EN ISO 10276:2021
(Main)Nuclear energy - Fuel technology - Trunnion systems for packages used to transport radioactive material (ISO 10276:2019)
Nuclear energy - Fuel technology - Trunnion systems for packages used to transport radioactive material (ISO 10276:2019)
This document covers trunnion systems used for tie-down, tilting and/or lifting of a package of radioactive material during transport operations.
Aspects included are the design, manufacture, maintenance, inspection and management system. Regulations which can apply during handling operation in nuclear facilities are not addressed in document.
This document does not supersede any of the requirements of international or national regulations, concerning trunnions used for lifting and tie-down.
Kerntechnik - Brennstofftechnologie - Tragzapfensysteme für Transportbehälter für radioaktives Material (ISO 10276:2019)
Dieses Dokument umfasst Tragzapfensysteme für das Verzurren, Kippen und/oder Anheben eines Transportbehälters für radioaktives Material während des Transports.
Berücksichtigte Aspekte sind die Gestaltung, Herstellung, Instandhaltung, Inspektion und das Managementsystem. Vorschriften, die bei der Handhabung in kerntechnischen Anlagen gelten können, werden in diesem Dokument nicht behandelt.
Dieses Dokument ersetzt keine der Anforderungen internationaler oder nationaler Vorschriften bezüglich Tragzapfen für das Anheben und Verzurren.
Énergie nucléaire - Technologie du combustible - Systèmes de tourillons pour colis de transport de matières radioactives (ISO 10276:2019)
Le présent document couvre les systèmes de tourillons utilisés pour l'arrimage, le basculement et/ou la manutention d'un colis de matières radioactives pendant les opérations de transport.
Les aspects traités couvrent la conception, la fabrication, la maintenance, le contrôle et le système de management. Les réglementations qui peuvent s'appliquer pendant la manutention dans les installations nucléaires ne sont pas traitées dans le présent document.
Le présent document n'annule ni ne remplace aucune des exigences des règlements internationaux ou nationaux relatifs aux tourillons utilisés pour manutentionner et arrimer les emballages.
Jedrska energija - Tehnologija goriv - Ovojni sistemi za pakete, ki se uporabljajo za prevoz radioaktivnih snovi (ISO 10276:2019)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2021
Jedrska energija - Tehnologija goriv - Ovojni sistemi za pakete, ki se uporabljajo za
prevoz radioaktivnih snovi (ISO 10276:2019)
Nuclear energy - Fuel technology - Trunnion systems for packages used to transport
radioactive material (ISO 10276:2019)
Kerntechnik - Brennstofftechnologie - Lastanschlagpunkte für Transportbehälter für
abgebrannte Brennstoffelemente (ISO 10276:2019)
Énergie nucléaire - Technologie du combustible - Systèmes de tourillons pour colis de
transport de matières radioactives (ISO 10276:2019)
Ta slovenski standard je istoveten z: EN ISO 10276:2021
ICS:
27.120.30 Cepljivi materiali in jedrska Fissile materials and nuclear
gorivna tehnologija fuel technology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 10276
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2021
EUROPÄISCHE NORM
ICS 27.120.30
English Version
Nuclear energy - Fuel technology - Trunnion systems for
packages used to transport radioactive material (ISO
10276:2019)
Énergie nucléaire - Technologie du combustible - Kerntechnik - Brennstofftechnologie -
Systèmes de tourillons pour colis de transport de Tragzapfensysteme für Transportbehälter für
matières radioactives (ISO 10276:2019) radioaktives Material (ISO 10276:2019)
This European Standard was approved by CEN on 25 July 2021.
CEN 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 CEN-CENELEC Management Centre or to any CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10276:2021 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
The text of ISO 10276:2019 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 10276:2021 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by February 2022, and conflicting national standards
shall be withdrawn at the latest by February 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 10276:2019 has been approved by CEN as EN ISO 10276:2021 without any modification.
