Summary Review on the Application of Computational Fluid Dynamics in Nuclear Power Plant Design

By IAEA

This publication documents the results of an IAEA coordinated research project (CRP)on the application of computational fluid dynamics (CFD) codes for nuclear power plant design. The main objective was to benchmark CFD codes, model options and methods against CFD experimental data under single phase flow conditions. This publication summarizes the current capabilities and applications of CFD codes, and their present qualification level, with respect to nuclear power plant design requirements. It is not intended to be comprehensive, focusing instead on international experience in the practical application of these tools in designing nuclear power plant components and systems. The guidance in this publication is based on inputs provided by international nuclear industry experts directly involved in nuclear power plant design issues, CFD applications, and in related experimentation and validation highlighted during the CRP.

• Language: English
• Publisher: International Atomic Energy Agency
• Release date: Mar 28, 2022
• ISBN: 9789201004215

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SUMMARY REVIEW ON THE

APPLICATION OF COMPUTATIONAL

FLUID DYNAMICS IN NUCLEAR

POWER PLANT DESIGN

IAEA NUCLEAR ENERGY SERIES No. NR-T-1.20

SUMMARY REVIEW ON THE

APPLICATION OF COMPUTATIONAL

FLUID DYNAMICS IN NUCLEAR

POWER PLANT DESIGN

INTERNATIONAL ATOMIC ENERGY AGENCY

VIENNA, 2022

COPYRIGHT NOTICE

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© IAEA, 2022

Printed by the IAEA in Austria

March 2022

STI/PUB1932

IAEA Library Cataloguing in Publication Data

Names: International Atomic Energy Agency.

Title: Summary review on the application of computational fluid dynamics in nuclear power plant design / International Atomic Energy Agency.

Description: Vienna : International Atomic Energy Agency, 2022. | Series: IAEA nuclear energy series, ISSN 1995–7807 ; no. NR-T-1.20 | Includes bibliographical references.

Identifiers: IAEAL 21-01473 | ISBN 978–92–0–100221–1 (paperback : alk. paper) | ISBN 978–92–0–100321–8 (pdf) | ISBN 978–92–0–100421–5 (epub)

Subjects: : LCSH: Nuclear power plants — Design and construction. | Computational fluid dynamics. | Nuclear reactors.

Classification: UDC 621.039.5:532 | STI/PUB1932

FOREWORD

The IAEA’s statutory role is to seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world. Among other functions, the IAEA is authorized to foster the exchange of scientific and technical information on peaceful uses of atomic energy. One way this is achieved is through a range of technical publications including the IAEA Nuclear Energy Series.

The IAEA Nuclear Energy Series comprises publications designed to further the use of nuclear technologies in support of sustainable development, to advance nuclear science and technology, catalyse innovation and build capacity to support the existing and expanded use of nuclear power and nuclear science applications. The publications include information covering all policy, technological and management aspects of the definition and implementation of activities involving the peaceful use of nuclear technology.

The IAEA safety standards establish fundamental principles, requirements and recommendations to ensure nuclear safety and serve as a global reference for protecting people and the environment from harmful effects of ionizing radiation.

When IAEA Nuclear Energy Series publications address safety, it is ensured that the IAEA safety standards are referred to as the current boundary conditions for the application of nuclear technology.

This publication presents the results of the coordinated research project (CRP) entitled Application of Computational Fluid Dynamics Codes for the Design of Advanced Water Cooled Reactors, which addresses the application of computational fluid dynamics (CFD) computer codes to the process of optimizing the design of water cooled nuclear power plants and their components. Building on past initiatives in which CFD codes have been applied to a wide range of situations in nuclear reactor technology, the 15 CRP participants from 11 Member States aimed to develop a systematic framework for the consistent application of CFD codes and to establish a common understanding of the capabilities of CFD codes and their level of qualification.

