NEA Mandates and Structures

Expert Group on a Holistic Process for Decision Making on Decommissioning and Management of Complex Sites (HDCS)

Chair(s): Secretary:  Martin BRANDAUER
Member(s):All NEA member countries
Full participant(s): European Commission
Under the NEA Statute
Observer(s)(International Organisation): International Atomic Energy Agency (IAEA)
By agreement
Date of creation:25 June 2020
End of mandate:30 June 2022

Mandate (Document reference):

  • Revised mandate of the Committee on Decommissioning of Nuclear Installations and Legacy Management approved under the written procedure on 11 January 2019 by the CDLM members [NEA/DLM(2018)3] and on 20 March 2019 by the Steering Committee members [NEA/NE(2019)8]
  • The Radioactive Waste Management Committee Statement [NEA/RWM(2016)7/REV1]
  • Sub-Group Reporting to the Parent Committee [NEA/CDLM/RWMC(2019)2]
  • Mandate of the Expert Group on Characterisation Methodology of Unconventional and Legacy Waste (EGCUL) (2018-2020) [NEA/RWM(2018)1/REV1]
  • Summary Record of the First Meeting of the Committee on Decommissioning of Nuclear Installations and Legacy Management [NEA/DLM/M(2019)6/FINAL]
  • Summary Record of the Bureau Meeting of the Committee on Decommissioning of Nuclear Installations and Legacy Management (CDLM) on 24 January 2020 [NEA/DLM/M(2020)3/FINAL, forthcoming]
  • Summary Record of the Extraordinary Bureau Meeting of the Committee on Decommissioning of Nuclear Installations and Legacy Management (CDLM) on 16 April 2020 [NEA/DLM/M(2020)4, forthcoming]
  • Mandate of the Expert Group on a Holisitic Process for Decision Making on Decommissioning and Management of Complex Sites (HDCS) [NEA/DLM(2020)6/FINAL]

Mandate (Document extract):

Extract from the document NEA/DLM(2020)6/FINAL



The HDCS will develop a holistic process for decision-making and provide guidelines to allow an integral progression from recognition to resolution to decommission and manage complex sites as a CDLM third-level expert group.


To provide an integral process for a progression from recognition1 to resolution of complex sites, the CDLM has determined to establish the Expert Group on a Holistic Process for Decision Making on Decommissioning and Management of Complex Sites (HDCS). The objectives of this expert group are:

1) To develop a reliable, effective and efficient process that identifies, assesses, controls and manages risk (societal, economic, environmental) associated with decommissioning and legacy management of complex sites. 

2) To develop guidelines and identify needed decisions on how to implement this process.

In this context, the HDCS will carry out the following key tasks:

i. Identify the key constraints affecting control of risks at complex sites from a holistic perspective (including nuclear, radiological, industrial and environmental) and develop an understanding of the key challenges to achieving overall optimisation of risk management taking into account all relevant factors and bearing in mind the long timeframes that may be involved;

ii. Develop recommendations on the type of information required to support risk-informed decision making processes;

iii. Identify the scientific, technical and regulatory basis needed to enable the implementation of a proportionate, graded and reasonable approach to decommissioning, waste retrieval and site remediation activities;

iv. Describe the overarching holistic process as a framework for moving from recognition of a complex situation at a site to resolving all issues, and develop what decisions may be needed for its effective application towards the intended end-state.

‘Framework’ here refers to a high-level strategic outline intended to support application of integrated approaches to planning and implementation of decommissioning and legacy management projects. The framework may incorporate sub-divisions addressing different stages in the process.

Working methods

The mode of operation of the HDCS is based upon annual plenary meetings and an ongoing, project-oriented, working programme, including sharing of experience through case studies and topical workshops.

A Bureau consisting of the Chair and one or more Vice-Chairs will coordinate and facilitate the work of the HDCS. The Bureau would normally meet once or twice a year, with one meeting normally held in conjunction with the annual HDCS plenary meeting. 

Communication within the HDCS will primarily take place through annual plenary meetings. The plenary meeting will be devoted to the following:

  • exchange of information on recent developments in the member countries;
  • in-depth discussions of current developments and of topical issues, where additional specialists may also be invited;
  • identification of main lessons to be reported to the CDLM, including organising topical sessions at the CDLM plenary meetings; and
  • discussion and co-ordination of the working programme.

The HDCS will report to the CDLM, or to the relevant second-level working party should such be created, at the annual meetings of the parent body.

Additionally, the HDCS: (i) will identify resources and schedules for its activities; (ii) will form task teams to work on specific projects and to organise workshops, as appropriate; and (iii) will review the working programme and the effectiveness of the programme.

In fulfilling its Mandate, the HDCS will primarily be supported by the staff of the NEA Division of Radioactive Waste Management and Decommissioning.


The HDCS is a task-oriented expert group. It aims for a composition that includes a diverse range of experts in the field of decommissioning and legacy management, nominated by the member organisations of the CDLM. This representation will be wide-ranging, including policy makers, regulators, implementers and decommissioning specialists in legacy management.


The work of the HDCS is complementary to that of the IAEA and the EC; HDCS will co-operate with its relevant counterparts as well as provide relevant input to the activities of these institutions, as appropriate.

Through the CDLM and the NEA Secretariat, the HDCS will co-operate with other NEA standing technical committees and their subsidiary bodies when relevant, in particular, those of the Radioactive Waste Management Committee (RWMC), and the Committee on Radiological Protection and Public Health (CRPPH). The HDCS may also co-operate with the NEA Co-operative Programme for the Exchange of Scientific and Technical Information Concerning Nuclear Installation Decommissioning Projects (CPD), the OECD Environment Directorate and other international organisations on matters of common interest.

In particular, the HDCS will take into account the following NEA reports and publications:

  • Challenges in Nuclear and Radiological Legacy Management: Towards a Common Framework for the Regulation of Nuclear and Radiological Legacy Sites and Installations. [NEA 7419: Challenges in Nuclear and Radiological Legacy Site Management]
  • The Evolving Use of Social Media as a Communication Tool by Nuclear Regulatory Organisations [NEA/CNRA/R(2019)5
  • Management of Radioactive Waste after a Nuclear Power Plant Accident [NEA 7305
  • Towards an All-Hazards Approach to Emergency Preparedness and Response [NEA 7308]


The expert group will produce a report with the support of the Secretariat.

[1] It is intended that the integral process will include advice on how to address a site with different levels of uncertainties, i.e. a site with no clear governance (e.g. policy, regulation) or funding.

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