INTERNATIONAL ISO
STANDARD 10276
Second edition
2019-12
Nuclear energy — Fuel technology —
Trunnion systems for packages used
to transport radioactive material
Énergie nucléaire — Technologie du combustible — Systèmes de
tourillons pour colis de transport de matières radioactives
Reference number
ISO 10276:2019(E)
©
ISO 2019
ISO 10276:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
ISO 10276:2019(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms, abbreviated terms, symbols and definitions . 1
3.1 Terms and definitions . 1
3.2 Symbols . 4
3.3 Abbreviations . 4
4 Regulatory requirements . 4
4.1 General . 4
4.2 Relevant regulations. 4
5 Design . 4
5.1 General . 4
5.2 Design methodology. 6
5.3 Materials . 6
5.3.1 Material selection . 6
5.3.2 Mechanical properties . 7
5.4 Design loads . 7
5.4.1 Assembly state . 7
5.4.2 Tie-down . 8
5.4.3 Lifting and/or tilting . . 9
5.4.4 Load cycles for fatigue analysis . 9
5.5 Methods of analysis and design criteria .10
5.5.1 General.10
5.5.2 Strength analysis using analytical methods .10
5.5.3 Strength analysis using FEA methods .11
5.5.4 Brittle fracture evaluation .12
5.5.5 Fatigue analysis .12
5.6 Other requirements and recommendations .12
6 Manufacture .13
6.1 General .13
6.2 Assembly .14
6.3 Inspection during manufacture and assembly .14
6.3.1 Dimensional and visual inspection .14
6.3.2 Non-destructive examination .14
6.4 Testing during manufacture and assembly .15
6.4.1 Scope of testing .15
6.4.2 Chemical analysis .15
6.4.3 Mechanical testing of material properties .15
6.4.4 Static testing .16
7 Maintenance .17
7.1 General .17
7.2 Maintenance schedule .17
7.3 Periodic inspection .18
7.3.1 General.18
7.3.2 Removable trunnions . .18
7.3.3 Welded trunnions . . .18
7.3.4 Trunnion surfaces .18
7.3.5 Attachment threads in packaging body .18
7.3.6 Attachment bolts . . .19
7.3.7 Feature dimensions .19
7.4 Periodic testing .19
ISO 10276:2019(E)
7.4.1 Types of testing .19
7.4.2 Trunnion system .19
7.4.3 Weld areas .19
7.5 Component replacement .19
7.6 Repairs .20
7.6.1 General.20
7.6.2 Features to be repaired and methods .20
8 Quality management system .21
Bibliography .22
iv © ISO 2019 – All rights reserved
ISO 10276:2019(E)
Foreword
ISO (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 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 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 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 .iso .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 will 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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 5,
Nuclear installations, processes and technologies.
This second edition cancels and replaces the first edition (ISO 10276:2010), which has been technically
revised. The main changes compared to the previous edition are as follows:
— The scope is extended to trunnion attachment components (trunnion systems are defined as being
the trunnions and their attachment components);
— The normative references have been updated (IAEA TS-R-1 replaced by IAEA SSR-6) and enlarged
to the IAEA SSG-26 (Appendix IV-1 - Package stowage and retention during transport);
— Quality Assurance is replaced by Management Systems;
— The load cases are to be defined by use of the minimum acceleration factors given in table IV-1 of the
Appendix IV of IAEA SSG-26;
— The calculation methods (analytical and finite element analysis) and the minimum associated
criteria are more precisely detailed;
— The bibliography has been updated and enlarged to the most recent recommendations, guidance
and standards as acceptable by most of the Competent Authorities;
— The structure of the document has been slightly modified to enhance its legibility and understanding.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
ISO 10276:2019(E)
Introduction
This document has been produced to enable package owners, designers, users and regulatory
organizations to have at their disposal a comprehensive document covering all aspects of trunnion
systems. Experience has been drawn from the extensive knowledge of owners, designers, users
and competent authorities. This document contains the minimum requirements and makes
recommendations covering various aspects of trunnion systems.
Intermediate devices (sometimes referred to as transport frames, supports or cradles) can be used
between the packaging trunnions and the transport conveyance to support and secure the package
during transport; however, the energy-absorbing effects that may be provided by these intermediate
devices are not taken into consideration in this document.
vi © ISO 2019 – All rights reserved
INTERNATIONAL STANDARD ISO 10276:2019(E)
Nuclear energy — Fuel technology — Trunnion systems for
packages used to transport radioactive material
1 Scope
This document covers trunnion systems used for tie-down, tilting and/or lifting of a package of
radioactive material during transport operations.
Aspects included are the design, manufacture, maintenance, inspection and management system.
