CM of INDEN on Light Elements (INDEN II)

Motivation

INDEN (International Nuclear Data Evaluation Network) is an initiative of the IAEA which aims at continuing the success of the NEA CIELO project in expediting advances in nuclear data evaluation through international collaboration among experts (TM CIELO).

The INDEN activities are split in three groups that focus on: nuclear data for actinides (and heavy elements) (INDEN I), light elements (INDEN II) and structural materials (INDEN III). The three working groups will meet at least once a year over the course of a 5-6 year period, and in addition there will be larger technical meetings of experts once every three year which will serve as a steering panel for the network.

The INDEN main goal is not only to produce improved (in terms of physics and/or performance in selected applications) evaluated data files for these nuclides, but in the process, to gain better understanding of the physics, to improve the models and approaches, the statistical analysis and treatment of uncertainties and hence to develop an evaluation methodology that is broadly accepted and adopted by the nuclear data community.

Therefore, the purpose of this forthcoming INDEN II meeting is to discuss the outstanding issues in the evaluation of light elements in the energy range from a few keV to 20 MeV. Such issues include lack of experimental data or discrepancies in experimental data, implementation of R-matrix algorithms where many channels are open (at higher energies), connecting the resolved-resonance region with unresolved resonance region and the statistical model regime, experimental covariances, etc.

The CIELO follow-up meeting that was held in Dec. 2017, identified three light systems as priorities for nuclear criticality and nuclear safety applications: neutrons on Be-9; N-14,15; Na-23. Although we would like to look into these nuclides and their existing data, and see what can be done to improve the evaluated data files, the meeting is open to discuss other cases with equally challenging issues, for example (alpha,n) reactions on F, O isotopes which are of particular interest in applications of spent fuel management.

By selecting one or two light systems from the above mentioned ones and working in the CIELO/INDEN collaborative way, the working group will address the above-mentioned issues and propose solutions or make important advances in the evaluation methodology and in the end produce improved data files.

Some of the technical topics that will be discussed at the meeting are:

• Experimental data covariances
• Data normalizations and treatment of uncertainties
• How to deal with dissociation thresholds
• How is R-matrix theory extended to higher energies with many more open channels?
• How are unresolved resonances (URR) treated?
• How is the connection with statistical model regime established? How are fluctuations treated?

Agenda

The Agenda is available here.

Report

The summary report is available as INDC(NDS)-0768.

Presentations