ISO/DIS 23467

DRAFT INTERNATIONAL STANDARD
ISO/DIS 23467
ISO/TC 85/SC 6 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-01-30 2020-04-23
Ice plug isolation of piping in nuclear power plant
ICS: 27.120.20
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ISO/DIS 23467:2020(E)
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ISO/DIS 23467:2020(E)
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Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and Definitions .................................................................................................................................................................................... 2

4 General Requirements .................................................................................................................................................................................... 3

4.1 Personnel ..................................................................................................................................................................................................... 3

4.2 Equipment ................................................................................................................................................................................................... 3

4.3 Preconditions ........................................................................................................................................................................................... 3

4.4 Requirements of Process ................................................................................................................................................................ 4

4.4.1 Material of pipe ................................................................................................................................................................. 4

4.4.2 Freezing medium ............................................................................................................................................................. 4

4.4.3 Position of ice plug ......................................................................................................................................................... 4

4.4.4 Ice plug jacket ..................................................................................................................................................................... 4

5 Preparation before Operation ................................................................................................................................................................ 5

5.1 Working Environment ...................................................................................................................................................................... 5

5.2 Construction Plan ................................................................................................................................................................................. 5

5.3 Tools of Construction ......................................................................................................................................................................... 5

5.4 Protective Measures ........................................................................................................................................................................... 5

5.5 Pipe Testing before Operation ................................................................................................................................................... 5

6 Ice Plug Construction ....................................................................................................................................................................................... 6

6.1 Generation of Ice Plug ....................................................................................................................................................................... 6

6.2 Judgment of Ice Plug generation .............................................................................................................................................. 6

6.3 Removal of Ice Plug ............................................................................................................................................................................. 6

7 Quality Assurance (QA) on ice Plugging ....................................................................................................................................... 7

7.1 QA before Ice Plug performance .............................................................................................................................................. 7

7.2 QA during Ice Plug Performance .............................................................................................................................................. 7

7.3 QA after Ice Plug Performance................................................................................................................................................... 7

8 Records and Reports ........................................................................................................................................................................................ 7

Annex A (informative) Reference table of ice plug jacket length ............................................................................................ 8

Annex B (informative) Ice plug jacket types ................................................................................................................................................. 9

(Construction Plan) ........................................................................................................................................................................................14

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This document (ISO 23467) has been prepared by Technical Committee ISO/TC 85, Nuclear Energy,

Nuclear Technologies, and Radiological Protection, Subcommittee SC 6, Reactor Technology.

Any feedback or questions on this document should be directed to the user’s national standards body. A

This document provides terms and definitions for basic concepts of nuclear energy, nuclear technologies,

and radiological protection. Terminological data are taken from ISO standards developed by the any

In the field of nuclear power, when the equipment or pipeline shall be disassembled or removed to

overhaul, often need to be isolated. Under normal circumstances, the upstream and downstream of

the equipment will be isolated or the internal media will be sprinkled, but there will be no isolation

equipment or isolation equipment near the equipment or pipe, while taking into account the safety

(some systems as a reactor hot trap at any time shall be filled with water, some of the system of liquid

with radioactive, worried about radioactive escape, etc.) and economy (system mass, sparse for a long

time, heavy water degradation, etc.), pipes and equipment can't be isolated, for the maintenance work

Based on years of practical experience, the development of this document is feasible. At the theoretical

level, the relevant literature has been studied and reported on the ice plug isolation technology. In the

actual maintenance work, the use of ice plug technology to the pipeline equipment isolation, to achieve

good results. Based on these theoretical and practical experiences, it is recommended that some

This document is designed to provide a standardized procedure for on-line isolation through the

freezing of the internal medium of the pipeline. It is expected that this document can be used to isolate

equipment without isolation facilities by ice plug technology. Standardized ice plug isolation technology

This document specifies requirements for the ice plug technique with liquid nitrogen or dry ice as

refrigerant (cryogenic medium) on metal pipes of nuclear power plants. The freezing liquid can be

This document specifies technical requirements of ice plug generation, formation judgment and

removal, measures before, during and after ice plugging and requirements for personnel and non-

This document is applicable for maintenance work, modification work and test inspections work when

The application of the ice plug isolation technique is principally not allowed on cladded pipes or pipes

with internal coatings. The application for pressure test is not in the scope of this document and should

The following documents, in whole 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 5579:2013, Non-destructive testing — Radiographic testing of metallic materials using film and X- or

ISO 19232-1:2013, Non-destructive testing — Image quality of radiographs — Part 1: Determination of the

ISO 19232-2:2013, Non-destructive testing — Image quality of radiographs — Part 2: Determination of the

ISO 19232-3:2013, Non-destructive testing — Image quality of radiographs — Part 3: Image quality classes

ISO 19232-4:2013, Non-destructive testing — Image quality of radiographs — Part 4: Experimental

ISO 19232-5:2018, Non-destructive testing — Image quality of radiographs — Part 5: Determination of the

image unsharpness and basic spatial resolution value using duplex wire-type image quality indicators

ISO 16811, Non-destructive testing — Ultrasonic testing — Sensitivity and range setting

ISO 16826, Non-destructive testing — Ultrasonic testing — Examination for discontinuities perpendicular

ISO 16827, Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities

ISO 16828, Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique as a

ISO 9934-1:2016, Non-destructive testing — Magnetic particle testing — Part 1: General principles

ISO 9934-2:2015, Non-destructive testing — Magnetic particle testing — Part 2: Detection media

ISO 9934-3:2015, Non-destructive testing — Magnetic particle testing — Part 3: Equipment

ISO 3452-1:2013, Non-destructive testing — Penetrant testing — Part 1: General principles

ISO 3452-2:2013, Non-destructive testing — Penetrant testing — Part 2: Testing of penetrant materials

ISO 3452-3:2013, Non-destructive testing — Penetrant testing — Part 3: Reference test blocks

ISO 3452-5:2008, Non-destructive testing — Penetrant testing — Part 5: Penetrant testing at temperatures

ISO 3452-6:2008, Non-destructive testing — Penetrant testing — Part 6: Penetrant testing at temperatures

ISO 17637:2016, Non-destructive testing of welds — Visual testing of fusion-welded joints

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

process of locally freezing the liquid in the pipe by using a cryogenic refrigerant, and then forming

a solid block of ice in the pipe that can withstand a certain system pressure to isolate the pipeline

temporarily, for the convenience of maintaining downstream pipelines, valves and other equipment

set of device wrapped outside the pipe and containing a refrigerant capable of freezing internal medium

Note 1 to entry: The length of jacket depends on the diameter of pipe. See Annex A for the length of jacket.

cryogenic medium which is used to generate an ice plug inside of the of the pipes

Managers and operators engaged in ice plug isolation construction shall undergo professional training

and safety training.For the implementation, only qualified and trained personnel should be deployed

4.2.1 Special ice plug jacket and other equipment and tools shall be equipped. Measurement tools

(such as thermometers, pressure gauges, oxygen meters, etc.) shall be calibrated and validated.

4.2.2 Anti-freezing, anti-asphyxia and other related safety protection products shall be provided.