Nuclear Safety
2023

CSNI Technical Opinion

Paper No. 21

Research Recommendations to
Support the Safe Deployment
of Small Modular Reactors

NE A

Nuclear Safety

CSNI Technical Opinion Paper
No. 21
Research Recommendations to Support
the Safe Deployment of Small Modular Reactors© OECD 2023
NEA No. 7660
NUCLEAR ENERGY AGENCY
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Cover photos: Research and development to support the advancement of small modular reactors (Canadian Nuclear Laboratories, CC BY-ND 2.0);
High-temperature Engineering Test Reactor (Japan Atomic Energy Agency).

FOREWORD

Foreword

There is growing interest worldwide in nuclear energy, including in small, modular systems thatcan generate energy efficiently and reliably while minimising the impact on the climate.
In order to support the safe deployment of these technologies, the Nuclear Energy Agency (NEA)
Committee on the Safety of Nuclear Installations (CSNI) convened the Expert Group on Small
Modular Reactors (EGSMR). The EGSMR’s mandate is to evaluate the needs of NEA member
countries for SMR safety research. The group is tasked with recommending CSNI actions that
can help countries address the identified knowledge gaps and safety challenges.
The EGSMR assessment of the needs of NEA member countries identified four major areasof interest related to SMR safety: 1) regulatory harmonisation, 2) cross-cutting safety issues,3) experimental campaigns, and 4) benchmarking for computer code validation and verification.
Several actions were suggested for the CSNI to investigate the technical knowledge gaps
identified in these areas as well as in new research areas that warrant further study. The actions
were prioritised based on their safety significance and relevance to the CSNI mandate and onwhether they can be addressed through CSNI working/expert group efforts, task force initiatives,
activity proposals and joint projects.
The EGSMR suggested actions to co-ordinate efforts by the CSNI and other NEA committees
and international organisations pursuing similar initiatives related to SMRs. These efforts supportand develop the scientific and technical knowledge base needed for the sound safety
demonstration of SMRs, thereby helping to pave the way for the deployment of SMRs as apromising source of clean energy that is much needed to meet the net zero CO2 emissions targets.
This report was approved by the CSNI at its 73rd meeting on 6 June 2023 and prepared for
publication by the NEA Secretariat.

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ACKNOWLEDGEMENTS

Acknowledgements

The members of the Nuclear Energy Agency (NEA), the Committee on the Safety of Nuclear
Installations (CSNI) and the Expert Group on Small Modular Reactors (EGSMR) wish toacknowledge the significant contributions of those individuals who had a key role in the
preparation of this technical opinion paper, and those who participated and contributed as
members of the EGSMR. Additional thanks are extended to the NEA Secretariat support for thisexpert group (specifically Vesselina RANGUELOVA), and to Rebecca FEGER and Francisco PARRA
for their editorial support.

Leading authors
Andrew MORREALE

Canadian Nuclear Laboratories (CNL), Canada – Chair of
the Expert Group on Small Modular Reactors (EGSMR)

Philippe DEJARDIN

Tractebel, Belgium

Vesselina RANGUELOVA

Nuclear Energy Agency (NEA), France

Fulvio MASCARI

Italian National Agency for New Technologies, Energy
and Sustainable Economic Development (ENEA), Italy

Anna ALVESTAV

Swedish Radiation Safety Authority (SSM), SwedenPeter YARSKY

United States Nuclear Regulatory Commission (USNRC),
United States

Information collection champions (SMR experimental facilities; SMR projects; SMR
PIRTs)
Andreas SCHAFFRATH

Gesellschaft für Anlagen- und Reaktorsicherheit (GRS),
Germany

Robert JANSEN

Authority for Nuclear Safety and Radiation Protection(AVNS), Netherlands

Contributors

4

Paula CALLE VIVESInternational Atomic Energy Agency (IAEA), Austria

Mikhail LANKINInternational Atomic Energy Agency (IAEA), Austria

Zièd EL HADHRIBEL V (subsidiary of FANC), Belgium

Angelgiorgio IORIZZO

European Communities, Belgium

Chantal MORIN

Canadian Nuclear Safety Commission (CNSC), Canada

David HARUT

Centrum vyzkumu Research Centre (CVREZ), Czech
Republic

Radim MECA

Nuclear Research Inst., Ustav jaderneho vyzkumu (UJVREZ),
Czech Republic

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ACKNOWLEDGEMENTS

Martina ADORNI

Nuclear Energy Agency (NEA), France

Debbie FRANCISEDF DT, FranceFrank MORIN

Centre d'Etudes Nucléaires de Grenoble (CEA), France

Victor Hugo SANCHEZ-ESPINOZA

Karlsruher Institut für Technologie (KIT), Germany

Andreas WIELENBERG

Gesellschaft für Anlagen- und Reaktorsicherheit (GRS),
Germany

Alessandro PETRUZZINuclear and INdustrial Engineering, Italy

Takeshi TAKEDA

Japan Atomic Energy Agency (JAEA), Japan

Hyun-Sik PARK

Korea Atomic Energy Research Institute (KAERI), Korea

Claire BLACKETT

Institutt for Energiteknik,(IFEHALDEN), Norway

Santiago ARENZANA ROMEO

Consejo de Seguridad Nuclear (CSN), Spain

Luis Enrique HERRANZ

Centro de Investigaciones Energeticas Medioambientalesy Tecnologicas (CIEMAT), Spain

Konstantin NIKITINPaul Scherrer Institute (PSI), Switzerland

Stephen BAJOREK

United States Nuclear Regulatory Commission (USNRC),
United States

HaldenRESEARCH RECOMMENDATIONS TO SUPPORT THE SAFE DEPLOYMENT OF SMALL MODULAR REACTORS, NEA No. 7660, © OECD 2023

Reactor

Project

5

TABLE OF CONTENTS

Table of contents

List of abbreviations and acronyms .................................................................................................... 9
Executive summary .............................................................................................................................. 11
Chapter 1. Introduction and background .......................................................................................... 15
Chapter 2. EGSMR assessment process ............................................................................................. 17
Chapter 3. Analysis of SMR deployment survey ............................................................................. 19
3.1.

Prerequisites – Technologies ................................................................................................ 19

3.2.

Prerequisites – International co-operation ......................................................................... 20

3.3.

Knowledge base requirements for SMRs ............................................................................ 21

3.4.

Graded approach .................................................................................................................... 21

Chapter 4. Areas of interest and suggested actions ........................................................................ 23
4.1.

AOI #1: Regulatory harmonisation....................................................................................... 23

4.2.

AOI #2: Cross-cutting safety issues...................................................................................... 25

4.3.

AOI #3: Experimental campaigns ......................................................................................... 28

4.4.

AOI #4: Benchmarking for code V&V ................................................................................... 31

4.5.

Conclusion and key suggested actions ............................................................................... 32

4.6.

EGSMR information collection ............................................................................................. 33

Chapter 5. EGSMR future efforts ......................................................................................................... 35
Conclusions............................................................................................................................................ 37
References .............................................................................................................................................. 39

List of annexes
A.

First questionnaire on SMR deployment and research status ........................................ 41

B.

CSNI and CNRA working and expert groups ...................................................................... 43

C.

Experimental facilities related to SMR safety .................................................................... 45

D.

Projects focused on SMR safety............................................................................................ 61

E.

PIRTs related to SMR safety .................................................................................................. 77

List of figures
2.1.

EGSMR assessment process .................................................................................................. 17

3.1.

Responses regarding which SMR technologies should be covered ................................. 20

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TABLE OF CONTENTS

List of tables
C.1.

SMR safety-related experimental facilities for WC-SMRs ................................................ 46

C.2.

SMR Safety-related experimental facilities for AT-SMRs ................................................. 52

C.3.

Existing experimental facilities for possible use in investigation of SMR safetyissues ....................................................................................................................................... 58

D.1.

National and multi-national projects (Belgium: Bel V and Tractebel) ............................ 61

D.2.

National and multi-national projects (Canada: CNL and CNSC) ..................................... 62

D.3.

National and multi-national projects (France: CEA) ......................................................... 63

D.4.

National and multi-national projects (Germany: GRS, KIT) ............................................. 64

D.5.

National and multi-national projects (Japan: Hitachi-GE, JAEA, MHI) ............................ 66

D.6.

National and multi-national projects (Netherlands: AVNS, NRG, TU Delft) .................. 67

D.7.

National and multi-national projects (Norway: IFE) ......................................................... 68

D.8.

National and multi-national projects (Korea: KAERI) ....................................................... 69

D.9.

National and multi-national projects (Sweden: SSM) ....................................................... 69

D.10. National and multi-national projects (United States, US: USNRC).................................. 70
D.11. Multi-national projects (Euratom) ....................................................................................... 71
D.12. Multi-national projects (GIF)................................................................................................. 73
D.13. Multi-national projects (IAEA) .............................................................................................. 74
D.14. Multi-national projects (NEA) ............................................................................................... 75

8

E.1.

Canada – PIRTs relevant to SMR safety ............................................................................... 77

E.2.

France – PIRTs relevant to SMR safety ................................................................................ 77

E.3.

Japan – PIRTs relevant to SMR safety .................................................................................. 78

E.4.

Korea – PIRTs relevant to SMR safety .................................................................................. 78

E.5.

United States – PIRTs relevant to SMR safety..................................................................... 79

E.6.

Euratom Projects – PIRTs relevant to SMR safety .............................................................. 79

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LIST OF ABBREVIATIONS AND ACRONYMS

List of abbreviations and acronyms

AECL

Atomic Energy of Canada Limited

ALFRED

Advanced Lead-cooled Fast Reactor European Demonstrator

ANVS

Autoriteit Nucleaire Veiligheid en Stralingsbescherming (Netherlands)

AOI

Area of interest

ATR

Advanced Test Reactor

AT-SMR

Advanced Technology Small Modular Reactor

BWR

Boiling water reactor

CAPS

CSNI Activity Proposal Sheet

CEA

French Alternative Energies and Atomic Energy Commission

CFD

Computational fluid dynamics

CHF

Critical Heat Flux

CIEMAT

Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (Spain)

CNL

Canadian Nuclear Laboratories

CNRA

Committee on Nuclear Regulatory Activities (NEA)

CNSC

Canadian Nuclear Safety Commission

CORDEL

Cooperation in reactor Design Evaluation and Licensing (WNA)

CRP

Co-ordinated research project

CRPPH

Committee on Radiological Protection and Public Health (NEA)

CSNI

Committee on the Safety of Nuclear Installations (NEA)

DiD

Defence in depth

EGSMR

Expert Group on Small Modular Reactors (NEA)

ENEA

Italian National Agency for New Technologies, Energy and Sustainable
Economic Development

EPZ

Emergency planning zone

ETSON

European Technical Safety Organisations Network

FOAK

First-of-a-kind

GIF

Generation IV International Forum

GRS

Gesellschaft für Anlagen- und Reaktorsicherheit (Germany)

HTGR

High-temperature gas-cooled reactors

HTO

Human Technology Organisation

HTTF

High-temperature test facility

HTTR

High-temperature engineering test reactor

IAEA

International Atomic Energy Agency

IKE

Institut für Kernenergetik und Energiesysteme (Germany)

IRSN

Institut de Radioprotection et de Sureté Nucléaire (France)

JAEA

Japan Atomic Energy Agency

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LIST OF ABBREVIATIONS AND ACRONYMS

10

KAERI

Korea Atomic Energy Research Institute

KIT

Karlsruhe Institute of Technology (Germany)

LFR

Lead fast reactor

LOCA

Loss-of-coolant accident

LOFC

Loss of forced cooling

LW

Light water

LWR

Light water reactor

LW-SMR

Light water small modular reactor

MASLWR

Multi-application small light water reactor

MMR

Micro Modular Reactor

MSR

Molten salt reactor

MWe

Megawatt electric

MYRRHA

Multi-purpose hYbrid Research Reactor for High-tech Applications

NEA

Nuclear Energy Agency

NHSI

Nuclear Harmonization and Standardization Initiative (IAEA)

NIST

NuScale Integral System Test

PIRT

Phenomena Identification and Ranking Table

PSA

Probabilistic safety analysis

PSI

Paul Scherrer Institute (Switzerland)

PWR

Pressurised water reactor

RCS

Reactor coolant system

RSWG

Risk and Safety Working Group (Generation IV International Forum)

SCWR

Supercritical water reactor

SDA

Standard design approval

SEGPD

Senior Expert Group on Preservation of Key Experimental Datasets (NEA)

SFR

Sodium-cooled fast reactor

SMR

Small modular reactor

SSM

Swedish Radiation Safety Authority

THYR

Thorium and Hybrid Reactor

TRL

Technological readiness level

TSO

Technical safety organisation

USNRC

United States Nuclear Regulatory Commission

V&V

Validation and verification

WC-SMR

Water-cooled small modular reactor

WGAMA

Working Group on Analysis and Management of Accidents (NEA)

WGEVWorking Group on External Events (NEA)WGFCSWorking Group on Fuel Cycle Safety (NEA)

WGFS

Working Group on Fuel Safety (NEA)

WGHOF

Working Group on Human and Organisational Factors (NEA)WGNTWorking Group on New Technologies (NEA)

WGPLWorking Group on Policy and Licensing (NEA)WGRISK

Working Group on Risk Assessment (NEA)

WNA

World Nuclear Association

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EXECUTIVE SUMMARY

Executive summary

The NEA Committee on the Safety of Nuclear Installations (CSNI) convened an Expert Group on
Small Modular Reactors (EGSMR) to help evaluate the safety impacts of small modular reactors(SMRs). A growing number of NEA member countries are investigating the potential deploymentof SMRs to efficiently and reliably increase energy generation while minimising the impacts on
the climate. A range of technologies are employed in SMR designs with a variety of coolants(water-cooled and non-water-cooled) and reactor sizes. SMRs are envisaged for multiple
applications (electricity, hydrogen production, process heat, etc.) and locations (grid-scale
generation, remote operations, floating power stations, mining/industrial operations). They alsoutilise a modular design, which should grant efficient construction through serial production ofmultiple identical units. Therefore, SMRs require supporting research and new safety evaluations.
The EGSMR is comprised of CSNI participants (23 organisations from 15 countries) with aninterest in SMRs along with international bodies (the International Atomic Energy Agency [IAEA],
and the European Commission [Euratom]). It is mandated firstly to evaluate NEA member needs
for SMR safety research and assessments, and secondly to recommend CSNI efforts to be
conducted to address them. The EGSMR co-ordinates with other NEA committees (e.g. theCommittee on Nuclear Regulatory Activities [CNRA]; and the Committee on Nuclear Science[NSC]) and with international organisations pursuing similar efforts related to SMRs in order topromote co-operation, complement efforts and avoid duplication. In this way, the CSNI ensuresthat it can properly support understanding of SMR safety to assist with their deployment.
A survey of EGSMR participants identified interest in both evolutionary water-cooled SMRs
(WC-SMRs) and innovative advanced technology SMRs (AT-SMRs; i.e. Generation IV). Given thehigh technological readiness level (TRL) and close deployment horizon of WC-SMRs, nearly all
respondents are interested in this technology, which can be well supported considering extensive
CSNI experience in large water-cooled reactor safety. There is also interest in AT-SMRs due to theirunique features (e.g. high-temperature process heat, fast neutron spectra, and fuel cycle impacts),
specifically high-temperature gas-cooled reactors (HTGRs). Sodium/lead fast reactors and molten
salt designs are of interest, though with a slightly longer deployment horizon. Micro-reactors(< 10 MWe) and their potential applications are also drawing attention. The survey also
highlighted the desire for international collaboration and consideration of the knowledge baseneeded to support new designs, as well as the importance of a graded approach.
The EGSMR has identified four major areas of interest (AOIs), and provides suggested actions(“a”), to address them:
1. Regulatory harmonisationa. While regulatory issues are primarily handled by the CNRA, the CSNI can provide
technical support for the regulatory safety assessments of SMRs. Thus, the CSNI needs
to maintain awareness of regulatory efforts underway, and be ready to respond torequests for assistance from partners and other international organisations.
2. Cross-cutting safety issues–

application of defence in depth (DiD) levels when passive safety is applied at multiple
levels;–probabilistic safety analysis (PSA) for innovative/first-of-a-kind designs;–

emergency planning zones (EPZ) and emergency response requirements for SMRs;–

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EXECUTIVE SUMMARY–

human factors (including remote operations and multi-unit/multi-module plants);–

multi-unit/multi-module design aspects and impacts on safety;–

transport of pre-fuelled/spent nuclear modules and transportable/floating SMRs;–

associated process applications: H2 production, process heat (e.g. chemical, mining,
district heating).

a.

The eight prioritised cross-cutting issues above should each be reviewed by a relevant
CSNI working/expert group to assess the issue, understand the work underway, andidentify gaps and research needs. The output of this effort should be a status reportfor the CSNI.

3. Experimental campaignsa.

Experiments form the basis of evidence to demonstrate safety, and it is therefore
suggested that support be provided to the determination of knowledge gaps, theleveraging of existing experimental data, the identification of existing facilities, andthe recommendation of new experiments.

4. Benchmarking for code validation and verification (V&V)
a.

Qualified modelling/analysis tools are an essential part of modern safetyassessments, which can be facilitated with the following activities: Developing V&V
guidance, extending validation matrices to include SMR safety, encouraging
benchmarking activities, and capturing modelling best practices.

Overall, the suggested key, short-term actions prioritised based on safety significance andrelevance to the CSNI mandate are:
1. Gathering SMR phenomena identification and ranking tables (PIRTs) to identify SMR
safety phenomena and prioritise future efforts.
2. Starting work on the high-priority cross-cutting issues (identified above).
3. Reviewing and updating the CSNI code validation matrix for SMR safety, and producing
a guidance report on V&V needs for code qualification.
4. Collecting and generating data through joint research projects to support SMR safety.
The EGSMR identified new research areas that warrant further study, including the impactof “external” events from associated processes connected to SMRs, and materials concerns for
AT-SMRs. The EGSMR has also conducted information collection efforts focused on SMR safety,
including data on experimental facilities, national and multi-national projects, and PIRTs.
The suggested actions and the areas for further study can be addressed through a
combination of efforts by relevant CSNI working/expert groups, and co-ordination with other
NEA committees and external organisations. Activities should be initiated within the relevantgroups to address the actions and produce the desired outcomes. These include internal
working/expert group efforts, co-ordinated task force initiatives between multiple groups (witha suitable leading group), CAPS (CSNI Activity Proposal Sheets) or NEA joint projects. Whileregulatory issues are primarily handled by the CNRA, the EGSMR concluded that in many cases
the CSNI could provide technical support to regulatory licensing activities.
Following the CSNI request to assist in co-ordinating efforts in the area of SMR safety, the
EGSMR will consider revising and expanding its mandate in order to ensure that future activitiesof the group are captured in a way that is consistent with CSNI expectations, and propose a
draft mandate for approval to the CSNI. The EGSMR could provide support to the other CSNI
working/expert groups to initiate and organise activities through the assignment of EGSMR
participants as “action champions”, providing background information and additional resources
during the start-up of activities.

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EXECUTIVE SUMMARY

A forum for exchange will be proposed (e.g. a periodic “SMR Safety Review” event) to trackprogress and disseminate results of internal CSNI efforts on SMR safety, and to connect withrelated external efforts by other international organisations. This can help to align common
pursuits, promote co-operation and avoid redundancy.
Through the efforts listed and discussed herein, the CSNI will be able to properly support
and advance the scientific and technical knowledge base for the safe deployment of SMRs.

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INTRODUCTION AND BACKGROUND

Chapter 1. Introduction and background

The NEA Committee on the Safety of Nuclear Installations (CSNI) is responsible for NEA
programmes and activities that support maintaining and advancing the scientific and technicalknowledge base of the safety of nuclear installations. Recently, there has been increased interest
among several NEA member countries in small modular reactors (SMRs), which are being
investigated for potential deployment to address challenges related to climate change and theincreased electrification of infrastructure and transportation. These SMRs are typically smaller
than large power reactors, with a modular design and the potential to realise the economies ofserial production. They also include a wide variety of technologies, with both water-cooled andadvanced (i.e. non-water-cooled) options. SMR designs are being proposed for differing roles (gridscale, remote operations, floating power stations, and mining/industrial process operations) andpower levels (generally < 300 MWe). Many of these SMR designs are quite different from currently
operating reactors and require new safety evaluations for both classical reactor issues andpotential new issues that may arise out of these designs.
Considering this move towards SMR deployment, the CSNI organised an Expert Group on
Small Modular Reactors (EGSMR) with the mandate to assess potential CSNI activities in the areaof SMR safety. The focus is on technologies close to deployment and activities relevant to CSNI
capabilities and experience. The EGSMR is charged with formulating an approach to identify
recommended activities/actions to be conducted/taken and determining any new technicalareas where the CSNI should develop expertise, including:•identifying important issues and phenomena;•

identifying and understanding knowledge gaps;•

determining how CSNI activities can best be used to fill those gaps.