Regulations which can apply during handling operation in nuclear facilities are not addressed in
document.
This document does not supersede any of the requirements of international or national regulations,
concerning trunnions used for lifting and tie-down.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
IAEA SSR-6, International Atomic Energy Agency (IAEA) Safety Standard No. SSR-6, Regulations for the
Safe Transport of Radioactive Material
IAEA SSG-26, International Atomic Energy Agency (IAEA) No. SSG-26, Advisory Material for the IAEA
Regulations for the Safe Transport of Radioactive Material
3 Terms, abbreviated terms, symbols and definitions
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IAEA SSR-6 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1.1
bending stress
variable component of normal stress (3.1.10), which might not be linear across the thickness
3.1.2
bolts
fasteners including bolts, screws and studs
3.1.3
designer
organization responsible for the design of the package
ISO 10276:2019(E)
3.1.4
independent expert organization
organization administratively and managerially separate from the designers, manufacturers or owners
of the subject package, constituted of specialized experts, or an insurance organization used to verify,
oversee, witness or check
3.1.5
linearized stress
sum of the membrane stress (3.1.9) and of the linear component of the bending stress (3.1.1)
3.1.6
load case
specific configuration of transport or lifting associated to a total mass (transport or lifting), specified
value and direction of acceleration, a given number of acting trunnions, and a given point/area of
application of the load on the trunnion
3.1.7
maintenance schedule
document drawn up by the designer that gives, in appropriate detail, the applicable frequency/
periodicity of maintenance items and details of methods to be employed; applied by the owner/operator
3.1.8
maximum service load
greater of total mass (lifting) (3.1.19) and total mass (transport) (3.1.20), subjected to gravity (1 g)
3.1.9
membrane stress
component of normal stress (3.1.10) that is uniformly distributed and equal to the average stress across
the thickness of the section under consideration
3.1.10
normal stress
component of stress normal to the plane of reference
3.1.11
owner
operator
organization responsible for maintaining the condition of the packaging for transport
Note 1 to entry: The condition of packaging shall be in accordance with IAEA SSR-6.
3.1.12
peak stress
maximum stress that occurs in a component by reason of geometry, local discontinuities or local
thermal stress, including the effects, if any, of stress concentration
3.1.13
periodic inspection
inspection of the trunnion system during the in-service life of the packaging at predetermined
periodicities defined in the maintenance schedules (3.1.7)
3.1.14
primary trunnion system
trunnion system provided as a primary means for lifting and/or tilting, tie-down and supporting of
the package
3.1.15
quality plan
document, or several documents, that together specify quality standards, practices, resources,
specifications, and the sequence of activities relevant for manufacture
2 © ISO 2019 – All rights reserved
ISO 10276:2019(E)
3.1.16
removable trunnion
trunnion, on a package secured by non-permanent methods, e.g. bolting
3.1.17
secondary trunnion system
trunnion system provided as an additional or alternative means for lifting and/or tilting, tie-down and
supporting of the package
3.1.18
tie-down
securing of the package to the conveyance
3.1.19
total mass (lifting)
maximum mass of a package as supported by the trunnion systems during lifting, fitted with all
necessary ancillaries and equipment, and including the radioactive material and water as appropriate
3.1.20
total mass (transport)
maximum mass of a package fitted with all ancillaries (shock absorbers, neutron shields, covers, transport
frame as appropriate, etc.), as presented for transport and as supported by the trunnion systems
3.1.21
transport cycle
complete round-trip journey of a package between two complete loadings
3.1.22
trunnion
projection, typically cylindrical in shape, attached on a packaging by various means and used for
lifting, tilting and/or tie-down (3.1.18) of the package; parts permanently attached to the trunnion are
considered as being part of the trunnion
Note 1 to entry: A trunnion is an example of an attachment point as defined in IAEA SSG-26, Appendix IV.
