OECD/NEA Projects & WGAMA Activities On Severe … 2019 - Presentations...de-stratification by jet...

© 2019 Organisation for Economic Co-operation and Development ERMSAR 2019, 18-20 March 2019

OECD/NEA Projects & WGAMA Activities

On

Severe Accidents

L.E. Herranz1, D. Jacquemain2, N. Sandberg3

1CIEMAT, Spain; 2IRSN, France; 3NEA, Safety Division

ERMSAR

Prague (Czech Rep.) March 18-20 2019

© 2019 Organisation for Economic Co-operation and Development © 2019 Organisation for Economic Co-operation and Development 2 ERMSAR 2019, 18-20 March 2019

OUTLINE

• INTRODUCTION

• OECD-PROJECTS

• WGAMA ACTIVITIES

• FINAL REMARKS


INTRODUCTION

© 2019 Organisation for Economic Co-operation and Development

• Argentina • Australia • Austria • Belgium • Canada • Chile • Czech Republic • Denmark • Estonia • Finland • France • Germany • Greece • Hungary • Iceland

• Ireland • Israel • Italy • Japan • Korea • Latvia • Luxembourg • Mexico • Netherlands • New

Zealand • Norway • Poland • Portugal • Romania • Russia

• Slovak Republic • Slovenia • Spain • Sweden • Switzerland • Turkey • United

Kingdom • United States

OECD and NEA member OECD member, not NEA NEA member, not OECD

OECD & NEA Membership


CSNI

NEA Committee on the Safety of Nuclear Installations (CSNI)

CSNI Program Review

Group (PRG)

Working Group on Risk

Assessment (WGRISK)

Working Group on Analysis

& Management of Accidents

(WGAMA)

Working Group on Integrity

and Ageing of Components

and Structures (WGIAGE)

Working Group Human &

Organisational Factors

(WGHOF)

Working Group on Fuel Cycle

Safety (WGFCS)

Working Group on External

Events (WGEV)

Working Group on Electrical

Systems (WGELEC)

Working Group on Fuel

Safety (WGFS)

Senior Expert Group on Safety

Research Facilities for

Existing/Advanced Reactors 2

(SESAR/SFEAR2)

OECD/NEA Severe

Accident Joint Projs:

• BIP-3

• STEM-2

• THAI-3

• HYMERES-2

• ROSAU

• BSAF-2

• TCOFF

• Pre-ADES

• ARC-F


OECD PROJECTS


BIP-3

• Behaviour of Iodine Project on formation of methyl iodide from irradiated epoxy paint: - methane-iodine irradiations; - iodine adsorption/desorption from paints; - iodine leaching; etc.

Led by CNL (Canada); complements STEM

• Status: - 12 countries. - Phase 3 is 2016-19 - Final meeting 13-14 March 2019

https://www.oecd-nea.org/nsd/docs/2016/csni-r2016-5.pdf https://www.oecd-nea.org/nsd/docs/2011/csni-r2011-11.pdf

Image source: CNL


STEM-2

• Source Term Evaluation and Mitigation, experiments and model development focusing on: - Paint ageing and I interaction. - I species stability including in mixed aerosol particles; and - Ru revaporization & transport Led by IRSN (France); complements BIP

• Status: - 10 countries. - Phase 2 (2016-19) - Experimental phases well advanced - Some form of follow-up project under discussion.

https://www.oecd-nea.org/nsd/docs/2016/csni-r2016-5.pdf

Ru experiments. Image source: IRSN


•Experiments on Thermal-hydraulics, Hydrogen, Aerosols & Iodine in containment conditions during a severe accident: - Passive Autocatalytic Recombiner (PAR); - FP remobilization (from pools & from H2 combustion) - H2 combustion in a two-compartment system. Led by BT supported by GRS.

• Status: - 23 partners (16 countries). - Phase 3 (2016 - mid-2019). - Complementary to BIP and STEM. - Most experiments conducted. - Follow-up project: proposal being developed.

https://www.oecd-nea.org/nsd/docs/2016/csni-r2016-8.pdf

THAI-3


Fukushima-related Projects

• BSAF-2: Benchmark Study of the Accident at the Fukushima Daiichi NPP; ended except for final report.