The EGSMR also supports information exchange between participating organisations andcountries on related SMR safety activities. Several international organisations, including theInternational Atomic Energy Agency (IAEA), the Generation IV International Forum (GIF) and theEuropean Commission Euratom (European Atomic Energy Community), are also conducting workin the area of SMR safety. The EGSMR, therefore, aims to co-ordinate with these internationalorganisations and, as appropriate, to make the activities complementary.
The EGSMR is comprised of representatives from 15 NEA countries (Belgium, Canada, theCzech Republic, France, Germany, Italy, Japan, Korea, the Netherlands, Norway, Spain, Sweden,
Switzerland, Türkiye and the United States) along with international bodies (IAEA and Euratom)with an interest in SMRs, and involves 23 organisations, including nuclear regulators, research
institutes and national laboratories, technical safety organisations (TSOs), and utilities. A list of
the EGSMR organisations and participants is provided in the ”Acknowledgements” section ofthis report.

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EGSMR ASSESSMENT PROCESS

Chapter 2. EGSMR assessment process

The NEA Expert Group on Small Modular Reactors (EGSMR) executed its assigned mandate
through a process of collecting and evaluating information and generating recommendations. The
information collection effort was in the form of questionnaires, which utilised the diversity of the
EGSMR participants and allowed the identification of issues relevant to NEA members. The
participants of the EGSMR also overlap with those of the NEA Committee on the Safety of Nuclear
Installations (CSNI) and its constituent working groups, allowing for input on the relevance of thegenerated information to CSNI capabilities and interests.
The process, illustrated in Figure 2.1, collected information to determine the areas of interest(AOIs) in SMR safety, which were then refined in a subsequent process that sought to propose
actions that the CSNI could take to address the AOIs.

Figure 2.1. EGSMR assessment process

Second questionaire• Collect up-to-date
information• Set common basis(presumptions andprerequisits)• Identify main areas• Refine ideas• Compile ongoing
activeties• Added value as CSNI or
CNRA activety• Combine and compile• Prioritise• Effort to get activities
startedFirst questionaire

Proposals

The first questionnaire gathered a variety of information (detailed in Annex A) to generatea picture of SMR safety analysis, research and deployment plans in NEA member countries.
Additionally, parallel international efforts related to SMR safety under the International Atomic
Energy Agency (IAEA), Euratom and the Generation IV International Forum (GIF) were identified.
The detailed results, discussed in Chapter 3, were then aggregated to determine specific AOIs
related to SMR safety where the CSNI could contribute. These AOIs were referred back to the
EGSMR in a second questionnaire, which sought to:•refine the AOIs (e.g. narrowing or broadening, identifying concerns or challenges, andany missing areas);•develop suggested actions for the CSNI to address these AOIs.

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EGSMR ASSESSMENT PROCESSThe suggested actions include: i) specific activities to address the AOIs; ii) adjustments tocurrent CSNI efforts already in progress; and iii) review of and potential collaboration withongoing efforts in other international organisations. These actions focus on the unique added
value of CSNI involvement and on activities beneficial to the NEA Committee on Nuclear
Regulatory Activities (CNRA) and regulators facing licensing of SMRs. They are linked to thestanding working or expert groups of the CSNI (see Annex B) or to those in other NEA
committees (e.g. CNRA), and some could be developed into potential international joint safety
research projects. The identified AOIs and suggested actions comprise the primary results ofthe EGSMR effort and are discussed in detail in Chapter 4, which outlines the four major AOIs,
their breakdown and the related suggested actions for the CSNI.
These results summarise the EGSMR assessment of CSNI activities of relevance to SMRs
which have a high technology-readiness level (TRL) and are anticipated to see near-term
deployment. In determining the priority of different proposals, the EGSMR evaluated each
proposal’s safety significance and the available CSNI capabilities. Experimental programmes,
key facilities and efforts conducted at other international organisations were also considered.
There are several areas and actions that focus on safety issues that cross a number of designs
and the EGSMR has identified new technical areas where the CSNI should develop knowledge.

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ANALYSIS OF SMR DEPLOYMENT SURVEY

Chapter 3. Analysis of SMR deployment survey

3.1. Prerequisites – Technologies
The term “small modular reactor (SMR)” can encompass a wide variety of technologies, sizes(power/thermal output) and aspects (e.g. modularity, multi-module operations, risk minimisation,
remote operation). To frame and delimit the work of the NEA Expert Group on Small Modular
Reactors (EGSMR), the NEA definition was adopted:“SMRs are defined today as nuclear reactors with a power output between
10 megawatts electric (MWe) and 300 MWe. They integrate by design
higher modularisation, standardisation and factory-based construction inorder to maximise economies of series (or the “series effect”). The different
modules can then be transported and assembled on site, leading topredictability and savings in construction times” (NEA, 2021a).
SMRs include a variety of reactor technologies in terms of coolants (water, gas, liquid metal,
molten salt, heat pipes, etc.) and fuels (UO2, TRISO, molten salt, etc.). The above definition aligns
with previous efforts of other organisations to come to a common understanding of the term
“SMR”. The EGSMR does maintain flexibility related to power output and technology, however,and considers in addition that SMR design features also offer potential increases in safety.
Within the EGSMR mandate is also an expectation to initially focus on SMR designs thathave a high technology-readiness level (TRL) and that are anticipated to see near-term
deployment. The first questionnaire explored the interest in new reactor technologies among
the respondents to understand plans for deployment (or not) in their countries, and find which
technologies are of interest in the near term and/or in a longer time frame. This helps to focus
the areas of interest (AOIs) and suggested actions to support NEA member needs and identify
common issues that could be addressed through international co-operation (potentially led by
the NEA or other organisations if better suited to the future task).
It is clear from Figure 3.1 that the technologies close to near-term deployment are primarily
water-cooled designs. These are also the technologies where the NEA Committee on the Safety of
Nuclear Installations (CSNI) is currently best able to provide support. Advanced technologies canoffer advantages that the current light water reactor (LWR) designs cannot. For example, a fastneutron spectrum can burn actinides or provide very high temperatures for industrial processes.
These technologies, while potentially farther from deployment, are also important to advance,
and the CSNI is well positioned to support this given the large resources and capabilities of theparticipating countries. It is for this reason that the EGSMR supports two tracks: 1) water-cooled
SMRs (WC-SMRs) and 2) advanced technology SMRs (AT-SMRs; i.e. Generation IV).
In terms of the prioritisation of AT-SMR designs, Figure 3.1 indicates that possible co-operation
could be beneficial in studying safety issues related to high-temperature gas-cooled reactors(HTGRs), sodium-cooled fast reactors (SFR), molten salt reactors (MSR), and lead fast reactors (LFR).

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ANALYSIS OF SMR DEPLOYMENT SURVEY

Figure 3.1. Responses regarding which SMR technologies should be covered
25

20

15

10

5

0
LWR

HTGR

SFR
First priority

MSR

LFR

Interesting

Source: The EGSMR first questionnaire results (CSNI EGSMR).

3.2. Prerequisites – International co-operation
The interest in new reactor technologies and SMRs has increased and resulted in initiatives inseveral countries and between several countries. Often the same experts and organisations
participate in different initiatives covering similar topics, but it is recognised that international
co-operation is valuable. It promotes the exchange of knowledge and development ofcompetences and allows issues to be analysed from different perspectives. When formulating
proposals for new efforts within the NEA, it is necessary to be informed about other ongoing work,
which can be considered for co-operation. Alternatively, the scope of the new efforts can belimited to ensure they are complementary.
The EGSMR has identified the following avenues of co-operation and to a large extent
suggests collaborating with them:20•

the International Atomic Energy Agency (IAEA), with initiatives like the Nuclear
Harmonization and Standardization Initiative (NHSI) (IAEA, n.d.) and the SMR Regulators
Forum (SMR RF) (NEA, 2022);•

the World Nuclear Association (WNA) CORDEL (Cooperation in reactor Design Evaluationand Licensing) working group, and other international industry associations/groups;•

the EU SMR Pre-Partnership effort (notably Work Stream WS2 on Licensing and WS5 on
R&D needs);•

Euratom Research Projects;•

the Generation IV International Forum (GIF);•

within the NEA, the Committee on Nuclear Regulatory Activities (CNRA) (especially theWorking Group on New Technologies [WGNT], and the Working Group on Policy andLicensing [WGPL]).

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ANALYSIS OF SMR DEPLOYMENT SURVEY

3.3. Knowledge base requirements for SMRs
Many proposed SMR designs rely on technologies different from those of established large watercooled reactors. The latter benefit from an extensive knowledge base built over decades ofresearch and operational experience in many countries. This foundation has been an essential
element supporting the safe operation of such reactors. There is the potential to apply thisknowledge to WC-SMRs, but there are still phenomena requiring further investigation (e.g. natural
circulation and passive cooling). For AT-SMRs, this water-cooled operating knowledge is lessapplicable. Given these challenges, it may not be realistic to expect a knowledge base of a similar
extent to be developed for AT-SMRs such as gas-cooled, molten salt, or liquid metal cooled(e.g. sodium, lead) designs.
New designs, both WC-SMRs and AT-SMRs, also promise safer operations than the existing
fleet of reactors, but the safety case has yet to be fully demonstrated to regulatory authorities.
Evidence of these claims needs to be built upon experimental support, experience and soundsafety assessments.
Delving deeper into the issue of gaining knowledge about new systems has revealed a few
important principles that the EGSMR recommends to apply in future development work andtasks.
•

It will be necessary to develop new analytical tools or validate current tools for new
applications to support investigations of new reactor technologies with new phenomena.
New tests and experiments will be necessary not only to demonstrate the phenomena
for the application in the design, but also to develop appropriate models for thosephenomena (over a full range of conditions from normal operations to design-basis
accidents, design extension conditions, severe accidents and long-term recovery) tojustify the safety analysis methods.

•

The safety case needs to be robust. However, systems and models for some new reactor
technologies are currently in a developing stage and their accuracy and precision may
not be fully realised. In developing stages, it is necessary to balance the level ofimprecision with appropriate safety margins.

•

Demonstration and first-of-a-kind (FOAK) SMRs need to be suitably equipped with
instrumentation and probes to collect comprehensive measurements. This could allow
high quality data generation, the identification of potential improvements, and future
reductions in margins.

An overarching goal for the EGSMR and the CSNI is to advance the scientific and technicalknowledge base for the safety of nuclear installations. Hence, it is well in line with CSNI goals
to develop the knowledge base regarding SMRs over the whole chain of safety justifications fromtests, through models and methods development, to the exchange of experience with actual
systems, as well as harmonisation between nations in these steps.

3.4. Graded approach
A graded approach for both WC-SMR and AT-SMR designs includes these main components:•

The level of analysis, verification, documentation, regulation, activities and procedures
used to comply with a safety requirement should be commensurate with the associatedradiation risks.
–•

Determine which elements are considered important and novel (or less mature;
maturity relates to the use of proven practices and calculation codes, proven design
features, operating experience from similar facilities, etc.) and prioritise these in a
pre-licensing process with safety authorities.

Appropriate consideration of the knowledge base and uncertainties must be taken to alevel that meets national regulatory standards and, as appropriate, the IAEA safety
standards.

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ANALYSIS OF SMR DEPLOYMENT SURVEY•–

The knowledge base must be sufficient to prove the safety claims that the vendor ismaking.

–

Sufficient accuracy and precision should be demonstrated to meet regulatory
standards, and when accuracy and precision are not high, larger safety margins may
be necessary. The level of accuracy should support a robust safety case.

Providing high-level, non-prescriptive, and objective-oriented regulations based on therevision of current LWR regulations could be an efficient way to quickly establish aregulatory base for novel reactors.
–

22This should be aligned with risk-informed design/regulation and keep risk as low asreasonably achievable (ALARA).

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AREAS OF INTEREST AND SUGGESTED ACTIONS

Chapter 4. Areas of interest and suggested actions

The NEA Expert Group on Small Modular Reactors (EGSMR) surveys have explored current
knowledge and ongoing programmes in order to determine areas of interest (AOIs) for further
work and especially to find topics for small modular reactor (SMR) safety that require attention.
The EGSMR analysis has resulted in a handful of suggested actions that would advance thescientific and technical knowledge base for the safety of nuclear installations. Thesesuggestions all include several parts that each can be expanded to specific tasks, activities or
projects. In some cases, similar actions are being performed in other international organisations(e.g. International Atomic Energy Agency [IAEA], Euratom, and Generation IV International
Forum [GIF]) and the NEA should actively seek information exchange with these efforts.
The identified AOIs for further consideration by the NEA Committee on the Safety of Nuclear
Installations (CSNI) and suggested actions focus on four categories:
1. Regulatory harmonisation: Foster international regulatory harmonisation regarding
SMR licensing.
2. Cross-cutting safety issues: Support understanding of broad cross-cutting SMR safetyissues that impact many different designs (detailed in Section 4.2).
3. Experimental campaigns: Organise reviews of international experimental campaigns anddefine new campaigns to improve phenomenological understanding and experimental
validation of SMR designs.
4. Benchmarking for code V&V: Support international benchmark activities for computermodelling V&V for SMR designs.
For all AOIs, the EGSMR recommends efforts into two parallel tracks: 1) WC-SMRs, and
2) AT-SMRs, with further prioritisation to support technologies/designs nearest to deployment.
These AOI are important areas for co-operation in the NEA, and most of the broad cross-cutting
SMR issues would be suitable for tasks in the respective CSNI working or expert groups. The
suggested actions to address these AOI are further elaborated on in the following sections.

4.1. AOI #1: Regulatory harmonisation
The first AOI identified by the EGSMR relates to the harmonisation at an international level ofregulatory requirements and practices for SMR licensing.
Clearly, this topic is not new and is already being explored in initiatives outside of the NEA
like the IAEA NHSI, the World Nuclear Association (WNA) CORDEL or the WS2 on Licensing of
the EU SMR Pre-Partnership.
The EGSMR, although organised within the CSNI, is also conscious that this AOI would be
primarily handled by the NEA Committee on Nuclear Regulatory Activities (CNRA), and that thismight already be the case to some extent within its working groups WGNT and/or WGPL.
Nonetheless, the EGSMR wants to emphasise that regulatory harmonisation remains afundamental AOI to enable the timely deployment of SMRs in the near term and for whichinternational collaboration must be fostered.
Safety demonstration requirements are clearly important to the CSNI, its working groups,
and their specific participants, who are stakeholders in their formulation and implementation.
Therefore, the CSNI needs to maintain awareness of regulatory and associated safety
demonstration efforts currently underway, and be ready to respond to requests for assistancefrom partners and other international organisations.

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AREAS OF INTEREST AND SUGGESTED ACTIONS

Consequently, to contribute to this collaboration, the EGSMR wanted to provide its view on
the main topics where CSNI efforts could support regulatory safety assessment and licensing
activities:•••

Development and application of regulation and guidance on simulation code qualification
verification, validation, and simulation model qualification; notably:–

Establishing guidelines on necessary V&V for new modelling and simulation tools (orenhancements of established codes to apply to SMRs).

–

Finding balance between preciseness and predictiveness of the codes and theacceptance of uncertainties for simulation tool results against safety margins.

–

Addressing existing model gaps or validation gaps in a safety demonstration, and the
expectations on simulation code user qualification.

–

Assessing the potential for reduced validation data (single validation per phenomena)and the potential of licensing a first “prototype” unit within a conservative envelope.

The application of graded approaches in establishing safety provisions (regulations) for
SMRs; notably:–

Paying specific attention to codes and standards, and to simulation code qualification.

–

Considering implementing risk-informed approaches to regulation.

The collection of information on phenomena to inform regulation, as well as theidentification of knowledge gaps and related research needs from a regulatory perspective.

As a result, in terms of overwhelming action for this first AOI, the CSNI should, possibly
through the EGSMR, maintain relationships and information transfers with other parties
exploring SMR safety. From the EGSMR’s perspective, these actions can be divided between“outside NEA initiatives” and “inside NEA initiatives”, in the following sub-actions:•

On the side of outside initiatives, this would mainly be to build and/or maintainrelationships with the following parties:–

IAEA (NHSI and the SMR Regulators Forum);–

WNA (CORDEL);–

Western European Nuclear Regulators Association (WENRA);–

Euratom Research Projects;–

EU SMR Pre-partnership, notably WS2 (Licensing), WS4 (Supply chain) and WS5 (R&D
needs);–ETSON (European Technical Safety Organisations Network);–

GIF (Risk and Safety Working Group).

In particular, the EGSMR notes that the CSNI, its working groups and their specific participants
should be aware of the differences in rules and responsibilities between the different parties andnotably between the NEA and IAEA working groups and committees. This is noted as a key
element to avoid, or at least reduce, duplication of efforts through proper information exchange.
These relationships should also allow building a better understanding from the different
stakeholders’ points of view, for instance from the regulatory or industry sides, of theharmonisation efforts, the possible challenges and the gaps to be filled.
Understanding the points of view of the different stakeholders is important as “harmonisation”
may present (at least) two different viewpoints: i) regulators aligning regulations, and ii) industryaligning interpretations of safety and licensing requirements to harmonise, for instance, thesafety demonstration methodologies. Overall, the EGSMR thinks that an open dialogue between
all stakeholders is beneficial to support harmonisation and that the CSNI could be one of therelevant and credible facilitators between regulators, research centres and industry stakeholders
through its activities generating research results and expert consensus to support harmonisation.

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AREAS OF INTEREST AND SUGGESTED ACTIONSAs one example, more interaction with the IAEA NHSI’s industry track would be beneficial for
NEA members as it could bring more co-operation and resource sharing for experiments and code
validation between experimental facilities, technology holders/developers and potentially TSOs.
•

On the side of internal efforts, the EGSMR sees two tracks that could be activated or towhich attention should be paid:–

The possibility of applying the NEA Multi-national Design Evaluation Programme(MDEP) mechanisms to SMR designs.

–

The maintenance of good information exchange with the CNRA and its working groups(e.g. WGNT and WGPL) regarding ongoing efforts in the regulatory space related to SMR
safety.

In summary, the suggested actions are for the CSNI (perhaps through the EGSMR) to
maintain relationships and information transfer with other parties exploring SMR regulatory
and industry harmonisation (both external and internal to NEA), including close informationexchange with the CNRA regarding ongoing efforts in the regulatory space.

4.2. AOI #2: Cross-cutting safety issues
The second AOI identified by the EGSMR covers the understanding of broad cross-cutting SMR
safety issues. These issues are more general safety concerns that impact a range of designs (bothWC-SMR and AT-SMR) and may pertain to the design, construction/assembly, operation andapplications of SMRs. In this section, these cross-cutting safety issues are described in detail alongwith the suggested actions to address them.
Before delving deeper into the cross-cutting issues identified by the EGSMR, it should be
acknowledged that most of the EGSMR participants have background expertise within the areasof nuclear fuel, thermal-hydraulics and severe accidents, which may therefore lead to some bias
in the identification of these cross-cutting safety issues. Thus, while an effort was made toinclude a variety of issues, the list provided should not be considered exhaustive and could
expand in the future, especially considering that international collaborations could be a source
for additional elements.
The EGSMR has identified the following eight cross-cutting SMR safety issues and ranked
them by priority according to their safety significance, timeline for resolution and relevance to
the CSNI mandate and capabilities, the first issue being of the highest priority:•

Application of defence in depth (DiD) (NEA, 2016; IAEA, 2005) when safety features(e.g. passive safety systems/features) are used on multiple DiD levels.
A common feature of the majority of SMR designs is the use of passive safety systems/
features, frequently spanning multiple levels of DiD. Generally, the requirements oncurrent large reactors aim for independence between the DiD levels as much aspracticable (IAEA, 2016). Thus, it is prudent to assess the extent of independence of DiD
levels that is practicable for designs with passive safety systems/features and theimpacts of such reliance on these systems on SMR safety. The reliability of these passive
systems is a key component of this assessment. It is suggested that reviews be
undertaken involving the Working Groups on Analysis and Management of Accidents(WGAMA), and Risk Assessment (WGRISK) to understand the evaluation of the reliabilityof passive systems and their integration in probabilistic safety analysis (PSA) as well as
deterministic and risk-informed decision making approaches. The EGSMR also suggeststhat the CSNI continue to exchange information and collaborate with the IAEA andothers on the development of methodologies for safety assessment and the regulationof designs with passive safety systems/features. Recommendations on reliability
requirements for passive systems would be of particular benefit.

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AREAS OF INTEREST AND SUGGESTED ACTIONS•PSA for innovative/FOAK designs.
SMRs might well employ innovative and FOAK components, systems and overall designthat are not fully explored in terms of reliability or probability of failure. This may include
module factory sites, fuel fabrication and processing facilities, which are quite different
from facilities employed for large water-cooled reactors. As a result, efforts should be madeto develop methods to apply the PSA to SMRs taking into account this issue. In addition,
the relative advantages of the PSA compared to both deterministic approaches of safetyassessment and to risk-informed decision making should be considered. The EGSMR
therefore suggests that the CSNI review PSA methods and their application to innovative
systems and FOAK designs. This is likely best led by WGRISK, with input from other WGs
as needed.

