RESULTS

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In the source term calculations, it is assumed that the wastes are disposed after a total storage period of 50 years (before and after reprocessing).

After meshing the model and applying the boundary conditions, transient thermal analysis is performed to obtain temperature distribution around a disposal canister over a period of 20 years after deposition.

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Figure 6.6. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.90 m, SUOX with 33000

MWd/tHM burnup

Figure 6.7. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 5.54 m, SUOX with 40000

MWd/tHM burnup

Figure 6.8. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 10.00 m, SUOX with 50000

MWd/tHM burnup

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6.3.2. Minimum Distance between HLW Loaded Canisters

For VHLWs from reprocessing of 33000, 40000 and 50000 MWd/tHM burnup SUOXs, minimum canister spacings are 4.00, 3.90 and 3.90 meter respectively.

Time-dependent temperatures on the canister surface and at the interface between bentonite and rock for VHLWs with 33000, 40000 and 50000 MWd/tHM placed at the minimum distances are shown in Figures 6.9 through 6.11. For each burnup value, maximum temperature on the canister surface is 79.70, 79.77 and 79.82 °C and is reached at 8.5, 7.5 and 7.0 years after disposal.

Figure 6.9. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 4.00 m, HLW from reprocessing

of 33000 MWd/tHM burnup SUOX

Figure 6.10. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.90 m, HLW from

reprocessing of 40000 MWd/tHM burnup SUOX

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Figure 6.11. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.90 m, HLW from

reprocessing of 50000 MWd/tHM burnup SUOX 6.3.3. Minimum Distance between SMOXSRNU Loaded Canisters

Minimum distance between SMOXSRNU canisters for 33000, 40000 and 50000 MWd/tHM burnup values are 3.00, 4.80 and 13.00 meter respectively. Figures 6.12, 6.13 and 6.14 show the time dependent temperatures on the canister surface and at the rock-bentonite interface for minimum canister spacings.

Maximum temperature on the canister surface is 79.92, 79.85 and 79.95 °C and is reached at 16.5, 16.5 and 13.5 years after disposal, for 33000, 40000 and 50000 MWd/tHM respectively.

Figure 6.12. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.00 m, SMOXSRNU with

33000 MWd/tHM burnup

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Figure 6.13. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 4.80 m, SMOXSRNU with

40000 MWd/tHM burnup

Figure 6.14. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 13.00 m, SMOXSRNU with

50000 MWd/tHM burnup

6.3.4. Minimum Distance between SMOXSRDU Loaded Canisters

Minimum distance between SMOXSRDU canisters for 33000, 40000 and 50000 MWd/tHM burnup values are 3.42, 5.54 and 18.80 meter respectively. Figures 6.15, 6.16 and 6.17 show time dependent temperatures on the canister surface and at the rock-bentonite interface for minimum canister spacings. Maximum temperature on the canister surface is 79.82, 79.98 and 79.97 °C and is reached at 16.5, 16.0 and 9.5 years after disposal, for 33000, 40000 and 50000 MWd/tHM respectively.

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Figure 6.15. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.42 m, SMOXSRDU with

33000 MWd/tHM burnup

Figure 6.16. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 5.54 m, SMOXSRDU with

40000 MWd/tHM burnup

Figure 6.17. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 18.80 m, SMOX^SRDU with

50000 MWd/tHM burnup

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6.3.5. Minimum Distance between SMOXCCPu Loaded Canisters

Minimum distance between SMOXCCPu canisters for 33000, 40000 and 50000 MWd/tHM burnup values are 3.10, 5.00 and 16.00 meter respectively. Figures 6.18, 6.19 and 6.20 show the time dependent temperatures on the canister surface and at the rock-bentonite interface for minimum canister spacings.

Maximum temperature on the canister surface is 79.70, 79.94 and 79.88 °C and is reached at 16.5, 16.0 and 10.5 years after disposal, for 33000, 40000 and 50000 MWd/tHM respectively.

