Computational Fluid Dynamics for Reactor Design and Safety-related - - PowerPoint PPT Presentation

Massachusetts Institute of Technology

NSE

Nuclear Science & Engineering at MIT science : systems : society

Computational Fluid Dynamics for Reactor Design and Safety-related Applications

Emilio Baglietto

emiliob@mit.edu

web.mit.edu/newsoffice/2012/baglietto-better-reactors.html

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

An Industrial/Research/Academic view

Wearing multiple hats:

Massachusetts Institute of Technology

• Assistant Professor of Nuclear Science and

Engineering, Massachusetts Institute of Technology.

• Deputy Lead TH Methods Focus Area,

CASL – a US Department of Energy HUB.

• Nuclear Industry Sector Specialist

CD-adapco.

• Member of NQA-1 Software Subcommittee.

Disclaimer: the following slides are intended for general discussion. They represent the personal view of the author and not that of MIT, CASL or the ASME NQA-1 Software Subcommittee.

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

• Nuclear Industry Competitiveness

 CFD for Nuclear Reactor Design  Leveraging the research/academia efforts

• Review - State of the art and current challenges

 Where and why CFD  Multiscale Applications  CFD as Multi-physics platform

• CFD for Safety Related Applications

 The US-NRC example  Commercial Grade Dedication of Software  Experience and Challenges

Contents

Emilio Baglietto - Nuclear Science & Engineering at MIT

Background

• 2011- present

Assistant Professor of Nuclear Science and Engineering, MIT

• 2006-2011

Director Nuclear Application, CD-adapco

• 2004-2006

Research Associate, Tokyo Institute of Technology

2012 2009

PBMR

2005

Emilio Baglietto - Nuclear Science & Engineering at MIT

Nuclear Industry Competitiveness

(since ICONE13 – 2005)

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

CASL: The Consortium for Advanced Simulation of Light Water Reactors

A DOE Energy Innovation Hub for Modeling & Simulation of Nuclear Reactors

Task 1: Develop computer models that simulate nuclear power plant operations, forming a “virtual reactor” for the predictive simulation of light water reactors.

Task 2: Use computer models to reduce capital and operating costs per unit of energy, ……

6

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

Licensing Time / O&M Cost

7

1

Core and core components

2

Upper Internals

3

Steam Generator Internals

4

Steam Lines

5

PRZ components

6

Pumps and seals

7

Flow mixing, fatigue, shedding

8

Stratification, hydrogen accumulation

Emilio Baglietto - Nuclear Science & Engineering at MIT

• Local T&H conditions such as

pressure, velocity, cross flow magnitude can be used to address challenge problems:

• GTRF
• FAD
• Debris flow and blockage
• The design TH questions under

normal operating and accident conditions such as:

• Lower plenum flow anomaly
• Core inlet flow mal-distribution
• Pressure drop
• Turbulence mixing coefficients

input to channel code

• Lift force
• Cross flow between fuel

assemblies

• Bypass flow
• The local low information can be used

as boundary conditions for micro scale models.

Model 1 Model 2

A “Typical” Multi-Scale Problem

Full-core performance is affected by localized phenomena

Emilio Baglietto - Nuclear Science & Engineering at MIT

STAR-CCM+ Platform for Multiphysics

High Fidelity T-H / Neutronics / CRUD / Chemistry Modeling

Petrov, V., Kendrick, B., Walter, D., Manera, A., Impact of fluid-dynamic 3D spatial effects

• n the prediction of crud deposition in a 4x4 PWR sub-assembly - NURETH15, 2013

Emilio Baglietto - Nuclear Science & Engineering at MIT

STAR-CCM+ Platform for Multiphysics

High Fidelity T-H / Neutronics / CRUD / Chemistry Modeling

Petrov, V., Kendrick, B., Walter, D., Manera- NURETH15, 2013

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

Not only Fuel Related Applications

11

Mature Applications

• Fuel

 Pressure Drops  Crud (CIPS/CILC)  Vibrations (GTRF)

• System and BOP

 Transient Mixing  Hot Leg Streaming  Thermal Striping  SG performance  Cooling Towers Interference

• Fuel Cycle and Beyond Design

Basis Applications

 Spent fuel transportation and

Storage

Emilio Baglietto - Nuclear Science & Engineering at MIT

Multiphase CFD

… better physical understanding

boiling heat transfer DNB void fraction

Emilio Baglietto - Nuclear Science & Engineering at MIT

CFD for Safety-Related Design and Analysis

• CFD is undoubtedly becoming a

fundamental instrument in the Safety Analyst Toolbox.

• CFD offers a unique opportunity for

improved physical understanding 

• Leads to more general applicability
• Reduced need for empirical

calibration, which means “lower costs!”