• TCOFF: Thermodynamic Characterisation Of Fuel Debris and FP based on scenario analysis of severe accident progression at Fukushima-Daiichi NPS

• Pre-ADES: Preparatory study on fuel-debris analysis; on-going.

• ARC-F: Examinations inside reactor buildings & containment vessels & water sampling. Recently launched.


HYMERES-2

• H2 Mitigation Experiments for Reactor Safety Project – Ph. ;

led by PSI.

- Flow impacting obstructions and containment internal structures.

- Radiative heat transfer.

- Suppression pools.

- Safety components operation (spray and cooler).

• Duration 4 years (2017-21)

• 10 countries participating.


ROSAU

• Molten-core concrete interaction, spreading & cooling, led

by USNRC, experiments to be conducted at ANL.

• Duration 5 years (2019-24)

• 16 organisations (9 countries).

• Kick-off meeting 30-31 May 2019, SNL, USA


Timeline of Severe Accident Projects

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

BIP-2 BIP-3 STEM STEM-2 THAI-2 THAI-3

ROSAU

HYMERES HYMERES-2

BSAF BSAF-2

PreADES

A R C - F

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023


WGAMA ACTIVITIES


WGAMA Objectives


Technical areas

• RCS and systems thermal-hydraulics (scaling, BE and UQ).

• Corium/debris progression and cooling in- and ex-vessel.

• Gas combustion risk and mitigation.

• Radioactive releases and mitigation.

Types of Activities

• State Of the Art Reports (SOAR), technical reports (SR; TOPs).

• Benchmarks, ISPs and PIRT exercises, code validation matrix.

• Workshops and seminars.

• Identification and follow-up of joint research projects.

Scope


“Post-Fukushima” Reports (2011-2015)

• SR on SFP under LOCA conditions

• SR on hydrogen management and related computer codes

• SR on FCVS

http://www.oecd-nea.org/nsd/docs/indexcsni.html

Other Technical Reports

• SR on Long Term Management and actions for a damaged NPP

• SOAR on MCCI and ex-vessel molten core coolability

• Technical opinion paper on FCI (2018)

• Informing SAMG and actions through analytical simulation (2017)


Assessment Activities

• Benchmark on CFD modelling of H2 de-stratification by jet in containment

• Ability to predict in-vessel core melt progression and degraded core

coolability – benchmark exercise on TMI-2 plant

• Benchmark of fast–running tools to model releases during nuclear accidents

• PIRT on SFP under LOC conditions (WGFS)

• Containment code validation matrix

http://www.oecd-nea.org/nsd/docs/indexcsni.html


Workshops & Seminars

• International Severe Accident Management Conference (ISAMC),

Ottawa, October 2018

• CFD4NRS-7

Shanghai Jiao Tong University, Sept. 2018

• THICKET-4

Budapest, July 2016

• Technical Worshop on Source Term

Paris, January 2019

Rhttp://www.oecd-nea.org/nsd/docs/indexcsni.html


Benchmarks

• On SFP-LOCA (recommended).

• On corium/debris coolability (under discussion).

Workshops and seminars

• SWINTH : Workshop on instrumentation in TH, scope of next workshop

extended to SA instrumentation,

October 2019, Livorno (Italy)

• CFD4NRS-8: November 2020, Paris

• Severe Accident Instrumentation workshop November 2020, Japan

SOAR

• SOAR on H2 and CO.

Forthcoming Activities


FINAL REMARKS


• Provide support to regulatory decision-making

• WGAMA is very active in the areas of TH, CFD & SA.

• Numerous & diverse activities.

• Peer-reviewed technical reports (industrious production).

• Outstanding group dynamics!


Acknowledgements:

The WGAMA Bureau members: F. Barré (IRSN); H. Nakamura (JAEA);

F. D’Auria (UNIPI); K. Choi (KAERI); S. Bechta (KTH); D. Jacquemain

(IRSN); R. Lee (USNRC).

All the WGAMA members and those scientific and engineers who

conduct an amazing work.

Thank you for your attention!


Benchmark on H2 Stratification Break-up

Objective: Blind benchmark on a PANDA test (PSI).

Upward buoyant jet pointing to a He-rich layer.

Participation: 19 submissions

Observations:

• Large results spreading.

• Many calcs. missed basic features of jet flow (spread)

• BPGs!!!

