PALAMA - PALAMA Project focused on analysis on nuclear fuel behaviour 4 years, 12.1 person-years, 14...

Click here to load reader

  • date post

    07-Mar-2020
  • Category

    Documents

  • view

    0
  • download

    0

Embed Size (px)

Transcript of PALAMA - PALAMA Project focused on analysis on nuclear fuel behaviour 4 years, 12.1 person-years, 14...

  • VTT TECHNICAL RESEARCH CENTRE OF FINLAND LTD

    PALAMA

    SAFIR2014 Final seminar

    19th – 20th March 2015

    Ville Tulkki

  • 2 2 17/04/2015

    Polttoaineen laaja-alainen mallinnus

    PALAMA

     Project focused on analysis on

    nuclear fuel behaviour

     4 years, 12.1 person-years, 14

    researchers, 1.45 M€

     Deliverables include 36

    technical reports, 15

    conference papers, 7 journal

    papers, 2 Master’s theses and

    1 Licentiate thesis

     Asko Arkoma, Santtu

    Huotilainen, Silja Häkkinen,

    Anitta Hämäläinen, Timo

    Ikonen, Seppo Kelppe,

    Joonas Kättö, Henri

    Loukusa, Anna Nieminen,

    Jan-Olof Stengård, Elina

    Syrjälahti, Ville Tulkki, Ville

    Valtavirta, Tuomas Viitanen

  • 3 17/04/2015 3

    PALAMA Highlights

     Completion of methodology for statistical assesment of the number of

    failed rods during large break LOCA

     Methodology development initiated in SAFIR2010 POKEVA

     Development of FINIX fuel module

     Improves fuel description in wide variety of host codes

     New methodology to describe cladding response to stresses

     To replace widely used strain hardening rule

  • Statistical evaluation of

    failed rods during large

    break LOCA

  • 5 17/04/2015 5

    Statistical methodology

     Holistic approach that provides a fraction of failed rods

     95% confidence that in 95% of LB LOCAs the actual number will be the

    same or less

     59 global APROS LB LOCA simulations, 1000 local fuel performance

    simulations per global case

     Also power histories from reactor physics codes required

     First application: EPR analysis performed for STUK

     STUK agreed to allow the publication of the results

     A. Arkoma et al., Nuclear Engineering and Design Volume 285, 15 April

    2015, Pages 1–14

  • 6 17/04/2015 6

    Calculation system

  • 7 17/04/2015 7

    Result

     At 95/95 confidence and probability, at most 1.2% of all the rods in the

    reactor fail

     10% maximum allowed for this kind of scenario

  • FINIX fuel module

  • 9 17/04/2015 9

    FINIX – fuel behavior model and interface for

    multiphysix applications

    Reactor

    physics

    Thermal

    hydraulics coolant conditions

    clad temperature

    Fuel

    behavior

  • 10 17/04/2015 10

    FINIX – fuel behavior model and interface for

    multiphysix applications

    Reactor

    physics

    Thermal

    hydraulics coolant conditions

    clad temperature

    FINIX

  • 11 17/04/2015 11

    FINIX models

     Coupled thermomechanical

    models

     Solves the time-dependent radial

    heat equation, in several

    independent axial nodes

     Rigid pellet (no elastic

    deformations)

     Cladding modeled as a thin-

    walled tube

     Thermal and mechanical solutions

    coupled through gap conductance

    and gap pressure

     Burnup effects can be taken into

    account in the initial state if given

    by, e.g., FRAPCON

  • 12 17/04/2015 12

    FINIX coupling

     Currently coupled to

     Serpent 2

     TRAB-1D/3D and Hextran

     Provides realistic description of

    fuel behaviour

    Fast transient with Serpent 2

    TMI-1 power peak with TRAB-1D

  • 13 17/04/2015 13

    FINIX

     More information on FINIX in PALAMA special

    article in the SAFIR2014 proceedings

     Also: ”Module for thermomechanical modeling

    of LWR fuel in multiphysics simulations”, T.

    Ikonen et al. Annals of Nuclear Energy (2014),

    accepted manuscript, in press.

     FINIX currently licensed to Aalto, KIT

    (Germany), Necsa (S. Africa) and CV Rez

    (Czech Republic)

     FINIX development continues in SAFIR2018

    PANCHO project

  • Cladding viscoelastic

    response

  • 15 17/04/2015 15

    Cladding creep response to changing

    conditions

     Cladding protects the fuel pellets

    from the environment and contains

    radioactive nuclides

     Creep deformation at high

    temperature and pressure

     Commonly assumed that changes in

    conditions can be accounted by

    strain hardening rule

     Accumulated strain invariant during

    changes

     Experiments show this is not true

  • 16 17/04/2015 16

    Viscoelastic model

     Metal anelastic behaviour

     Slow reversible deformation

     Usually assumed insignificant

     Irradiation and fuel behaviour

    make it relevant in cladding

     Can be illustrated with mechanical

    analogs

     Springs and dashpots parallel

    and in series

     Anelastic + permanent strain =

    viscoelasticity

  • 17 17/04/2015 17

    Cladding creep

    response

     Viscoelastic model enables

    reproduction of cladding response

    to transient stresses

    V. Tulkki, T. Ikonen Journal of Nuclear Materials,

    457 (2015) , pp. 324-329

    V. Tulkki, T. Ikonen, Journal of Nuclear Materials,

    445 (2014) pp. 98-103.

  • 18 17/04/2015 18

    Stress relaxation behaviour

     Viscoelastic model also

    capable of simulating stress

    relaxation behaviour

     Figure displays model

    performance in stress

    relaxation with coefficients

    fitted to creep experiment

     Doctoral thesis ”Modelling fuel

    behaviour and cladding

    viscoelastic response” due this

    summer V. Tulkki, T. Ikonen, “Modelling anelastic contribution to

    nuclear fuel cladding creep and stress relaxation”,

    submitted to Journal of Nuclear Materials (2015)

  • 19 17/04/2015 19

    Summary

     PALAMA was 4 year project focused on fuel

    performance issues

     Wide variety of case studies, model

    development, code development and analysis

     Several highlights presented here

     Completion of methodology for statistical

    assesment of the number of failed rods during

    large break LOCA

     Development of FINIX fuel module

     New methodology to describe cladding response

    to stresses

     More can be found from the SAFIR2014 Final

    seminar proceedings

  • TECHNOLOGY FOR BUSINESS