Abstract
Near-field calculations for the Swedish Nuclear Power Inspectorates Project-90 safety assessment have been performed using CALIBRE model. In most cases considered, the redox front migrates through the bentonite buffer and into the rock, where it becomes effectively immobilised. The fracture remains in a reducing state, which means that for solubility-limited nuclides, the concentration at the bentonite/fracture interface can never be greater than the reducing solubility limit. The calculations also show that significant retardation occurs for nuclides which are even moderately sorbed. The effect is less pronounced in the wider fracture and high flow cases, as the opportunity for diffusion from the fracture to the rock matrix is reduced. In contrast, the release from the near-field of poorly-sorbed nuclides which are not solubility limited is governed by the release rate from the fuel, the diffusive mass transfer resistance of the buffer, rock matrix and fracture, the initial inventories and the nuclide half-lives. In the reference case, the maximum dose potential of nuclides emerging from the near-field occur for I-129 and was 3.2 x 10{sup -7} Sv per canister-year, assuming the flux to be discharged directly into the wall receptor biosphere. The parameters which have the most impact on the reference base
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Worgan, K;
Robinson, P
[1]
- Intera Information Technologies, Chiltern House, Henley-on-Thames (United Kingdom)
Citation Formats
Worgan, K, and Robinson, P.
Project-90 Near-field calculations using CALIBRE.
Sweden: N. p.,
1992.
Web.
Worgan, K, & Robinson, P.
Project-90 Near-field calculations using CALIBRE.
Sweden.
Worgan, K, and Robinson, P.
1992.
"Project-90 Near-field calculations using CALIBRE."
Sweden.
@misc{etde_10138337,
title = {Project-90 Near-field calculations using CALIBRE}
author = {Worgan, K, and Robinson, P}
abstractNote = {Near-field calculations for the Swedish Nuclear Power Inspectorates Project-90 safety assessment have been performed using CALIBRE model. In most cases considered, the redox front migrates through the bentonite buffer and into the rock, where it becomes effectively immobilised. The fracture remains in a reducing state, which means that for solubility-limited nuclides, the concentration at the bentonite/fracture interface can never be greater than the reducing solubility limit. The calculations also show that significant retardation occurs for nuclides which are even moderately sorbed. The effect is less pronounced in the wider fracture and high flow cases, as the opportunity for diffusion from the fracture to the rock matrix is reduced. In contrast, the release from the near-field of poorly-sorbed nuclides which are not solubility limited is governed by the release rate from the fuel, the diffusive mass transfer resistance of the buffer, rock matrix and fracture, the initial inventories and the nuclide half-lives. In the reference case, the maximum dose potential of nuclides emerging from the near-field occur for I-129 and was 3.2 x 10{sup -7} Sv per canister-year, assuming the flux to be discharged directly into the wall receptor biosphere. The parameters which have the most impact on the reference base results are high flow, wide aperture and poor chemistry (i.e. high solubility limits and low sorption distribution coefficients). The effects of combining extreme values of parameters does not give results which are in proportion to their effect when applied in isolation. In the worst case variant (early canister failure high flow, wide aperture and poor chemistry) the maximum dose potential is 1.0 x 10{sup -4} Sv per canister-year, compared with 8.9 x 10{sup -6} Sv in the high flow case, 4.5 x 10{sup -7} in the wide aperture case, 2.3 x 10{sup -6} in the poor chemistry case and 3.9 x 10{sup -6} in the early failure, wide aperture and high flow case. (au).}
place = {Sweden}
year = {1992}
month = {Feb}
}
title = {Project-90 Near-field calculations using CALIBRE}
author = {Worgan, K, and Robinson, P}
abstractNote = {Near-field calculations for the Swedish Nuclear Power Inspectorates Project-90 safety assessment have been performed using CALIBRE model. In most cases considered, the redox front migrates through the bentonite buffer and into the rock, where it becomes effectively immobilised. The fracture remains in a reducing state, which means that for solubility-limited nuclides, the concentration at the bentonite/fracture interface can never be greater than the reducing solubility limit. The calculations also show that significant retardation occurs for nuclides which are even moderately sorbed. The effect is less pronounced in the wider fracture and high flow cases, as the opportunity for diffusion from the fracture to the rock matrix is reduced. In contrast, the release from the near-field of poorly-sorbed nuclides which are not solubility limited is governed by the release rate from the fuel, the diffusive mass transfer resistance of the buffer, rock matrix and fracture, the initial inventories and the nuclide half-lives. In the reference case, the maximum dose potential of nuclides emerging from the near-field occur for I-129 and was 3.2 x 10{sup -7} Sv per canister-year, assuming the flux to be discharged directly into the wall receptor biosphere. The parameters which have the most impact on the reference base results are high flow, wide aperture and poor chemistry (i.e. high solubility limits and low sorption distribution coefficients). The effects of combining extreme values of parameters does not give results which are in proportion to their effect when applied in isolation. In the worst case variant (early canister failure high flow, wide aperture and poor chemistry) the maximum dose potential is 1.0 x 10{sup -4} Sv per canister-year, compared with 8.9 x 10{sup -6} Sv in the high flow case, 4.5 x 10{sup -7} in the wide aperture case, 2.3 x 10{sup -6} in the poor chemistry case and 3.9 x 10{sup -6} in the early failure, wide aperture and high flow case. (au).}
place = {Sweden}
year = {1992}
month = {Feb}
}