Framework for Irradiation Experiments II (FIDES-II)

Strategic Plan
A product of the FIDES-II Membership, April 2023

TABLE OF CONTENTS
Executive Summary ...................................................................................................................................... 3
1

Introduction ........................................................................................................................................... 5
1.1 Background .................................................................................................................................... 5
1.2 Purpose of FIDES-II ........................................................................................................................ 5
1.3 Scope of this document ................................................................................................................. 6

2

Strategic Objectives ............................................................................................................................... 6
2.1 Research Objectives ...................................................................................................................... 6
2.1.1 Technical Readiness Level .................................................................................................. 6
2.1.2 Nuclear Fuel and Cladding ................................................................................................. 8
2.1.3 Structural Materials and Manufacturing Processes .......................................................... 9
2.2 Framework objectives ................................................................................................................. 11
2.2.1 Maintaining and Developing Capabilities ....................................................................... 122.2.2 Size and Composition of Experimental Program............................................................. 13
2.2.3 Size and Composition of FIDES-II Framework ................................................................. 14
2.2.4 Community Building ......................................................................................................... 15
2.2.5 Cross-cutting Activities..................................................................................................... 15

3

Referencing the Strategic Plan in Proposals ....................................................................................... 16

4

References............................................................................................................................................ 17

Appendix A, Data Needs for Nuclear Fuel and Cladding ........................................................................... 19
Appendix B, Data needs for Structural Materials ..................................................................................... 21
Appendix C, Numbered List of Objectives to Reference in Proposals ...................................................... 24

FIDES-II Strategic Plan

Page 2

Executive Summary
FIDES-II was established following the shut-down of the Halden Reactor to address the ongoing
irradiation testing needs of stakeholders across the nuclear power sector. Irradiations andaccompanying post irradiation examination (PIE) within FIDES-II are conducted at multiple facilities inseveral countries, where the main aim is to collect data to support qualification, licensing, and safety
analyses of nuclear fuel, cladding, core components, and structural materials for their safe and efficientuse in current and future nuclear power plants (NPPs). This document describes the strategic objectivesof FIDES-II until ca. 2030, in terms of Research Objectives and Framework Objectives.
The primary purpose of FIDES-II is to acquire data through irradiation testing. Research Objectives aredescribed in terms of the data needs to be addressed via irradiation testing which span simple tocomplex irradiation tests of mature and less-mature fuel, cladding, core components, and structural
material concepts, for application in both current and future NPPs.
Framework Objectives are related to building and maintaining a sustainable, robust framework, that inturn enables conducting the necessary irradiation testing. Framework Objectives include the FIDES-II
position on supporting and developing facilities and capabilities. While it is not the primary mission of
FIDES-II to maintain or develop facilities and capabilities separate from a defined research program, it isrecognized that such facilities and capabilities are essential for addressing both existing and future
Research Objectives. Other key Framework Objectives are that the FIDES-II experimental program
should aim to grow to ca. 5 to 10 JEEPs in parallel by ca. 2030. For the experimental program
composition to be considered appropriately balanced, equal attention should be paid to fuel/claddingand structural materials experiments, while it is recognized that a greater percentage of the budget will
likely be allocated to fuels activities, due to the increased complexity of those tests.

FIDES-II Strategic Plan

Page 3

Acronyms and Abbreviations:
AOO

Anticipated Operating Occurrence

AR

Advanced Reactors

ASME American Society of Mechanical Engineers
BDBA

Beyond Design Basis Accident

BWR
CCA

Boiling Water Reactor
Cross Cutting Activity

DBA

Design Basis Accident

DNB

Departure from Nucleate Boiling

DPA

Dislocations Per Atom

FFRD Fuel Fragmentation, Relocation, and Dispersal
FIDES Framework for Irradiation Experiments
Gen III Generation three (nuclear plant)
Gen IV Generation four (nuclear plant)

GFR
HAZ
HEA
HRP
HTGR

Gas Fast Reactor
Heat Affected Zone
High Entropy Alloy
Halden Reactor ProjectHigh Temperature Gas Reactor

IASCC

Irradiation Assisted Stress Corrosion Cracking

IFA
JEEP
LOCA
LWR
MOX
MTR
NEA
NEST
NPP
OA
ODS
OECD
PCI
PCMI
PIE
PIRT
PWR
RIA

Instrumented Fuel Assembly
Joint Experimental Program
Loss of Coolant Accident
Light Water Reactor
Mixed Oxide
Materials Test Reactor
Nuclear Energy Agency
Nuclear Education, Skills and Technology Framework
Nuclear Power Plant
Operating Agent
Oxide Dispersion Strengthened (alloy)
Organization for Economic Cooperation and Development
Pellet Clad Interaction
Pellet Clad Mechanical Interaction
Post Irradiation Examination
Phenomena Identification and Ranking Table
Pressurized Water Reactor
Reactivity Insertion Accident

RIS
SCC
SCWR

Radiation Induced Segregation
Stress Corrosion Cracking
Super Critical Water Reactor

SMR
TRL
VVER

Small Modular Reactor
Technical Readiness Level
Water-Water Energetic Reactor (Voda-Vodyanoi Energetichesky Reaktor)

FIDES-II Strategic Plan

Page 4

1 Introduction
1.1 Background
There is an ongoing need among the global community of nuclear power sector stakeholders1 to
conduct irradiation testing in material test reactors (MTRs) to support the safe and efficient operation of
nuclear fuel, cladding, core components, and structural materials in current and future nuclear power
plants (NPPs)2, where the ultimate objective of such irradiation testing is to ensure and improve safety
and efficiency of the installations.
In recent decades, the OECD-NEA Halden Reactor Project (HRP) was the primary framework forstakeholders to conduct joint international fuel and materials irradiation testing. The unexpected
closure of the Halden Reactor in 2018 resulted in sudden loss of capacity and capabilities for performing
such irradiation experiments and revealed the vulnerability with consolidating in-pile nuclear fuel andmaterials testing, almost exclusively, at a single facility.
FIDES-II was created to effectively address the consequences of the shut-down of the Halden reactor,
offering a new OECD-NEA framework for conducting joint international fuel and materials irradiation
experiments. These are performed utilizing a robust network of multiple MTRs, instead of a single
irradiation facility, as was the case in HRP. Besides this, the framework and membership base of HRP
and FIDES-II are very similar.

