IEC 60951-4:2009

IEC 60951-4 ®
Edition 2.0 2009-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation important to safety – Radiation
monitoring for accident and post-accident conditions –
Part 4: Equipment for continuous in-line or on-line monitoring of radioactivity in
process streams
Centrales nucléaires de puissance – Instrumentation importante pour la sûreté –
Surveillance des rayonnements pour les conditions accidentelles et post-
accidentelles –
Partie 4: Equipement pour la surveillance en continu des rayonnements internes
ou externes aux flux de procédé

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IEC 60951-4 ®
Edition 2.0 2009-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation important to safety – Radiation
monitoring for accident and post-accident conditions –
Part 4: Equipment for continuous in-line or on-line monitoring of radioactivity in
process streams
Centrales nucléaires de puissance – Instrumentation importante pour la sûreté –
Surveillance des rayonnements pour les conditions accidentelles et post-
accidentelles –
Partie 4: Equipement pour la surveillance en continu des rayonnements internes
ou externes aux flux de procédé

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
M
CODE PRIX
ICS 27.120.20 ISBN 978-2-88910-349-2
– 2 – 60951-4 © IEC:2009
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.7
2 Normative references .7
3 Terms and definitions .7
4 Design principles.8
4.1 General .8
4.2 Basic requirements related to functions .8
4.3 Range of measurement .8
4.4 In-line detectors mechanical features.8
4.4.1 General requirements .8
4.4.2 Pressure-containing parts.9
4.4.3 Materials .9
4.4.4 Verification of material processing .9
5 Functional testing .10
5.1 General .10
5.2 Environmental performance test .10
5.2.1 Stability of performances with variation of ambient and stream
conditions.10

Table 1 – Overview of the standards covering the domain of radiation monitoring.5
Table 2 – Additional tests to complement the general tests required in IEC 60951-1.12

60951-4 © IEC:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION IMPORTANT TO SAFETY –
RADIATION MONITORING FOR ACCIDENT
AND POST-ACCIDENT CONDITIONS –

Part 4: Equipment for continuous in-line or on-line monitoring
of radioactivity in process streams

FOREWORD
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60951-4 has been prepared by subcommittee 45A:
Instrumentation and control of nuclear facilities, of IEC technical committee 45: Nuclear
instrumentation.
This second edition of IEC 60951-4 cancels and replaces the first edition issued in 1991. It
constitutes a technical revision.
The main technical changes with regard to the previous edition are as follows:
• To clarify the definitions.
• To update the references to new standards published since the first issue.
• To update the units of radiation.

– 4 – 60951-4 © IEC:2009
This standard is to be read in conjunction with IEC 60951-1.
The text of this standard is based on the following documents:
FDIS Report on voting
45A/737/FDIS 45A/759/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.
A list of all parts of IEC 60951 series, under the general title Nuclear power plants –
Instrumentation important to safety – Radiation monitoring for accident and post-accident
conditions, can be found on the IEC website.
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.
60951-4 © IEC:2009 – 5 –
INTRODUCTION
a) Technical background, main issues and organisation of this standard
This IEC standard specifically focuses on radiation monitoring systems used for accident and
post-accident operations.
This standard is intended for use by purchasers in developing specifications for their plant-
specific radiation monitoring systems and by manufacturers to identify needed product
characteristics when developing systems for accident monitoring conditions. Some specific
instrument characteristics such as measurement range, required energy response, and
ambient environment requirements will depend upon the specific application. In such cases
guidance is provided on determining the specific requirements, but specific requirements
themselves are not stated.
This standard is one in a series of standards covering post-accident radiation monitors
important to safety. The full series is comprised of the following standards.
• IEC 60951-1 – General requirements
• IEC 60951-2 – Equipment for continuous off-line monitoring of radioactivity in gaseous
effluents and ventilation air
• IEC 60951-3 – Equipment for continuous high range area gamma monit
...