Transcript Presentation Title - University of Manchester

SARNET – Severe Accident Research Network
University of Manchester
School of Mechanical Engineering, G. Begg Building
CFD Workshop on Test-Cases, Databases & BPG
for nuclear power plants applications
16th July 2008
M. Reeks1 and T. Haste2,1
1University
of Newcastle-upon-Tyne
2PSI Villigen, Switzerland,
INTRODUCTION
OVERVIEW

SARNET is a Network of Excellence in the Nuclear Fission area of the
EU 6th Framework Programme, with the general aim of integrating in a
sustainable manner European research on severe accident
phenomenology in light water reactors

The network started in April 2004 and will finish in September 2008; a
successor project is being negotiated for a further 4 years in the 7th
Framework programme

After a brief summary of project organisation and aims, this presentation
indicates how CFD methods are used in the project overall, with focus
on the Source Term area, that studies the release and transport of
radioactive fission products from the reactor core to the environment
T Albiol et al. ‚ SARNET: Severe Accident Research Network of Excellence, ICONE15, Nagoya, Japan, April 2007
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Severe
Accident
Research
NETwork of excellence
Currently:
–
18 European Countries and Canada
–
51 organizations
 19 Research organizations
 10 Universities
 11 Industry organizations
 4 Electricity producers
–
 7 Safety authorities and technical support
organisations
800 to 900 person-months per year
About 10M€ effort per year (1.6M€
funded by the EC per year)
–
SARNET – CFD Workshop, University of Manchester, July 2008
–
More than 230 researchers
–
About 20 PhD students
www.sar-net.org
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MAIN OBJECTIVES
SARNET OBJECTIVES

Resolution of still pending issues important for reactor safety

Optimised use of available resources and competences on severe
accidents throughout Europe

Knowledge transfer for safety application

Perpetuate the competence on severe accidents

Encapsulation of the knowledge base on severe accidents through the
lumped-parameter ASTEC code
–
this program calculates the progress of severe accidents in light water reactors from
initiating event through to release of radioactive fission products to the environment
–
it enables the results of the scientific research to be used in reactor applications
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ORGANISATION
SARNET ACTIVITIES


SARNET is organised into a number of work packages
covering
–
integrating activities (such as research prioritisation, database
management, ASTEC development)
–
jointly executed scientific research (focussed on corium,
containment and source term matters), and
–
spreading of excellence (such as organisation of training courses
and mobility of researchers)
CFD is one of a number of analysis methods used in the
jointly-executed scientific research (‘topical’) areas
–
used in all these areas, but mainly for containment and source term studies
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WORK PACKAGES
Integrating activities
Jointly executed
research activities
WP 1 : ACT
WP 2 : USTIA
WP 9,10,11 : CORIUM
Development of an
Advanced
Communication Tool
ASTEC Users Support
and Training,
Integration, and
Adaptation
Early phase core degradation
Late phase core degradation
Ex-vessel corium recovery
Implementation of
Experimental
Database
WP 3 : PHYMA
WP 12,13 : CONTAINMENT
WP 7 : SARP
WP 4 : RAB
WP 6 : IED
Definition of Severe
Accident Research
Priorities
WP 8 : IA
Integration
Assessment
ASTEC PHYsical
Model Assessment
ASTEC Reactor
Application
Benchmarking
WP 5 : PSA2
Level 2 PSA
methodology and
advanced tools
SARNET – CFD Workshop, University of Manchester, July 2008
Hydrogen behaviour
Fast Interaction in Containment
Spreading of
excellence activities
WP 17 : ET
Education and Training
WP 18 : BOOK
Book on severe accident
phenomenology
WP 19 : MOB
Mobility programme
WP 14,15,16 : SOURCE TERM
FP Release and Transport
Aerosol Behaviour impact on Source
Term
Containment Chemistry impact on
Source Term
WP 20 : Management
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ASTEC

CPA-THY
SYSINT
Containment
Thermal hydraulics
CPA-AFP
Aerosols and FP in
containment
SOPHAEROS
Aerosols and FP
In the reactor circuits
Safety system
management
IODE
ASTEC integrates the technical knowledge in SARNET
 Integral numerical simulation of reactor accident with core
melting (Severe Accidents)
DIVA
 IRSN-GRS property : ~ 10 m-y/y in charge of software
dt
development and user support
ELSA
ISODOP
CESAR
Radioactivity in
Containment
ELSA
FP relaese
DIVA
Core degradation
CESAR
Circuit
Thermalhydraulics
dt
SOPHAEROS
dt
 Has been distributed to 26 SARNET organizations
RUPUICUV
dt
DATABASE
SARNET scientists support
for model improvement
and
physical assessment:
MEDICIS/WEX
dt
 ASTEC capitalizes, in terms of models, all the knowledge
CPA-THY
dt
produced in the frame of the Network
CPA-AFP
dt
 40 trained users contribute
to joint validation
programme
Dt
(mobilizes around 20 m-y/year)
IODE
MEDICIS/WEX
Molten core concrete
interaction
RUPUICUV
Molten core ejection
And direct heating
Of containment
dt
 One major version delivered
in July 2005 (V1.2)
ISODOP
dt
SYSINT
 Size: ~ 350 000 instructions
 Speed: ~ 3-10 hours to compute 24 h of transients
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USE OF CFD - GENERAL
USE OF CFD METHODS IN SARNET