1.2 Purpose of FIDES-IIFIDES-II aims to be the premier international framework for performing joint, international, nuclear fueland materials irradiation experiments to acquire data in support of operation, safety, qualification, andlicensing of nuclear fuels, claddings, and structural materials in current and future NPPs. This is formally
expressed in the following excerpt from the FIDES-II agreement [1], where the purpose is to:1) Establish a framework for international collaboration to provide continuity and sustainability ofexperimental capacities, foster and facilitate irradiation experiments to test materials and fuels,
through the gathering of a large multinational community in the field of safety, industry and researchthat will share goals, resources and results to define and implement joint experimental programmes(JEEPs) and cross-cutting activities (CCAs).
2) Create and provide the necessary conditions, including the due identification of needs, funding, andcapacities by providing access to JEEP Facilities for the use and sustainability of the current and futureworld-wide available nuclear capacities (research reactors, hot cells, related skills, etc.) to allow for
the implementation of JEEPs and any other activity associated with their implementation.
Within FIDES-II, the focus is on data collection via irradiation testing and accompanying post irradiation
examination (PIE). PIE or out-of-pile experiments without associated irradiation testing should be
avoided within FIDES-II, since there are separate international frameworks for these efforts.
1

Nuclear Power Plant operators, regulators, national laboratories, Technical Support Organizations, etc.
In this document, future NPPs are also referred to as next generation NPPs, Advanced Reactors, and Generation
IV Reactors (Gen IV), and also include Light Water (LW) Small Modular Reactors (SMRs).
2

FIDES-II Strategic Plan

Page 5

1.3 Scope of this document
This document gives an overview of the strategic objectives of FIDES-II, comprising a summary of thedata needs for nuclear fuel, cladding, and structural materials to be addressed by means of irradiation
testing, as well as other objectives pertaining to building and maintaining a robust framework that inturn enables the irradiation testing. The prioritization of current and future irradiation tests and othergoals is outside the scope of this document and is not addressed here; however, important near-term
data needs are identified in this document and it will be left to specific JEEPs to prioritize and addressthese needs.
The time-consuming nature of conducting irradiation experiments and associated PIE means that the
research goals cover a period of years. Some data needs can be met by performing irradiation
experiments in the immediate future, while other data needs will be met incrementally over time, likely
over a span of many years, or even decades. This document pertains to the period extending to ca.
2030.

2 Strategic Objectives
The strategic objectives of FIDES-II are divided into two categories: Research Objectives, and Framework
Objectives. Research Objectives correspond to the data needs to be primarily addressed via irradiation
testing, and Framework Objectives correspond to the needs for maintaining a sustainable, robust
framework, with available expertise, capacity, and capabilities, etc. to enable the achievement of the
Research Objectives.

2.1 Research Objectives
The primary purpose of the FIDES-II framework is to facilitate acquisition of data that can only beobtained through irradiation testing and accompanying PIE, ultimately in support of operation, safety,
qualification, and licensing of nuclear fuels, claddings, and structural materials in current and future
NPPs. The data needs comprise determining fundamental properties under irradiation, evaluating safety
and performance of the selected fuels, claddings, core components, and structural materials in relevant
in-pile environments and operation scenarios, as well as acquiring information of relevance to develop
models and fuel performance codes.
Despite being focused on acquisition of data via irradiation testing, some out-of-pile testing may be
warranted/necessary within FIDES-II, when it is complementary to the in-pile/PIE data or otherwise
needed to interpret the in-pile/PIE data. Since many nuclear fuels, claddings, and structural materials
are relevant for use in both current and future NPPs, and since the stakeholders for current and future
NPPs are largely the same, FIDES-II activities may be relevant for both current and next generation NPPs.
The approach to achieving the Research Objectives is described in section 2.1.1, while the Research
Objectives, in terms of data needs, are summarized in the specific context of FIDES-II in section 2.1.2 fornuclear fuel and cladding, and section 2.1.3 for structural materials and manufacturing processes.

2.1.1 Technical Readiness Level
The aim of collecting data from irradiation testing and PIE is to assess and predict the safety andperformance of currently-used as well as future fuel, cladding, core components, and structural
FIDES-II Strategic Plan

Page 6

materials by developing a robust understanding of the results of these irradiation experiments, including
through modelling. When dealing with innovative fuels, claddings, core components, and structural
materials and associated manufacturing processes, it is useful to apply the concepts of the Technical
Readiness Level (TRL). Figure 1 was developed by the authors of this document (members of FIDES-II)and illustrates the progression of TRLs, for innovative fuel and cladding, structural materials, andmanufacturing processes, going from TRL 4, studies of fundamental properties, to TRL 8-9, full-scale use
in NPPs, indicating the relationship between TRL, the types of test objects, and the method/conditionsof testing.

Figure 1, Illustration of the general progression of Technical Readiness Level for innovative fuel andcladding, structural materials, and manufacturing processes, starting with investigations of fundamental
properties, and ending with use of full-scale fuel assemblies and components in NPPs.
As illustrated in Figure 1, the yellow cells roughly correspond to cases where out-of-pile testing is theprimary test method, the green cells correspond to cases where irradiation testing is primarily
conducted in MTRs, and the blue cells primarily correspond to irradiation in NPPs. Note, however, thatthese domains are not exclusive: in-pile testing may, in some cases, be conducted in the yellow domain,some irradiations that typically fall within the blue domain (in NPPs) may be conducted in the green
domain (in MTRs), and some irradiations that have traditionally been performed in MTRs may be
conducted in NPPs.
Importantly, the TRL applies to a specific fuel, cladding, structural material, and/or manufacturing
process in a specific environment or specific set of operating conditions, so the effective TRL will
necessarily be considered reduced for an otherwise high-TRL fuel, cladding, structural material, or
manufacturing process, when it is introduced into a “new” environment. Thus, currently used (i.e., TRL8-9) fuel rod designs and/or structural materials/components may require further irradiation testing,corresponding to a lower-TRL, if they are to be qualified for use in new/extended environments oroperating conditions, or if other previously irrelevant, or not-yet-fully-understood behaviour is observed
and/or becomes relevant.
FIDES-II Strategic Plan

Page 7

A single irradiation test may address data needs across multiple TRLs, e.g., where a structural material
sample may “piggy-back” on a fuel rodlet test if there is available space, or where the fundamental
properties of the material sample may be investigated (i.e., TRL 4) during the same irradiation where thefuel rodlet is tested in prototypic conditions (i.e., TRL 6).
As stated, PIE or out-of-pile experiments without an associated irradiation test should be avoided within
FIDES-II. However, some out-of-pile testing may be warranted/necessary within FIDES-II whencomplementary to, or needed to interpret, the in-pile/PIE data.

