NEA Mandates and Structures

Expert Group on Liquid Metal Technology

Chair(s):	Paul SCHUURMANS, Belgium	Secretary:	Stéphanie CORNET (stephanie.cornet@oecd-nea.org)
Member(s):	All NEA member countries^*
	Russia (Suspended*)
	^*Russian Federation suspended pursuant to a decision of the OECD Council.
Full participant(s):	European Commission Under the NEA Statute
Observer(s)(International Organisation):	International Atomic Energy Agency (IAEA) By agreement
Date of creation:	30 June 2015
End of mandate:	29 June 2021

Mandate (Document reference):

Approved at the 26^th meeting of the Nuclear Science Committee in June 2015 [NEA/SEN/NSC(2015)2]
Revised and extended at the 15th Meeting of the Working Party on Scientific Issues of the Fuel Cycle in February 2017 [NEA/SEN/NSC/WPFC(2017)2]
Mandates of the Working Party on Scientific Issues of the Fuel Cycle (WPFC) and its Expert Groups [NEA/SEN/NSC/WPFC(2018)1]
Summary Record of the 17^th meeting of the Working Party on Scientific Issues of the Fuel Cycle held on 6 February 2019 [NEA/SEN/NSC/WPFC(2019)1]
Mandates of the Working Party on Scientific Issues of the WPFC and its Expert Groups [NEA/SEN/NSC/WPFC(2019)2]

Mandate (Document extract):

Extract from document [NEA/SEN/NSC/WPFC(2019)2]

Mandate

The former Expert Group on Heavy Liquid Metal (HLM) technology was active for several years. Its main objective was to issue a handbook with a collection of theoretical approaches and experimental data in order to deliver recommendations relevant for the design of HLM nuclear systems. After the second version of the handbook was issued, the EGHLM has re-discussed its scope and future related activities. In particular, as suggested by the Working Party on Scientific Issues of the Fuel Cycle (WPFC), it has been decided to include liquid sodium (Na) activities in the future work plan of the expert group. Secondly, the expert group will aim to take the next step in the assessment of available data to bring it closer to application in design, construction and licensing issues on the one hand and operation, in-service inspection, handling and maintenance on the other hand.

Objectives & Scope

Under the guidance of the WPFC, the Expert Group on Liquid Metal Technology (EGLM) will undertake activities, with the goal to "translate" fundamental scientific understanding to application in support of (1) the development of construction codes used for design (design rules); (2) key technical issues for licensing; and (3) recommendations for operation, inspection and handling.

The topical areas and objectives of the expert group are:

Environmental conditions and factors that affect materials behaviour relevant for the structural integrity of confinement barriers and components. These include the impact on mechanical properties from the environment such as irradiation effects and liquid metal embrittlement, as well as environmental assisted property effects like corrosion.

The objective for this topical area is to assess the environmental effects relevant for construction standards via a fundamental understanding of materials behaviour (corrosion and mechanical properties in the liquid metals and under irradiation). The possibility of experimental data sharing among participants and analyses is to be investigated.

Coolant and cover gas issues. The focus is placed on issues relevant for radiological impact assessment, operation, including maintenance, inspection and handling, etc. Topics to be addressed are the chemistry, radiochemistry and physics of the coolant, its interaction with the cover gas, the impact of irradiation, the influence of corrosion, transport of radionuclides in the coolant, etc.

The objective for this topical area is to answer key technical issues to address radiological impact, operation, handling, maintenance and inspection as relevant for licensing.

Thermal-hydraulics for liquid metals. Thermal hydraulic behaviour of the coolant is a crucial factor in the sense that it essentially determines a large part of the environmental conditions for materials and the cooling such as the flow distribution and mixing, temperatures distribution, stratification and instabilities, pressure variations, coolant structure interactions, etc.

The objective for this topical area is to collect and assess experimental data in order to improve knowledge of the environmental conditions for materials and the coolant behaviour.

Working Methods

Two taskforces will be established on Na and HLM. To improve efficiency, the taskforces will meet in parallel. At each meeting, a plenary session will be organised to discuss and compare results in order to identify potential commonalities and synergies.

The activities of the two taskforces are to:

Survey current fundamental knowledge on the effect of liquid metal environment on material behaviour;
Assess data management requirements with regards to the type of data, type of test and access conditions;
Compile and assess data on the effect of liquid metal environment on material behaviour;
Survey and compare existing methodologies to understand the underlying degradation mechanisms;
Identify further research and development needs to complement experimental databases and improve the modelling methodologies;
Generate status report on liquid metal environmental effects (on materials);
Compile and assess data for operation, inspection, handling, and maintenance of liquid metal reactors, with due account to operating experience feedback;
Identify key technical issues and lessons learned for safe and reliable operation, inspection, handling, and maintenance in support to reactor and system design and future operation;
Compile and assess data on liquid metal thermal hydraulics (for Na the analysis will focus on data related to environmental conditions for materials);
Provide assessment of thermal-hydraulic experiments and identify further research and development needs to improve knowledge of the environmental conditions for materials;
Code-to-code, code-to-experiment benchmark studies.

Deliverables

The deliverables of the EGLM will be the following:

State-of-the-art report on the liquid metal environmental effects on materials;
Report on data management requirements for structural materials and thermal-hydraulic;
Report on key technical issues and lessons learned for safe and reliable operation, inspection, handling, maintenance, decommissioning and waste management of liquid metal cooled reactors;
Report on liquid metal thermal hydraulics.

Relationship with other bodies

The expert group will liaise closely with other NEA working groups, especially the Expert Group on Innovative Structural Materials (EGISM) and those operating under the guidance and the Committee on the Safety of Nuclear Installations (CSNI) in order to ensure the respective work programmes are complementary and to provide advice and support, where required, and undertake common work, where appropriate. The EGLM will also work in co-operation with the IAEA Nuclear Power Technology Development Section and in particular the Technical Working Group on Fast Reactors (TWG-FR) and with the Sodium Properties and Safe Operation of Experimental Facilities in Support of the Development and Deployment of Sodium-cooled Fast Reactors project (NAPRO). Key sources of experimental data to be reviewed include (but are not limited to) output from NAPRO and the Material Database of the European Commission (MatDB).