3.1.23
trunnion attachment method
method of attaching the trunnion (e.g. welding, bolting, threaded attachment, interference fitting and
bolting, or any combination of these methods) to the packaging body
3.1.24
trunnion attachment components
attachment components, e.g. welding to the packaging body, bolts, removable shear discs, female
threads or housing in the packaging body, removable baseplates, etc., used to secure the trunnion to the
packaging body
3.1.25
trunnion system
assembly of trunnion (3.1.22) and trunnion attachment components (3.1.24)
3.1.26
welded trunnion
trunnion directly secured to the packaging by welding
ISO 10276:2019(E)
3.2 Symbols
K plane strain fracture toughness
Ic
R (T) guaranteed yield strength or guaranteed 0,2 % proof strength at the operating temperature, T
e
R (T) guaranteed minimum tensile strength at the operating temperature, T
m
T operating temperature
3.3 Abbreviations
FEA Finite Element Analysis
MT Magnetic particle test
NDE Non-destructive examination
PT Liquid penetrant test
SCC Stress corrosion cracking
UT Ultrasonic test
VT Visual inspection test
4 Regulatory requirements
4.1 General
In this document, the word “shall” denotes a requirement; the word “should” denotes a recommendation;
and the word “may” denotes permission, i.e. neither a requirement nor a recommendation. Imperative
statements also denote requirements. To conform to this document, all operations shall be performed
in accordance with its requirements, but not necessarily with its recommendations.
The word “can” denotes possibility rather than permission.
4.2 Relevant regulations
The main applicable document is IAEA SSR-6. Other relevant national or international transport
regulations should also be considered to ensure that any differences with the IAEA Transport
Regulations are taken into account.
This document does not relieve the relevant parties of the responsibility for compliance with any
[3]
requirement of the regulations applicable within the nuclear power plants (e.g. KTA 3905 or
[4]
ANSI N 14.6 ).
5 Design
5.1 General
5.1.1 Trunnion systems as part of a package design shall be designed in accordance with IAEA SSR-6
with consideration of IAEA SSG-26, and in particular its Appendix IV.
4 © ISO 2019 – All rights reserved
ISO 10276:2019(E)
5.1.2 Trunnion attachment to a packaging may be carried out by welding, bolting, threaded attachment,
interference fitting and bolting, or any combination of these methods. This document applies to these
methods of trunnion attachment; see Figure 1 a), b) and c).
a) Welded trunnion b) Removable trunnion c) Removable trunnion
(bolted) (threaded)
Key
1 weld 5 body thread
2 trunnion 6 removable baseplate
3 packaging body 7 removable shear disc
4 attachment bolt 8 body housing
Figure 1 — Examples of trunnions
5.1.3 Trunnions are fitted to the packaging to provide the following:
— a means of tie-down of the package during transport; and/or
— a means of providing lifting, or lifting and tilting, the package (with particular designs of package,
the trunnions are used in tilting the package from horizontal to vertical position and vice-versa).
5.1.4 The designer shall consider how the package is supported during transport and lifting and/or
tilting with respect to the trunnions. For these situations the load distribution for the trunnion system
shall be derived. The designer shall consider the number of trunnions on the package required to fulfil a
particular function (e.g. lifting, tilting, supporting) and the value, the direction of forces that are imposed
on the trunnions and the way they are applied (point of application, width, angle of repartition.). See 5.4
for more details.
The load transferred by the trunnion system to the packaging body needs to be considered but is not
part of this document.
5.1.5 The design of the trunnion system shall be capable of performing for a temperature range as
defined in the IAEA Transport Regulations. In particular, minimum and maximum operating temperatures
due to design heat load and worst case ambient conditions shall be considered. Differential thermal
expansion between the conveyance means and the packaging may add stresses to the trunnion system
unless specific design arrangements are made to avoid those effects.
5.1.6 The designer should ensure that the combination of environment, component materials, bolt
coatings, bolt strength, grade, and tensile stress do not render the trunnion system vulnerable to the
ISO 10276:2019(E)
effects of stress corrosion cracking (SCC). Where the effects of SCC are not avoided by design, the designer
shall specify a regime of inspection to detect the early effects of SCC and to allow for bolt replacement
before there is damage.
5.1.7 Any trunnion systems shall be so designed that, under normal and accident conditions of
transport, the forces in those trunnion systems shall not impair the ability of the package to meet the
requirements of the IAEA Transport Regulations.
5.1.8 Specific surface finish limits shall be specified by the designer. Smooth surfaces and gradual
changes of section aid decontamination and are also beneficial for fatigue properties. Liquid traps shall
be avoided. Applying sealant or using gaskets can prevent the ingress of liquids.