2.1.2 Nuclear Fuel and Cladding
The data needs are described in this document for three categories of fuel and cladding: Current Fuel,Near-term New Fuels, and Advanced Fuels. The fuel and cladding materials that fall within thesecategories are shown in Table 1 and can generally be considered to have high-, medium-, and lowerlevel TRLs, respectively. Note that the definitions of the fuel types in the table generally correspond to
the fuel and cladding descriptions in [2], where current fuel corresponds to fuel rod designs in use incurrent NPPs, Near-term New Fuels correspond to fuels and claddings targeted for relatively near-term
use in current NPPs3, and where Advanced Fuels correspond to fuels and claddings intended for use in
future NPPs, but that can also potentially be used in current NPPs. However, some materials that are
being considered for cladding in GenIV concepts are not listed in Table 1, although they are included in
the list of structural materials (see section 2.1.3).

Fuel Types

Cladding Materials

Table 1, Categorization of fuel and cladding.
Fuel and Cladding Material Type
“Standard” Zirconium-based cladding alloys (including liner
claddings)
Coated and improved Zr-alloys. The primary candidate for PWRs
is Cr-based coatings. Coating materials for BWRs are still underdevelopment.
Refractory metal claddings: Lined Mo-alloy cladding
Advanced steel cladding: FeCrAl
SiC“Conventional” UO2 and (U,Pu)O2“Conventional” UO2, > 5% enrichment
Doped UO2 (e.g. with Gd, Cr)
Improved UO2: High-thermal conductivity UO2 fuelHigh-density fuel (Nitride, Silicide, Carbide, and Metallic fuels)
TRISO-SiC-composite pellets

Current
Fuelx

Near-term
New Fuels

Advanced
Fuels

x

x
x
x
x
x
x†

x†
x
x
x

†

Doped UO2 fuel is an example of a fuel at two different TRLs based on the stakeholders’ perspectives, where doped fuel may
be considered as a Current Fuel and a Near-Term New Fuel. Doped pellets have been a reload product in Boiling Water
Reactors (BWRs) for about a decade and constitute full cores in some BWR plants (corresponding to TRL 9), but doped fuels
are uncommon in Pressurized Water Reactors. As such, data needs for doped fuels going forward can be considered as
belonging to both the Current Fuel and Near-term New Fuel categories.

3

Note that this includes what is typically referred to as “Accident Tolerant Fuel” and “ATF”; however, such terms
were avoided in this document since there are no clear, internationally-agreed-upon definitions of these terms.

FIDES-II Strategic Plan

Page 8

Appendix A contains tables for Current Fuel, Near-term New Fuels, and Advanced Fuels, where the typesof data needed for each category are briefly described and the typical type of irradiation experiment
performed to acquire that type of data is indicated. In general, the needs for assessing performance of,developing, and/or qualifying/licensing nuclear fuels and claddings consist of establishing andunderstanding the following [3]-[10]:







Fundamental properties under irradiation
Fuel and cladding performance under steady-state conditions
Response to power events
Response to Loss of Coolant Accidents
Response to Reactivity Insertion Accidents
Response of failed fuel rods to transients

These needs are valid for new materials (e.g., SiCf-/SiC cladding tubes) as well as existing materials under
new conditions (e.g., Zr based cladding with UO2 beyond the current burnup range or subjected to thetransients anticipated in LWR SMRs).

2.1.3 Structural Materials and Manufacturing Processes
Data needs are described in this document for the following categories of structural materials: Current
Materials (currently used in LWRs), Near-term New Materials (e.g. for use in current NPPs or near-term
SMR applications, as well as in Advanced Non-LWR (ANLWR) prototypes), and Advanced Materials (foruse in future NPPs, including ANLWRs). Structural materials, grouped in the categories Nickel Alloys,
Low Alloy Steels, Austenitic Stainless Steels, and Other Materials, are listed in Table 2 under the relevant
application. Nickel alloys, low alloy steels and austenitic stainless steels include the materials used incurrent NPPs and those presently identified for potential use in advanced reactors (i.e., near-term SMRs
and future generation NPPs). Other materials include, for example, additively manufactured (AM)materials, graphite, carbon and SiC composites, FeCrAl alloys and oxide-dispersion steels, mainly foradvanced reactors, where more extreme conditions (e.g., temperature, coolant chemistry) are expected.
However, advanced materials are not necessarily precluded from current reactor designs. In addition to
the base materials listed in Table 2, the associated joints and weld materials must be qualified for thesame conditions as the base materials; however, these materials are not listed here. Aluminum alloys
are also not included since they are only suitable for low temperature (<100⁰C) operating reactors, i.e.,
MTRs, which are currently considered outside the scope of FIDES-II.
Table 2, Categorization of structural materials.
Material
Category‡

Current Materials(i.e. in use in LWRs)

Nickel Alloys

Super alloys, Hastelloy N andvariants, Alloys 690 and 718

Low Alloy
SteelsReactor Pressure Vessel (RPV)
steels, e.g. SA-533 Grade B
Class 1, SA-508 Class 2,
16MND5, and CrMo steels

FIDES-II Strategic Plan

Near-term Materials (e.g.
Advanced Materials
SMR applications and next
generation reactor
prototypes)
Super alloys, Hastelloy N and variants, Alloys 690 and 718, andAdditive Manufacturing (AM) grades of these alloys, 800H, 617

Page 9

Austenitic
Stainless steels

3XX series (e.g. 316L&H,
304L&H, 347, and 321), castaustenitic

Other
Materials

3XX series (e.g. 316L&H,
304L&H), AM316, castaustenitic
Ferritic/Martensitic (F/M) highCr steels; alumina forming
steels (FeCrAl as F/M; alumina
forming austenitics, AFA; any
AM material, either of a typealready in use or not.

Alloys 709, D9, 15-15Ti

Ferritic/Martensitic (F/M) highCr steels and their ODS (oxide
dispersion strengthened)versions; alumina forming
steels (FeCrAl as F/M; alumina
forming austenitics, AFA),
refractory materials such as
Mo and V based alloys,
ceramics for high temperatureapplications (e.g., carbon and
SiC composites, graphite, andZr3Si2), high entropy alloys(HEA). All of these may be AM
materials.
‡
Weld materials and joints associated with each category of structural base material must be qualified for thesame conditions as the base materials. Note that these materials are not specified in this table.
‡‡
Not necessarily already used for LWRs, but considered for future ones

Appendix B contains a more detailed summary of testing needs for structural materials. These are
generally focused on the following issues:









Irradiation hardening and embrittlement [12]Irradiation assisted stress corrosion cracking (in water) [13]Synergy between irradiation and corrosion/dissolution/erosion in non-aqueous environments[14], [15], [16], [17], [18]Radiation-induced swelling [19]Radiation-induced creep and stress relaxation [20]
Synergy between irradiation and fatigue/creep-fatigue [21]Combined effect of mild irradiation and thermal ageing [22]Microstructural and microchemical evolution under irradiation (e.g., defect production, soluteclusters and precipitates, radiation induced segregation, etc.) [23], [24], [25], [26]FIDES-II Strategic Plan

