The fifth Research Co-ordination Meeting (RCM) of the Co-ordinated Research Project (CRP) on "Updated Codes and Methods to Reduce the Calculational Uncertainties of the LMFR Reactivity Effect" was held during 1-5 November 2004 in Vienna, Austria.

The general objective of the CRP is to validate, verify and improve methodologies and computer codes used for the calculation of reactivity coefficients in fast reactors aiming at enhancing the utilization of plutonium and minor actinides.

The objectives of the fifth RCM were:

• to review the progress acheived since the 4th RCM;
• to review and finalize the draft synthesis report on BN-600 MOX Fueled Core Benchmark Analysis (Phase 4);
• to compare the results of Phase 5 (BFS Benchmark Analysis)
• to agree on the work scope of Phase 6 (BN-Full MOX Minor Actinide Core Benchmark);
• to discuss the preparation of the final report.

In this context, review and related discussions were made on the following items:

• summary review of Actions and results since the 4th RCM;
• finalization of the draft synthesis report on BN-600 full MOX-fueled core benchmark analysis (Phase 4);
• presentation of individual results for Phase 5 by Member States;
• preliminary inter-comparison analysis of the results for Phase 5;
• definition of the benchmark model and work scope to be performed for Phase 6;
• details of the work scope and future CRP timetable for preparing a final report.