• A coarse-meshing better results than fine meshing!

• Still too large-domain problem for CFDs?


International Severe Accident

Management Conference (ISAMC) Objective Recent advances made in the understanding, development,

implementation and verification of SAM.

• Lead: CNSC, KAERI, IRSN

• Held in Ottawa, 15-18 October 2018 (~200 participant; 21 countries)

• One day on human and organisational factors (WGHOF)


Objectives:

• Status of SFP accident and mitigation strategies.

• Current experimental and analytical knowledge.

• Strengths and weaknesses of analytical methods.

• Identify and list additional research needs.

Participation: Belgium, Canada, Czech Rep., EC-JRC, France, Germany,

Hungary, Italy, Japan, Spain, Switzerland & USA

Recommendations

• …

• Development of a CANDU-SFP tool is needed.

• Specific user guidelines for code applications to SFP accidents needed.

• Experiments targeting LWR SFP accidents needed.

• Identify important uncertainties via a PIRT exercise

• …

http://www.oecd-nea.org/nsd/docs/2014/csni-r2015-2.pdf


Objectives

• Review approaches to HMgmt in member states covering:

– safety requirements;

– mitigation systems & their implementation;

– accident management options;

– code validation.

• Identify advantages & drawbacks of the HMgmt options.

Participation: 16 countries (Canada)

Conclusions:

• Remaining research gaps:

- Impact of engineered systems (containment spray, air cooler, etc.).

- Assessment of R&D implementation in NPP safety analysis.

- Assessment of R&D implementation in SAMGs.

• Pressure loads due to H2 &/or CO combustion

http://www.oecd-nea.org/nsd/docs/2014/csni-r2014-8.pdf


Objectives:

Based on previous benchmark (TMI-2) conclusions.

Core-melt progression and impact of SAM actions

(core reflood & molten core slumping+corium behaviour)

• Simulate representative sequences with well-defined boundary conditions

• Sensitivity studies on more important and uncertain key parameters.

Participation: 10 organizations

Conclusions:

• …

• Early-phase degradation: similar in all codes (input-decks harmonized)

• Late-phase degradation: marked divergences (≠ degradation models +

choices of model options + discretization).

• Reflood phase (highly-degraded core):

- strongly depends on relocation & LH models & user-defined parameters;

- uncertainties still high, more effort on models.


• Synthesis of the last 30 years of research on melt coolability and MCCI.

• Emphasis on top flooding as a SAM

• 13 participants

Remaining issues

• Lack of data for long duration transients

• Improving the realism in plant simulations

• Effect of metal-rich composition

• Initial conditions of MCCI (debris/melt transfer to the pit)

• Improving melt coolability under top flooding

• Facilitating spreading

• Flooding in early MCCI

• Promoting melt eruption (e.g. sacrificial concrete

with high C content)

Reactor pitlocalized corium pouring and

accumulation

basemat

with or without

water

fast ablation

solid debris/crust

molten corium


CEA-JAEA-OECD/NEA WORKSHOP July 10-12, 2019

Materials Science for Severe Accident and Fukushima Daiichi decommissioning

SESSIONS: 1 - Integral and/or mechanistic severe accident codes 2 - Experimental set ups and high temperature experiments 3 - Thermodynamic (Calphad) modeling 4 - Accident Tolerant Fuels 5 - Uncertainties and Reliability

Thermodynamic Characterization Of Fuel Debris and Fission Products based on Scenario Analysis of Severe Accident Progression at Fukushima-Daiichi NPS (TCOFF)

Where ? JAEA/CLADS, Fukushima, Japan at FRC (Fukushima Research Conference)

KEY DATES:

Deadline for submission of abstracts: 20 April 2019

Deadline for Seminar registration: 31 May 2019

http://www.oecd-nea.org/confdb/confdb/conf?id=357

More information on the Workshop and the TCOFF Project:

https://www.oecd-nea.org/science/tcoff/

Contact persons: Dr Pascal Piluso (CEA): [email protected] Dr Davide Costa (NEA): [email protected] Dr Masaki Kurata (JAEA, local coordinator): [email protected]









mailto:[email protected]





OECD/NEA Projects & WGAMA Activities On Severe … 2019 - Presentations...de-stratification by jet...

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