•

Investigation of emergency planning zones (EPZs) and emergency response
requirements for SMRs.
This cross-cutting safety issue was identified as many SMR designs expect to reach an
accident robustness level sufficient to demonstrate that EPZs would be limited to the siteboundary and no off-site emergency response requirements would be needed. This is arather challenging position to attain and further actions are needed to address emergency
preparedness and response issues for SMRs. The EGSMR is aware that this issue is coveredby the ongoing efforts of many regulators and by the IAEA, including a CoordinatedResearch Project (CRP) specifically focused on the EPZ (IAEA, 2017). In addition, there are
efforts under the NEA Committee on Radiological Protection and Health (CRPPH) that arefocused on the EPZ. It is therefore recommended that the CSNI consider the output of theseactions before determining if any further CSNI action is needed.

•

Fuel safety of SMRs (both WC-SMR and AT-SMR).
Reactor safety is never assumed but demonstrated by proper analysis with verified andvalidated tools. It terms of fuel safety, the EGSMR assumes that near-term deployable
WC-SMR designs will rely on proven fuel design technologies that have been demonstrated
through irradiation in conventional LWRs. Therefore, there will be fewer open questions
related to fuel performance and safety than for SMR designs that utilise novel fuel concepts.
The AT-SMR designs may rely on more novel fuel design concepts that require further
research on fuel performance topics. This area of research is suggested to be explored by
the Working Groups on Fuel Safety (WGFS), Fuel Cycle Safety (WGFCS) and WGAMA andthere are connected efforts being conducted by the NEA Committee on Nuclear Scienceand the McSAFER Euratom Research project. The topical areas fall in a few categories, withspecific issues, as follows:
–

–

–

26

Reactor physics:–

WC-SMR: Fuel designs; V&V of fuel behaviour/neutronics codes for SMRs; fuelradionuclide inventory for source term prediction.

–

AT-SMRs: Use of more detailed neutronics simulations (multi-group, detailed
cross-sections); novel fuel designs (e.g. liquid fuels); fuel burnup/transmutation.

Fuel performance (both materials and burnup):–

All SMRs: Efficiencies in SMR cores and generation of actinides; in-reactor fuelbehaviour in normal operations and accident conditions; fuel safety criteria.

–

AT-SMRs: Core lifetime limits related to material concerns; impact of fuel/coolant chemistry and corrosion issues.

SMR fuel cycles:–

WC-SMR: Potential impacts to spent-fuel management and final repositories(including burnup and fuel volume).

–

AT-SMRs: impact of novel designs on fuel cycle back end (long-term management).

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AREAS OF INTEREST AND SUGGESTED ACTIONS•Human factors (including remote operations and multi-unit/multi-module plants).
The differences in the design, applications and operational states of SMRs compared toconventional large reactors also present challenges related to human factors. This isspecifically evident for remote operations, maintenance and emergency preparedness(potentially with significantly reduced or no on-site operations staff), and for the control ofmulti-unit/multi-module plants by a team of operators. In the case of remote operations
or multi-unit/multi-module plants, the impacts of shared control rooms may be of interest.
Additionally, from a technology point of view, aspects related to operator interaction/
control of passive safety systems/features are of interest. The EGSMR suggests a review ofefforts in this area, most suitably by the WG on Human Factors (WGHOF), whose
participants are particularly skilled and are already beginning some research in this area.
Such a review could also form a suitable foundation for the development of guidance on
addressing these aforementioned human factor challenges to mitigate issues that may
arise. In this area there are important connections to the following:•–

Activities being conducted at the Halden HTO (Human Technology Organisation).
The CSNI can exchange information and provide support to ongoing and newly
planned efforts related to SMR remote operation.

–

Regulators investigating these human factor issues, which warrants consultation
with the CNRA and a review of ongoing work.

Exploration of multi-unit/multi-module design aspects to determine the impacts on
safety (including shared systems, adjacent unit/module accidents and common mode
failures).
This topic was identified because several SMR designs include a multi-unit/multimodule configuration and/or a potentially closer link with adjacent plants compared tothe majority of currently operating large nuclear reactors. This issue is therefore focusedon gathering information on these aspects to provide sound recommendations that
could be addressed through updates to PSA (or other deterministic or risk-informed)
methods. This gathering of information would primarily concern:•–

Information on the safety assessment of multi-unit facilities in operation (including
the Fukushima Daiichi accident, other LWR stations, and CANDU multi-unit plants
with shared containment).

–

Information on multi-module SMR designs and the differences from traditional
multi-unit stations (e.g. licensing experience for PRISM, NuScale and HTR-PM).

–

Information on specific design measures based on the design characteristics of SMRs,
including PSA methodology development for multi-module applications.

Safety and security aspects related to the transport of fuelled nuclear modules andtransportable/floating nuclear power plants (SMRs).
This safety issue relates to some SMR designs exhibiting either transportable fuelled
nuclear cores (for delivery to, or the return of a spent core from, a plant site; e.g. the
USNC Micro Modular Reactor, or Westinghouse eVinci) or floating vessel configurations(multiple possible sites e.g. KLT-40S, OFPU RITM-200, and Seaborg Power Barge). For thisissue, the EGSMR provided the following two recommendations:–

To consult with the IAEA initiative on the design safety of transportable nuclear
power plants; it is recommended that the CSNI review the output of this effort before
determining if further action is needed.

–

A joint assessment of this cross-cutting issue by multiple CSNI WGs (led by one WG)
may be beneficial with potential input from the WGFS, WGRISK and WGAMA.

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AREAS OF INTEREST AND SUGGESTED ACTIONS•

Understanding of safety implications related to interconnections between SMRs andassociated process applications (hydrogen production, process heat for chemicals,
mining, etc.).
This issue was identified because SMRs are generally advertised as disruptive means ofelectricity and/or heat production (e.g. district heating) that could support the
decarbonisation of industrial process applications (hydrogen generation, desalinisation,mining, etc.). However, the impact on SMR safety of such closely connected processes has
so far, to the knowledge of the EGSMR, not been sufficiently investigated. This isunderstandable as it needs to bring together the two different worlds of nuclear reactor
developers/operators, who are less knowledgeable of industrial constraints, and industrial
developers/operators, who are less knowledgeable of nuclear safety requirements. The
EGSMR is advocating for building and maintaining, within the CSNI and its working groups,
greater understanding and an assessment of the safety implications related tointerconnections between SMRs and associated process applications through the following
concrete actions:–

A consultation with the CNRA and the Euratom Research TANDEM Project, with thesuggested involvement of the CSNI Working Group on External Events (WGEV).

–A review of JAEA work on the coupling of the HTTR (High-Temperature Engineering
Test Reactor) to a hydrogen production facility (Shibata, 2022), as this could provide
insight into the safety impacts and connections challenges, which are applicable tointerconnections with process applications for HTGR-SMR.

–

An investigation of the following topics in priority:–

decoupling possibilities between the nuclear island and balance of plant/
connected infrastructure/associated process applications to enhance safety;–

the impact on credible “external events” of different “load losses” related toprocesses;–

the level of detail and validation of numerical tools needed for the safety
demonstration of an SMR within an energy hub (e.g. high-level complex systems
modelling). For this point, consultation with national laboratories working on
Energy Hubs is recommended (e.g. Idaho National Laboratory [INL], US; National
Renewable Energy Laboratory [NREL], US; Canadian Nuclear Laboratories [CNL];
the French Alternative Energies and Atomic Energy Commission [CEA]; theInstitute of Energy Economics of Japan [IEEJ]; Japan Atomic Energy Agency [JAEA];
Energy Systems Catapult, UK; National Nuclear Laboratory [NNL], UK [NNL, n.d.]).

The overall suggested action is that for each of the seven cross-cutting SMR safety issues, a
relevant CSNI working or expert group be assigned to conduct a review and assessment of theissue (including understanding work underway, gaps and research needs) and generate a status
report for the CSNI. In some cases, it may be best to have one WG lead a joint assessment by
multiple WGs.

4.3. AOI #3: Experimental campaigns
Experimental campaigns are necessary to improve the understanding of important phenomena
affecting SMR safety and to form the basis for evaluation model development and assessment.
The EGSMR recognises conducting large-scale experiments for a variety of different SMR designconcepts is resource intensive and therefore proposes a series of activities aimed at prioritisingresearch resources towards phenomena with a high safety significance and low current
knowledge level. To this end, the EGSMR proposes conducting the following next steps:
1. determining knowledge gaps of the highest safety significance;
2. leveraging existing experimental data to address knowledge gaps;
3. identifying existing experimental facilities that may be suitable for addressing gaps;
4. recommending new experiments, for any remaining gaps, and providing guidance forthose experiments.

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AREAS OF INTEREST AND SUGGESTED ACTIONSAs mentioned earlier, for all AOIs the EGSMR recommends efforts into two parallel tracks:
1) WC-SMRs, and 2) AT-SMR, with further prioritisation to support technologies/designs closest
to deployment.

4.3.1. Determining knowledge gaps
To prioritise limited resources for experimental campaigns, the EGSMR recommends collecting
phenomena identification and ranking tables (PIRTs) for relevant WC-SMR and AT-SMR designs.
PIRTs are formulated with the purpose of identifying, for a specific design and event, thephenomena that have the most important influence on the consequences (USNRC, 2005). PIRTs
are routinely produced during the development of evaluation models for performing safety
analysis and the EGSMR plans to leverage the insights captured in existing PIRTs where possible.
First, the EGSMR will collect existing WC-SMR and AT-SMRs PIRTs (e.g. from internationalor national projects). Second, as needed, the EGSMR can co-ordinate with the CSNI to generate
further PIRTs for different SMR designs and events (e.g. design-basis accidents, anticipatedtransients, severe accidents), which would be led by a relevant working group. By examining
the near-term deployable SMR designs in concert with the PIRTs for the highest safetysignificant events, a relevant CSNI WG(s) can identify and prioritise those phenomena mostsignificant to SMR safety. An initial PIRT collection effort by the EGSMR is currently underway(see Section 4.6, and Annex E). PIRTs routinely categorise the knowledge level associated withthe phenomena (USNRC, 2005), but even if the PIRTs lack this information, the WGs can look to
relevant, historical experimental data to determine if the highly important phenomena havebeen well studied or if there are gaps in the experimental assessment.
The EGSMR would co-ordinate the grouping of different PIRTs with the WGs that willconduct the assessments. The culmination of these combined efforts would be to produce areport that summarises the phenomena with high safety significance and low knowledge level,
first for WC-SMRs and then for AT-SMRs. This will help to identify gaps that can be addressed
through future international efforts, including those within the CSNI.

4.3.2. Leveraging existing experimental data
In evaluating the PIRT insights, consideration will need to be given to both the importance of thephenomena and the current level of knowledge of those phenomena. The current knowledge isdictated by the existing body of experimental data. The EGSMR, therefore, recommends leveraging
existing experimental data that may be relevant to support SMR safety to address the identified
knowledge gaps.
The EGSMR recognises the effort of the Senior Expert Group on Preservation of Key
Experimental Datasets (SEGPD) to produce high-level guidance on best practices and strategies indata collection and preservation. As this guidance will be technology-neutral, it will be applicableto the collection of data pertaining to SMR safety. The guidance should be applied to the different
areas of safety-related experimental data such as fuel performance, thermal-hydraulics andcontainment (including, as appropriate, design-basis accidents, design extension conditions,severe accidents and long-term events). The SEGPD guidance will be valuable to collecting andmanaging data related to SMR safety in the future.
In addition to the organisation of future data collection, efforts must be made to collect andevaluate existing experimental databases, details of the test facilities, and scaling impacts. As afuture activity, the EGSMR (and/or other CSNI WGs) can correlate the documented data to thephenomena of interest (as identified in the collection of PIRTs).The review of existing data
should consider historical data sets collected for large-scale LWRs that may be applicable to
WC-SMRs and data from joint experimental programmes organised through the NEA. Examples
include data on containment behaviour, source term, etc. from projects such as Halden (NEA,
n.d. a), THEMIS (NEA, n.d. b), PANDA (PSI, n.d.), and HYMERES (NEA, n.d. c). Data should also be
available from experiments, prototypes and operations of non-light water-cooled reactor
technologies that could be applicable to AT-SMRs. Data suitable for the qualification of passive
systems and their reliability should be included. This data collection i) may include the recoveryof data from closed facilities (from their parent organisations or archives), ii) should document

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AREAS OF INTEREST AND SUGGESTED ACTIONS

the findings generated along with the raw data, and iii) may require furnishing databases tostore the information. There is also the potential to share existing data between different
organisations (OECD, IAEA, Euratom, etc.), which should be explored.
The EGSMR proposes that an effort be organised to collect these databases and document
the test facility details, including any known scaling distortions, and to correlate these existingdata sets with the previously identified, highly important phenomena. This will be an extensive
effort and will need commitment and resources from NEA members (and their associatedorganisations) to share data from databases they own, and support the data collection, as wellas conduct the documentation and correlation efforts.

4.3.3. Identifying existing facilities
The EGSMR has initiated an effort to collect preliminary information about participating
countries’ experimental facilities/capabilities (see Section 4.6 and Annex C). This initial effort
should be expanded to produce a report that provides a standardised set of information about
the countries’ experimental facilities. This information should include test facility descriptions,
testing capabilities and scaling information. The EGSMR can consult with the upcoming
WGAMA Specialists Workshop on Advanced Instrumentation and Measurement Techniques for
Nuclear Reactor Thermal Hydraulics and Severe Accidents (SWINTH; next meeting in 2024)
regarding current large facilities involved in NEA joint experimental projects and other facilities
with applications to SMR safety. The resulting report can be used in future efforts by the CSNI
to match knowledge gaps in high importance phenomena with existing facilities that are well
suited to study those phenomena, providing a list of key facilities to support SMR safety.

4.3.4. Recommending new experiments
Having identified the highly important phenomena, correlated those phenomena with existingdata sets and collected information about existing experimental capabilities, the EGSMR willpropose a path forward. This path will identify SMR safety research topics (including, as
appropriate, design-basis accidents, design extension conditions, severe accidents and longterm events) based on gaps in the existing data relative to the important phenomena and will
estimate the resources needed to close those gaps. In formulating this path forward, the EGSMR(supported by other CSNI working groups) will consider whether a single set of validation data
is sufficient to close any given gap, and if licensing a FOAK prototype within a conservative
operating envelope would be a viable option.
In this manner, the CSNI can push for new experimental campaigns to close knowledge/data
gaps, using both new and existing facilities, with a focus on the concerns and data needs forcode qualification/validation. This push should support both WC-SMR and AT-SMR designs andcan utilise NEA joint projects, CAPS (CSNI Activity Proposal Sheets) and dedicated efforts byworking groups to facilitate the efforts.
For existing facilities, the efforts in PIRT collection and facility identification can be leveraged
to correlate important phenomena gaps (from PIRTs) to current experimental facilities. This effort
can also highlight experimental gaps that may require new facilities or refurbishments to existing
facilities.
In order to support new experimental campaigns and new or refurbished facilities, the
EGSMR proposes that the CSNI develop guidance for those campaigns, which will support
validation activities for SMR safety. This guidance should include best practices for
instrumentation of full-scale experiments, demonstrator test facilities, or FOAK prototypes andassociated documentation requirements. The instrumentation should consider SMR safety
specific issues (e.g. passive safety systems, natural circulation). The documentation should
include information about the experiment/test-facility/FOAK-prototype (e.g. geometry, scaling,available conditions), and on the instrumentation used and measurement data collected(e.g. data channel descriptions, data format). This effort can borrow from the report on existing
facilities, as it will provide a partial platform for standardising test facility descriptions.

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4.4. AOI #4: Benchmarking for code V&V
Safety conclusions for new WC-SMRs and AT-SMRs will rely on safety analyses performed using
qualified evaluation models. These must be validated against relevant experimental data tocover important phenomena over the range of conditions encountered during risk significant
events, be they design-basis accidents, severe accidents or anticipated transients. In addition to
the recommended path forward of collecting the necessary experimental data to cover the mostimportant phenomena, as discussed in Section 4.3, the EGSMR also recommends efforts tofacilitate code validation, evaluation model development and benchmarking. These efforts
should prioritise design types and activities to ensure that targeted studies, focused on safetysignificant issues and with timely added value, can be implemented with the limited resourcesof the CSNI’s participating countries.
The EGSMR recommends reviewing and updating the CSNI code validation matrix to cover
the important safety phenomena for typical near-term deployable WC-SMR and AT-SMR
designs. In addition, the EGSMR recommends that the CSNI (via relevant WGs) prepare a
guidance report on V&V needs for code qualification, including:•Suggestions on a minimum set of validation cases to provide coverage of the full scope of
the key phenomena. Currently, AT-SMRs are relying on modelling and simulation morethan experimental tests compared to previous LWR development, so recommendations ondata needs and margins are important.

•

Reaching consensus and providing guidance on the reliance of integral effects testing
compared to separate effects testing. It may be that adequate qualification can beachieved with a heavier reliance on integral tests than separate effect tests.

•

Guidance on how many assessment cases constitute a sufficient validation basis for code
qualification. For example, a single high quality validation assessment case may besufficient to provide the necessary coverage for certain key phenomena. Validation caseresolution must be sufficient to ensure it is properly captured by the simulation code
system.

•Consideration of the recommended path forward on experimental data discussed in
Section 4.3.

An experienced systems analyst will understand that a code alone does not constitute anevaluation model appropriate for safety analysis. The evaluation model also incorporates
modelling practices, such as nodalisation choices, that are required to achieve the necessary
degree of accuracy. Favourable comparisons of the code results to experimental data are
insufficient alone to qualify an evaluation model. The modelling practices required to achievethat agreement must be part of the evaluation model. Therefore, the EGSMR recognises theimportance of not only reviewing the agreement between codes and experimental results, butalso understands the importance of best modelling practices. The EGSMR recommends
capturing the important modelling practices that are discovered through the benchmarking
process, including the development of best practice guidelines for modelling and simulation.
International standard problems and other cross-walk comparisons are an ideal platform
for developing and disseminating best modelling practices. In these kinds of international
activities, participating nations perform calculations or validation assessments using their own
codes and methods and the results are compared between the participants. Those approaches
yielding the most accurate results can be captured in these cross-walks and shared as findingsin the final reports.
Models and documentation from benchmarking activities or even standard problems for
WC-SMRs and AT-SMRs could be saved and shared by the NEA through technology-specificvirtual test beds. In these test beds, the participants of each country can share their codes, input
decks, models and documentation. This forum would allow for easier sharing of successfulmodelling practices and other lessons learnt.

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AREAS OF INTEREST AND SUGGESTED ACTIONSThe EGSMR recommends that the CSNI take a stance and encourage these benchmarking
activities as part of joint projects and in working groups. Specifically, the EGSMR recommends
that the CSNI:•

Create WC-SMR and AT-SMR validation matrices for near-term deployable technologies,
and, as applicable, reference aggregated test facility information and experimental
databases.

•

Organise participating countries’ efforts to validate existing analysis codes against key
phenomena based on existing data or potential future experiments in existing facilities.

•

Develop technology-specific virtual test beds to facilitate sharing code decks, evaluation
models and best modelling practices.

•

Encourage benchmarking of passive safety systems, like the PERSEO test and cross-walk(NEA, 2021b) (NEA, 2021c), and encourage assessment of modern capabilities(e.g. computational fluid dynamics, CFD) for passive systems.

•

Provide guidance and criteria for benchmarking activities such as cross-walks andinternational standard problems. This guidance should include how to document lessons
learnt, especially in terms of best modelling practices.

•

Maintain cognisance of ongoing international benchmarks through other fora (e.g. IAEA,
Euratom, GIF) and review this work to avoid redundant efforts.

The EGSMR’s recommendations are intended to facilitate the assessment and qualificationof SMR evaluation models so these can be used by designers and regulators alike to determine
safety findings for the proposed near-term deployable designs.

4.5. Conclusion and key suggested actions
The detailed AOIs and suggested actions were reviewed and initial key actions were prioritised
based on their safety significance and relevance to the CSNI mandate. The EGSMR presents thefollowing key suggested actions for the CSNI:•

Gather SMR PIRTs to identify unique SMR safety phenomena and prioritise future efforts(discussed in Section 4.3.1 and 4.6).

•

Start working on the high-priority cross-cutting issues (identified in Section 4.2).

•

Engage in V&V activities (detailed in Section 4.4) including:•–

Reviewing and updating the CSNI code validation matrix for SMR safety.

–

Producing a guidance report on V&V needs for code qualification.

Initiate new efforts or promote ongoing efforts to collect and generate experimental data
through joint projects to support SMR safety (detailed in Section 4.4).

Within the EGSMR efforts, new areas have been identified that warrant further studies by
the CSNI to support SMR safety, such as:•

The impact of “external” events from associated processes on safety.

•

Materials concerns for AT-SMRs.