CFD is used in a number of applications, such as
–
design of experiments
–
interpretation of experimental results
–
plant studies, e.g. to determine the parameter ranges for separate-effect tests
–
benchmarking system-level codes, in this case principally ASTEC
–
one also notes use in reactor applications outside SARNET to look at detailed aspects where
lumped-parameter methods are not sufficient, e.g. where 3-D flows are important, CFD results can
be used to guide the use of lumped parameter codes regarding noding, X-flow resistances, other
tuneable parameters etc.
Validation of CFD methods and development of best practice per se are not main aims
within SARNET
–
the codes are applied rather than developed and validated, and the users are assumed to know
how to use their codes effectively
–
note also the CFD activities within OECD/NEA/GAMA, http://www.nea.fr/html/nsd/csni/cfd.htm, with
best practice guidelines, http://www.nea.fr/html/nsd/docs/2007/csni-r2007-5.pdf, these are not within
SARNET but many of the same organisations are involved
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USE OF CFD – CONTAINMENT STUDIES
CONTAINMENT STUDIES

Examples are:
–
Interpretation of results from the TOSQAN and MISTRA tests on influence of
containment sprays on the atmosphere behaviour (depressurisation, gas
mixing), comparison of LP and CFD methods, see also OECD International
Standard Problem 47 report http://www.nea.fr/html/nsd/docs/2007/csnir2007-10.pdf
–
Investigation of processes inside passive autocatalytic recombiners (PARs)
using data from the REKO-3 facility, influence on the containment
atmosphere and of steam condensation, hydrogen recombination, effects of
steam and oxygen depletion
–
Investigation of hydrogen combustion using data from the ENACCEF facility,
effect of concentration gradients on flame acceleration/deceleration
H Wilkening et al. ‚ European Research on Issues concerning Hydrogen Behaviour in Containment within the
SARNET Network of Excellence , ICAPP’08, Anaheim, USA, June 2008
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USE OF CFD – CONTAINMENT STUDIES
H Wilkening et al. ‚ op cit.
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USE OF CFD – SOURCE TERM STUDIES
SOURCE TERM STUDIES

Examples are:
–
Reactor calculations in combination with other codes such as the LP programs
ICARE/CATHARE and ASTEC to determine gas flows and compositions that may result
from air ingress into the vessel following hot leg and lower head breach (EdF, IRSN),
determining conditions for separate-effect tests on air oxidation of fuel and cladding
–
Design calculations for facilities investigating the dynamic chemical interactions of iodinecontaining and ruthenium-containing species in the primary circuit under severe accident
conditions (IRSN, VTT)
–
Interpretation of circuit chemistry aspects of the Phebus-FPT2 integral in-reactor
experiment on core degradation, and fission product release and transport, and
behaviour in-containment (IRSN)
–
Interpretation of an integral ThAI experiment (Becker Technologies) on iodine behaviour
in-containment coupled with thermal hydraulic and aerosol aspects, in the frame of a
SARNET benchmark led by GRS with contributions from GRS, IRSN and AECL
–
Investigation of results of the RECI experiments (IRSN) on the effects of PARs on
airborne iodine in the containment (IRSN, Demokritos, et al.)
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USE OF CFD – SOURCE TERM STUDIES
Reactor meshing for CFD calculation (Saturne)
Coarse meshing in the dome
40.000 to 60.000 cells
Refined meshing in the annulus zone
SATURNE calculation of flows in the lower head and cavity under air ingress conditions (EdF)
A Auvinen et al. ‚ Progress on Ruthenium Release and Transport under Air Ingress Conditions,
ERMSAR2007, FZ Karlsruhe, June 2007
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USE OF CFD – SOURCE TERM STUDIES
Illustrations of the ThAI facility
http://www.becker-technologies.com/web-e/html/Reaktorsicherheit/thai-anlagen.html
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CONCLUSIONS
CONCLUDING REMARKS

CFD methods have an important role within SARNET for support of
experiments, in plant studies and for benchmarking more detailed
models, for example in the major European severe accident analysis
code ASTEC, that is a main product of the network

The focus is on application rather than on development and validation

The applications are mainly in the areas of containment studies, and in
source term research

It is expected that CFD methods will continue to be used in the followon SARNET2 project in the 7th Framework programme, subject to the
satisfactory outcome of negotiations with the EC that are currently in
progress
The authors thank the European Commission for funding SARNET, in the 6th Framework Programme area
“Nuclear Fission: Safety of Existing Nuclear Installations”, under contract number FI6O-CT-2004-509065.
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