provide closely similar indications for repeated
applications of the same measurand under the same conditions of measurement
NOTE 1 These conditions include reduction to a minimum of variation due to the observer, the same measurand
procedure, the same observer, the same measuring equipment used under the same conditions, the same location,
repetition over a short period of time.
NOTE 2 Repeatability may be expressed quantitatively in terms of dispersion characteristics of the indications.
60861 IEC:2006 – 23 –
3.28
reproducibility (of results of measurements)
closeness of the agreement between the results of successive measurement of the same
measurand carried out under the changed conditions of measurement
NOTE 1 A valid statement of reproducibility requires specification of the conditions changed.
NOTE 2 The changed conditions may include principle of measurement, method of measurement, observer-
measuring instrument, reference standard location, conditions of use, time.
NOTE 3 Reproducibility may be expressed quantitatively in terms of the dispersion characteristics of the results.
NOTE 4 Results are here usually understood to be corrected results.
3.29
linearity error
deviation from a reference straight line of the curve representing the output indication
variation as a function of the input quantity variation
3.30
exchange coefficient
for water loaded with particles in suspension, ratio between the mass activity of the particles
and volumetric activity of the water. This coefficient, Kd, is expressed in (becquerels/
kilogram)/(becquerels/liter)
3.31
type test
conformity testing on the basis of one or more specimens of a product representative of the
production
3.32
routine test
test to which each individual instrument is subject during or after manufacture to ascertain
whether it complies with certain criteria
3.33
acceptance test
contractual test to prove to the customer that the instrument meets certain conditions of its
specification
3.34
maintenance test
prescribed test following specific maintenance
3.35
manufacturer
designer and seller of the equipment
3.36
purchaser
user of the equipment
3.37
units
SI system of units. The following units of practical importance will also be used where
appropriate:
– for time: year (y), day (d), hour (h), minute (min);
– for energy: electronvolt (eV).
60861 IEC:2006 – 25 –
4 Classification of equipment
Monitors may be classified according to the type of radiation detected:
– gross beta and/or gamma monitors;
– gross alpha and/or beta monitors;
– gross gamma monitor including specific radionuclide channels.
They may be also classified according to their method of operation:
– simultaneous measurement;
– discrete sequential measurement;
– direct measurement.
5 Equipment design
5.1 Measurement and indication characteristics
5.1.1 Measurement characteristics
If the monitor indicates a gross activity or a volumetric activity, the manufacturer shall specify
the radionuclide of reference for which the activity (or volumetric activity) is indicated (a list of
reference radionuclides is given in Table 1).
The manufacturer shall indicate the decision threshold and the effective range of
measurement of the equipment for nuclides of interest. These characteristics should be given
for the specified radionuclides taking into account the reference gamma radiation background
level (200 nGy/h).
The monitor shall give an indication when the measurement is outside the effective range.
The dynamic range of the equipment shall be at least 10 for the measurement of the
environmental water and 10 for the liquid effluents.
NOTE For monitoring environmental water, the effective range of measurement should include a level of activity
4 3 8 3
of 1 × 10 Bq/m and for liquid effluents 2 × 10 Bq/m .
The manufacturer shall specify the response of the assembly to radionuclides other than that
of the reference mentioned in Table 1. The list of radionuclides of interest shall be agreed
upon between manufacturer and purchaser.
The manufacturer should specify the achievable decision threshold for nuclides of interest, as
a function of the ambient gamma background at detector assembly.
5.1.2 Measurement display
The measurement display shall indicate the value in appropriate units to the measurement
technique and shall be agreed upon between manufacturer and purchaser.
In the case of a beta measurement carried out directly on the liquid, the indication should be
the observed quantities, for example, counts per second. Under referenced conditions, for
example, for a known radionuclide and observed count rate, the indication may be expressed
in activity or in volumetric activity.
60861 IEC:2006 – 27 –
5.2 Reliability
AIl equipment shall be designed to a high standard of reliability.
The manufacturer shall specify the frequencies of the routine maintenance operations and
fully describe each maintenance procedure. These maintenance requirements shall be kept to
the practicable minimum.
The equipment shall be designed to “fail safe” so that interruption of power supplies or failure
of a main component causing loss of the measurement will result in the triggering of an alarm.
5.3 Sampling assembly
5.3.1 Sampling and exhaust pipes
The following characteristics shall be considered in the design of the sampling system in
order to minimize particle traps, corrosion or erosion:
– internal diameter of pipes, pipe length and number and radius of bends;
– finish of internal surfaces;
– connections;
– nature of constructional material.
If the controlled liquid effluent or water is likely to contain particles in suspension, the design
of the sampling and exhaust pipes should be such as to minimize plate out of particles.
The sampling and exhaust pipes shall be appropriate to the chemical and physical properties
of the liquid being monitored and the type of radiation measured.
In the case of discrete sequential measurement, the collection time and the delay between
collection and measurement shall be appropriate to the estimated residence time of the
radioactivity at the point of measurement after instantaneous release of activity.
5.3.2 Inlet mesh
Where appropriate, a mesh may be placed in a holder at the sampling circuit inlet to remove
certain materials in suspension from the liquid under control.
Access to the mesh shall be designed in such a manner as to permit fast and easy removal
for cleaning. Care shall be taken in order to protect the measurement cell and the detector
during this operation.
The design of the holder of the mesh shall take account of the mechanical strength of t
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