Figure 6.18. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.10 m, SMOXCCPu with

33000 MWd/tHM burnup

Figure 6.19. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 5.00 m, SMOXCCPu with

40000 MWd/tHM burnup

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Figure 6.20. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 16.00 m, SMOXCCPu with

50000 MWd/tHM burnup

6.3.6. Minimum Distance between SMOXCCEU Loaded Canisters

As seen in Figure 4.13, decay heat generation of SMOXCCEU is much lower than other SMOX types under consideration and it is in the same order of SUOX decay heat generation. When disposal canister is loaded with one SMOXCCEU assembly, the thermal limits cannot be attained. Thus, four SMOXCCEU assemblies are loaded into disposal canister. Minimum distance between SMOXCCEU canisters for 33000, 40000 MWd/tHM burnup values are 5.80 and 9.50 meter respectively. For 33000 and 40000 MWd/tHM, maximum temperature on the canister surface is 79.79 and 79.94 °C and is reached at 10.0 and 7.5 years after disposal, respectively. Figures 6.21 and 6.22 show the time dependent temperatures on the canister surface and at the rock-bentonite interface for minimum spacings for canisters loaded with 33000 and 40000 MWd/tHM SMOXCCEU assemblies, respectively. For 50000 MWd/tHM, temperature limits are exceeded shortly after canisters are placed in to disposal hole. Time dependent temperatures on the canister surface and at the rock-bentonite interface for 50000 MWd/tHM is given in Figure 6.23.

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Figure 6.21. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 5.80 m, SMOXCCEU with

33000 MWd/tHM burnup

Figure 6.22. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 9.50 m, SMOXCCEU with

40000 MWd/tHM burnup

Figure 6.23. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, SMOXCCEU with 50000 MWd/tHM

burnup

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6.3.7. Minimum Distance between SMOXPC Loaded Canisters

Minimum distance between SMOXPC canisters for 33000, 40000 and 50000 MWd/tHM burnup values are 3.10, 4.94 and 13.70 meter respectively. Figures 6.24, 6.25 and 6.26 show the time dependent temperatures on the canister surface and at the rock-bentonite interface for minimum canister spacings.

Maximum temperature on the canister surface is 79.55, 79.94 and 79.99 °C and is reached at 19.5, 16.0 and 11.0 years after disposal, for 33000, 40000 and 50000 MWd/tHM respectively.

Figure 6.24. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 3.10 m, SMOXPC with 33000

MWd/tHM burnup

Figure 6.25. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 4.94 m, SMOXPC with 40000

MWd/tHM burnup

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Figure 6.26. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 13.70 m, SMOXPC with 50000

MWd/tHM burnup

6.3.8. Minimum Distance between SRc-MOXSRNU Loaded Canisters

Minimum distance between canisters loaded with 33000 MWd/tHM burnup SRc-MOXSRNU assemblies is 12.60 meters. Maximum temperature on the canister surface is 79.88 °C and is reached at 14.5 years after disposal. Figure 6.27 shows time dependent temperature on the canister surface and at the rock-bentonite interface for minimum spacing for disposal canisters loaded with 33000 MWd/tHM SRc-MOXSRNU assemblies. In case of loading canisters with 40000 and 50000 MWd/tHM burnup SRc-MOXSRNU assemblies, temperature limits are exceeded very quickly. Figure 6.28 and 6.29 show time dependent temperatures on the canister surface and at the rock-bentonite interface for disposal canisters loaded with 40000 MWd/tHM and 50000 MWd/tHM SRc-MOXSRNU assemblies, respectively.

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Figure 6.27. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, spacing 12.60 m, SRc-MOXSRNU with

33000 MWd/tHM burnup

Figure 6.28. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, SRc-MOXSRNU with 40000 MWd/tHM

burnup

Figure 6.29. Temperature as a function of time on the canister surface and at the interface between bentonite and rock, SRc-MOXSRNU with 50000 MWd/tU

burnup

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