NEA Mandates and Structures

Joint Evaluated Fission and Fusion (JEFF) Nuclear Data Library Co-ordination Group

Mandate (Document reference):

• Established at the meeting of the NEA Steering Committee in October 1981
• Extension of the mandate approved at the 15^th meeting of the Executive Group on the Nuclear Science Committee [NEA/SEN/NSC/EG(2006)4]
• Extension of the mandate - Progress Report for 2005, Work in Hand in 2006 and Programme of Work for 2007 [NEA/SEN/NSC/EG(2006)2]
• Extension of the mandate approved at the 18^th Meeting of the Executive Group of the Nuclear Science Committee [NEA/SEN/NSC/EG(2009)4]
• Extension and modification of the mandate approved at the 19th meeting of the Executive Group of the Nuclear Science Committee NEA/SEN/NSC/EG(2010)4
• Extension of the mandate approved at the 22^nd Meeting of the Executive Group of the Nuclear Science Committee [NEA/SEN/NSC/EG(2013)4]
• Extension of the mandate approved at the 23^rd Meeting of the Executive Group of the Nuclear Science Committee [NEA/SEN/NSC/EG(2014)8]
• Extension and modification of the mandate approved at the 24^th Meeting of the Executive Group (Data Bank Management Committee) of the Nuclear Science Committee [NEA/SEN/NSC/EG(2015)6]
• Extension and modification of the mandate approved at the 5^th Meeting of the Management Board for the Development, Application and Validation of Nuclear data and Codes (MBDAV) [NEA/SEN/MBDAV(2018)2]
• Extension and modification of the mandate approved at the Eighth Meeting of the Management Board for the Development, Application and Validation of Nuclear Data and Codes (MBDAV) [NEA/SEN/MBDAV(2021)3] forthcoming
• Mandate of the Joint Evaluated Fission and Fusion (JEFF) Nuclear Data Library Co-ordination Group [NEA/SEN/MBDAV(2021)2]

Mandate (Document extract):

Extract from document NEA/SEN/MBDAV(2021)2

BACKGROUND

The objective of the Joint Evaluated Fission and Fusion (JEFF) project of the OECD/NEA is to develop and promote the use of high quality evaluated nuclear data sets in standard formats for a wide range of scientific and technical applications. The JEFF project assesses the needs for nuclear data improvements by initiating the necessary measurements, evaluations and benchmarking efforts. It is a collaborative effort between NEA Data Bank member countries. The JEFF Coordination Group (JEFF CG), whose members are nominated by the Management Board for the Development, Application and Validation of Nuclear data and Codes (MBDAV), has responsibility for the overall management of the project. The deliverable of the JEFF project is the JEFF library.

Following the successful release of version 3.3 of the JEFF nuclear data library (referred to as JEFF-3.3), the JEFF CG is now focusing on the demands for a JEFF-4.0 library with more ambitious requirements in terms of completeness, accuracy, physical consistency, uncertainties/margins, benchmarking/validation, processing and code interfacing. A quality assurance (QA) process and modern software developments will be implemented. The range of applications of a nuclear data library is wide and the corresponding needs are varied. This is clearly witnessed by the contributions presented by participants at the technical sessions organised by the JEFF CG and by the outputs of the Nuclear Science Committee (NSC) Working Party on International Nuclear Data Evaluation Co-operation (WPEC) meetings that reflect the interests of the contributing institutes and organisations. The JEFF CG will take on board the experience accumulated during the development of JEFF-3.2 and 3.3 (regarding the use of increased automation, computer power, new data formats and software interfaces) and will set new standards for the JEFF-4.0 nuclear data library and the methods by which it is developed and tested.

For the completion of JEFF-4.0, a two-step approach was identified in 2018. In the first step (2018-2021), standards and methods for the production, testing and maintenance of the JEFF Nuclear Data Library have been explored and developed. This first period has ended with the production of a test-library (JEFF-4T0) that is the vehicle for establishing proof of principle of the different aspects for development of the final library JEFF-4.0 and for increasing its range of applications and users.

In the second step (2021-2024), the new methods will be applied to produce the JEFF-4.0 library with a full set of uncertainties and covariance matrices, and a clear link to the experimental database underlying the estimates, uncertainties and covariances. The JEFF Project aims at a clear specification of the role of the basic microscopic reaction database and the role of the included integral benchmarks in the production of the library and its testing.

