Technology Advances in Fast Reactors and Accelerator Driven Systems

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 CRP includes two stages. The first stage consists of analytical benchmarks on the BN-600 partially MOX (hybrid UOX/MOX) fuelled- and fully MOX fuelled- core models (Phases 1-4), and analyses supported by some experimental evidence obtained in the BFS critical facility (Phase 5). The second stage will extend the work to cases considering cores fuelled with minor actinides as analytical benchmark exercises (Phase 6).

The BN-600 hybrid core benchmark analyses in the first stage comprised three phases during 1999-2001: RZ homogenous (Pase 1), Hex-Z homogenous (Phase 2), and Hex-Z heterogenous and burnup benchmark (Phase 3). In the hybrid BN-600 core benchmark analyses, the results for several relevant reactivity parameters obtained by the participants with their own state-of-the-art basic data and codes were compared in terms of calculational uncertainty, and their effects on the ULOF transient behaviour of the BN-600 hybrid core were evaluated. The results of the BN-600 hybrid core benchmark analyses were presented at PHYSOR 2002. A synthesis report on the Phases 1, 2, and 3 studies is under final review.

From the recognition of significant interest in such cases, the benchmark analyses in the first stage were extended to the study of a BN-600 fully MOX fuelled core with sodium plenum above the core, including the transient analyses (additional Phase 4, BN-600 Fully MOX Fuelled Core Benchmark).

The comparison of the BN-600 MOX fuelled core benchmark results for the Phase 4 study shows good agreement between most parameters except for the sodium density coefficient. However, differences between the values of the main reactivity coefficients obtained by the participants, appear to be larger in the reference model (BN-600 full MOX core model) than those obtained in the previous model, with a traditional core arrangement (BN-600 hybrid core model). This arises mainly because of uncertainties in the proper modelling of the axial sodium plenum above the core. The Phase 4 study also concludes that the safety analysis of such a design would require the use of the most advanced computational tools (transport theory and three-dimensional Hex-Z modelling are required) which should be checked by representative experiments. A synthesis report on the Phase 4 study is under review. A paper on the results of the Phase 4 benchmark analyses, including the transient analysis, was submitted to PHYSOR 2004.

The Phase 5 study focused on checking the capability of predicting the criticality and sodium void reactivity effect (SVRE) value distribution through analysis of a benchmark model derived from BFS 62-3A (hybrid configured) critical experimental results in support to the analytical benchmark analyses performed in the previous phases of the CRP. In conclusion for both the criticality and the sodium void worth from the comparison of the (C-E) values of the results from the different participants, the uncertainty associated with the nuclear data is of the same size as the uncertainty in the simplified adjusted homogeneous benchmark experimental values. The Phase 6 study (BN-600 Full MOX Minor Actinide Core Benchmark) will focus on the use of minor actinides in BN-600 type reactors based on a closed fuel cycle concept. The Phase 6 study will consider the safety characteristics of a BN-600 reactor loaded with VVER plutonium and minor actinides from LWR typed VVER discharged fuel.

working materials

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First Research Coordination Meeting of the Coordinated Research Project on "Updated Codes and Methods to Reduce the Calculational Uncertainties of the LMFR Reactivity Effects"

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Working Material (ref: IWGFR-100) (restricted access only, contact scientific officer)
(format: pdf, 5463kB)

Second Research Coordination Meeting of the Coordinated Research Project on "Updated Codes and Methods to Reduce the Calculational Uncertainties of the LMFR Reactivity Effects"

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Summary Report (ref: IWGFR/103) (restricted access only, contact scientific officer)
(format: pdf, 16388kB)

Third Research Coordination Meeting of the Coordinated Research Project on "Updated Codes and Methods to Reduce the Calculational Uncertainty of the LMFR Reactivity Effects"

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Working Material (ref: TWGFR-106) (restricted access only, contact scientific officer)
(format: pdf, 24243kB)

Fourth Research Coordination Meeting of the Coordinated Research Project on "Updated Codes and Methods to Reduce the Calculational Uncertainties of LMFR Reactivity Effects"

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Working Material (ref: TWGFR-113) (restricted access only, contact scientific officer)
(format: pdf, 27454kB)

Fifth Research Coordination Meeting of the Coordinated Research Project on "Updated Codes and Methods to Reduce the Calculational Uncertainties of LMFR Reactivity Effects"

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Working Material (ref: TWGFR-120) (restricted access only, contact scientific officer)
(format: pdf, 11628kB)

Sixth Research Coordination Meeting of the Coordinated Research Project on "Updated Codes and Methods to Reduce the Calculational Uncertainties of LMFR Reactivity Effects"