Fig. 1. Layout of radial scheme of FA with moderator mixed in fuel

Fig. 2. Layout of radial scheme of FA with insert moderator rods (color online)

Fig. 3. Layout of radial scheme of FA with external moderator layer

Fig. 4. Axial scheme of the single FA model (color online)

Fig. 5. Spectra comparison of FAs with different moderators mixed in fuel (a) Spectra of FAs with fuel mixed with different fractions of graphite, (b) Spectra of FAs with fuel mixed with different fractions of BeO, (c) Spectra of FAs with fuel mixed with different fractions of ZrC, (d) Spectra of FAs with fuel mixed with different fractions of ZrH₂

Fig. 6. k_eff results of FAs with different moderators mixed in fuel

Fig. 7. Comparisons of burnup curves (a) and spectra (b) of FAs with different moderator rods (color online)

Fig. 8. Burnup curves (a) and spectra comparison (b) of FAs with different moderator layers (color online)

Fig. 9. Variation of RTC of FA with the density of ZrH₂ moderator

Fig. 10. Schematic structure of the GFR core (color online)

Fig. 11. Calculation results of RTC of the GFR core

Fig. 12. Temperature field results of the fuel rod with peaking power