The JEFF-4.0 version and its successors aim to become fully consistent general-purpose libraries, containing all needed data (neutrons and other incoming particles, incident energies, target nuclides, reaction types, outgoing products and properties) and associated covariance information, which can be reliably used for a large range of applications, with a proven performance level equal or better than that of JEFF-3.3. The 4.0 release will also address the production of statistically-sampled, so-called ‘random’ files for JEFF-4.0, which are used for uncertainty quantification and propagation.

This long-term goal requires revising the JEFF evaluation and benchmarking process for improved coherence and efficiency. Completeness, version management, internal consistency, storage format and interaction with user code systems will be thoroughly reviewed to comply with modern software, database management and data visualisation tools, with the aim of ensuring flexibility and enhanced quality control for JEFF users in a modern computational setting.

The released JEFF libraries are publicly available without restrictions and distributed by the Data Bank in the form of computer files through a dedicated webpage.

SCOPE

The purpose of the Joint Evaluation Fission and Fusion (JEFF) Co-ordination Group (JEFF CG) is to develop, compile, verify, validate, document, distribute and promote high-quality sets of evaluated nuclear data in standard formats for a wide range of scientific and technical applications, with an emphasis on fission and fusion applications, under the label “Joint Evaluated Fission and Fusion (JEFF) Nuclear Data Library”.

GENERAL OBJECTIVES

The JEFF CG assesses the needs for nuclear data improvements and addresses those needs by initiating and actively promoting the necessary measurements, evaluation and benchmarking efforts in participating institutions. The results of these efforts contribute to the JEFF libraries. The JEFF CG aims at catering to the widest possible range of applications in NEA Data Bank participating countries with modern tools of development and dissemination.

The NEA Data Bank participating countries involved in JEFF will actively engage nuclear data users and evaluators from their national institutions to provide feedback on JEFF libraries, improved nuclear data evaluations and services.

WORKING METHODS AND INTERACTIONS

The JEFF CG is responsible for giving the final approval of all updates to the JEFF nuclear data library and for scheduling their official release.

The JEFF CG will collaborate with other similar national initiatives or projects aimed at improving evaluated nuclear data, including the NEA Working Party on International Nuclear Data Evaluation Co-operation (WPEC).

The JEFF CG will also co-operate with major international nuclear data projects and institutions, including:

• the International Atomic Energy Agency (IAEA), through the International Nuclear Data Committee (INDC) and the Nuclear Data Section (NDS);
• EURATOM-funded activities, such as the nuclear data projects of the European Union Framework Programme for Research and Innovation Horizon Europe, including the fission and fusion activities;
• the Joint Research Centre of the European Commission (JRC);
• the TENDL Nuclear Data Library initiative.

As is the case with all major nuclear data evaluation projects, the JEFF CG may choose to adopt nuclear data evaluations for its own JEFF releases from other national or international nuclear data evaluated libraries that are publicly available.

The NEA Data Bank Secretariat shall provide the following services to the JEFF CG:

• Organisation of JEFF meetings and Nuclear Data Weeks in consultation with the JEFF CG.
• Publication and distribution of JEFF CG documents, updating the corresponding web pages, and producing official summary records of each JEFF CG meeting.
• Assemble, release and distribute the official versions of the JEFF Nuclear Data Library. It is also responsible for collecting users’ feedback, maintaining up-to-date information, and archiving past file versions and records.
• Implement and co-ordinate a comprehensive quality assurance (QA) process involving verification, testing and benchmarking tasks according to well-defined criteria.
• As part of broader nuclear data services to the NEA Data Bank participating countries, provide a number of testing, processing and benchmarking services for evaluated nuclear data files.

MEMBERSHIP

As a mandated NEA Data Bank initiative, it is open for participation to all Data Bank member countries.

DELIVERABLES  

• A roadmap plan leading to the final release of JEFF-4.0. This will consider the successive release of test libraries as milestones where new proposals and upgrades are incorporated. This will allow JEFF participants to test these files and progressively gain confidence in the quality of the library in the making, while also revealing in time issues to address in subsequent test files.
• A series of specification documents that will consolidate other important milestones in the process of making JEFF-4.0. These will include:
  • the requirements for the contents of the JEFF-4.0 library;
  • the description of the enlarged suite of benchmarks covering the physics interests of the community;
  • the description of the new working methods for the production and quality assurance of JEFF nuclear data libraries, including the selection of codes that will be used for systematic benchmarking.
• The release of the JEFF-4.0 library at the end of 2024.