These initial key suggested actions, as well as all the suggested actions discussed in detailin Sections 4.1 to 4.4, and the areas for further study can be addressed through a combinationof efforts by the EGSMR and relevant CSNI working groups/expert groups, and co-ordination
with other NEA and external organisations.

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AREAS OF INTEREST AND SUGGESTED ACTIONS

4.6. EGSMR information collection
In support of the AOIs and suggested actions discussed in the earlier sections, the EGSMR has
embarked on information collection efforts to help set a foundation for future efforts in SMR
safety. These were conducted through surveys of the EGSMR participants, which comprise asignificant portion of the NEA member countries and include many of the countries actively
deploying or expressing interest in deploying SMRs. It should be noted that these informationcollection efforts, while yielding good results, are by no means exhaustive and are meant as abasis to jump start future dedicated information collection and tracking efforts related to SMR
safety. The information collections have the following focus (the results are presented in
Annexes to this report):•

Experimental facilities to support SMR safety research (discussed in Section 4.3.3),
working from a baseline of previous NEA efforts (NEA, 2021d) (NEA, 2016b); presented in
Annex C.

•

National and multi-national projects related to SMR safety, and relevant projects
underway at international organisations (Euratom, IAEA and GIF); presented in Annex D.

•

PIRTs related to SMR safety (discussed in Section 4.3.1); presented in Annex E.

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EGSMR FUTURE EFFORTS

Chapter 5. EGSMR future efforts

The mandate of the Expert Group on Small Modular Reactors (EGSMR) from the Committee on
the Safety of Nuclear Installations (CSNI) identifies specific outputs, including:•Summarising the assessment of CSNI activities of relevance to small modular reactors(SMRs) with a high technology-readiness level (TRL) that are anticipated to see near-term
deployment.

•

Providing a prioritised ranking of the safety knowledge gaps and recommendations toaddress the gaps, with a focus on safety issues that cross a number of designs.

•

Identifying any new technical areas the CSNI needs to develop, the experimental
programmes that are required and some of the key facilities.

•

Considering what is being done in other international organisations (e.g. the International
Atomic Energy Agency, IAEA).

This technical opinion paper details the areas of importance (AOIs) for SMR safety, presentssuggested actions for the CSNI to address them, and provides initial summaries of experimental
facilities and projects related to SMR safety. Therefore, this effort addresses the mandated
EGSMR outputs directly or suggests specific actions to complete them through future efforts ofthe EGSMR and/or other relevant CSNI working/expert groups.
The AOIs and suggested actions identified by the EGSMR must be followed up with further
efforts to complete these actions and produce the desired outcomes in order to ensure the CSNI
is able to properly support safe SMR deployment. These suggested actions, described in Chapter 4,
are in some cases best accomplished directly by the EGSMR, and in others are more suitably led
by standing CSNI working/expert groups. The suggested actions need support to be initiated andstood up as activities to accomplish the desired objectives. Given that the EGSMR has relevant
background knowledge and directly formulated these suggested actions, it is logical for it toprovide such support. Thus, the EGSMR’s future efforts would be conducting activities toaccomplish the suggested actions assigned to the EGSMR and providing support to the other CSNI
working/expert groups in the initiation of activities to accomplish suggested actions relevant totheir specific areas of expertise. To facilitate this support of other WG/EGs in the organisation andlaunching of initiatives, specific EGSMR participant(s) will champion each of the recommended
actions. These action champions will provide background information and resources to therelevant CSNI working/expert groups to help initiate activities.
Part of the current EGSMR mandate is to assist in co-ordinating CSNI efforts related to SMR
safety, including supporting information exchange between CSNI participating organisations/countries as well as interactions with the SMR-related activities of other NEA committees andexternal international organisations to avoid duplication and promote complementary efforts.
It is envisaged that the EGSMR would support the CSNI Programme Review Group (PRG) to follow
the progress and outcomes of the various CSNI efforts regarding SMR safety and provide
reporting back to the CSNI (and possibly the Committee on Nuclear Regulatory Activities, CNRA).
In addition, the EGSMR would provide a forum for the exchange of information on SMR safety
from internal (CSNI, CNRA) and external (International Atomic Energy Agency, Generation IV
International Forum, Euratom) efforts. These could take the form of a “SMR Safety Review” event
organised periodically by the EGSMR to discuss the progress on SMR safety-related activities
both inside and outside the CSNI.
Therefore, the EGSMR’s proposed future efforts are two-pronged: i) conducting/supporting
activities to follow through on the suggested actions, and ii) supporting the co-ordination of CSNI
efforts in the area of SMR safety and interacting with internal NEA and external internationalorganisations conducting similar pursuits.

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CONCLUSIONS

Conclusions

The Nuclear Energy Agency (NEA) Committee on the Safety of Nuclear Installations (CSNI) formed
the Expert Group on Small Modular Reactors (EGSMR) at the end of 2021 to ensure its capabilities
to support the safety of SMRs. Throughout 2022 and into 2023, the EGSMR conducted anassessment process to evaluate the SMR safety landscape. This included: i) collecting information
related to SMR safety and deployment in participating countries (results presented in Chapter 3),ii) determining areas of interest (AOIs) related to SMR safety (Chapter 4), and iii) suggesting actions
for the CSNI to address these areas and support safe SMR deployment (Sections 4.1 to 4.5).
In addition, the EGSMR began information collection efforts (Section 4.6) focused on experimental
facilities, projects, and phenomena identification and ranking tables (PIRTs) related to SMR safety
through surveys of the EGSMR participating countries and international organisations(International Atomic Energy Agency, Generation IV International Forum, Euratom) also working
to support safe deployment and operation of SMRs.
The suggested actions (presented in Sections 4.1 to 4.5) require follow-on efforts by CSNI
working and expert groups to produce the desired outcomes. It is suggested that some of these
activities be conducted directly by the EGSMR, while others are better suited to be executed by
one or more of the other standing CSNI working or expert groups whose areas of focus are
relevant to the specific actions (a lead group will be identified for co-ordinated efforts).
Following a CSNI request to the group to assist in co-ordinating CSNI efforts in the area of SMR
safety, the EGSMR will consider revising and expanding the group mandate in order to ensure that
future activities of the group are captured in a way that is consistent with CSNI expectations.
It will propose a draft mandate for approval by the CSNI.
The EGSMR proposes to define its future role by co-ordinating CSNI efforts in the area of SMR
safety (presented in Chapter 5). This can include interacting with both internal NEA and externalinternational organisations also supporting SMR safety, providing a forum (e.g. an “SMR Activities
Review” event) to exchange information on these internal and external efforts, and then informing
the CSNI about progress and providing advice on future priority activities. Such information
sharing makes it possible to co-ordinate efforts and promote complementary efforts.
The EGSMR, in addition to conducting its own activities, could provide support to the other
CSNI groups to initiate and organise activities to address the suggested actions. The support could
be facilitated by EGSMR participants assigned to be “action champions”, which would see themproviding background information and insight on the suggested actions as well as resources toassist in getting associated activities up and running. The activities could take the form of internal
working or expert group efforts, co-ordinated task force initiatives between multiple working/expert groups, CAPS, or NEA joint projects.
The suggested CSNI actions and associated efforts will allow the CSNI to properly support
and advance the scientific and technical knowledge base needed for the safe deployment of
SMRs as part of the portfolio of nuclear energy installations.

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REFERENCES

References

IAEA (n.d.), “Small Modular Reactor (SMR) Forum”, web page (last consulted in July 2023), IAEA,
Vienna, www.iaea.org/topics/small-modular-reactors/smr-regulators-forum.
IAEA (2022), “IAEA Initiative Sets Ambitious Goals to Support the Safe and Secure Deploymentof SMRs”, web page (last consulted in July 2023), IAEA, Vienna, www.iaea.org/newscenter/news/iaea-initiative-sets-ambitious-goals-to-support-the-safe-and-secure-deployment-ofsmrs.
IAEA (2017), Cooperative Research Project (CRP-I31029): Development of Approaches, Methodologies andCriteria for Determining the Technical Basis for Emergency Planning Zone for Small Modular Reactor
Deployment, IAEA, Vienna, www.iaea.org/projects/crp/i31029.
IAEA (2016), Safety of Nuclear Power Plants: Design, IAEA Safety Standards Series No. SSR-2/1(Rev. 1), IAEA, Vienna, www-pub.iaea.org/MTCD/Publications/PDF/Pub1715web-46541668.pdf.
IAEA (2005), Assessment of Defence in Depth for Nuclear Power Plants, Safety Reports Series No. 46,
IAEA, Vienna, www-pub.iaea.org/MTCD/Publications/PDF/Pub1218_web.pdf.
NEA (n.d. a), “Halden Reactor Project – Fuels and Materials”, web page (last consulted in July2023), NEA, www.oecd-nea.org/jcms/pl_24970/halden-reactor-project-fuels-and-material.
NEA (n.d. b), “THAI Experiments on Mitigation measures, and source term issues to support
analysis and further Improvement of Severe accident management measures (THEMIS)
Project”, web page (last consulted in July 2023), NEA, www.oecd-nea.org/jcms/pl_58863.
NEA (n.d. c), “Hydrogen Mitigation Experiments for Reactor Safety (HYMERES) Project”, web page
(last consulted in July 2023), NEA, www.oecd-nea.org/jcms/pl_24982/hydrogen-mitigationexperiments-for-reactor-safety-hymeres-project.
NEA (2021a), Small Modular Reactors: Challenges and Opportunities, OECD Publishing, Paris,
www.oecd-nea.org/jcms/pl_57979.
NEA (2021b), Status Report on Reliability of Thermal-Hydraulic Passive Systems (Addendum: PERSEO
Benchmark Report), NEA/CSNI/R(2021b)2, OECD Publishing, Paris.
NEA (2021c), WGAMA PERSEO Benchmark Results Report, NEA/CSNI/R(2021c)2/ADD, OECD Publishing,Paris.
NEA (2021d), Nuclear Safety Research Support Facilities for Existing and Advanced Reactors: 2021
Update, OECD Publishing, Paris, www.oecd-nea.org/jcms/pl_60542.
NEA (2017), A State-of-the-Art Report on Scaling in System Thermal-hydraulics Applications to Nuclear
Reactor Safety and Design, OECD Publishing, Paris, www.oecd-nea.org/jcms/pl_19744.
NEA (2016), Implementation of Defence in Depth at Nuclear Power Plants, OECD Publishing, Paris,
www.oecd-nea.org/jcms/pl_14950.
Shibata, T. et al. (2022), “Present status of JAEA’s R&D toward HTGR deployment”, Nuclear
Engineering and Design, Vol. 398, Article ID 111964, Elsevier, Amsterdam, https://doi.org/
10.1016/j.nucengdes.2022.111964.

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ANNEX A

Annex A. First questionnaire on SMR deployment
and research status

The initial information collection effort by means of the EGSMR’s first questionnaire sought tounderstand the “Current Status of SMR Deployment/Research” in the participating countries
and organisations. The information gathered included:•

The specific definition of SMR used in the organisation/country.

•

The SMR deployment landscape such as designs planned/constructed/operating,technological readiness levels (TRL) for the proposed technologies, and major knowledge
gaps.

•

Specific SMR technologies of interest (high TRL and near-term deployment).

•

Important safety impacts of SMRs based on: application of the SMR, the operating
location, or the potential for multi-module configurations.

•

Planned research activities related to SMR safety (including international efforts) and theavailability of experimental facilities/data to support code validation to benefit SMR
safety.

•The knowledge base needed for SMRs including:–Applicability of current knowledge base and required extensions to support thesafety of water-cooled SMR designs.

–

Extent of the knowledge base needed to support confidence in the safety case ofnovel/advanced (non-water-cooled) SMRs.

–

SMR issues/topics requiring specific attention (or which are potentially lessimportant) compared to the safety cases of conventional currently operating designs.

•

Balancing analysis accuracy with the urgency for deployment.

•

Valuable areas for CSNI to contribute to SMR safety to support deployment.

The above areas not only yielded information on activities in the individual countries, butalso identified parallel international efforts related to SMR safety under the IAEA, Euratom, andGIF.

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ANNEX B

Annex B. CSNI and CNRA working and expert groups

The list of CSNI working and expert groups is provided below:•

Working Group on Risk (WGRISK)•Working Group on Analysis and Management of Accidents (WGAMA)•

Working Group on Fuel Safety (WGFS)•

Working Group on Human and Organisational Factors (WGHOF)•

Working Group on Integrity and Ageing of Components and Structures (WGIAGE)•

Working Group on Fuel Cycle Safety (WGFCS)•Working Group on External Events (WGEV)•Working Group on Electrical Power Systems (WGELEC)•

Senior Expert Group on Preservation of Key Experimental Datasets (SEGPD)•

Expert Group on Small Modular Reactors (EGSMR)

The list of CNRA working and expert groups is provided below:•

Working Group on Policy and Licensing (WGPL)•

Working Group on New Technology (WGNT)•Working Group on Supply Chain (WGSUP)•

Working Group on Leadership and Safety Culture (WGLSC)•

Working Group on Reactor Oversight (WGRO)•

Expert Group on Operating Experience (EGOE)

Many of the suggested actions presented by the EGSMR connect to one or more of the CSNI
and/or CNRA working/expert groups mentioned above. The EGSMR, through the suggested
action champions, will be supporting the initiation of activities in these groups to address them.

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ANNEX C

Annex C. Experimental facilities related to SMR safety

Provided below are the results of the EGSMR information collection effort on SMR safety-related
experimental facilities. The responses are provided in alphabetical order and include
contributions from the following:•

16 organisations (ANVS, CEA, CNL, CIEMAT, ENEA, GRS, IKE, IRSN, JAEA, KAERI, PSI,SEABORG, SIET, SSM, Tractebel, USNRC)

from•

12 countries (Belgium, Denmark, France, Germany, Italy, Japan, Netherlands, Korea,
Spain, Sweden, Switzerland and the United States)

The collection herein builds on previous NEA facility collection efforts described in thefollowing NEA reports:•

NEA (2021), Nuclear Safety Research, Support Facilities for Existing and Advanced Reactors: 2021
Update, OECD Publishing, Paris, www.oecd-nea.org/jcms/pl_60542.

•

NEA (2017), A State-of-the-Art Report on Scaling in System Thermal-hydraulics Applications to
Nuclear Reactor Safety and Design, OECD Publishing, Paris, www.oecd-nea.org/jcms/pl_19744.

For the sake of clarity, the test facilities were sorted according to technologies (WC-SMRs and
AT-SMRs) and countries (both in an alphabetical order). The list includes information on test
facilities specifically for SMRs, and test facilities originally designed for other reactors, research
reactors and/or hot cells, in which certain SMR safety-related phenomena can be investigated.
Some of these facilities are designed for LWR safety support so the applications to SMRs may
be limited, though potentially impactful for WC-SMRs. Many of these experimental activities are
devoted to developing/designing high (CFD-grade) resolution set-ups or material investigations.
Three tables are presented: i) SMR safety-related experimental facilities for WC-SMRs, ii) SMR
safety-related experimental facilities for AT-SMRs, and iii) information on experimental facilities,
in which SMR issues can be investigated in principle. In addition, selected literature references (ifprovided) are included after each table.

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ANNEX C

Table C.1. SMR safety-related experimental facilities for WC-SMRs
Facility nameSTATUSCAPCN(High Pressure Natural
Convection Loop)

Operator

Type of SMR(s)covered

INVAP for CNEA

CAREM

CAPCN is used to verify dynamic thermal-hydraulic response andcritical heat flux for the CAREM nuclear power plant byproducing validation data for modelling codes covering the
CAREM operating states. CAPCN replicates the CAREM primaryloop and the boundary conditions for the steam generator.
Operational parameters are reproduced approximately for
intensive magnitudes (pressures, temperatures, void fractions,
heat flux, etc.) and scaled for extensive magnitudes (flow,
heating power, size, etc.), while height is 1:1. The CAPCN primaryloop (150 bar: 340°C) can operate in saturated (self-pressurised),or subcooled (dome pressure increased by nitrogen injection)
regime, with heating power up to 300 kW and different hydraulicresistance. The secondary side is 60 bar 340°C (Boado, 1998;
Delmastro, 2018).

CNL/Atomic
Energy of Canada
Limited (AECL)

WC-SMR

Study direct reactor auxiliary cooling systems (DRACS) and reactor
cavity cooling systems (RCCS). In particular, behaviour of couplednatural circulation loops and instability modes that may beevident. Potential extension to study ICS behaviour.

CNL/AECL

iPWR and small
BWR

The SCCA is a rectangular vessel (3.66 m tall) with one heatedwall and one chilled wall, as well as steam, helium and aerosol
injection capability. It is designed to study aerosol transport
behaviour and gas mixing phenomena (including thermal
stratification and strong steam condensation against a cooled
surface; i.e. a vertical wall, ceiling, or passive containment
cooling system). The SCCA also simulates radionuclide transport
in water-cooled SMR containments, with large windows
enabling detailed optical particle measurements. Initial
experiments for iPWR containment configuration and concepts
are being explored for modifications to represent small BWR
containment volumes.

LUT University

Several SMR

Investigation of heat exchanger performance and crossflow(Sanchez-Espinoza, 2021; Sanchez-Espinoza, 2022)

OPERATING

Coupled Loop Passive
Safety Facility (CPSF)
DESIGNEDSCCAiPWR – OPERATING
BWR – IN MODIFICATIONMotel
OPERATING

Brief description of facility and test programme

power: < 1 MW
pressure: < 2.5 MPaloop height: 8.8 m
test section height: 3.7 m

ALCINA (NAtural
CIrculation AnaLysis)
OPERATING
EVEREST
IN CONSTRUCTION
KoKoMo(COndensation in a
Containment MOdel
facility)

IRSN (Institut deRadioprotection
et de Sureté
Nucléaire)

Several SMR

Thermal-hydraulic loop dedicated to the analysis of parameters
influencing the natural two-phase circulation and the evaluationof the pressure drops.

CEA (no data
available)iSMR

SMR Nuward, dedicated to Safety Condenser.

IRSN

Several SMR

Containment cooled by a condensation wall dedicated to thestudy of convective flow and effects of coupled condensationstratification.

OPERATING

46

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ANNEX C

Table C.1. SMR safety-related experimental facilities for WC-SMRs (cont’d)
Facility nameSTATUSPASTISIN CONSTRUCTIONATHOSOPERATINGCOSMOS-H
OPERATING

Type of SMR(s)covered

Brief description of facility and test programme

IRSN (no data
available)

PWR and iSMR

Dedicated to Safety Condenser.

Universität
Stuttgart IKE(Institut für
Kernenergetik
undEnergiesysteme)

iPWR in general

Passive cooling of large water pools (SMR water wall) to avoid
evaporation (Krüssenberg et al., 2019; Grass et al., 2022).

Karlsruhe
Institute ofTechnology (KIT)

iPWR(e.g. CAREM,NUWARD,
NuScale and
SMART)

Operator(access toselected data formembers of the
McSafer usergroup)

pressure: ambient
no. tubes: < 2 x 9height/diameter: 10 m/0.032 m
Designed for investigation of boiling phenomena (e.g. boiling
crisis) and complex flow regimes, e.g. in FA test bundles fordevelopment and validation of high-performance, advanced
analytical methods for the safety evaluation of generic SMRs
(Sanchez-Espinoza, 2021; Sanchez-Espinoza, 2022)
power: < 2 MWpressure: 5 – 17 MPaheight/diameter: 3.5 m/0.08 m
no. heated rods / tubes: 1-5

THAI+(Thermal-hydraulic,
Aerosol, Iodine) – SMR
containment test section
OPERATING

BeckerTechnologies

iPWR in general(free access forGerman project
partners, forinternational
partners via GRS)

Heat transfer at containment inner walls at presence of noncondensables, heat transfer at the other containment wall towater pools at high Ra numbers
power: < 1 MW
pressure: < 2 MPaheight: 9 m
Ra: < 1015

ELSMOR
STAND BYELSMOR
consortium

iPWR

Tests of an Emergency Heat Removal System (EHRS) based on anatural circulation loop including a type‐plate heat exchanger(as SG) and an in‐Pool heat exchanger with vertical tubes.
Scaling: 1/50-power, 1/1 height to the E‐SMR.

NuScale SGFIV

NuScale PowerOPERATING(proprietary data)

NuScale TF2

NuScale PowerOPERATING(proprietary data)

SIET

NuScale PowerVOYGR

Investigate modal frequencies and flow induced vibration of
VOYGR steam generator. Full scale (reduced tube banks).

NuScale PowerVOYGR

Investigate heat transfer and density wave oscillations (DWO) of
VOYGR steam generator. Full scale (reduced tube banks).

ENEA

iSMR

PERSEO (not SMR) and ELSMOR (SMR), dedicated to Safety
Condenser.