5.1.9 As far as practicable, ease of decontamination shall be considered in the design of trunnion
systems, particularly with regard to the bolted attachments.
5.2 Design methodology
Structural analysis of trunnion systems shall include a strength analysis and a fatigue analysis. If
necessary, issues such as brittle fracture and structural stability should be considered.
This analysis can generally be performed by the following methods:
— analytical methods,
— finite element analysis (FEA), or
— a combination thereof.
The applicability of the chosen method shall be checked and justified by the designer.
In the case of trunnion systems with complex geometry and load situation, FEA is preferred as it leads
to more detailed stress and strain results for complex structures.
Clarification on method and criteria are given in 5.5.
5.3 Materials
5.3.1 Material selection
Materials used for the trunnion systems shall be selected or treated to avoid corrosion, including SCC
effects, as appropriate, during the life of the packaging. This includes, but is not limited to, the following
considerations:
— the environment conditions in loading operation (borated water, moisture, protection or
decontamination agents which might include demineralized water, oxalic acid, steam, nitric acid,
caustic solution, NaOH-tartaric acid, lubricants, or other proprietary products),
— ambient conditions (maritime, rain, snow,…) during transport or storage period,
— bolt grease, sealant (used in the packaging design),
— galvanic interaction (materials shall be chosen to ensure that the electro-potential sensitivity
between components is minimal).
It is recommended that trunnions are made from corrosion-resistant steel. For the trunnions, the use of
stainless steel cladding of a carbon-alloy-steel substrate can be justified (example of a clad trunnion is
in Figure 2), provided the designer has carefully considered all aspects of inspection and maintenance
that are likely to be most challenging. For the trunnion attachment system, the use of adapted specific
coating, sealants or leaktight additional devices may be sufficient.
6 © ISO 2019 – All rights reserved
ISO 10276:2019(E)
For duplex-steel welded trunnions, care shall be taken to prevent risk of brittle intermetallic phases
that can reduce toughness and corrosion resistance.
Key
1 base material
2 stainless steel cladding
Figure 2 — Example of a clad trunnion
5.3.2 Mechanical properties
For the selected materials the minimum mechanical strengths R (T) and R (T) shall be specified.
e m
In case where ferritic steels are used for trunnions, to ensure that the material is sufficiently ductile
and tough, it shall be capable of achieving the following:
— Charpy impact test energy of 27 J minimum at the minimum temperature according to the IAEA
Transport Regulations (see 5.1.5),
— Tensile test elongation to failure of 14 % minimum at 20 °C.
Where trunnions are not wholly stainless steel, but are stainless-steel covered, the mechanical
properties used in calculations, for both the base and cladding materials, shall be those of the base
material.
Consideration shall be given to the hardness of the trunnion and attachment component materials to
minimize any surface incompatibility that can arise due to the material hardness of interface equipment.
Fracture toughness properties, such as K , of the materials shall be specified if needed to enable a
Ic
fracture mechanics analysis of the trunnion system.
The designer shall specify the requirement of intercrystalline corrosion tests where this is relevant.
5.4 Design loads
5.4.1 Assembly state
Where the trunnion attachment includes bolts, the bolt minimal ensured preload shall be appropriate
to avoid any loosening of the bolts and sliding of the trunnion under the bolt heads during operation,
including the effects of vibrations during transport. The bolt minimal ensured preload shall be
determined considering uncertainties (tightening techniques and friction coefficients).
Depending on the assembling method, the bolt preload can vary due to the friction values between
the bolts and their contact surfaces and also due to the uncertainties of tightening techniques. This
ISO 10276:2019(E)
assembly state is also applicable to the threaded trunnion type attachment. The bolt preload can also
be affected by differential thermal expansion due to temperature change between assembly and design
conditions. See References [7] to [10] for further details.
5.4.2 Tie-down
Designers may consider using different numbers of trunnions on packages to suit different operational
or transport requirements. Where trunnions are used for tie-down, the total number of trunnions in
any one plane may be restrained unequally. Consideration should be given to alignment on both the
package and the tie-down equipment when four (or more) trunnions share a load. Local positioning
imperfections or variations in tolerances can lead to high variations in the loads acting on each
trunnion. Therefore, in the absence of justification, it shall be considered that the load is supported by
only two trunnions. Example of trunnion restraints is in Figure 3.