Page 10

All these issues need to be addressed for baseline materials, welds/joints, and also heat-affected zones(HAZ), i.e., regions of the material that have been affected by heat during welding/joining (the details, ofcourse, depend on the welding/joining technique). It is important to consider the evaluation of
microstructural and microchemical evolution under irradiation during the design of a test series. If this is
not able to be explicitly included or completed as part of the irradiation testing, experiment designers
should ensure that components/materials from the irradiated experiment are available for such
evaluation in follow-on efforts.
It can be noted that, depending on the phenomenon to be studied, the temperature regime of interest
may differ significantly. E.g., hardening and ensuing embrittlement in a steel will occur below 400C, thelower temperature, the harsher; while radiation-induced swelling and creep will occur above 330C.
Thus, the temperature range of the experiment needs to be accurately selected and appropriately
controlled. In addition, the flux of MTRs may not always be representative of operation conditions, thus
requiring reliable correlations to correctly interpret the results. For example, for RPV steels the MTR flux
may be 4-5 orders of magnitude higher, requiring that this difference be addressed in safetyassessments based on such data.

2.2 Framework objectives
The FIDES-II Framework Objectives are those goals that are not specific to the Research Objectives, andwhich reflect the needs for maintaining a sustainable, robust framework, with available expertise,
capacity, and capabilities to enable achieving the Research Objectives. Framework Objectives aregrouped into the following categories and are further described in the sections 2.2.1 through 2.2.5:


Maintaining and Developing Capabilities: Ensuring relevant irradiation and PIE facilities andexperimental capabilities are maintained and developed, such that they are available to the
FIDES-II framework when needed.

Size and Composition of Experimental Program: The number and mix of experiment types to be
performed should ensure that members obtain sufficient value in return for their membershipcontributions to the framework and should be sufficient to attract and maintain a robust
membership community.



Maintaining and Expanding the Size and Composition of FIDES-II Framework: The number andtype of framework members should be maintained at a sufficient level to provide the necessary
budget, facilities, and expertise to maintain a sufficient size and composition of theexperimental program.

Community Building: Building and fostering a robust community promotes collaboration, andthus enhances the value of experiments, which in-turn encourages continued participation andaids in attracting new members.



Cross-cutting Activities: Extending the value of JEEPs and acquired data beyond the value of justthe data itself, e.g., modelling tools’ assessment, training and education, data preservation, etc.

FIDES-II Strategic Plan

Page 11

2.2.1 Maintaining and Developing Capabilities
While it is not the mission of FIDES-II to maintain or develop facilities and capabilities, the existence andavailability of the needed facilities and capabilities is a pre-requisite for being able to accomplish the
FIDES-II Research Objectives. Independently of FIDES-II, it is also a general concern for nuclear powerstakeholders that the necessary facilities and capabilities be available when needed [11]. Therefore,
from the perspective of the FIDES-II members, it is desirable that appropriate support is given to ensurethat relevant facilities and capabilities are maintained and developed to ensure their availability going
forward.
The focus of the research conducted within FIDES-II is on irradiation testing, but it is important to notethat while much data is acquired “online” during the irradiation tests, significant data typically comesfrom PIE, performed at research reactor sites and in dedicated hot laboratories. It can additionally be
noted that samples are prepared for irradiation in hot laboratories. PIE and sample preparation areimportant components of acquiring data from irradiation testing, and PIE facilities / hot laboratories are
therefore equally of concern regarding the FIDES-II position on maintaining and developing capabilities.
The needs for maintaining and developing facilities and capabilities can be broken down into thefollowing priorities:
1) Maintain current facilities and capabilities i.e., prevent further loss of facilities and capabilities.
2) Increase capacity and develop capabilities in existing facilities, both to replace what was lostwith the shutdown of the Halden Reactor and to enable needed testing in conditions beyond
what was possible/feasible in Halden.
3) Add redundancy and build in commonality, when possible, to build a more robust network ofavailable facilities/capabilities, to mitigate unexpected unavailability of specificfacilities/capabilities and to account for any experimental bias connected to specificfacilities/capabilities.
In the context of FIDES-II, the facilities and capabilities are primarily the responsibility of the Operating
Agents (OAs). It is recognized that each of these individual OAs is governed by their own set of
local/national boundary conditions which impose varying constraints on them, thus determining thefinal strategy concerning the maintenance and development of facilities and capabilities. This further
implies that the support necessary to ensure maintaining and developing facilities and capabilities mayvary depending on the OA, e.g., OAs may have varying degrees of other sources of support for thispurpose.
Short of providing direct funding to OAs solely to operate, maintain, or develop facilities and capabilities,
FIDES-II is able to provide support in several ways:

Perform experiments within FIDES-II JEEPs using the needed facilities and capabilities. Thisexplicitly demonstrates the ongoing needs, contributes funding towards the use of such facilities
and capabilities, and aids in maintaining expertise in their use.
Communicate clearly with OAs in good time about future proposed experiments which makeuse of either existing or not-yet-developed facilities/capabilities, with the aim to provide OAs’
with longer-term view of the potential need for existing and future facilities/capabilities. ThisFIDES-II Strategic Plan

Page 12will provide input towards: justification for maintaining existing facilities and capabilities;
direction for development of new capacities and capabilities; and a background for finding
synergies with other complementary efforts that may, for example, co-fund development ofneeded capabilities.
Allow for the possibility of including funding within JEEPs to support development of newcapabilities, when required for the associated irradiation testing.
Promote and facilitate cooperation between stakeholders when new capabilities are being
developed so that “transferable” solutions can be created whenever possible, such that they
may be readily adaptable for use in multiple facilities/organizations.

It is, however, outside the scope of this document to specify in detail which capabilities and capacities
should be maintained and/or developed and which areas should be targeted for finding transferable
solutions, or where equipment, instruments, techniques, etc. could be developed to be readily
adaptable for use in multiple facilities.