Hitachi-GE
Nuclear Energy

BWRX-300

One of world’s largest test facilities owned by plant
manufactures. HUSTLE was used to evaluate detailed two-phaseflow behaviour around fuel of BWR temperature and pressure
conditions and characteristics of in-core components of BWR(Ishihama et al., 2013; Katono et al., 2015; Marquino et al., 2014;
Nishi-da et al., 1994; Takahashi et al., 2013).

CLOSEDHUSTLE(Hitachi Utility Steam
Test LEading facility)
OPERATING(part of test data
is public via
papers)Apply the scaling methodology in some experiments.

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ANNEX C

Table C.1. SMR safety-related experimental facilities for WC-SMRs (cont’d)
Facility nameSTATUSEOS (Establishment of
Safety) loop
OPERATING

SF6 (sulfar hexafluoride) ethanol test
facility

Operator

Type of SMR(s)coveredMHI

PWR

EOS loop provides a model with full height but reduced power
and volume of PWR to simulate high pressure and temperature
conditions of primary and secondary systems for PWR.

PWR

Visualise gas-liquid two-phase flow under low temperature andpressure conditions using alternative fluid against PWR underhigh temperature and pressure conditions.

(part of test data
is public via
papers)MHI

Brief description of facility and test programme

OPERATING(part of test data
is public via
papers)FESTA (ITF)

KAERI

iPWR

FESTA (otherwise known as SMART-ITL) supports the SMART
design (110 MWe) and is used to investigate integral thermalhydraulic characteristics during major design-basis accidents, tovalidate the simulation capability of safety analysis codes, andthe system performance of SMART-specific design features.
Scaling = 1:1 height, 1:7 diameter and 1:49 volume of SMART.

KAERI

iPWR

FINCLS supports the SMART and is used to investigate singleand two-phase natural circulation phenomena in SMART and tovalidate the simulation capability of safety analysis codes.

OPERATINGFINCLS(SETF) OPERATING

Scaling: 1:1 height and 1:750 volume of SMART.
SISTA-2 (SETF)

KAERI

iPWR

OPERATINGSISTA-2 supports the SMART. It has 1/1-height and 1/750volume of SMART and is used to validate TH characteristics of
SMART CPRSS design and to simulate its long-term cooling
performance.
Scaling: 1:1 height and 1:750 volume of SMART.

VISTA-ITL

KAERI

SMART

Scaling: 1:2.77 length scale; 1:473 area scale; 1:1310 volume
scale; 1:1.664 time scale; 1:2.77 pressure drop.

OPERATING

HWAT

KTH

UNDER UPGRADE(access toselected data formembers of the
McSafer usergroup)

ATR(Advanced Test Reactor)

Idaho National
Laboratory

OPERATING

48

Passive residual heat removal sys-tem (NEA, 2020; Park, 2023).

iPWR, BWR

Transient heat transfer in natural circulation (transition fromforced to natural circulation) including Departure from nucleateboiling (DNB) and CHF in conditions typical for LWR SMRs.
Measurement of flow local parameters including void fraction.
Representative for SMRs height, heat fluxes, pressure andtemperatures.

SMR

At 250 MW, the ATR is the world’s largest, most powerful andversatile test reactor. Its unique design and thermal spectrum
capabilities serve a wide range of vital missions for the
Department of Energy’s Office of Nuclear Energy, the US Navy,
universities in the United States and overseas, as well as for the
nuclear industry. ATR’s distinctive cloverleaf core design createsnine high flux traps, six of which currently have independently
controlled pressurised loops that allow irradiations to occur
using different coolant types under a wide range of prototypic
conditions. In addition to the 9 flux traps, 66 other test locations
can accommodate drop-in capsule tests, and work is under way
to add two additional pressurised loops in the next few years.

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ANNEX C

Table C.1. SMR safety-related experimental facilities for WC-SMRs (cont’d)
Facility nameSTATUSISTOPERATING

MARBLEOPERATINGMASLWR/NIST(MASLWR = MultiApplication Small Light
Water Reactor;
NIST = NuScale Integral
System Test)

Type of SMR(s)covered

Brief description of facility and test programmeCentre forAdvancedEngineering andResearch (CAER)

SMR

Passive residual heat removal system (NEA, 2020)

University ofMichigan – Ann
Arbor

WC-SMR

8x8 water/air bundle with gamma tomography for highresolution two-phase distributions.

Oregon State
University (OSU)

iPWR

MASLWR was an integral systems thermal-hydraulic testing
facility at OSU and included a scaled-down reactor primarysystem, containment, cooling pool, and the secondary system
venting to atmosphere. It was designed as a proof-of-concept
system for natural circulation driven reactors.

Operator

Scaling: 1:1 length scale, volume and mass flow rates are scaledwith power(selected test
data is public via
books, papers)

In 2008, MASLWR was modified into NIST, which is a 1:3 height,
1/254 volume, 1:1 time scaled, electrically heated (rods), fullpressure and temperature (1 650 psia, 610°F), NuScale reactor
model. It also consists of a primary reactor system, containment,cooling pool, and pressurised secondary system. NIST is
designed to produce experimental data in support of verificationand validation of thermal-hydraulic codes for safety andoperational analyses. It can perform loss-of-coolant accident,
flow stability, long-term cooling, decay heat removal system,and separate effect tests.

OPERATING

PUMA

Purdue(Purdue University
Multi-dimensional Test
Assembly)(selected test
data is public via
books, papers)

WC-SMROPERATING

PUMA is a scaled replica of an Advanced Boiling Water Reactor(ABWR) which uses an electric heated core simulator. It isequipped with 400 advanced instruments. PUMA is unique inthat it is designed so that the facility can be used to simulate
other advanced light water reactors, including LWR-based SMRs
(Kim, 2017)
Scaling: 1:400 volume scale, 1:4 height scale.

RBHT

Penn State

WC-SMR

The test section consists of a 7x7 array of simulated fuel rods thatare 9.5 mm outer diameter x 3.66 m long with a pitch spacing of
12.6 mm. These rod dimensions are prototypical of a commercial
PWR fuel rod assembly. Power for the rods is provided by a
750 kW DC power supply. The facility is capable of operatingfrom 137-412 kPa, with rod temperatures up to 1 204°C. Reflood
water can be delivered at constant or oscillatory rates up to
20.3 cm/s and up to 127°C.

Idaho National
Laboratory

various SMR

The Transient Reactor Test Facility uses uranium oxide dispersed
in graphite blocks to yield a core that affords strong negative
temperature feedback. Automatically controlled, fast-acting
transient control rods enable TREAT to safely perform extreme
power manoeuvres – ranging from prompt bursts to longer
power ramps – to broadly support research on postulated
accidents for many reactor types.

University ofMichigan – Ann
Arbor

iPWR

Helical coil facility for two-phase flow behaviour in a helical coiltube (with very high resolution instrumentation). It is water/air,but the instrumentation (high-speed X-ray) would work also forwater/steam at high pressure.

(Rod Bundle Heat
Transfer test facility)
OPERATING

TREAT(Transient Reactor Test
Facility)
OPERATING

UM Helical Coil Facility
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ANNEX C

Table C.1. SMR safety-related experimental facilities for WC-SMRs (cont’d)
Facility nameSTATUSUIUC MTDL(Multiphase Thermofluid Dynamics
Laboratory)

Operator
University of
Illinois – Urbana
Champaign(UIUC)

Type of SMR(s)covered
WC-SMROPERATING

Brief description of facility and test programme
The MTDL Loop is a closed steam-water loop (pressure under
0.1-1 MPa) capable of capturing various two-phase phenomena.
The phasic density ratio changes by one order of magnitude
over the pressure range allowing the flexibility to highlight or
suppress low pressure phenomena such as flashing. A wide flowrate range (1-20 GPM) is available, driven by natural circulationor forced convection.
The modular test section is 5 m in height with previous
experiments using a 3 m internally heated annulus followed by a
2 m adiabatic chimney. The channels are 1.5” outer diameter andcan contain a 0.75” or 1” diameter heater rod (up to 54 kW; uniform
heat flux up to 300 kW/m2). Instrumentation measures flow rate,pressure, temperature and two-phase parameters including radial
profile. Transparent view ports allow for high-speed visualisation,and steady-state and periodic flows can be captured withdedicated techniques. Data has been generated for phenomena(boiling, flashing, condensation, and flow area transition) andsystematic dynamics (single-phase natural circulation, two-phasenatural circulation, and flashing instability), which has supported
modelling, validation, and general experimental investigation.

UM Post-CHF Facility
OPERATING
UWM-HPCHF(University of
Wisconsin, Madison
Thermal Hydraulics
Laboratory; THL)

University ofMichigan – Ann
Arbor

iPWR

75 bar water/steam facility for high resolution measurements of
two-phase flows from bubbly flow regimes all the way to postCHF flow regimes.

University of
Wisconsin

iPWR

The CHF test facility is comprised of two interconnected loops. The
low pressure loop is for Departure from nucleate boiling (DNB) and
LOCA experiments in an annular flow channel geometry underatmospheric conditions with high-speed flow visualisation and a
direct heated test section (40 cm in length). The high pressure loop
allows DNB experiments under PWR and BWR prototypicalconditions of temperature, pressure, and heat flux profiles (i.e.
cosine shape); it is indirectly heated and can accommodate fulllength fuel pins. Experiments can be conducted for an annular
flow channel with a single simulated pin (140 kW max power) or a4 x 4 bundle (560 kW max power; 140 kW each). This loop is also
capable of performing heat transfer experiments with supercriticalwater up to 25 MPa and 500°C. Fibre-Optic Distributed
Temperature Sensors (FO-DTS) provide high-spatial and hightemporal resolution wall temperature measurements throughout
the simulated fuel pin length detailing the DNB phenomenon Thisis valuable in the assessment of CHF location, peak cladding
temperature, post-CHF heat transfer, rewetting characteristics,
quenching etc. THL also has X-ray imaging to analyse simulated
fuel pin integrity before/after testing to assess any damage to therod (due to high temperatures during DNB).

Sandia National
Laboratories

Applicable toboth WC- andAT-SMRsVQSEC in New Mexico is a unique group of experimental andcomputational capabilities that create and/or simulate a broad
range of extreme operational or abnormal environments. The
facilities are secure and remote, and are routinely used toperform tests with energetic and hazardous materials including:

OPERATING

VQSEC(Validation andQualification Sciences
Experimental Complex)
OPERATING

50- detonation of large explosive charges- high velocity, high gas or rocket-assisted mechanical events- high heat flux fire tests, across a spectrum of fuel types.

RESEARCH RECOMMENDATIONS TO SUPPORT THE SAFE DEPLOYMENT OF SMALL MODULAR REACTORS, NEA No. 7660, © OECD 2023

ANNEX C

References for SMR Safety-related experimental facilities for WC-SMRs:
Boado, H.J. et al. (1998), Carem project: 1995 Status of Engineering and Development, IAEA-TECDOC-999,
1 February 1998.
Delmastro, D. (2018), Design and Technology Development of CAREM for Near-Term deployment, andthe Status of the construction of CAREM25 prototype, First Meeting of the Technical Working
Group for Small Modular Reactors (TWG-SMR), April 2018, Vienna.
Grass, C. et al. (2022), Experimental Investigation on Atmospheric Passive Spent-Fuel Pool Cooling by
Two-Phase Closed Thermosyphons, Proceedings of the NURETH 19, virtual meeting, 6-11 March
2022.
Ishihama, K. et al. (2013), “Development of a Plate Heat Exchanger for High-Temperature andHigh-Pressure”, Proceedings of the ASME 2013 Power Conference, POWER2013-98061, Boston,
29 July to 1 August 2013.
Katono, K. et al. (2015), “Three-Dimensional Time-Averaged Void Fraction Distribution
Measurement Technique for BWR Thermal Hydraulic Conditions Using an X-ray CT system”,
Journal of Nuclear Science and Technology, Vol. 52 (3), pp. 388-395, https://doi.org/10.1080/
00223131.2014.952699.
Kim, S., Ishii, M. (2017), Purdue University Thermal Hydraulic Experiment Facility – LWR & SMR Group,
Nuclear Thermal-hydraulics Capabilities Workshop, 13 July 2017, Idaho Falls.
Krüssenberg, A. et al. (2019), Passive Lagerbeckenkühlung durch Wärmerohre - Verbesserung und
Validierung numerischer Modelle, Report GRS-564, September 2019.
Marquino, W. et al. (2014), “Analysis of HUSTLE test data and ESBWR application”, Proceedings of2014 International Congress on Advances in Nuclear Power Plants (ICAPP 2014), 6-9 April 2014,
Charlotte.
NEA (2020), Status Report on Reliability of Thermal-Hydraulic Passive Systems, Draft – rev. 12, Status
31 July 2020.
Nishida, K. et al. (1994), “Spacer Effect on Liquid Film Flow and Critical Power in BWR Fuel
Bundles”, Journal of Nuclear Science and Technology, Vol. 31 (3), pp. 213-221.
Park, H.-S. (2023), Korean SMART Design and Its Technical, EG-SMR Meeting, 27 March 2023,
Copenhagen.
Sanchez-Espinoza, V.H. et al. (2022), The H2020 McSafer Project, ETSON conference 2022: TSO
Challenges for SMR Topics, 12 October 2022, Garching.
Sanchez-Espinoza, V.H. et al. (2021), “The H2020 McSafer Project: Main Goals, Technical Work
Program, and Status”, Energies 2021, Vol. 14, 6348, https://doi.org/10.3390/en14196348.
Takahashi, S. et al. (2013), “Development of BWR Steam Dryer Loading Evaluation Methods
Through Scale Model Tests Under Actual Steam Conditions”, Proceedings of ASME 2013
Pressure Vessels and Piping Conference, PVP2013-97564, 14-18 July 2013, Paris.

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ANNEX C

Table C.2. SMR Safety-related experimental facilities for AT-SMRs
Facility nameOperator

Type of SMR(s)covered

CNL/AECL

HTGR

An apparatus is being designed to study the onset of natural
circulation of air through the core region in a postulated HTGR
primary circuit break. Scaling down of the previous HighTemperature Air Ingress Facility (HTAIF) concept is in progress.
Construction of the new apparatus is planned to start in 2024.

CNL/AECLHTGR

TRISO analysis and manufacturing facilities. This includes
development of TRISO particle manufacturing, production offuel compacts/pellets, irradiation testing, and post irradiation
examination.

CNL/AECLHTGR/MSR

Measurement of emisivity of non-metalic components at hightemperature (up to 1 400°C)

HTTR

JAEA

HTGR

OPERATING(part of test data ispublic via papers)

Demonstrate inherent safety features of HTGR under
OECD/NEA/CSNI Loss of Forced Cooling (LOFC) project (seeNEA (2011)) as a multilateral international co-operation.

HAIRE (Helium Air
Ingress gas Reactor
Experimental)

University ofMichigan – Ann
Arbor

HTGR

The HAIRE facility provides insight into the flow phenomena
associated with small and medium sized break air ingress
accident scenarios of HTGRs. It is a scaled separate effect test
facility (1/20 scaling of the general atomics GT-MHR). HAIRE
provides high resolution experimental data (including pressure,temperature, oxygen concentration, and 2-D velocimetry) for
both CFD and system code validation of the depressurisation
and air ingress phases of the air ingress accident scenario. HAIRE
also provided valuable insight about the additional variables that
help to determine the depressurisation behaviour over time, as
well as showing additional variables that determine the air
ingress rate for small and medium sized breaks that were notpreviously discussed in nuclear literature. While the HAIRE facility
is quite mature, it continues to provide meaningful data for CFD,
system level codes, and even HTGR cavity design consideration.

University ofMichigan – Ann
Arbor

HTGR

The RIMPLE facility is a new experimental facility to study theflow phenomena in HTGR pebble bed reactors during accident
and steady-state conditions. Flow measurements takeadvantage of the refractive index matching technique where
the spheres in the pebble bed are matched to the fluid's index
of refraction. With a matched index of refraction the pebbles
visually disappear during the experiment. The RIMPLE facility is
unique to other pebble bed fluid dynamic experiments
because of its scale. The facility takes advantage of quarter coresymmetry, but retains the diameter ratio between the pebble
and core diameter (1:50). Therefore over 15 000 spheres arepresent for the flow experiment in RIMPLE.

University of
Wisconsin

HTGR,

UWTHL operates a Supercritical carbon dioxide pump cart thatis capable of flow rates to 0.6 kg/s pressures to 4 000 psi anddepending on configuration sCO2 temperatures up to 800°C.
The loop consist of a triplex pump with a series of recuperates
to capture lost heat. The system can conduct heat exchanger
tests and can be coupled to either the salt or sodium loops
which are part of the THL suite of flow loops. The system canalso be used to test valves, seals and other components thatwould be used in sCO2 power cycles.

STATUS
Air ingressexperimental
apparatus (to be
named)IN PLANNING
Advanced Fuels TRISO
Facilities
IN DEVELOPMENT
Emissivity Bell-Jar
Apparatus

Brief description of facility and test programme

UNDER CONSTRUCTION

OPERATINGRIMPLE(Refractive Index
Matched PebbLe Bed
facility)
OPERATINGUWTHL (University of
Wisconsin Thermal
Hydraulics Laboratory)sCO2 Loop
OPERATING52

GFR

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ANNEX C

Table C.2. SMR Safety-related experimental facilities for AT-SMRs (cont’d)
Facility nameSTATUSATHENA

Operator

Type of SMR(s)coveredRATEN-ICN

LFR

Lead large pool for integral tests, 10 m height, 3.2 m diameter,
800 tons coolant, components testing for LFR applications,2.21 MW multi-assemblies core simulator.

ENEA

LFR

Lead pool facility, coolant chemistry and oxygen control,
coolant conditioning.

RATEN-ICN

LFR

Study of the coolant chemistry and lead conditioning.

ENEA

LFR

Lead bismuth eutectic large pool, 10 m height, 1.2 I.D., 90 tons
coolant. Pool Thermal-hydraulics, components testing,transient analysis, SGTR, coolant chemistry.

newcleo

LFR

Loop facility, lead-cooled, coolant and oxygen control, material
testing, flowing corrosion up to 650°C.

ENEA

LFR

Loop, 4 tons of lead, component testing, FIV study, pumpcharacterisation, instrumentation qualification.

ENEA

LFR

Separated effect test facility, 100 litres pool, interaction
between heavy liquid metals and water, coolant chemistry,
pressure wave propagation study.

ENEA

LFR

Lead bismuth eutectic loop, 250 kW wire wrapped FPS test
section. heavy liquid metals thermal-hydraulics under gas
enhanced and natural circulation regimes.

newcleo

LFR

Multipurpose loop-type facility, lead-cooled, component
testing, mechanical pump. 2.5 MW installed.

newcleo

LFR

Pool facility representative of the new-cleo LFR design, integral
tests, proof of concept. 10 MW installed.

ENEA

LFR

Heavy liquid metal laboratory, coolant chemistry and oxygen
control, sensor testing, stagnant corrosion in lead.

SIET

LFR

Testing of a passive decay heat removal system with noncondensable gases, 20 m height, power-to-volume scaling
approach with respect to the ALFRED DHR.

IN CONSTRUCTION
BID-1
OPERATING
CHEM-LAB

Brief description of facility and test programme

IN CONSTRUCTIONCIRCE
OPERATING
CORE
IN CONSTRUCTIONHELENAOPERATING
LIFUS-5
OPERATING
NACIE-UP
OPERATINGPERFORMANCEOPERATING
PRECURSORPLANNEDRACHELOPERATING
SIRIO(ALFRED)OPERATINGSEFACE

KTH (no)

LFR

Experimental investigation of flow accelerated corrosion/
erosion of structural materials under different flow andtemperature condition in molten lead.

KTH (no)

LFR

Experimental facility for study of pump duty and impeller
erosion and corrosion in molten lead.

IN CONSTRUCTION
CTF
IN CONSTRUCTIONRESEARCH RECOMMENDATIONS TO SUPPORT THE SAFE DEPLOYMENT OF SMALL MODULAR REACTORS, NEA No. 7660, © OECD 2023

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ANNEX C

Table C.2. SMR Safety-related experimental facilities for AT-SMRs (cont’d)
Facility nameSTATUS
COSTA

Operator

Type of SMR(s)covered

KTH (no)

LFR

Experimental facility testing corrosion in stagnant liquid leadand lead bismuth eutectic. Includes small strain rate testing andconnects to materials characterisation laboratories (SEM, XRD,EDX, XPS, etc.)

CNL/AECL

Heat Pipe
Reactors

A 5x5 array of sodium heat pipe in a steel monolith for testingof heat pipes during off-normal scenarios. Single heat pipes(sodium and potassium) to produce data for model
development.