The designer shall consider the different modes of transport the package is intended for. It is possible
that the directional orientation of a package can differ between different modes of transport, e.g. the
orientation of a package during sea transport may be at right angles to the orientation of the same
package during rail transport. The designers shall consider all reasonably foreseeable package
orientation during transport to determine the highest load case combination.
Key
1 vertical restraint by four trunnions 4 trunnion
2 vertical and longitudinal restraints by two trunnions 5 packaging support
a
3 packaging Restraint directions.
Figure 3 — Example of trunnion restraints
The designer shall identify all the possible allowed tie-down configurations and shall define for each
the load case. Each load case shall be associated to:
— maximal load,
— load direction,
— bearing area of trunnion with transport means,
— number of acting trunnions.
The maximal load applied shall generally be the total mass (transport) multiplied by the “acceleration”
factor shown in Table IV.1 and in associated paragraphs of IAEA SSG-26, Appendix IV. Other values may
be used subject to appropriate justification.
8 © ISO 2019 – All rights reserved
ISO 10276:2019(E)
5.4.3 Lifting and/or tilting
Depending upon the design for operation, the package may have the capability of being lifted and/or
tilted on the same trunnions. In some cases, packages might not be designed to be tilted. Whichever case
applies, the total mass (lifting) that applies at any time to the minimum justified number of trunnions
shall be taken into account.
In some cases, the designer may include packages fitted with secondary trunnion systems; see Figure 4.
The primary and secondary trunnion systems shall be designed to act independently of each other.
Where trunnions are used for lifting and/or tilting, the total number of trunnions in any one plane may
be restrained unequally. Consideration should be given to alignment on both the package and the lifting
and/or tilting equipment when four (or more) trunnions share a load. Local positioning imperfections
or variations in tolerance can lead to high variations in the loads acting on each trunnion. Therefore, in
the absence of justification, when four (or more) trunnions share a load, the load shall only be supported
by the two diagonally opposite trunnions.
Key
1 primary trunnion
2 secondary trunnion
Figure 4 — Packaging with primary and secondary trunnions
The designer shall identify all the possible allowed lifting or tilting configurations and shall define for
each the load case. Each load case shall be associated to:
— maximal load,
— load direction,
— bearing area of trunnion with lifting or tilting means,
— number of acting trunnions.
The maximal load applying for a given load case shall be the corresponding lifting mass multiplied by a
snatch factor of 1,8 g by Reference to [3]. Other values may be used subject to appropriate justification
e.g. References [3], [4] or [11].
5.4.4 Load cycles for fatigue analysis
The designer shall take into account the fact that the in-service life can be reduced due to the effects
of fatigue caused by cyclic stresses during transport, lifting or a combination of both. Fatigue analysis
shall consider the whole lifetime of the trunnion system with load combinations from transport and
lifting and/or tilting operations.
ISO 10276:2019(E)
It is not possible to define universally valid load cycles for a transport on public routes therefore these
must be specified both on the basis of the requested modes of transport (road, rail, sea or air) and on
the basis of the length and number of anticipated transport cycles.
In addition to experimental determination of the transport load cycles, reference may also be made to
published measurements. The transfer to other packages or transport routes may necessitate the use of
correction factors before being considered in the fatigue strength analysis.
See IAEA SSG-26, Appendix IV for further details.
5.5 Methods of analysis and design criteria
5.5.1 General
For all the components of the trunnion system, the maximal equivalent stress (local or if allowable
linearized stress) shall not exceed the predetermined limit value. This limit value is generally derived
from correspondent R (T) taking into account a safety factor depending on analysis method (see 5.5.2
e
or 5.5.3).
Specific considerations shall be evaluated for bolted trunnions to ensure the safe assembly is justified
as specified in 5.4.1.
An additional safety factor shall be included for welded joints/interfaces. To justify the value of the
safety factors to be used, due consideration should be given to the method of welding, NDE, and
management system.
Strength analysis due to the load transferred by the trunnion system to the packaging body shall be
justified but is not part of this document. In case of bolted trunnions, the required length of engagement
in the packaging body shall be ensured.
More stringent safety factors may be added according some specific applicable national requirements,
for instance in References [3] or [4].
Examples of approaches for strength analysis method and design criteria for trunnion systems are
given in References [5] and [11].
5.5.2 Strength
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