Technical Meeting on the Nuclear Data Processing

4 - 7 December 2017, IAEA Headquarters, Vienna, Austria

Objectives

The Meeting is a follow-up meeting of the Consultancy Meeting on "New Evaluated Data File Processing Capabilities", held at the IAEA Headquarters in Vienna on 5-9 October 2015
(Summary report available at: INDC(NDS)-0695).
The purpose of the Technical Meeting is to assess the current status, availability of nuclear data processing systems, with emphasis on their capability/capacity to support Monte Carlo calculations that includes the treatment of self-shielding in the unresolved resonance region. An assessment of the influence of the processing steps on the nuclear responses: criticality and reaction rates are to be made.

Background

At the previous Meeting in October 2015 a number of different processing systems were presented as being under development, so the time seems appropriate to review their performance and initiate an intercomparison exercise with legacy ones. Candidate codes include the following:
• NJOY
• GRUCON
• ACEMAKER/PREPRO
• FRENDY
• CALENDF
• RULER
• FUDGE
• Other
Meeting participants are expected to present the current status of the codes system and short-term development plans, particularly the code capabilities to support the preparation of application libraries for Monte Carlo codes, including self-shielding in the Unresolved Resonance Range. The emphasis is on (but not limited to) ACE formatted files.

Basis

An earlier work was performed that compares results and methods for a number of different processing systems when computing for Monte Carlo and deterministic simulation average cross sections and self-shielding factors from probability tables in the unresolved resonance range CEA-R-6227.
Some preliminary work has also been performed on the comparison of performance of 2-band parameters (MB) prepared with the GROUPIE module of PrePro versus 20-bin probability tables (PT) generated with the PURR module of NJOY. The results are summarised in the report available on the IAEA-NDS web site INDC(NDS)-0711. In this report a series of benchmarks that are highly sensitive to self-shielding were identified.
The intercomparison exercise could consist of the following steps:

1. Prepare ACE's files with PT/MB for a few major nuclides (235U, 238U, 239Pu, etc.) from a given ENDF file (preferably IAEA-CIELO) with different processing codes,
2. Compare the effective cross sections entered into the ACE file, including self-shielded cross sections (or self-shielding factors) derived from the PT/MB (use ACELST and COMPLOT)
3. Run one Monte Carlo code using identical inputs but different ACE files for the major nuclides, taking the rest from a selected major library.
4. Intercompare Monte Carlo simulation responses for the cases with/without self-shielding.
5. Repeat step 4 using a different processing code and/or different Monte Carlo code.
Agreement on the details regarding the intercomparison exercise and understanding of the intercomparison results is one of the goals of the Meeting. It is expected that participants undertake individual simulations and provide responses to the IAEA a few weeks before the meeting so that at the Meeting the focus can be on the results and not the work to be done in the future.

Expected Output

• Document summarizing the status of the various codes.
• Working plan for a further processing code intercomparison exercise.
• Analysis of benchmarking results and recommendations.

Outcomes

The expected outcome is to improve the dependability and reliability of different processing codes and steps to generate fully fledged application libraries for Monte Carlo transport calculations, including self-shielding methods in the Unresolved Resonance Range. It also will lead to nuclear data format frame recommendations.