The results of this CRP are expected to be of interest to a broad range of Member States, including those currently operating or embarking on nuclear power programme. As of March 2022, there were 441 nuclear power plants in operation around the world, with a further 51 under construction, bringing the total operating experience to slightly over 19 000 reactor years. Advanced nuclear power plants that increasingly use CFD codes in their design are being offered by various vendors.

This publication presents examples of CFD applications in nuclear power plants component and system design from Member States participating in the CRP. The publication focuses on CFD aided modelling in technology development and design, and thus complements existing publications that concentrate largely on the use of CFD codes for nuclear safety analyses. Issues and interests common to both efforts, lessons learned and application guidelines derived from validation against relevant scaled experiments are also described to aid in the correct and practicable application of these tools.

The IAEA expresses its appreciation for the contributions of several Member States. It is particularly grateful to the participants of the CRP for their contributions to the publication. The IAEA officer responsible for this publication was M. Krause of the Division of Nuclear Power.

EDITORIAL NOTE

This publication has been edited by the editorial staff of the IAEA to the extent considered necessary for the reader’s assistance. It does not address questions of responsibility, legal or otherwise, for acts or omissions on the part of any person

Although great care has been taken to maintain the accuracy of information contained in this publication, neither the IAEA nor its Member States assume any responsibility for consequences which may arise from its use.

Guidance provided here, describing good practices, represents expert opinion but does not constitute recommendations made on the basis of a consensus of Member States.

The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries.

The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA.

The IAEA has no responsibility for the persistence or accuracy of URLs for external or third party Internet web sites referred to in this book and does not guarantee that any content on such web sites is, or will remain, accurate or appropriate.

The authoritative version of this publication is the hard copy issued at the same time and available as pdf on www.iaea.org/publications. To create this version for e-readers, certain changes have been made, including a the movement of some figures and tables.