2.2.2 Size and Composition of Experimental Program
The number and types of experiments conducted within FIDES-II should quantitatively and qualitatively
be of sufficient value to the members, such that the members continue to find value in their continued
membership in FIDES-II.
In the inaugural year of FIDES-II (2022), there were three ongoing JEEPs. It is desired that the size of theexperimental program is gradually grown to include 5 to 10 JEEPs in parallel by ca. 2030. This number ofexperiments is generally regarded among the FIDES-II members as sufficient to ensure that eachmember will obtain data which they consider valuable and reflects a program that is sufficiently large tojustify their continued participation in the framework, i.e. a program of this size ensures that it is more
likely that the particular interests of each member are met at least in one of the JEEP.
For the experimental program composition to be considered appropriately balanced, equal attention
should be paid to fuel/cladding and structural materials experiments irrespective of the fact that most
likely a greater percentage of the budget will end up being allocated to fuel/cladding activities due tothe increased complexity of those tests. This will aid in creating and maintaining a robust program withparticipation from experts in these overlapping fields and will create synergy from the perspective of thefunding organizations that will further help in justify continued membership.
The complexity-level of experiments conducted within FIDES-II should not be limited to the highest
complexity level (most time-consuming and most expensive integral tests), nor should it be limited torelatively simple experiments (less time-consuming, and less expensive separate effects tests). Rather,
the aim is for the experimental program to be balanced, with integral tests complemented by separate
effects tests in representative conditions and/or so-called piggy-back experiments. In these, materials ofinterest occupy otherwise free space in an irradiation rig, or space otherwise filled with dummymaterials for, e.g., modelling purposes (model alloys), or with low TRL materials, where the behaviour
under irradiation is almost totally unknown, so that any data under any conditions may be valuable.
This corresponds to the progression of TRL via irradiation testing of fuel, cladding and structural
materials, as described in section 2.1.1, where “simple” irradiations are first performed to determine

FIDES-II Strategic Plan

Page 13basic properties, after which the tests become progressively more complex, thus increasing the TRL(illustrated in Figure 1).
In addition to balancing the complexity-level of experiments, a balance should also be kept between
experiments using existing equipment and techniques vs. experiments using still to be developed
equipment and techniques. This directly affects the expected time or JEEP duration until results or data
can be expected as well as the likelihood of unexpected delays and cost increases of an experiment or
JEEP. Such a well-balanced approach would allow developing new capabilities, while also ensuring thatthe needs of framework participants more interested in data generation are equally met.
In summary, the aims for the size and composition of the experimental program are the following: Grow to ca. 5 to 10 JEEPs by ca. 2030.
 Aim for ca. 50% fuel/cladding experiments and ca. 50% structural materials experiments.
 Experimental program to be comprised of complex as well as relatively simpler experiments.
 Experimental program to be comprised of experiments using existing equipment and techniques
as well as experiments using still to be developed equipment and techniques.

2.2.3 Size and Composition of FIDES-II Framework
The number and type of members in FIDES-II affects the robustness and ultimately the sustainability of
the framework. It is desirable to have many members since this enables the cost and risk of experiments
to be shared at an acceptable level, effectively facilitating performance of experiments that are often
too costly for a single member to fund on their own.
It is also desirable that the membership of FIDES-II is made up of a wide variety of nuclear powerstakeholders, including fuel and reactor vendors, regulators, Technical Support Organizations,
universities, national laboratories, etc. According to their different roles in the nuclear power sector,
participants from these types of members bring their competing and complementary perspectives tothe experiments. Experience from the HRP demonstrated that when these various stakeholders
collaborate on experiments, including specification and interpretation, the acquired data is of thehighest value, and facilitates acceptance of the results by the stakeholders.
While there is no specific target for the number of members or for the number of each type of
stakeholder, there are nevertheless several advantages to recruiting additional members:

Increase in the total budget (or reduced cost burden on members if the budget is kept
constant).
Participation from new experts, giving added insight into experiment design, analysis, etc.,
ultimately increasing the value of the experiments.
Possible participation from new OAs, potentially making additional capacity, facilities, andcapabilities available to FIDES-II.

In summary, the following points should be considered regarding the FIDES-II framework membershipcommunity:

It is advantageous to add new members with regard to budget, expertise, facilities, and reach of
the FIDES-II framework

FIDES-II Strategic Plan

Page 14The types of stakeholders comprised by the membership should be considered when recruiting
new members, so that stakeholders with valuable and perhaps unrepresented, or underrepresented expertise, facilities, perspectives, may be targeted for recruitment.

2.2.4 Community Building
Fostering a robust community within the FIDES-II membership is an important aspect of ensuring thatthe framework is a long-lasting and effective one for conducting joint international irradiation
experiments. A robust community facilitates open, honest discussions among members, and adds value
to experiments when all stakeholders (regulators, vendors, NPP operators, research centers, etc.) can
openly discuss and agree on experiment specifications and interpretation of results. This in-turn adds
value to the framework, encouraging continued participation by the members, and giving prospective
new members confidence in the FIDES-II framework.
It should be noted that the robust community within HRP is regarded as one of the key success factorsof that long-running (over 60 years) framework. In the case of HRP, the community was actively
cultivated to ensure it remained robust. It is likewise warranted within FIDES-II to actively cultivate thecommunity, especially considering that FIDES-II is newly established.
Based on the HRP example, Framework Community Building efforts include activities such as:






Hosting TAG and GB meetings at the members’ sites, including site tours when possible.
Holding “conference”-type meetings open to participants from member organizations who are
outside the normal TAG, GB, and JEEP Core Groups, and where members are encouraged topresent non-FIDES-II related work facilitated by FIDES-II JEEPs, etc. (similar to the Enlarged
Halden Programme Group meetings hosted every 1.5 years). Such meetings with HRP included(engineer-friendly) social events and banquets.
Establishing cooperation frameworks with external scientific communities dedicated to nuclear
materials science and research.
Rotating chairmanship of the TAG and GB.

2.2.5 Cross-cutting Activities
Cross-cutting activities are aimed at extending the value of JEEPs and the acquired data beyond thevalue of just the data itself. These activities are, therefore, not directly related to data gathered on
specific fuels, claddings, or structural materials. Cross-cutting activities are appropriate to be addressedat the GB and TAG levels, including NEA staff and working parties’ involvement, and may extend acrossseveral individual JEEPs. Such cross-cutting activities consist of items such as the following:

Data preservation and quality assurance:
Due to the nature of FIDES-II, irradiation experiments and PIE will be conducted in multiple
facilities located in multiple countries and will be conducted by multiple organizations. As aresult, care must be taken to ensure that the collected data is preserved and quality-assured in amanner such that it may be used by other member organizations – both now and in the future.
This also requires ensuring data consistency and curation between different laboratories,
especially considering the importance that the use of data-driven, machine learning-based
techniques is increasingly acquiring. It is generally considered within the FIDES-II membership

FIDES-II Strategic Plan

Page 15

that much of this effort will be addressed organically through the regular “peer-review” of the
JEEPs within FIDES-II. However, in the future it could be envisioned that resources are dedicatedspecifically to data preservation and quality assurance activities.
Training, education, and dissemination of results:
There is a need to collect data through irradiation experiments within the FIDES-II framework,
since the needed data is currently not available. As such, data collected through irradiation
experiments and PIE within FIDES-II will inevitably add to the scientific body of knowledge.
There is a responsibility to the FIDES-II community and the scientific community in general toshare these additions to the scientific body of knowledge with the scientific community (within
the constraints of the FIDES-II agreement, and other Intellectual Property agreements). Sharingof data/research is in the interest of FIDES-II members to inform continued research within
FIDES-II, to demonstrate the value of the framework to funding bodies, and to build andmaintain relevant competence throughout the sector and among young scientists. Not only
should publications and reports be issued as appropriate within the various JEEPs, but training
and education should also be offered to FIDES-II members and non-FIDES-II members, whereappropriate. This can be accomplished e.g., in the form of HRP-style Summer Schools. A
partnership with the Nuclear Education, Skills and Technology (NEST) Framework is also
envisioned to add structure and visibility to FIDES-II training and education activities. In the
future it could be envisioned that resources are dedicated to support training and education
activities.