Universität Stuttgart(Institut für
Kernenergetik und
Energiesysteme) IKE

MMRs likeeVinci,
Kilopower, andMegapower

High-Temperature Heat Pipe Test facility (test heat pipe < 4 m,
operation temperature up to 700°C, heating and coolingpower < 15 kWth)

Universität Stuttgart(Institut für
Kernenergetik und
Energiesysteme) IKE

SMRs, where
CO2 power
cycles could be
attached

CO2-test loop for components of innovative power cycles
attached to MicroSMR (<10 MWth). The test section inlet
conditions are: mass flow < 100 g/s, pressure < 14 MPa,
temperature < 150°C, installed heating power = 36 kW, andcooling power (total) = 48 kW

CNL/AECL

MSRCapabilites for molten salt characterisation and verification ofthermodynamic properties (Differential Scanning Calorimeterfor melting points; Laser Flash for thermal diffusivity;
Dilatometer for liquid density; and thermoconductivity).
Corrosion of materials in contact with salts. Development offacilities for the synthesis of actinide flourides and chlorides.
Molten salt fission product behaviour experiments in hot cell(flouride and flouride-cloride salts with UF and dissolved
fission products; conducted in 2018). Simsalt production andexperiments on fission product behaviour and retention indevelopment including studies of conversion of UO2 to UF.
Initial testing with stable sim-salts and then potential
irradiation of simsalts in later phases.

CNL/AECLMSRNatural circulation loop for studying salt compatible R&D
instumentation, and effects of small geometrical changes onnatural convection flow. Generate data to benchmark codes.

CNL/AECL

MSR

Study intrinsic differences between heat transfer behaviour
under natural circulation for externally heated fluid and fluidwith internal heat generation.

Seaborg
Technologies

MSR

•
•

Large-scale salt component testing
Prototyping

Seaborg
Technologies

MSR

•
•
•
•

Fluoride salt laboratories
Thermal analysis
Microprep
Radiolab (under commissioning)

Seaborg
Technologies

MSR

•
•
•

Hydroxide laboratories
Molten salt loop facilities
New loop platform (under commissioning)

OPERATING

Heat Pipe Apparatuses
OPERATING

PHIRE (Potas-sium Heat
pIpe expeRimental
dEvice)IN CONSTRUCTIONSCARLETT – (Supercritical Carbon Dioxide
Test Loop)
OPERATING
Advanced Fuels Molten
Salt Analysis Faci-lities
OPERATING +EXPANDING CAPABILITIES

Molten Salt Natural Convection – Heat Transfer(MSNC-HT) loop.

Brief description of facility and test programme

IN COMMISSIONING
Microwave self-heating
fluid apparatus
IN DESIGN
Amager Facilities
OPERATING
Symbion Facilities
OPERATING

Titanhus Facilities
OPERATING

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ANNEX C

Table C.2. SMR Safety-related experimental facilities for AT-SMRs (cont’d)
Facility nameSTATUSUWTHL (University of
Wisconsin Thermal
Hydraulics Laboratory)

Operator
University of
Wisconsin

Type of SMR(s)covered
MSR

Brief description of facility and test programme
UWTHL operates a few molten chloride test loops. This loop
operates with a MgCl2:KCL:NaCL salt but could be used with avariety of molten chlorides.
The first loop is mainly designed for pump testing and isfabricated out of 2-inch pipe. It is equipped with a salt holding
tank, a molten salt valve and venturi flow metre all capable ofoperation up to 750°C. This loop allows development of pumpflow/head curves. There are ports for insertion and testing ofprobes.

Chloride Salt Loop
OPERATING

The second loop is constructed of 1-inch in 625 piping and is a
simple rectangular loop able to do materials testing anddiagnostic testing of different instruments. It has a hermeticallysealed magnetic coupled pump and can gene-rate velocities inthe test section up to 10 m/s. It is equipped with a calibrated
venturi flow metre to measure flow rate. Chloride purification,
the UW Thermal Hydraulics Laboratory also has chloride saltchemical purification facilities to purify up to 70 kg at a time.
University of
Wisconsin

MSR

UWTHL operates a molten flibe (lithium fluoride Beryllium
fluoride mixture) loop and flibe purification facilities. The loop is
primarily designed for materials testing and is configured with
two legs that can operate at different temperatures such as
750°C and 700°C. Velocities in the test sections range from
0-5 m/s approx., and 50 kW of heat can be added with cartridge
heaters and are subsequently removed with an air cooler. The
loop is designed to enable insertion and removal of samples
during operation and without coming into contact with theatmosphere. This is achieved through a double ball valves
sample retrieval system. The loop is also hermetically sealed(verified with helium leak detection) with a magnetic coupledcustom molten salt pump. The system can accommodate longruns and insertion of test probes or samples.

University of
Wisconsin

MSR

UWTHL operates a two story (20 feet tall) molten nitrate salt loop
used for testing instrumentation, heat exchangers, heaters,coolers etc. The primary loop is constructed out of 2-inch pipe,
the loop utilises on the order of 1 000 lb of molten salt and ispump at flow rates up to 120 GPM. The temperature limit isdictated by the salt decomposition of around 580°C and the loop
currently has heat input and removal of about 30 kW. This loop
can be coupled to a sCO2 flow loop through a heat exchanger totest the performance of advanced heat exchangers.

JOYO

JAEA

SFR

COMMISSIONING UNDERREGULATORY REVIEW(part of test data ispublic via papers)

Obtain irradiation test data for materials and fuels for SFR(Takamatsu et al., 2013).

PLANDTL (Plant
Dynamics Test Loop)

JAEA

SFR

Investigate thermal-hydraulic behaviours of sodium by
simulating core, primary main cooling system, secondary main
cooling system, and decay heat removal system for SFR (Ono,et al., 2020). Natural circulation decay heat removal test
programme under birateral SFR development collaboration.

UWTHL Flibe Loop
OPERATINGUWTHL Nitrate Salt
Loop
OPERATING

OPERATING(part of test data ispublic via papers)

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ANNEX C

Table C.2. SMR Safety-related experimental facilities for AT-SMRs (cont’d)
Facility nameSTATUS

Operator

Type of SMR(s)covered

Brief description of facility and test programme

JAEA(part of test data ispublic via papers)

SFR

Thermal-hydraulic characteristics of fuel subassemblies andcomponents in the thermal transportation system have beentested in the sodium loop (Kamide et al., 1998).

AtheNaJAEA

SFR(Advanced Technlogy
Experiment Sodium (Na)Facility)(part of test data ispublic via papers)

Investigate sodium behaviour for enhancing the safety of SFR
and demonstrating technology for the development of largescale sodium components and systems (Imamura et al., 2019).

SFR

Out-of-pile test facility to investigate the molten core material
behaviour in SFR severe accidents. Molten material sodium
interaction test and its data analysis under Japan-France SFR
development collaboration (Journeau et al., 2022).

SFR

Test facility to evaluate the tube failure / pressure propagation
caused by water leak from heat transfer tube in steam
generator of SFR (Beauchamp et al., 2013).

SFR

STELLA-2 supports the PGSFR (150 MWe) and SALUS (100 MWe).
It has 1/5-height and 1/125-volume of PGSFR and can simulate
the trasients to evaluate plant dynamic behaviours and todemonstrate its decay heat removal performance.

CCTL(Core Component
Thermal-hydraulic Test
Loop)
OPERATING

OPERATING
MELT

JAEA

OPERATING(part of test data ispublic via papers)

SWAT (Sodi-um-water
Reactor Test Rig)

JAEA

OPERATING(part of test data ispublic via papers)

STELLA-2(ITF)KAERIOPERATING

Scaling: 1:5-height and 1:125-volume of PGSFR.
MISOH1 & 2
OPERATINGNaSCoRDHISTORICAL DATABASE

56

University ofMichigan – Ann
Arbor

SFR

Experimental facilities to investigate the behaviour of sodium
heat pipes with high resolution instrumentation. #1 facility isfor an individual heat pipe. #2 facility is for a mini core toinvestigate the effect of a heat pipe failure on the heat
redistribution and potential occurrence of cascade failure
effects for multiple heat pipes.

Sandia National
Laboratories

SFR

NaSCoRD (Sodium System and Component Reliability Database)mission is to re-create the capabilities of the legacy Centralized
Reliability Database Organization (CREDO) database. The CREDO
database provided a record of component design andperformance documentation across various systems that usedsodium as a working fluid but was lost by its US custodian in the
1990s. Raw data of US origin was only recently recovered fromJAEA with whom the US had established a joint database. This
NaSCoRD database uses reconstructed CREDO data (CREDO-I)
with reliability information sourced from operational
documents, unusual occurrence reports, and design documents,
called CREDO-II.

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Table C.2. SMR Safety-related experimental facilities for AT-SMRs (cont’d)
Facility nameSTATUSUWTHL (University of
Wisconsin Thermal
Hydraulics Laboratory)
Sodium loops
OPERATING

Operator
University of
Wisconsin

Type of SMR(s)covered
SFR

Brief description of facility and test programme
The UWTHL operates several liquid sodium loops, which arelocated in an underground building with reactive metal fire
suppression and a 3 000 SCFM water cyclone exhaust systemand stack to handle any potential planed or unplaned sodium
fires or burns. The facility currently has approximately
400 gallons of sodium inventory and five different loops
designed to look at different thermal-hydraulic phenomena.
Two of the loops of similar flow rate and configurations(rectangular flow loop geometry with 1.315 OD pipe) are used
for heat transfer measurements and instrument testing. Eachof these loops uses a moving magnet pump capable of 30 GPM
and 20 ft of head and can be operated at temperatures from150-700°C.

References for SMR safety-related experimental facilities for AT-SMRs:
Beauchamp, F. et al. (2013), “Cooperation on impingement wastage experiment of Mod. 9Cr-1Mo
steel using SWAT-1R sodium-water reaction test facility”, Proceedings of International
Conference on Fast Reactors and Related Fuel Cycles; Safe Technologies and Sustainable
Scenarios (FR13), 4-7 March 2013, Paris.
Imamura, H. et al. (2019), Construction of the sodium test loop in advanced technology experimentsodium facility (AtheNa), JAEA-Technology 2019-005, 163 pages (in Japanese).
Journeau, C. et al. (2022), “French-Japanese experimental collaboration on fuel-coolant
interactions in sodium-cooled fast reactors”, Proceedings of International Conference on Fast
Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22), IAEA, Paper
CN291-302, 19-22 April 2022, Vienna.
Kamide, H. et al. (1998), “An Experimental study of inter-subassembly heat transfer during
natural circulation decay heat removal in fast breeder reactors”, Nuclear Engineering and
Design, Vol. 183, pp. 97-106.
NEA (2011), Loss of Forced Coolant (LOFC) Project, https://oecd-nea.org/jcms/pl_25168/loss-offorced-coolant-lofc-project.
Ono, A. et al. (2020), “Preliminary Analysis of Sodium Experimental Apparatus PLANDTL-2 forDevelopment of Evaluation Method for Thermal-Hydraulics in Reactor Vessel of Sodium Fast
Reactor Under Decay Heat Removal System Operation Condition”, Mechanical Engineering
Journal, Vol. 7 (3), pp. 19-00546.
Takamatsu, M. et al. (2013), Restoration work for obstacle and upper core structure in reactor vessel ofexperimental fast reactor Joyo (2), 4-7 March 2013, Fast reactors and Related Fuel Cycles: Safe
technologies and Sustainable Scenarios (FR13), Paris.

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ANNEX C

Table C.3. Existing experimental facilities for possible use
in investigation of SMR safety issues
Facility nameOperator

Type of SMR(s)covered

ZED-2 (Zero Energy
Deuterium) Reactor

CNL/AECL

VariousZED-2 is a versatile tank type, heavy water moderated low power
research reactor. It has the flexibility to accept large experimental
assemblies with few restrictions, and It is primarily used for
performing reactor physics measurements and fuel studies in thedevelopment of neutron cross-section data and for instrumentation
development. This facility has been utilised extensively over many
decades in support of CANDU reactors, and today supports thedevelopment of new reactor designs and advanced fuel cycles.
ZED-2 is currently being assessed in terms of its abilities to support
various proposed SMR designs.

NOKO

BWR

CLOSEDFZJ (part oftest data ispublic via
papers)Not dedicated to SMR but passive systems (emergency condenser,
building condenser, plate condenser, passive pressure pulse
transmitters) (Fethke et al., 1998; Schaffrath et al., 1999).

PKL (Primärkreislauf)

Framatome

PWR

Not dedicated to SMR but relative to passive systems (safety
condensers).

LSTF

JAEA/USNRC

PWR/(Large-Scale Test
Facility)(part of test
data is public
via papers)Westinghouse
AP600

Modified LSTF provides a 1/30.5 volumetric-scaled full height modelof AP600 based on power-to-volume scaling (Kukita et al., 1996).

NRG

All

The High Flux Reactor is a material test reactor which can be used
for fuel and material R&D for all types of nuclear reactors,
including all types of SMRs.

NRG

All

The PALLAS reactor is aimed at replacing the HFR. Apart fromproduction of medical isotopes, also R&D for fuel and material will
be accommodated www.pallasreactor.com).

TUD

All

The Hoger Onderwijs Reactor is a research reactor at the TU Delft
which is available for fuel and material R&D for all types of nuclear
reactors.

CIEMAT

Non-specific

LASS is designed for aerosol & thermal-hydraulics investigation andsafety systems performance testing. LASS houses the PECA facility,
which was designed to withstand temperatures and pressuresaround 140°C and almost 3 bar, respectively. With an 8 m3 vessel, so
far experimental campaigns on pool scrubbing; aerosol
agglomeration; gas submerged injection; SGTR-secondary systemfiltering effect; etc. have been experimentally addressed in theframe of national and international projects (CIEMAT, 2018).

STATUS

CLOSED(ROSA/AP600)

Brief description of facility and test programmeContribute to certificate of conformity for AP600 throughconfirmation of effectiveness of passive safety systems (Yonomoto
et al., 1997; and Yonomoto et al., 1998).

OPERATING(AP600 COMPONENTS
CLOSED)HFROPERATINGPALLASIN CONSTRUCTIONHOROPERATINGLASSOPERATING

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Table C.3. Existing experimental facilities for possible use
in investigation of SMR safety issues (cont’d)
Facility nameSTATUS
Studsvik Hot cells

Operator

Type of SMR(s)coveredStudsvik

non-specific

In addition to LOCA and Fuel integrity during interim storage also
have capabilities for out-of-pile RIA, new materials properties
verifications. Advanced characterisation capabilities for both fueland materials studies, e.g.: OM with hardness measurements,
SEM/FIB/EDS/WDS/EBSD/in-situ heating/mechanical testing, XRD(crystal structure, phase composition, residual stressmeasurements), ICP-MS, ICP-OES, Gas-MS, Laser ablation coupledwith ICP-MS, STA (TGA, DSC, online gas mass spectrometry), thermal
hot bridge (thermal diffusivity), carbon and sulphur analysis,
ferritescope measurements, residual stress measurements, oxygenand nitrogen analysis.

Chalmers
University ofTechnology

All

Fabrication facility for full actinide fuels.

Chalmers
University ofTechnology

All

Fully licenced for handling of substantial amounts of alpha active
material.

Chalmers
University ofTechnologyAll

Hot cell with manipulators.

Chalmers
University ofTechnology

All

Co-60 source with max dose rate of 5 kGy/h.

OPERATING

Chalmers – Fuellaboratory
OPERATING
Chalmers – Alphalaboratory
OPERATING
Chalmers – Gamma
laboratory
IN RENOVATION
Chalmers – Gamma
irradiation source
OPERATING
Chalmers –Interaction lab\
OPERATING
Odqvist laboratory

Chalmers
University ofTechnology

Facilities for investigating fuel/coolant/cladding interactions.
Tested with MOX, nitrides and molten sodium and molten lead(and lead/bismuth).

KTH

All

The KTH engineering mechanics laboratory. Mechanical testing ofmaterials and components, fluid mechanical testing, high-speed
imaging, etc. Not for active materials.

KTH

All

The KTH central materials science laboratory. Wide range ofadvanced micro-structural characterisation techniques available.
Not for active materials.

Uppsala
University

All reactor types
using defined fuelgeometries

Test facility for developing tomographic methodologies for use
on irradiated fuel assemblies. The goal is to supply the industry
and regulator with instruments for PIE and safeguards.

Uppsala
University

General purposes

High-intensity neutron source for supporting activities indevelopment of e.g. new structural materials and education.

OPERATING
Hultgren laboratory
OPERATING
BETTANOPERATINGNESSA
IN CONSTRUCTION

Brief description of facility and test programme

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Table C.3. Existing experimental facilities for possible use
in investigation of SMR safety issues (cont’d)
Facility nameSTATUSPANDA
OPERATING

Operator
PSI

Type of SMR(s)coveredWater-cooled(PWR/iPWR/BWR,
e.g. Rolls-Royce
SMR, SMART,
NuScale, Holtec160, NUWARD,
BWRX-300)

Brief description of facility and test programme
PANDA is a large-scale, multi-compartment facility dedicated tocontainment cooling, suppression pool phenomena, passive
safety systems, heat transfer from immersed containment towater pool, condensation, and natural circulation
Pressure: 0.2-10 bar
Power: 1.5 MWe
Loop height: 25 m (possible up to 30 m)

References for existing experimental facilities for possible use in investigation of SMR safetyissues:CIEMAT (2018), LASS: Laboratory for Analysis of Safety Systems – Facility and Experiments, Madrid.
Fethke, M., A. Schaffrath et al. (1998), “Experimental investigation of the operation mode ofpassive safety systems”, Proceedings of ENC ’98 World Nuclear Congress, 25-28 October 1998,
Nice.
Kukita, Y. et al. (1996), “ROSA/AP600 testing: Facility modifications and initial test results”,
Journal of Nuclear Science and Technology, Vol. 33 (3), pp. 259-265.
Schaffrath, A. et al. (1999), “Experimental and analytical investigations of the operation of theemergency condenser of the SWR1000”, Nuclear Technology, Vol. 126(5), pp. 123-142.
Yonomoto, T. et al. (1997), “Core makeup tank behaviour observed during the ROSA-AP600
experiments”, Nuclear Technology, Vol. 119, pp. 112-122.
Yonomoto, T. et al. (1998), “Heat transfer analysis of the passive residual heat removal system
in ROSA/AP600 experiments”, Nuclear Technology, Vol. 124 (1), pp. 18-30.

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ANNEX D

Annex D. Projects focused on SMR safety

Provided below are the results of the EGSMR information collection on national and multinational projects focused on SMR safety. The collection also includes lists of Euratom projects
and other activities underway at the IAEA, GIF, and NEA.
The responses are provided in alphabetical order by country (with each country presented
in a separate table), followed by the Euratom project summary at the end. Note that somecountries reported on the international (Euratom, IAEA, GIF, and NEA) projects, which they are
involved resulting in some duplication across this collection. The organisations and countries
that contributed to this collection are as follows:•

18 organisations (ANVS, Bel V, CEA, CNL, CNSC, Euratom, GRS, GIF, Hitachi-GE, IAEA, IFE,
JAEA, KAERI, KIT, MHI, NEA, NRG, SSM, Tractebel, TU Delft, USNRC)

from•

10 countries (Belgium, Canada, France, Germany, Japan, Netherlands, Norway, Korea,
Sweden and the United States)

Table D.1. National and multi-national projects (Belgium: Bel V and Tractebel)
Project nameNation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

IRSN

PWR

Ongoing

Challenges and opportunities for licensing process andsafety assessment of light water small modular reactors(LW-SMRs).

variousvarious

Ongoing

Tractebel co-operates in EU, NEA and IAEA projects related
to SMR safety.

Bel V
ETSON SMR
ReportTractebel
EU, NEA, and
IAEA projects

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ANNEX D

Table D.2. National and multi-national projects (Canada: CNL and CNSC)
Project nameNation(s)involved/lead

Type of SMR(s)coveredCanada –NSERC-CNSC

All

StatusBrief description of project focus and scope

Upcoming(Grantprogramme
and research
to begin in
2023)

This is a five-year SMR Research Programme that CNSC isadministering through the Natural Sciences and Engineering
Research Council (NSERC). The NSERC-CNSC SMR Grant
Initiative is a CAD 15 million programme and research will
begin later this calendar year.

CNSC
NSERC-CNSC
SMR Grant

Research AOIs include:•

Chemistry and materials (consequences of hightemperature on reactor components, chemistry control
for various materials and fuel types)•

Environmental and radiological protection (source term
characterisation, geotechnical and effect of theenvironment on SMR design and operation, emergency
planning)•

Human and organisational factors (interface design,
digital I&C)•

Safeguards and security (cybersecurity, safeguards
inspection methods)•

Novel fuel compositions

CNL
AECL-FNSTWork Plan

Canada – AECL/
CNL

All

Ongoing

This national programme administered by the AECL
includes science and technology work related to SMRs
(both water-cooled and advanced designs) including
safety. Safety-related projects include modelling/analysis
and experiments covering a variety of topics including
safety analysis, materials, chemistry, fuel performance andmanufacturing (including molten salt and TRISO fueltypes), thermal-hydraulics, containment physics, hybrid
energy systems, and severe accidents.

CNRI

Canada – CNL

All

Ongoing

The Canadian Nuclear Research Initiative is a collaborative
research programme with an annual intake of proposals forcommercial projects with clean energy technology andSMR vendors/developers, as well as academia, to pursue
collaborative work in key focus areas, including specificissues/phenomena related to design, development, andsafety of advanced reactors.

