Abstract
The work described in this report presents simplified and advanced calculations in EU project EURAD work package 8 Spent Fuel Characterization and Evolution Until Disposal (SFC) subtask 2.1. The report presents Serpent 2 depletion calculations of one sample in a 6x6 BWR assembly. The Serpent calculated nuclide concentrations are compared to measured concentrations available in SFCOMPO-2.0. Decay heat of the calculated sample is also examined.
The calculations were performed for a two dimensional and a three dimensional assembly using different nuclear data libraries JEFF-3.2 (and JEFF-3.1.1), ENDF/B-VII.1 and JENDL-4.0. All calculations were repeated three times normalizing the reaction rates to different power densities based on different measurements of sample or assembly burnup. The best correspondence to measurement data was achieved using normalization based on 148Nd NDA measurement of sample burnup. The 3D model agreed with the measurements somewhat better than the 2D model particularly for the calculated plutonium and curium concentrations. One explanation to this is probably more realistic neutron spectrum at sample position resulting from more realistic coolant properties as a function of assembly height. Largest differences of the order of 10 % between calculations with different nuclear data libraries occur for 244Cm. Significant differences between 3-6 % are present also for 238Pu and 242Cm concentrations.
Both 2D and 3D calculations agreed with the measurement data within reported measurement uncertainties for nuclides 148Nd, and 238U and in the 3D calculations also for 240Pu and 242Cm. For the other ten/eight nuclides, differences were larger than measurement uncertainties. However, discrepancies in some of the measurement results indicate that the measurements might not be as accurate as claimed at least for some of the nuclides. Sensitivity and uncertainty analysis of the calculated concentrations are conducted in a second report related to SFC task 2.1.
The calculations were performed for a two dimensional and a three dimensional assembly using different nuclear data libraries JEFF-3.2 (and JEFF-3.1.1), ENDF/B-VII.1 and JENDL-4.0. All calculations were repeated three times normalizing the reaction rates to different power densities based on different measurements of sample or assembly burnup. The best correspondence to measurement data was achieved using normalization based on 148Nd NDA measurement of sample burnup. The 3D model agreed with the measurements somewhat better than the 2D model particularly for the calculated plutonium and curium concentrations. One explanation to this is probably more realistic neutron spectrum at sample position resulting from more realistic coolant properties as a function of assembly height. Largest differences of the order of 10 % between calculations with different nuclear data libraries occur for 244Cm. Significant differences between 3-6 % are present also for 238Pu and 242Cm concentrations.
Both 2D and 3D calculations agreed with the measurement data within reported measurement uncertainties for nuclides 148Nd, and 238U and in the 3D calculations also for 240Pu and 242Cm. For the other ten/eight nuclides, differences were larger than measurement uncertainties. However, discrepancies in some of the measurement results indicate that the measurements might not be as accurate as claimed at least for some of the nuclides. Sensitivity and uncertainty analysis of the calculated concentrations are conducted in a second report related to SFC task 2.1.
| Original language | English |
|---|---|
| Publisher | VTT Technical Research Centre of Finland |
| Commissioning body | European Union - Horizon 2020 |
| Number of pages | 17 |
| Publication status | Published - 2 Jul 2021 |
| MoE publication type | D4 Published development or research report or study |
Publication series
| Series | VTT Research Report |
|---|---|
| Number | VTT-R-00631-21 |
Keywords
- serpent 2
- Depletion
- spent fuel
- nuclide inventory
- sfcompo-2.0
- burnup