Know-how
It is in the interest of FIDES-II to ensure that members, across their various facilities, havesufficient know-how to design, fabricate, conduct, and analyse irradiation experiments and PIE.
In this document, Know-how is distinguished from the Training, education, and dissemination of
results bullet above, in that know-how pertains to the practices for execution of experiments
and PIE, whereas Training, education, and dissemination of results pertains mainly todissemination and use of scientific results from the JEEPs. Notwithstanding, maintaining knowhow among the FIDES-II members could e.g., be carried out through establishment of bestpractices for various activities, and may also include training activities e.g. for those that design
and/or operate experimental systems. Securing know-how within the community is exemplified
by the DEVICE group and may also be advanced through NEST fellowships.

3 Referencing the Strategic Plan in Proposals
The existing guidelines for proposing JEEPs within FIDES-II are given in [27]; however, this document predates FIDES-II (and in fact also FIDES). It is expected that this document will either be updated or
replaced with a specific document for FIDES-II that contains updated guidelines for proposing JEEPs andother activities as well as guidance for the TAG and GB for evaluating proposals. Future proposals shouldreference the strategic objectives described in this document. To facilitate referencing this document, a
numbered list, corresponding to the strategic and framework objectives, is provided in Appendix C.
A common goal of FIDES-II activities is filling in known and anticipated gaps in experimental andtheoretical knowledge on fuel behaviour and material properties under irradiation. Quantification andcomparison of the need in certain data may become a challenging task for decision-making. For
FIDES-II Strategic Plan

Page 16

instance, some type of index of importance can be used by core groups when proposing JEEPs (e.g.
based on a PIRT [28]), or independently by TAG and/or GB, as a way to quantify the importance.
For the time being, when addressing important topics, the portfolio of the HRP experiments may betaken as a starting point of what is FIDES-II trying to achieve. However, great care must be taken since
not everything was possible in the Halden reactor and some studies were not performed there fortechnical reasons, thus it does not mean there was no need for particular experiments just because they
weren’t performed in Halden. For example, the IFA-650 LOCA test series was designed to investigate theeffect of the fuel relocation within the rod on cladding temperature and oxidation in the ballooned
region and secondary hydriding of the rod. As such, the experiment was designed as a single rod
experiment with large space around the rod and the temperature history corresponding only to a laterpart of a PWR/VVER/BWR LOCA event and lacking a capability for post-test examination of thesignificant amount of fuel dispersed through the cladding rupture. Current and future needs might bedifferent, for example bundle tests or tests focused on the period following the full LOCA transient
history, e.g., for quantification of the dispersed fuel state, might be more important for understanding
the Fuel Fragmentation, Relocation, and Dispersal (FFRD) phenomenon.

4 References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]

[13]

[14]

FIDES-II Agreement
OECD Report 2018 “State-of-the-Art Report on Light Water Reactor Accident-Tolerant Fuels”
Nuclear Fuel Safety Criteria Technical Review (second edition), ISBN 978-92-64-99178-1, OECD
2012.
Nuclear Fuel Behaviour in Loss-of-coolant Accident (LOCA) Conditions: State-of-the-art Report,
ISBN 978-92-64-99091-3, NEA No. 6846, OECD 2009.
State of the Art Report on Nuclear Fuel Behaviour in Loss-of-Coolant Accident (LOCA) Conditions,
Update and Revision of the Report NEA No. 6846. (restricted to OECD/NEA CSNI WGFS members)
LOCA Criteria Basis and Test Methodology, CSNI Technical Opinion Papers No. 13, NEA No. 6986,
OECD 2011.
Report on Fuel Fragmentation, Relocation and Dispersal (FFRD). NEA/CSNI/R(2016)16, OECD 2016.
State-of-the-art Report on Nuclear Fuel Behaviour Under Reactivity-initiated Accident Conditions.
NEA No. 7575, OECD 2022.
Applicability of Nuclear Fuel Safety Criteria to Accident-Tolerant Fuel Designs. CSNI Technical
Opinion Paper No. 19. NEA No. 7576, OECD 2022.
Leaking Fuel Impacts and Practices. NEA/CSNI/R(2014)10, OECD 2014.
Nuclear Safety Research Support Facilities for Existing and Advanced Reactors: 2021 Update, OECD
2021
Martin L. Grossbeck, 1.05 - Effect of Radiation on Strength and Ductility of Metals and Alloys, in:Comprehensive Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller,
Elsevier, 2012, 130-152, https://doi.org/10.1016/B978-0-08-102865-0.00004-2.
Peter L. Andresen and Gary S. Was, 4.07 - Irradiation Assisted Stress Corrosion Cracking, in:Comprehensive Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller,
Elsevier, 2019, 190-217, https://doi.org/10.1016/B978-0-08-102865-0.00111-4.
Serena Bassini, Sebastiano Cataldo, Carlo Cristalli, Angela Fiore, Camillo Sartorio, Mariano
Tarantino, Marco Utili, Paolo Ferroni, Michael Ickes, Alessandro Alemberti, Michele Frignani, 4.08

FIDES-II Strategic Plan

Page 17

[15]

[16]

[17]

[18]

[19]

[20]

[21]
[22]

[23]

[24]

[25]

[26]

[27]
[28]