• Challenge:
• Provide a path for application of CFD in

Safety Analysis.

• Assure that the process will capture all

“critical characteristics” of the application.

• Make the process “Applicable”.

13

Emilio Baglietto - Nuclear Science & Engineering at MIT

Can we apply CFD to Safety-Related Design and Analysis ?

14

Let’s try to reformulate the question:

• Is there a process that is robust, flexible, and cost effective

allowing application of CFD to Safety-Related Design and Analysis.

• Does the process guarantee confidence in the application
• f CFD.

Corollary:

• Is the application of CFD completely

different from that of system codes..

• Is it more challenging.
• Is it more costly.

Emilio Baglietto - Nuclear Science & Engineering at MIT

Commercial Off-The-Shelf (COTS)

CFD is apt to rely on COTS

General Purpose CFD…

…reasons

• It has been heavily used by other industries with success.
• Requires very large investment for development.
• Inherits “experience” and verification practices.
• Allows leveraging a very large base of users for testing.
• What are the requirements for use of COTS?

15

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

The fear of change …

• Changes from NQA-1-2008 to NQA-1a-2009 Part II, Subpart 2.7

Section 302 require application of:  Part I, Requirement 7, Control of Purchased Items and Services  and Part II Subpart 2.14, Quality Assurance Requirements for Commercial Grade Items and Services

• For acquisition of software that has not been

previously approved under a program consistent with NQA-1 for use in its intended application.

• Is it really that bad?
• Is it going to make it too costly to adopt COTS?
• Is adoption of COTS more challenging or more costly?

16

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

A realistic challenge

• Subpart 2.14 had not really been written for software, therefore

not a straightforward interpretation for an applicant.

• There was a need to provide a guidance for CGD of software

which would for example include. NQA-1-2012 Non-Mandatory Appendix (NMA)

 Focused on dedication of Design and Analysis Computer Programs  Aligns with each of the Sections of SP 2.14 and provides information

where the SP cannot be clearly interpreted as it applies to computer programs

 Unique Definitions that apply to computer programs  Limits application of Like-for-Like  Omits Equivalency unless complete evaluation is possible

17

Emilio Baglietto - Nuclear Science & Engineering at MIT

The process:

Commercial Grade Dedication

• U.S. NRC Regulatory

Guide 1.28 Rev. 4, June 2010

• NQA-1-2008 with NQA-

1a-2009 addendum NQA-1-2012 Non-Mandatory Appendix (NMA) EPRI 2012 - CGD Guidance for Safety- Related Design and Analysis

18

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

NQA-1-2012 Non-Mandatory Appendix (NMA)

CC Description Acceptance Criteria Method of Verification Host computer

• perating

environment The manufacture and model number of the host assembly

• r computer hardware

computer program is intended to reside. This critical characteristic is applicable to all computer programs. Host computer operating environment criteria must match the purchase

• specification. This should include the

manufacturer name and model from a supplier’s catalog. (e.g., Dell PowerEdge T110 Tower Server, IBM AIX & System, and Dell Precision T3500 Workstation, Siemens Simatic S7-400) Verified through one or more of the following:

• Inspection of receipt inspection

documentation (Method 1)

• Inspection of test system operating

system identifiers. (Method 1) Host computer

• perating

system identifier Vendor name, operating system version, service packs or patch identifiers that are needed for the computer to be executed. This critical characteristic is applicable to all computer programs. Host computer operating system identifier must match the identifier in the vendor product list (e.g., Microsoft Windows 7, UNIX Operating System Version 5.1, B-5, and Yokogawa Pro- Safe-RS R2.01.00) Verified through one or more of the following:

• Inspection of receipt inspection

documentation (Method 1)

• Inspection of test system operating

system identifiers. (Method 1) Software Name The full name of the software. It should be the same identifier as used for during the procurement/acquisition

• process. This critical

characteristic is applicable to all computer programs. Software name must match the product name from vendor catalog. (e.g., CFAST, Wolfram Mathematica 8, Monte Carlo N-Particle Transport Code System (MCNP5), Emerson valve Link, and Organic Concatenater) Verified through one or more of the following:

• Inspection of receipt inspection

documentation (Method 1)

• Inspection of test system operating

system identifiers. (Method 1) Software Version Identifier The complete version identifier including any

• patches. This critical

characteristic is applicable to all computer programs. Software version identifier must match the product identifier from the vendor catalog that includes software name- major functional version, minor functional version. corrective revision (e.g., CFAST-05.00.01, Hotspot- 02.07.01, Emerson valve Link-02.04-13, and Organic Concatenater-3.1b) Verified through one or more of the following:

• Inspection of receipt inspection

documentation (Method 1)

• Inspection of test system operating

system identifiers. (Method 1)

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

How does it apply to CFD

4 Categories of Critical Characteristics

• Identification
• i.e., version, build date, release name, or part or catalog number
• Physical
• physical media (e.g., CD, tapes, downloads, or remote access)
• Performance/Functional
• required functionality of the computer program to perform its safety

function and the accuracy of its results

• Dependability (unique to computer programs)
• Evaluation to develop judgment regarding built-in quality
• Includes attributes related to the supplier’s software development

process such as review of the computer program’s lifecycle processes and output documentation, review of configuration management activities, testing and V&V activities, and other activities.