CEDIR

Canada – CNL

All

Ongoing

The Clean Energy, Demonstration, Innovation, and Research(CEDIR) Initiative was developed to support the research,development and demonstration of the clean energy
technologies needed to help the Government of Canada
achieve its national target of net zero by 2050.
The initiative has two phases: 1) CEDIR Labs focusing on
modelling, simulation and benchtop experiments of various
aspects of low-carbon technologies and hybrid energy
systems. 2) CEDIR Park, is a future vision of a collaborative
research park where clean energy technologies can be
developed and demonstrated within a hybrid energy system.

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ANNEX D

Table D.2. National and multi-national projects (Canada: CNL and CNSC) (cont’d)
Project nameNation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

EGSMR (NEA)

NEA

All

Ongoing

The CSNI organised EGSMR seeks to assess the SMR safety
landscape, identify important AOIs and suggest specificactions for CSNI to take in support of SMR safety. CNL isparticipating in and chairing this expert group.

SASPAM-SA (EUProject)

Euratom

Water-cooled
SMRs (iPWR
primary; small
BWRsecondary)

Ongoing

The SASPAM-SA EU project is focused on severe accident
behaviour of water-cooled SMRs including passive safetysystems (see full description in Euratom projects list). CNL
is participating with integrated severe accident analysis,
experimental data/benchmarking on iPWR containment
behaviour, and evaluations of EPZs and emergency
response for SMR.

IAEA CRP on
EPZ (I31029)

IAEA

All

Participation in IAEA CRP I31029 Development ofApproaches, Methodologies and Criteria for Determining
the Technical Basis for Emergency Planning Zone for SMR
Deployment. IAEA TECDOC summarising the CRP work andoutcomes is currently in preparation.

GIF RSWG

GIF

All (especiallyadvanced
technology/
Generation IV
designs)

Membership in the GIF Risk and Safety Working Group(RSWG). The RSWG advises the GIF Experts Group and
Policy Group on matters related to the safety of Gen-IV
systems and leads GIF interaction with the IAEA and the
NEA WGSAR (now WGNT).

ECC-SMART
Project

Euratom,
Canada, China

Supercritical
Water Reactor(SCWR)

Ongoing

Oriented towards assessing the feasibility and identificationof safety features of an intrinsically and passively safe small
modular reactor cooled by supercritical water (SCW-SMR),
taking into account specific knowledge gaps related to the
future licensing process and implementation of thistechnology. ECC-Smart (ecc-smart.eu)

Table D.3. National and multi-national projects (France: CEA)
Nation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

ELSMOR

Lead -VTTiSMR

Ongoing

Dedicated to assessing the feasibility of a European SMR
licensingTANDEM

Lead – CEAiSMR

Ongoing

Dedicated to the integration of SMR plant in a global
cogeneration or hybrid electricity smart grid (withrenewables)

PASTELS

Lead – EDF

PWR

ClosedDedicated to the passive systems reliability assessment andvalidation code (safety condensers)

SASPAM

Lead – ENEA

iSMR

Ongoing

Dedicated to the severe accident mitigation demonstration
for a European SMR

Project name
CEA

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ANNEX D

Table D.4. National and multi-national projects (Germany: GRS, KIT)
Project nameNation(s)involved/lead

Type of SMR(s)coveredGRS

All types of
SMR

StatusBrief description of project focus and scope

Completed

This report documents the work and results of the project
RS1521 Study of Safety and International Development of
Small Modular Reactors (SMR). The aims of this study are

GRS
SMR Study

THYR
Study

GRS

SeveralThorium andHybrid Reactors(THYR)

Completed•setting-up of a sound overview on SMR•

identification of essential issues of reactor safety
research and future R&D projects•

identification of needs for adaption of system codes of
GRS used in reactor safety research.

This report documents the work and results of the project
RS1578 Study of Safety and International Development of
THYRs. The aims of this study are•

setting-up of a sound overview on THYRs•

identification of essential issues of reactor safety
research and future R&D projects•

identification of needs for adaption of system codes of
GRS used in reactor safety research.

FENNECS

GRS

Several types of
SMRs

Completed

The objective of this research project is the further
development of the 3-d few-group neutron kinetic code
FENNECS for the safety assessment of (v)SMR – (very) Smalland Medium size Reactors – and advanced and innovative
reactor systems with complex and irregular geometries.
The peculiarities of the cores of such systems or concepts
are, e.g., their compactness, which can have large neutron
flux gradients and increased leakage, long cycle times, theircomplex geometries that deviate from regular grids andtheir heterogeneous material composition with special
fuels, absorbers and cooling media.

AC2
Development
and Validation

GRS

Several types of
SMRs

Completedand ongoing

There are multiple challenges for the AC² system code
package regarding model improvements and validation for
SMRs, which GRS is in the process of resolving. Consequently,
GRS’ new nationally funded projects for the development
and validation of AC² put a specific focus on issues related toadvanced LWR and integral PWR SMR reactor designs. This isaccompanied by collaborations with national andinternational partners on specific topics.
There is ongoing work in AC2 module COCOSYS
development and validation to improve models for passive
containment cooling systems, covering both heatexchangers with natural circulation heat transfer to external
water pools and condensation heat transfer at large
containment structures.

VASIL

64

GRS

Several types of
SMRs

Ongoing

GRS initiated the national research alliance VASIL. One
objective is the implementation and validation of dedicatedmodels for innovative heat exchangers of the compact plate,bayonet and helically coiled type. Also, improved models forevaporation from water pools will be implemented. Finally,
AC²/ATHLET is validated by performing test calculations forgeneric input decks of extant SMR designs and assessing
their quality against available information in the literature.

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ANNEX D

Table D.4. National and multi-national projects (Germany: GRS, KIT) (cont’d)
Project nameNation(s)involved/lead

Type of SMR(s)covered

PALAWERO

GRS

MISHA

GRS and IKE

StatusBrief description of project focus and scope

SMRs using
heat pipee.g. for coolingof water pools

Completed

Within a joint national R&D project, GRS has improved
ATHLET models for water-filled wickless heat pipes(thermosiphons) proposed for cooling of water pools(e.g. in which SMR containments are submerged) andvalidated them against dedicated experiments at the
University of Stuttgart. This work continues with the
PALAWERO-II project, where further improvements for
ATHLET models will be derived, implemented and tested
against experiments at the ATHOS test facility in Stuttgart.

Liquidpotassium heatcooled MMRs

Ongoing

Extension of the national computational simulation chain
for MMRs and validation against experimental andanalytical results (e.g. the special purpose reactors designs
A and b). This includes inter alia•

creation of a 3D neutronics model for analyses using
the GRS code FENNECS and validation•

further development of AC2 module ATHLET for MMR
with potassium-filled heat pipes, validation andqualification against published reference data•experiments on potassium-filled HPs to supportmodel development•

further development of ATHLET for CO2 and air-based
Joule cycles as operational heat rejection for power
generation•

specification of a consistent MMR model andqualification of the computational chain throughintegral simulations of MMR operational and accident
behaviour.

SiFeKoMPA Stuttgart

Several types of
SMRs

Ongoing

The aim of the research cluster is to build up wide-ranging
competencies for the safety assessment of the new reactor
types in connection with SMR. The focus is on
manufacturing, damage developments and effects, and to
be able to evaluate the safety of such plants accordingly.

NukSiFutur

Universität der
Bundeswehr
MünchenSeveral types of
SMRs

Ongoing

The NukSiFutur junior research group con-tributes to thecompletion of the analysis chain for nuclear safety. The aim
is to improve CFD simulations for multi-physics problems
with pronounced multi-scale, i.e. generally turbulent,
multiphase, non-isothermal and reactive flows.

Germany

LW-SMR

Ongoing

BMBF funded strategic initiative to study the safety of SMRs
in the HGF-centres (KIT, HZDR and FZJ) devoted to core
physics, transient analysis, containment issues.

KIT
InnoPool
SMR

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Table D.4. National and multi-national projects (Germany: GRS, KIT) (cont’d)
Project name
McSAFER
H2020

Nation(s)involved/lead

Type of SMR(s)coveredGermany(COOR),
Belgium,
Sweden,Finland, Czech,
Spain,
Argentina, UK,
France

LW-SMR(naturalcirculation,
forcedconvection,boron /noboron free
concepts, HEX
and SQUARE
FAs)

StatusBrief description of project focus and scope

Ongoing,
started in2020 and willend inFebruary2024

KIT is co-ordinator of McSAFER. The goal is to improve thesafety analysis methods for design-basis accident and it
includes multi-physics/multi-scale methods. Investigations
are complemented by an experimental programme at 3 EU
Facilities located at KIT (COSMOS-H), LUT (MOTEL) and KTH(HWAT), where safety-relevant experiments for the core,helical HX representative for different SMR designs (F-SMR,
CAREM, SMART, NuScale) are being performed.
The different safety analysis methodologies will be applied
to investigate accidents like REA (SMART, NuScale), cold
water injection (F-SMR, CAREM), boron dilution (NuScale),
ATWS (SMART) and SLB (NuScale, SMART) and they will bebenchmarked to each other.
The experimental data generated in McSAFER will be used tovalidate different kind of thermal-hydraulic codes e.g. CFD,
sub-channel, and system thermal-hydraulic codes.

EU Horizon
Europe project
SASPAM-SA

Italy (COOR),
Germany,
Switzerland,
Belgium,
France, Czech,
Finland, Spain,
Lithuania,
Romania,
Ukraine,Bulgaria,

LW-SMR(two designs;
see description)

Started in
October 2022
and will lastfor 4 years

The focus is on investigations of severe accidents of two
generic SMR designs with different severe accident codes,
assess the experimental data base for IVMR-phenomena,
accident management, radiological dispersion and impact
around the site. Containment issues is also an important goalof the investigations using different kind of tools including
CFD.
Design 1: Generic iPWR characterised by a submerged
containment and electric power of about 60 MWe.
Design 2: generic iPWR characterised by the use of several
passive systems, a dry containment and an electric powerof about 300 MWe.

Table D.5. National and multi-national projects (Japan: Hitachi-GE, JAEA, MHI)
Nation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

OPG’sDarlington new
nuclear project

OPG in Canada,
GE Hitachi
Nuclear Energy(Hitachi-GE
Nuclear Energy
will support
this project)

BWRX-300

Ongoing

Deploy a BWRX-300 SMR at the Darlington new nuclear sitethat could be completed as early as 2028.

PRISM

GE Hitachi
Nuclear
Energy/HitachiGE Nuclear
EnergyPRISM

Ongoing

Introduce PRISM to Japan.

RBWR

Hitachi-GE
Nuclear Energy/US and UK
academia

RBWR

Ongoing

Conduct benchmarking for nuclear analysis codes for
RBWR in collaboration with US (i.e. UCB and UM) and UK
academia (i.e. University of Cambridge).

Project name
Hitachi-GE

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ANNEX D

Table D.5. National and multi-national projects (Japan: Hitachi-GE, JAEA, MHI) (cont’d)
Project nameNation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

JAEA

HTGR

Ongoing

Demonstrate inherent safety features of HTGR to validate
code predictive capability and accuracy of models, through
LOFC tests and loss-of-coolant flow test by the HTTR.

JAEA
NEA/CSNI LOFC
project(CzechRepublic,
France,Germany,
Hungary, Japan,
Korea and theUnited States)

Mitsubishi Heavy Industries (MHI)
Mitsubishi
Small PWR

MHI

iPWR

Ongoing

Develop plant conceptual design by using Japanese
government (Ministry of Economy, Trade and Industry)
subsidies.

Mitsubishi
HTGR

MHI

HTGR

Ongoing

Develop plant conceptual design by using Japanese
government (Ministry of Economy, Trade and Industry)
subsidies.

Mitsubishi
Micro-Reactor

MHI

Micro Reactor

Ongoing

Develop plant conceptual design by using Japanese
government (Ministry of Economy, Trade and Industry)
subsidies.

MCR(Mitsubishi
Compact
Reactor)

MHI/MFBR

SFR

Ongoing

Develop plant conceptual design by using Japanese
government (Ministry of Economy, Trade and Industry)
subsidies.

Table D.6. National and multi-national projects (Netherlands: AVNS, NRG, TU Delft)
Nation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

WSMR

NRG
(Netherlands)

iPWR

Completed

Safety analyses for the Westinghouse SMR.

SMR

NRG
(Netherlands)All

Ongoing

Drafting of a white-paper on SMR for Dutch government
and public.

GEMINI4.0

NCBJ(Poland)

HTGR

Ongoing

Safety analyses for the GEMINI HTGR prismatic block
reactor design.

FALCON

AnsaldoNucleare(Italy)LFR

Ongoing

Safety analyses for the ALFRED reactor design.

SEALER

LeadCold(Sweden)

LFR

Completed

Safety analyses for the SEALER reactor design and its
electric mock-up SEALER-E.

Project nameAVNS and NRG

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Table D.6. National and multi-national projects (Netherlands: AVNS, NRG, TU Delft) (cont’d)
Project nameNation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

HTTF

OECD/NEAHTGRStarting

Preparation for participation to the future OECD/NEA
benchmark on the US High-Temperature Test Facility (HTTF)
safety analyses.

RMV

NRG
(Netherlands)

iPWR

Completed

Implementation of reflood models in the SPECTRA system
thermal-hydraulics code.

Thorizon

Thorizon(Netherlands)

MSR

Ongoing

Design of a modular MSR (www.thorizon.com/)

Ubattery

TUD(Netherlands)

HTR

Ongoing

Design of a micro reactor.

MIMOSA

TUD(Netherlands)

MSR

Ongoing

Plutonium burning in small MSR.

TU Delft

Table D.7. National and multi-national projects (Norway: IFE)
Project nameNation(s)involved/lead

Type of SMR(s)coveredInstitute forEnergyTechnology,
NorwayStudies are notlimited to aparticular SMR
designStatusBrief description of project focus and scope

Ongoing

The focus and scope of these efforts include:

IFE
Halden HTO
Project

68•

Staffing•

Human-machine interface•

Organisational factors•

Human performance•

Management of unplanned/unanticipated events•

Safety management•

Automation•

Evolving concepts of operation•

Human factors•

Teamwork, crew roles, conduct of operations

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Table D.8. National and multi-national projects (Korea: KAERI)
Nation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

SMART

Korea, KSA

iPWRCompleted

SMART is an integral PWR with a rated electrical power of
110 MWe from 365 MWt. The first standard design approval(SDA) is issued in July 2012 but with further modification it
is in the last phase for the second SDA of SMART100
expected to be issued within 2023.

iSMR

Korea

iPWR

Ongoing

The “iSMR” is an innovative small modular PWR producing
540 MWt with an electrical power of 170 MWe. It has fully
passive safety systems and is in the conceptual designphase with the target of SDA in 2028.

PGSFR

Korea

SFR

Pending

The PGSFR is a pool-type SFR with a rated electrical powerof 150 MWe from 392.2 MWe. After the specific design
safety analysis report (SDSAR) was issued in 2017, theproject has been suspended and waiting for determining
the national nuclear spent management policy.

SALUS

Korea

SFR

Ongoing

SALUS is a pool-type SFR with a rated electrical power of
100 MWe with 268 MW thermal power. It is a long-termsustainable SMR with a cycle length of 20 years and is
exploring its licensability.

Project name
KAERI

Table D.9. National and multi-national projects (Sweden: SSM)
Nation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

McSAFER(Euratom)

KIT

iPWR

Ongoing

Development, improvement, validation, and application ofnumerical simulation tools (traditional, advanced loworder and high-fidelity) validated with experimental data
generated in European facilities (COSMOS-H, MOTEL,
HWAT) that are relevant for the majority of SMR designs.

SUNRISE

KTH

LFR

Ongoing

Development of R&D platform for materials andcomponents’ testing in support of design and safety analysis
of a Swedish lead-cooled research reactor (SUNRISE-LFR) andan electrical mock-up prototype (Solstice).

FREDMANS(Euratom)

Chalmers

LFR

Ongoing

Nuclear fuel design and manufacturing methods for leadcooled SMRs.

PASCAL(Euratom)

ENEA

LFR

Ongoing

To pave the way to the future licensing of LFRs and ADSs by
supporting the further advancement of the pre-licensing of
the ALFRED and MYRRHA demonstrators in line with thepriorities identified by the European Sustainable Nuclear
Industrial Initiative (ESNII). Safety of the fuel, reactor
coolant systems and containment.

Project name
SSM

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Table D.9. National and multi-national projects (Sweden: SSM) (cont’d)Nation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

SASPAM(Euratom)

ENEA

iPWR

Ongoing

A sound demonstration of iPWR ability to address thechallenges posed by SA with particular emphasis on
specific accident management aspects, for example: In
Vessel Melt Retention (IVMR), Ex-vessel phenomena andfission products release to the environment. Two reference
generic iPWR designs with forced and natural primarycoolant circulation

Solstice

SMR AB

LFR

Ongoing

An electrically powered non-nuclear prototype for the
SUNRISE-LFR and the SEALER-55 reactors is underconstruction at Oskarshamn. The facility will be used fortesting and verifying materials and technology in anenvironment of molten lead at high temperatures

ANItA

Sweden(Uppsala
University)

LWR SMRs andAMRs

Ongoing

Gather the Swedish academic and industrial nuclear
technology competence onto one platform. The mission isthrough multidisciplinary research and development work,
supply the political sphere and policy makers withknowledge-based information to be able to implement
SMRs as fast as possible in Sweden. ANIta – Uppsala
University, Sweden (uu.se)

Project name

Table D.10. National and multi-national projects (United States, US: USNRC)
Project nameNation(s)involved/lead

Type of SMR(s)covered

NEA

Non-specific,
but relevant to
SMRs withstraight-tubed,
decay heatremoval heatexchangers

NEA (operated
by KAERI)

Non-specific,
but relevant to
SMRs that use
naturalcirculation andpassive safetysystems

StatusBrief description of project focus and scope

Ongoing

One of the objectives of ETHARINUS is to investigate theperformance of passive heat removal systems. The project
scope also facilitates a common database to contribute to
the experimental verification of cool down procedures,operation modes and systems (including passive ones) for
different transients.

Ongoing

Full pressure integral effects test facility scaled to APR1400
with additional systems beyond those in APR1400. A large
focus on beyond design-basis events or design extension
conditions, natural circulation, and passive safety systems
yields large applicability to SMRs.

USNRC

ETHARINUS

ATLAS

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Table D.11. Multi-national projects (Euratom)
Project nameNation(s)involved/lead

Type of SMR(s)coveredCo-ordinated by
VTT Teknologian
Tutkimuskeskus
Oy (Finland)Light Water(LW)

StatusBrief description of project focus and scope

Duration
42 months,
Start date
1 September
2019,
End date
28 February
2023

Towards European Licensing of Small MOdular Reactors

Euratom
ELSMOR(15 participants,
8 countries)
McSAFER

Co-ordinated by
KIT – Karlsruher
Institut fuer
Technologie(Germany)

LW(12 participants,
9 countries)
SASPAM-SA

Co-ordinated by
ENEA (Italy)

LW(21 participants,
13 countries)

GEMINI+

Co-ordinated by
NarodweCentrum Badan
Jadrowych(Poland)

HTGR(26 participants,
12 countries)
ECC-SMART

Co-ordinated byCentrum
Vyzkumu Rez
Sro (Czech
Republic)

SCWR(19 participants,
16 countries)
GEMINI For
Zero Emission

Co-ordinator:
Framatome(France)(26
participants,
14 countries)

HTGR

Duration
36 months,
Start date
1 September
2020,
End date
31 August2023
Duration
48 months,
Start date
1 October2022,
End date
30 September
2026.
Duration
42 months,
Start date
1 September
2017,
End date
28 February2021

https://cordis.europa.eu/project/id/847553
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf

High-Performance Advanced Methods and Experimental
Investigations for the Safety Evaluation of Generic SMRs
https://cordis.europa.eu/project/id/945063
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf
Safety Analysis of SMR with PAssive Mitigation strategies –Severe Accident
https://cordis.europa.eu/project/id/101059853
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf
Conceptual design for a HTGR for supply of process steam
to industry, a framework forthe licensing of such system
and a business plan for a full-scale demonstration
https://cordis.europa.eu/project/id/755478
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf

Duration
48 months,
Start date
1 September
2020,
End date
31 August2024

Joint European-Canadian-Chinese Development of Small
Modular Supercritical Water-cooled Reactor Technology

Duration
36 months,
Start date
1 June 2022,
End date
31 May 2025

Nuclear cogeneration, polygeneration, decarbonisation,high emperature reactor

https://cordis.europa.eu/project/id/945234/reporting
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf

https://cordis.europa.eu/project/id/755478/reporting
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf

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Table D.11. Multi-national projects (Euratom) (cont’d)
Project nameANSELMUS

Nation(s)involved/lead

Type of SMR(s)coveredCo-ordinator:
SCK-CEN(Belgium)

Liquid Metal(15 participants,
9 countries)

ESFR-SIMPLE

Co-ordinator:
CEA (France)

Sodium Fast
Reactor(11 participants,
9 countries)

MIMOSA

Co-ordinator:
ORANO (France)

Molten Salt
reactors(12 participants,
4 countries)

TANDEM

Co-ordinator:
CEA (France)

LW and GEN-IV(17 participants,
9 countries)

HARMONISE

Co-ordinator:
Lietuvos
Energetikos
Institutas(Lithuania)(22 participants,
11 countries)

72

Licensing of
fusion andfissioninstallations

StatusBrief description of project focus and scope

Duration
48 months,
Start date
1 September
2022,
End date
31 August2026

Advanced Nuclear Safety Evaluation of Liquid Metal Using
Systems

Duration
48 months,
Start date
1 October2022,
End date
30 September
2026
Duration
48 months,
Start date
1 June 2022,
End date
31 May 2026

Duration
36 months,
Start date
1 September
2022,
End date
31 August2025
Duration
36 months,
Start date
1 June 2022,
End date
31 May 2025

https://cordis.europa.eu/project/id/101061185
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf
European Sodium Fast Reactor - Safety by Innovative
Monitoring, Power Level flexibility and Experimental
researchhttps://cordis.europa.eu/project/id/101059543
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf
Multi-recycling strategies of LWR SNF focusing on Molten
Salt technology
https://cordis.europa.eu/project/id/101061142
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf
SMR for a European safe and Decarbonised Energy Mix
https://cordis.europa.eu/project/id/101059479
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf

Towards harmonisation in licensing of future nuclear
power technologies in Europe
https://cordis.europa.eu/project/id/101061643
https://research-andinnovation.ec.europa.eu/system/files/202302/ec_rtd_smr-project.pdf

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ANNEX D

Table D.12. Multi-national projects (GIF)
Project nameNation(s)involved/ lead

Type of Gen. IV
reactors covered

StatusBrief description of project focus and scope

Activesince 2005

Development and maintenance of Integrated Safety
Assessment Methodology (ISAM) as a technology-neutral
toolkit to support a design and evaluate risk and safety.
Development of Safety Design Criteria and Guidelines toestablish basic requirements for design, fabrication,
construction, inspection, and operation of Gen IV plants.