- Material Performance in Lead and Lead-Bismuth Alloy, in: Comprehensive Nuclear Materials(Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2020, 218-241,
https://doi.org/10.1016/B978-0-12-803581-8.00749-9.
Yoonjo (Jo Jo) Lee, 4.09 - Material Performance in Molten Salt, in: Comprehensive Nuclear
Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2020, 242-265,https://doi.org/10.1016/B978-0-12-803581-8.00750-5.
Richard N. Wright, Jill Wright, Celine Cabet, 4.10 - Material Performance in Helium-Cooled
Systems, in: Comprehensive Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings,
Roger E. Stoller, Elsevier, 2019, 266-291, https://doi.org/10.1016/B978-0-08-102865-0.00114-X.
Todd R. Allen, Y. Chen, X. Ren, K. Sridharan, L. Tan, Gary S. Was, E. West, D. Guzonas, 4.11 Material Performance in Supercritical Water, in: Comprehensive Nuclear Materials (Second
Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2012, 292-338,
https://doi.org/10.1016/B978-0-08-102865-0.00115-1.
Meimei Li, Krishnamurti Natesan, Wei-Ying Chen, 4.12 - Material Performance in Sodium, in:Comprehensive Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller,
Elsevier, 2020, 339-356, https://doi.org/10.1016/B978-0-12-803581-8.11753-9.
Arunodaya Bhattacharya and Steven J. Zinkle, 1.12 - Cavity Swelling in Irradiated Materials, in:Comprehensive Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller,
Elsevier, 2020, 406-455, https://doi.org/10.1016/B978-0-12-803581-8.11599-1.
Fabien Onimus, Thomas Jourdan, Cheng Xu, Anne A. Campbell, Malcolm Griffiths, 1.10 Irradiation Creep in Materials, in: Comprehensive Nuclear Materials (Second Edition), Editor(s):Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2020, 310-366, https://doi.org/10.1016/B978-0-12803581-8.11645-5.
Wolfgang Hofflener, Damage assessment in structural metallic materials for advanced nuclear
plants, J. Mater. Sci. (2010) 45, 2247–2257, DOI 10.1007/s10853-010-4236-7.
K. Lindgren, M. Bjurman, P. Efsing, M. Thuvander, Integrated effect of thermal ageing and low flux
irradiation on microstructural evolution of the ferrite of welded austenitic stainless steels, Journalof Nuclear Materials (2021) 551, 152967,https://doi.org/10.1016/j.jnucmat.2021.152967.
W.G. Wolfer, 1.01 - Fundamental Properties of Defects in Metals, in: Comprehensive Nuclear
Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2020, 1-49,
https://doi.org/10.1016/B978-0-08-102865-0.00001-7.
Shradha Agarwal, Steven J. Zinkle, 1.03 - Experimental Studies on Primary Damage Formation, in:Comprehensive Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller,
Elsevier, 2020, 74-90, https://doi.org/10.1016/B978-0-12-803581-8.11597-8.
Steven J. Zinkle, 1.04 - Radiation-Induced Effects on Microstructure, in: Comprehensive Nuclear
Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2020, 91-129,
https://doi.org/10.1016/B978-0-12-803581-8.12075-2.
Maylise Nastar, Frédéric Soisson, 1.08 - Radiation-Induced Segregation, in: Comprehensive
Nuclear Materials (Second Edition), Editor(s): Rudy J.M. Konings, Roger E. Stoller, Elsevier, 2020,
235-264, https://doi.org/10.1016/B978-0-12-803581-8.00668-8.
NEA Framework for Irradiation Experiments (FIDES-II): Proposal for Basic Principles and Operating
Procedures
Phenomena Identification and Ranking Table. R&D Priorities for Loss-of-Cooling and Loss-ofCoolant Accidents in Spent Nuclear Fuel Pools. NEA/CSNI/R(2017)18, OECD 2018

FIDES-II Strategic Plan

Page 18

Appendix A

LOCA/RIA

LOCA/RIA/power
ramp
RIA

PCI/PCMI

x

x
x

x
x
x
x
x

x
x
x
x
x

x
x
x
x
x
x
x
x
x
x
x
x
x

Advanced Fuels

Type of data needed
Effects of fuel state on fuel dispersal, particularly, during a LOCA, e.g., conditions related to burnup, pellet-cladding bonding,properties affected by pre-transient power, pressure, and volume of the entraining gas, etc.
Ballooning, embrittlement, burst.
MOX behaviour.
Fuel fragmentation, relocation, dispersal.
Effects of axial distribution of gas pressure in fuel rods in consideration of transient fission gas release and restricted axial
gas flow.
Effects of fuel doping (by burnable absorbers, like Gd, or chromium and/or aluminium additives) on fuel rod behaviour.
Fuel to coolant interaction.
Fission Gas Release.
Behaviour of the cladding coating
Post-DNB behaviour, including cladding ballooning and burst, as well as high temperature oxidation-induced failure.
Post-failure behaviour, including fuel relocation and dispersal, as well as Fuel-to-Coolant Interaction.
Cladding failure by PCMI.
Effects of localized crud deposition and/or oxidation on PCMI/PCI failure limits of the cladding.
Axial and diametral cladding loading (stress- and strain bi-axiality), fuel to cladding contact conditions.
Fuel chemistry and corrosion fission products behavior.
Performance to SCC-PCI failure

Near-term New Fuels

OperatingConditions /Experiment type
LOCA

Current Fuels and LWR SMRs

Appendix A, Data Needs for Nuclear Fuel and CladdingAdvanced Fuels

Type of data needed
Behaviour under more demanding conditions, e.g., basic properties in normal and off-normal conditions, including changesof thermophysical and mechanical fuel and cladding properties with irradiation, at higher temperature, stress, strain rateand irradiation dose, etc.
Basic properties of new fuels in normal and off-normal conditions, viz.:

Near-term New Fuels

OperatingConditions /Experiment type
Base Irradiation
and AnticipatedOperational
Occurrences

Current Fuels and LWR SMRs

Appendix A

x

x

Fuel:
 Temperature, fission gas retention and release, internal pressure.
 Microstructural evolution under irradiation (fuel densification and swelling, cracking, recrystallization, etc.).
 Stress – free dimensional changes (e.g., densification and sintering), dimensional changes under loading (e.g., creep).
 Changes of thermophysical and mechanical properties with irradiation, including thermal conductivity, thermal
diffusivity, specific heat, and coefficient of thermal expansion (up to or near the fuel melting point), yield stress, creep
rate (irradiation induced creep and thermal creep), fracture toughness, elastic moduli.
 Chemistry, migration, and release of volatile fission products.

Base irradiation,
AOO, DBA, BDBA

Cladding:
 Stress – free dimensional changes (irradiation growth), as well as dimensional changes under loading (creep).
 Interaction with the coolant (corrosion, hydrogen pickup and migration, hydride re-orientation, stress corrosion cracking) Creep, growth, and swelling, behavior of the coating, Microstructural evolution under irradiation
 Mechanical and chemical interaction between fuel and cladding materials under irradiation
Failure mechanisms and analytical limits, including Effects of power maneuvering (e.g., load-follow operation) on cladding
failure, including new cladding materials.