CONTENTS

1. Introduction

1.1. Background

1.2. Objective

1.3. Scope

1.4. Structure

2. Roles of System Codes and Computational Fluid Dynamics in the Nuclear Power Plant Design Process

3. Activities involving Computational Fluid Dynamics in Support of Nuclear Power Plant Design

3.1. Reactor designers

3.2. Utilities

3.3. Code developers of computational fluid dynamics

3.4. Research organizations

4. Status of Verification and Validation for the Use of Computational Fluid Dynamics in Nuclear Power Plant Design

4.1. Design applications

4.2. Validation gaps and issues involved

5. Future Use of Computational Fluid Dynamics for Selected Reactor Types

5.1. Supercritical water reactor

5.2. Water–water energetic reactor

5.3. Sodium cooled fast reactors

5.4. Pressurized water reactors

6. Best practice Guidelines in the Use of Computational Fluid Dynamics for Nuclear Power Plant Design

6.1. Best practice guidelines for safety analyses

6.2. Specific examples

7. Summary of Experimental Requirements for Producing Computational Fluid Dynamics Grade Data

7.1. General experimental requirements

7.2. Validation of two phase flow modelling for computational fluid dynamics

8. User Qualification

8.1. General requirements for practitioners of computational fluid dynamics

8.2. Specific knowledge areas

8.3. Summary of training courses in computational fluid dynamics for reactor design

9. Uncertainty Quantification

9.1. Overview

9.2. Aspects of uncertainty quantification

9.3. The GEMIX benchmark

9.4. Conclusions

10. Gaps in Computational Fluid Dynamics Technology Applied to Nuclear Power Plant Design Issues

10.1. Verification and validation

10.2. Range of application of turbulence models

10.3. Stratification and buoyancy effects

10.4. Coupling system/computational fluid dynamics codes

10.5. Coupling with other physics codes

10.6. Computing power limitations

11. CONCLUSIONS

REFERENCES

ABBREVIATIONS

CONTRIBUTORS TO DRAFTING AND REVIEW

STRUCTURE OF THE IAEA NUCLEAR ENERGY SERIES

1. Introduction

1.1. Background

The growth in computer hardware over the last 30 years, accompanied by the development of stable and efficient numerical algorithms, has created opportunities for the use of computational methods, greatly reducing the earlier reliance on experimental testing in the design and development of multiple industrial systems. The rise of computational fluid dynamics is part of this advancement. However, during a period of low growth in the nuclear power industry (starting in the mid-1980s), the primary driving force for the development of CFD technology has been in the non-nuclear area, such as in the aerospace, automotive, marine, turbomachinery, chemical and process industries and, to a lesser extent, in the environmental and biomedical fields. In the power generation area, the principal applications have again been non-nuclear: combustion dynamics for fossil fuel burning and gas turbines, vanes for wind turbines, etc.

A resurgence of interest in nuclear technology between 2005 and 2011, the much heralded ‘nuclear renaissance’, was interrupted directly by the accident on 11 March 2011 at the Fukushima Daiichi nuclear power plant in Japan, and indirectly by the low cost of alternative energy production methods, especially gas turbines, and renewable sources such as solar and wind power. Nevertheless, many countries are still actively pursuing NPP construction policies as part of their future energy mix.

The IAEA has long been aware that there will be increasing interest in the use of CFD codes and, in particular, in their verification, validation and uncertainty quantification. As a result, it has collaborated with the OECD Nuclear Energy Agency (OECD/NEA) in sponsoring the initial exploratory effort to document the progress of CFD as a simulation tool in the field of nuclear reactor safety, and advance it by proposing numerical benchmarking exercises and organizing international workshops. These jointly sponsored activities remain ongoing. This coordinated research project ) seeks to fill a gap in the original initiative, recognizing the growing use of CFD tools for reactor design purposes, while maintaining the existing synergy with the OECD/NEA by continuing efforts in the area of reactor safety.

In recognition of the increased use of CFD in the design of advanced water cooled reactors, a publication on the subject was requested from the IAEA in 2010 by the technical working groups on advanced technologies for light water reactors (LWRs) and heavy water reactors (HWRs). In addition, these two technical working groups also suggested the preparation of a CRP on the Application of CFD Codes for the Design of Advanced Water Cooled Reactors, to be initiated in 2012.

As a first step in the establishment of this CRP, a Technical Meeting was convened in Vienna in December 2010 which served to showcase current efforts in the field. A number of major reactor vendors were represented, as well as CFD researchers from academia and national institutes. There was a consensus that this subject be formalized in terms of a fully developed CRP, and that an IAEA publication on the subject be published. Sixteen organizations from 11 Member States participated in the CRP: Algeria, Canada, China, France, Germany, India, Italy, Republic of Korea, Russian Federation, Switzerland and the United States of America (USA).

1.2. Objective

This CRP addresses the application of CFD computer codes to the process of optimizing the design of water cooled NPPs, though it is not limited to this reactor type. Building on past initiatives in which CFD codes have been applied to a wide range of situations in nuclear reactor technology, this CRP aims to define a framework for the consistent application of CFD codes for NPP design purposes, and to establish a common understanding of the capabilities of CFD codes and their level of qualification.

The primary objective of this publication is to determine to what extent CFD has become a part of the NPP design process over the past ten years, how it is expected to develop over the coming years, and how CFD will continue to contribute to the assessment base of the technology. The role of the IAEA is to report on the current status of CFD in NPP design and sponsor international CFD benchmarking exercises in areas of relevance to design engineers. One of the benchmark activities is based on rod bundle tests [1], relating directly to design optimization of a fuel assembly spacer grid, while the other benchmark [2] applies to safety considerations. Selected results have also been summarized in a recent conference paper [3].

1.3. Scope

This publication summarizes the current capabilities and applications of CFD codes, and their present qualification level, with respect to NPP design requirements. It is not intended to be comprehensive, focusing instead on international experience in the practical applications of these tools in designing NPP