GIF Research Projects/WGs
Risk and Safety
Working Group(RSWG)

GIF members
and IAEA

All six GIF
Generation IV
systems(VHTR, SCWR,
SFR, MSR,

www.gen-4.org/gif/jcms/c_9366/risk-safety
Proliferation
Resistance andPhysicalProtection
Working Group(PRPPWG)

GIF members
and IAEA

All six GIF
Generation IV
systems

Activesince 2004

PRPPWG develops, implements and fosters the use of anevaluation methodology to assess Gen IV systems withrespect to GIF PRPP Goa; and to provide the designers andpolicymakers a technology-neutral framework and a formal
comprehensive approach to evaluate PRPP characteristics
of advanced nuclear systems.
www.gen-4.org/gif/jcms/c_9365/pr-pp

Gas Fast
Reactor (GFR)
Conceptual
Design and
Safety Project

Euratom,
FranceGFR

Activesince 2009

R&D in support of safety – mainly focused on ALLEGRO,
benchmarking and experimental activities, developmentof safety design criteria.

Supercritical
Water-Cooled
Reactor (SCWR)
Thermalhydraulics andSafety Project

Canada, China,
Euratom

Sodium Fast
Reactor (SFR)
Safety andOperation
Project

France, Japan,
Korea and theUnited States

SFR

Activesince 2009

Methods, models and codes for safety evaluation,
experimental programmes, operational experience, andbenchmark analyses.

Very HighTemperature
Reactor (VHTR)
Computational
Methods
Validation andBenchmarks
Project

China, Euratom,
Japan, Korea,
the UnitedStates

VHTR

Activesince 2022

Validation of new computational methods and codes in theareas HTR thermal hydraulics, thermal mechanics, core
physics and chemical transport for licensing assessment ofreactor performance in normal, upset and accident
conditions. Benchmark tests and code-to-code comparisons.

Advanced
Manufacturingand Materials
Engineering
Task ForceGIF Members

All six GIF
Generation IV
Systems

Activesince 2020

The overarching main objective of the AMMETF is topromote the use of Advanced Manufacturing and Materials
Engineering technology to reduce the time to deployment ofadvanced reactor systems. The specific recommended focus
areas and potential activities include qualifications (including
codes and standards development), demonstration anddeployment, and design and modelling.

www.gen-4.org/gif/jcms/c_42148/gas-cooled-fastreactor-gfr
SCWR

Activesince 2009

Safety requirements and evaluation, heat transfer, hydrauliccharacteristics, stability, development of system codes andmethodologies, safety analysis.
www.gen-4.org/gif/jcms/c_42151/supercritical-watercooled-reactor-scwr

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Table D.13. Multi-national projects (IAEA)
Project nameNation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

Ongoing(ends
December
2024)

Economic Appraisal of Small Modular Reactors Projects:
Methodologies and Applications

Completed(endedFebruary
2023)

HTGR Reactor Physics, Thermal-Hydraulics and Depletion
Uncertainty Analysis

Completed(ended May
2016)

Benchmark Analysis of an EBR-II Shutdown Heat Removal
Test

Completed(endedOctober
2019)

Application of CFD Codes for Nuclear Power Plant Design

Completed(endedFebruary
2023)

Modular HTGRs Safety Design

IAEA Cooperative Research Projects
I12007

I31020I31021

I31022

I31026

I31029I31031

I31032

I31033

IAEA (countries
in weblink)

IAEA (countries
in weblink)

IAEA (countries
in weblink)

Various

HTGR

Sodium Fast
Reactor

IAEA (countries
in weblink)

Various

IAEA (countries
in weblink)

HTGR

IAEA (countries
in weblink)

Variouswww.iaea.org/projects/crp/i12007

www.iaea.org/projects/crp/i31020

www.iaea.org/projects/crp/i31021

www.iaea.org/projects/crp/i31022

www.iaea.org/projects/crp/i31026

Ongoing(expected
end wasAugust 2021)

Development of Approaches, Methodologies and Criteria
for Determining the Technical Basis for Emergency
Planning Zone for SMR Deployment

Ongoing(expected
end wasFebruary
2022)

PSA Benchmark for Multi-Unit/Multi-Reactor Sites

Neutronics Benchmark of CEFR Start-Up Tests

www.iaea.org/projects/crp/i31029

IAEA (countries
in weblink)

Various

IAEA (countries
in weblink)

Sodium Fast
ReactorOngoing(ends
December2024)

www.iaea.org/projects/crp/i31032

IAEA (countries
in weblink)

Water-cooled
ReactorOngoing(ends June
2024)

Advancing the State-of-Practice in Uncertainty andSensitivity Methodologies for Severe Accident Analysis in
Water-Cooled Reactors

www.iaea.org/projects/crp/i31031

www.iaea.org/projects/crp/i31033
I31034

I3103874

IAEA (countries
in weblink)

IAEA (countries
in weblink)

SCWR

Liquid Metal
CooledOngoing(ends April
2026)

Advancing Thermal-Hydraulic Models and Predictive Tools
for Design of SCWR Prototypes

Ongoing(ends August
2026)

Benchmark of Transition from Forced to Natural Circulation
Experiment with Heavy Liquid Metal Loop

www.iaea.org/projects/crp/i31034

www.iaea.org/projects/crp/i31038

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Table D.13. Multi-national projects (IAEA) (cont’d)
Project nameI32009I32010I32012

T12031

T12032Nation(s)involved/lead

Type of SMR(s)covered

IAEA (countries
in weblink)

Sodium Fast
Reactor

IAEA (countries
in weblink)

IAEA (countries
in weblink)

Various

Various

IAEA (countries
in weblink)

Fast Reactors

IAEA (countries
in weblink)

Water-cooled
Reactor

StatusBrief description of project focus and scope

Completed(EndedMarch 2021)

Radioactive Release from the Prototype Fast Breeder
Reactor under Severe Accident Conditions

Ongoing(expected
end wasDecember
2021)

Design and Performance Assessment of Passive Engineered
Safety Features in Advanced SMRs

Ongoing(ends April
2026)

Technical Evaluation and Optimisation of NuclearRenewable Hybrid Energy Systems

Ongoing(ends June
2023)

Fuel Materials for Fast Reactors

Ongoing(ends August2024)

Testing and Simulation for Advanced Technology and
Accident Tolerant Fuels (ATF-TS)

www.iaea.org/projects/crp/i32009

www.iaea.org/projects/crp/i32010

www.iaea.org/projects/crp/i32012

www.iaea.org/projects/crp/t12031

www.iaea.org/projects/crp/t12032

Table D.14. Multi-national projects (NEA)
Project nameNation(s)involved/lead

Type of SMR(s)covered

StatusBrief description of project focus and scope

All

Ongoing

EGSMR seeks to assess the SMR safety landscape, identify
important areas of interest and suggest specific actions andresearch projects for CSNI to take in support of SMR safety.

NEA Joint Projects
EGSMR(Expert Groupon SmallModular
Reactors)
Nuclear Safety
Research Joint
Projects

NEA (Chair –Canada)www.oecd-nea.org/jcms/pl_79842/expert-group-onsmall-modular-reactors-egsmr
NEA

LWR andadvanced
technologies

Ongoing

NEA Joint Safety Research Projects support the safe
operation of nuclear installations. Typical safety research
projects include the conduction of a set of experimentsthat address a safety issue and closes a safety knowledge
gap; or the exchange of experimental information andmodelling results to better understand safety-related
phenomenology.
www.oecd-nea.org/jcms/pl_72332/nuclear-safetyresearch-joint-projects

NEA Data BankNEA

LWR andadvanced
technologies

Ongoing

The NEA Data Bank is an international reference centre forcomputer codes, nuclear and thermochemical data. You
can learn more about us and our three services below.
www.oecd-nea.org/jcms/rni_6525/data-bank

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ANNEX D

Table D.14. Multi-national projects (NEA) (cont’d)
Project name
LOFC
(Loss of Forced
Coolant)

FIDES-II

Nation(s)involved/lead

Type of SMR(s)coveredLead – Japan andCzech Republic,
France, Germany,
Hungary, Korea
and the UnitedStatesHTR

Belgium, Czech
Republic, Finland,
France, Germany,
Hungary, Japan,
Netherlands,
Spain, Sweden,
Switzerland, theUnited States,
EuropeanCommission (EC)LWR andadvanced
technologies

Current
mandate2022-2024

The NEA Second Framework for Irradiation Experiments(FIDES-II) supports the fuel and material experimental
needs of nuclear safety regulators, technical support
organisations, research institutions and industry andsafeguards experimental knowledge for future
generations. FIDES-II connects a global network of
research facilities to perform high-priority experiments
through joint experimental programmes (JEEPs).

HTR(1958-1975),
completed

Dragon was the first experimental HTGR built in the
1960s. A very high-temperature reactor is one of theGeneration IV concepts and several countries are
considering HTR technology as one of the promisingconcepts to be utilised for SMRs. Projects on construction
and operation of modular pebble-bed reactors (PBR) arealso under way.

DRAGON, HTGR
Reactor ProjectStatusBrief description of project focus and scope

Current
mandate2011-2027

The LOFC experiments plan to study effects of reactor
cavity cooling system (RCCS) performance reduction arehighly relevant for safety assessments of advanced
reactors such as high-temperature reactor (HTR).
www.oecd-nea.org/jcms/pl_25168/loss-of-forcedcoolant-lofc-project

www.oecd-nea.org/jcms/pl_51567/dragon-project
HALDEN HTO,
Human,
Technology
Organization
Project

Canada, China,
France, Germany,
Japan, Korea,
Netherlands,
Norway, Sweden,
UAE, the United
Kingdom, theUnited States

LWR andadvanced
technologies

QUENCH-ATF

Czech Republic,
France, Germany,
Japan, Sweden,
Switzerland, theUnited Kingdom,
the United States

LWR andadvanced
technologies

Current
mandate2021-2025

The purpose of the QUENCH-ATF project is to investigate
the chemical, mechanical and thermal-hydraulics
behaviour of ATF claddings in design-basis accidents andbeyond design-basis accidents scenarios.

Joint project on
Wasteintergration for
Small andAdvanced
Reactor Designs(WISARD)

NEA – ongoing
preparation

Advanced
technologies

To be started

The project focuses on the development of a set of waste
acceptance criteria for different types of waste producedby the next generation SMRs and ARs.

76

Current
mandate2021-2023

Halden HTO’s 2021-2023 goal is to advance in the HTO
field by working on aspects of human performance,
reliability and organisation in various stages of the plantlife, including during accident situations.
www.oecd-nea.org/jcms/pl_61937/halden-humantechnology-organisation-hto-project

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ANNEX E

Annex E. PIRTs related to SMR safety

Provided below are the results of the EGSMR information collection on PIRTs related to SMR
safety. This represents an initial effort in PIRT collection for the EGSMR and will be expandedupon.
The responses for national PIRTs are provided in alphabetical order by country (with eachcountry presented in a separate table) followed by a single table for the Euratom project related
PIRTs. The countries that contributed to this collection are:•Canada, France, Italy, Japan, Netherlands, Korea, Switzerland and the United States

Table E.1. Canada – PIRTs relevant to SMR safety
Nation(s) involved(owner)Type of SMR(s)covered

StatusBrief description of PIRT focus and availability

HTGR
limiting
accident PIRT

CanadaHTGR

Completed

Executed for a hypothetical limiting accident (withsignificant radionuclide releases) in a generic small
HTGR. The intent was to envelope and evaluate mostor all phenomena that could occur in a beyond designbasis accident. Summary published in open-literature:https://pubs.cnl.ca/doi/full/10.12943/CNR.2019.00006

Molten Salt
limiting
accident PIRT

CanadaMSR

Completed

Executed for a hypothetical limiting accident (withsignificant radinuclide releases) for two small MSR
concepts. The intent was to envelope and evaluate
most or all phenomena that could occur in a beyond
design-basis accident. Summary was presented at the
Fourth International Conference on Generation IV andSmall Reactors (G4SR-4) and is included in theconference proceedings.

Designextension
condition

CanadaBWR

To be started

Development of a PIRT for Design Extension
Conditions in a BWRX-300 to explore potential
accident progression and source terms.

PIRT title

Table E.2. France – PIRTs relevant to SMR safety
PIRT title
Validation
Code Task
Force

Nation(s) involved(owner)Type of SMR(s)covered

StatusBrief description of PIRT focus and availability

French Consortium

IPWR Nuward

Completed

Physical phenomenon and code validation
requirements for the licensing of Nuward (confidential
data)

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ANNEX E

Table E.3. Japan – PIRTs relevant to SMR safety
Nation(s) involved(owner)Type of SMR(s)covered

StatusBrief description of PIRT focus and availability

PIRT under
NC decayheat removal
operation

Japan (JAEA)JSFR (Japan SFR)

Completed

Develop PIRT for JSFR (Japan SFR) under NC decay heatremoval operation (Doda et al., 2012).

PIRT forsodium fireJapan (JAEA)

SFR

Ongoing

Develop PIRT for sodium fire event in SFR to validate
sodium fire analysis codes (Ohno et al., 2012; Aoyagi etal., 2019).

PIRT forunprotected
loss of flow

Japan (JAEA)

SFR

Ongoing

Develop PIRT for unprotectd loss of flow in SFR tovalidate code for simulation of initiating phase of coredisruptive accident (Ishida et al., 2020; Kawada andSuzuki, 2021).

PIRT title

References
N. Doda, et al. (2012), “Development of PIRT for Fast Reactor under Natural Circulation Decay Heat Removal Operations”, Transactionsof the Japan Society of Mechanical Engineers, B, 78 (787), 465-467 (in Japanese).
S. Ohno, et al. (2012), “Development of PIRT and Assessment Matrix for Verification and Validation of Sodium Fire Analysis Codes”,
Journal of Power and Energy Systems, Vol. 6 (2), pp. 241-254.
M. Aoyagi, et al. (2019), “Identification of important phenomena through the PIRT process for development of sodium fire analysis
codes”, Nuclear Engineering and Design, Vol. 353, Article ID 110240.
S. Ishida, et al. (2020), “Validation study of SAS4A code for the unprotected loss-of-flow accident in an SFR”, Mechanical Engineering
Journal, Vol. 7 (3), 19-00523.
K. Kawada and T. Suzuki (2021), “Study on dominant aspects of unprotected loss-of-flow to be evaluated in the initiating phase for a
sodium-cooled fast reactor”, Journal of Nuclear Science and Technology, Vol. 58 (3), pp. 347-360.

Table E.4. Korea – PIRTs relevant to SMR safety
Nation(s) involved(owner)Type of SMR(s)covered

StatusBrief description of PIRT focus and availability

SMART PIRT(2009)

Korea (KAERI)

iPWR

Completed

Developed for SMART with passive residual heatremoval system (PRHRS) focusing on 9 safety-related
design-basis accidents in 2009. It was used for themultipurpose (test programmes establishment, facility
scaling and analysis model development) of the design
certification (in Korean, publically unavailable).

SMART PSSPIRT (2013)

Korea (KAERI)

iPWR

Completed

Developed for thermal-hydraulic phenomena of
SMART with full passive safety system focusing on
SBLOCA and MSLB in 2013. In this report, the reactor
coolant system (RCS) of SMART was reviewed as well as
PRHRS, passive safety injection system (PSIS) andautomatic depressurisation system (ADS) (in Korean,publically available).

iSMR PIRT(2023)

Korea (KHNP,KAERI)

iPWR

Preparing

The PIRT process is expected to start during 2023 (inKorean, publically unavailable).

PGSFR PIRT
(2016)

Korea (KAERI)

SFR

Pending

Developed to evaluate suitability of the MARS-LMR codefor safety analysis and determine physical phenomenaduring transients in the PGSFR (150 MWe). It is for DEC(design extension condition) scenarios such as UTOP
(unprotected transient over-power), ULOF (unprotected
loss of flow), and ULOHS (unprotected loss of heat sink)(in Korean, publically available).

PIRT title

78

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ANNEX E

Table E.5. United States – PIRTs relevant to SMR safety
PIRT title

Nation(s) involved(owner)Type of SMR(s)covered

StatusBrief description of PIRT focus and availability

Pre-PIRT
Report for
NuScale-like(iPWRs)United States(USNRC)

iPWR

Completed

PIRT applies to LOCA and Rod Withdrawal. Redacted
version will be publicly available.

PIRT Reportfor NuScale
Stability

United States(USNRC)

iPWR

Completed

PIRT applies to thermal-hydraulic stability of the
NuScale RCS. Redacted version will be publicly available.

Table E.6. Euratom Projects – PIRTs relevant to SMR safety
PIRT title
PIRTs
developed
withinELSMOR
Project
Including
WP3.1

Nation(s) involved(owner)Type of SMR(s)covered

StatusBrief description of PIRT focus and availability

Various

VariousComplete

The PIRTs developed within the ELSMOR project are ofhigh quality and may be referenced to many LW-SMRs(iPWRs), e.g.

including France
and Switzerland

https://ec.europa.eu/research/participants/documents/downloadPublic?documentIds=080166e5cdaebbb7&appId=PPGMS
and
https://ec.europa.eu/research/participants/documents/downloadPublic?documentIds=080166e5dc79c953&appId=PPGMS
Analysis of simplified PIRTs VOYGR, SMART, IRIS (opendata) SBO & LOCA.

ANSELMUS

Italy, Belgium,
Germany, Romania,
Netherlands,
EuropeanCommission,(Ansaldo Nucleare,
Italy)

LFR

OngoingWithin the frame of the EU Horizon Europe collaborative
project ANSELMUS, PIRTs will be developed for the
ALFRED and MYRRHA reactor based SMRs. Work will
start early 2023.
The focus is on the impact/uncertainties of relevant
phenomena in the safety demonstration of the ALFRED
and MYRRHA reactors. The objective is to drive future
R&D need, both experimental and numerical, to bringlicensing forward. PIRT results will be publicly available.

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79

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CSNI Technical Opinion Paper

No. 21

While there is a growing interest in the deployment of small modular reactors (SMRs) as a promising
option to help mitigate climate change, further international efforts are needed to accelerate thedevelopment and safety demonstration of the innovative technologies that are being considered formany of these SMRs. This publication presents the actions taken by the NEA Committee on the Safetyof Nuclear Installations (CSNI) and its expert group on SMRs to define the areas of future CSNI researchand safety assessment work needed to support sound safety demonstrations for SMRs. The proposed
activities address four areas: support for regulatory harmonisation, common safety issues of interestfor different designs, experimental campaigns, and benchmarking for computer code validation andverification.

Nuclear Energy Agency (NEA)
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92100 Boulogne-Billancourt, France
Tel.: +33 (0)1 73 21 28 19
nea@oecd-nea.org www.oecd-nea.org

NEA No. 7660