FIDES-II Strategic Plan

Page 20x

Appendix B
Appendix B, Data needs for Structural Materials

LWR / ARLWR / ARLWR / ARLWR / ARLWR / AR

Irradiation hardening and embrittlement (<400ºC)
 Evaluation and prediction of fracture toughness and ductile-brittle transition temperature in RPV low alloy steels(especially low flux/high dose, i.e. > 0.2 dpa)
 Loss of ductility under irradiation in austenitic stainless steels (not for all steels, only for those not codified yet)
 Low temperature embrittlement and loss of uniform elongation in Fe-9-14%Cr steels up to tens of dpa
 Irradiation effects on strength, ductility, and fracture toughness of additively manufactured (AM) steels and nickel alloys
IASCC: Evaluation of crack growth rate, initiation condition and water chemistry under irradiation (in supercritical water inthe case of SCWR)
 Comparison with similar results in primary PWR water chemistry without irradiation or after irradiation
 Static and transient mechanical loading
Void swelling 3xx series for GenIII up to tens of dpa, especially at relatively low flux
 15-15Ti for AR up to 120 dpa
 Ni-based alloys up to high dose (tens of dpa) with He production due to transmutation (especially under non-CANDU
conditions)Long-term thermal ageing of austenitic stainless steel base material and welds under mild (< 1 dpa) irradiation (also for Nacooled AR)
Radiation effects on corrosion fatigue
Irradiation creep and creep-fatigue / stress relaxation under irradiation
 3xx series for GenIII, up to 120 dpa, 350-400ºC or higher
 F/M and alumina forming steels for GenIV, similar conditions as above

Advanced Materials

LWR / AR

Stainless Steels

Properties/phenomena 

Low alloy Steels

MATERIALS 

x

x

x

x

x

x

x

x

x

x

x

x
x

x

Ni-based alloys

LWR orAdvanced
reactors(=AR)

Appendix BxAR

Synergy between irradiation and corrosion/dissolution/erosion in non-aqueous environments
 In Na : 15-15 Ti stainless steels, ODS F/M steels
 In liquid Pb and relevant liquid alloys (e.g. PbBi eutectic): 15-15 Ti stainless steels and coated version, coated anduncoated F/M steels, alumina forming steels (AFA and FeCrAl)
 In He with impurities: 15-15 Ti stainless steels, Ni-based alloys
 In molten salt: Ni-based alloys, SICf/SIC, coated materials
Fast spectrum, high temps, with He productiono
For unloaded and creep/stress relaxation

x

AR

4

Advanced Materials

Microstructure evolution:4
 Evolution of radiation defects up to relevant dpa in any material/condition
 Radiation induced segregation (RIS) at radiation and extended defects in low alloy steels (round 300ºC especially at low
flux/high dose, i.e. > 0.2 dpa) and austenitic steels (at 350-400ºC or higher, up to tens of dpa)
 Precipitation of ’’ in Ni alloys in a wide range of temperatures and dpa
 Stability of corrosion-protecting layers (coatings or self-healing) versus temperature and dpa in F/M and austentic
stainless steels

Stainless Steels

LWR / AR

Properties/phenomena 

Low alloy Steels

MATERIALS 

Ni-based alloys

LWR orAdvanced
reactors
(=AR)

x

x

x

x

x

x

Note that this entry does not necessarily refer to bespoke experiments, but to the need of foreseeing microstructure examination specimens in experiments
dedicated to other issues. In addition, often the bottleneck in these experiments is not only, or not really, the irradiation, but rather the fact that postirradiation microstructural characterization is a costly and time-consuming activity, which sometimes requires several years before being concluded, or ends up
not being concluded.

FIDES-II Strategic Plan

Page 22AR

HTGR/GFR
 Carbon and SiC Composites:o Radiation induced embrittlement : evolution of pseudo-ductility versus dose and temperature
o Fatigue crack initiation and growth of carbon under irradiation in helium with impurities or supercritical
CO2 environments.
o Irradiation effects on the microstructure of graphite, and interphase stability, especially under higher
irradiation temperatures (up to 900°C)
o Composite architecture stability under irradiation (e.g., effect of differential fiber-matrix swelling)o Leak-tightness under irradiationo Thermal properties (thermal expansion, conductivity, etc.) versus radiation dose Graphite (grades on interest)o Irradiated properties of per ASME Code Sec. III Div. 5.
Molten Salt
 Graphite (grades on interest)o Irradiated properties per ASME Code Sec. III Div. 5., salt infiltration

FIDES-II Strategic Plan

Page 23

Stainless Steels

Properties/phenomena 

Low alloy Steels

MATERIALS 

Ni-based alloys

LWR orAdvanced
reactors(=AR)

Advanced Materials

Appendix BxAppendix C
Appendix C, Numbered List of Objectives to Reference in Proposals
Research Objectives:
1) Motivationsa) Support of operationb) Support fuel qualificationc) Support licensing of nuclear fuels
2) Research Subjectsa) Nuclear Fuel and Claddingi) Current Fuel (see table 1)ii) Near-term New Fuels (see table 1)iii) and Advanced Fuels (see table 1)b) Structural Materials and Manufacturing Processesi) Current Materials (currently used in LWRs)ii) Near-term New Materials (e.g. for use in current NPPs or near-term SMR applications)iii) Advanced Materials (for use in future NPPs including Advanced Non-LWR (ANLWR) Reactors)
3) Research Objectivesa) Nuclear Fuel and Claddingi) Fundamental properties under irradiationii) Fuel and cladding performance under steady-state conditionsiii) Response to power eventsiv) Response to Loss of Coolant Accidentsv) Response to Reactivity Insertion Accidentsvi) Response of failed fuel rods to transientsb) Structural Materials and Manufacturing Processesi) Irradiation hardening and embrittlementii) Irradiation assisted stress corrosion cracking (in water)iii) Synergy between irradiation and corrosion/dissolution/erosion in non-aqueous environmentsiv) Radiation-induced swellingv) Radiation-induced creepvi) Radiation-enhanced stress relaxationvii) Synergy between irradiation and fatigue/creep-fatigueviii) Combined effect of mild irradiation and thermal ageingix) Microstructural and microchemical evolution under irradiation (e.g., defect production, soluteclusters and precipitates, radiation induced segregation, etc.)
Framework Objectives:
1) Maintaining and Developing Capabilities: Ensuring relevant irradiation and PIE facilities and experimental
capabilities are maintained and developed, such that they are available to the FIDES-II framework whenneeded.
2) Size and Composition of Experimental Program: The number and mix of experiment types to be performed
should ensure that members obtain sufficient value in return for their membership contributions to theframework and should be sufficient to attract and maintain a robust membership community.
3) Size and Composition of FIDES-II Framework: The number and type of framework members affects thepotential scope and value of the experimental program, e.g., via the available budget, facilities, and expertise.
4) Community Building: Building and fostering a robust community promotes collaboration, and thus enhances
the value of experiments, which in-turn encourages continued participation and aids in attracting newmembers.
5) Cross-cutting Activities: Extending the value of JEEPs and acquired data beyond the value of just the data itself,e.g., modeling tools assessment, training and education, data preservation, etc.

FIDES-II Strategic Plan

Page 24