Emilio Baglietto - Nuclear Science & Engineering at MIT

Performance/Functional CCs

• Item characteristics
• Critical Characteristics for

Performance/Functional

• Item characteristics
• Critical Characteristics for

Performance/Functional

COTS CFD

Emilio Baglietto - Nuclear Science & Engineering at MIT

Striking a good balance

• It is fundamental to balance the application
• f the Process and the Analysis Methodology.
• Failures in applying CFD to Safety-Related

Design and Analysis are related to incorrect use of the process.

Method

• Failures are not unique to CFD, but it is a “common” failure

mode.

• Adoption of CFD for Safety-Related Design and Analysis requires

the active contribution from CFD experts*.

Let’s look at 2 representative examples of Incorrect CGD

• f CFD Software for Safety-Related Design and Analysis

Emilio Baglietto - Nuclear Science & Engineering at MIT

“Faith in the box” failure

• Solving Navier-Stokes is just like solving another problem (e.g.

structural analysis).

• Very personal view: the CGD guidelines are a very natural approach to

support CFD.

• The process will quickly become lighter and faster as the number of CFD

applications grows.

V&V Support Routine

STAR Japanese Conference 2013

CFD for Reactor Design and Safety-related Applications

A more challenging example…

• The Flux Capacitor would most likely be

considered a safety grade component.

• SAR would need to include predictions of

HTCs during all normal and off-normal

• perational conditions.
• CFD provides an excellent method to support

Safety-Related Design and Analysis.

Nuclear Powered DeLorean DMC-12

CFD model of Flux Capacitor

Emilio Baglietto - Nuclear Science & Engineering at MIT

Example of SAR

• Is this sufficient / adequate ?

Validation of CFD applicability based on separate effects analysis:

• Flow in a Y – junction
• 2D Cavity Buoyant flow
• Air tests for single tube from literature, HTC data

available at representative Re.

• Literature recommends K-w SST Model for better

HTC prediction due to “superior performance in modeling the near wall region”.

Emilio Baglietto - Nuclear Science & Engineering at MIT

Validation example

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0.01 0.1 1 10

Nu/Nu0 Bo

Data of Easby (1978) Data of Parlatan et al (1996)

• CFD results are well within the uncertainty bounds.
• Good prediction of Buoyancy effect.
• K-w SST results are conservative.
• Sensitivity shows acceptable influence of turbulence models.

K-e model K-w SST model

• Is this sufficient / adequate ?

Emilio Baglietto - Nuclear Science & Engineering at MIT

0.3 0.5 0.7 0.9 1.1 1.3 1.5 0.01 0.1 1 10

Nu/Nu0

Bo

k-omega-SST Model (ACME CFD) k-omega-SST Model (BCME CFD)

DBA conditions, flow reversal

• CFD Model predict 2x higher HTCs at Bo=0.2
• Did CFD fail?
• Was the Process Correct?
• This is not looking good

Emilio Baglietto - Nuclear Science & Engineering at MIT

CFD Results – failure mode analysis

Low-Re k-e K-w SST Velocity Turbulent Kinetic Energy

Emilio Baglietto - Nuclear Science & Engineering at MIT

How did we fail?

• Performance/Functional
• required functionality of the computer program to perform its safety

function and the accuracy of its results

 …  Must account for effect of buoyancy on heat transfer.  ..

• Missing a

fundamental critical characteristic.

• The model equations

do not have a buoyancy term for TKE and dissipation.

CFD – Code Manual

Gb ??

Emilio Baglietto - Nuclear Science & Engineering at MIT

Conclusions

• Yes, it can be done and it has been done.
• The CGD process provides a robust and flexible framework

to adopt CFD for Safety Analysis.

• The CGD process requires rigorous assessment of the

“functionality of the computer program to perform its safety function and the accuracy of its results”.

• For CFD this means understanding of the physical models

and VUQ of the models on the intended application.

• The CGD formalizes a process that is applied to all

Safety-Related Design and Analysis.

Can we apply CFD to Safety-Related Design and Analysis ?