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7.0 DESIGN FEATURES AND ADMINISTRATIVE CONTROLS
The controls listed in the following sections are derived from the analysis in this
evaluation, and the controls are credited in the analysis to provide the barriers
necessary to prevent a criticality accident.
7.1 CONTROLS
The following controls could be implemented:
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1. |
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One aggregate accumulation of removed Capture
Coating & InstaCote material containing a maximum of 200 Grams of fissile material is
allowed. |
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Basis: |
200 grams or less of Pu in an aggregate
accumulation may be verified in two ways. First, assay scans must indicate 200 grams or
less (at the upper 95% confidence level) in the entire glovebox (including assay
uncertainty). Second, an area can be determined for which the maximum fissile accumulation
is less than 200 grams (at the upper 95% confidence level) using assay areal density data
and area calculations. Once the section(s) of coating material, potentially containing 200
grams of Pu, is removed from the glovebox, additional amounts of material may be removed
from the walls and removed subsequently from the glovebox. Once an accumulation of
stripcoat material potentially containing 200 grams of Pu is removed from the
glovebox,
the probability that multiple accumulations or containers totaling either 520 grams in a
plutonium-water mixture or 270 grams in Capture Coating & InstaCote material is
extremely small. |
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2. |
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An accumulation of less than 200 grams of
removed Capture Coating and InstaCote material can be collected and removed from the
Glovebox in any number of 4-liter containers. |
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Basis: |
By restricting the maximum container volume to
4 liters or less and the material mass to 200 grams or less, the probability that the
fissile material could accumulate into a critical configuration is extremely small. |
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3. |
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No storage of 200-gram accumulations nor
additional fissile material is allowed in the glovebox. |
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Basis: |
By restricting the maximum accumulation of
material to 200 grams or less, the probability that multiple accumulations or containers
totaling either 520 grams or 270 grams of Pu is extremely small. |
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4. |
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No mechanical compaction of stripcoat material
allowed. |
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Basis: |
By restricting the compaction of the stripcoat
to hand methods only, the naturally occurring densities for the dry and cured
plutonium-InstaCote material mixture cannot be exceeded. The use of the dry and cured
plutonium-InstaCote material mixture system to bound these stripcoat scenarios is
conservative for InstaCote densities of 1.629 g/cc or less and for plutonium masses not to
exceed 200 grams. |
7.2 ENGINEERED SAFETY FEATURES
No Nuclear Criticality Safety Engineered Safety Features are required for this operation.
8.0 SUMMARY AND CONCLUSIONS
The application and removal of Capture Coating & InstaCote material in gloveboxes has
been shown to meet the requirements of the double contingency principle provided that the
necessary controls listed in Section 7.1 are followed. While uniformly mixed
plutonium-glycerin-water systems were found to be somewhat less reactive than uniformly
mixed plutonium-water systems for the same amount of plutonium content, uniformly mixed
plutonium-InstaCote systems were found to be more reactive. The unlikely conditions
credited in this evaluation are as follows:
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either 520 grams of Pu in mixture with water or 270 grams of Pu in mixture with dry
Capture Coating & InstaCote,
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formation into either a 17-liter compact or spherically shaped plutonium-water mixture
or a 6-liter compact or spherically shaped (i.e., plutonium-InstaCote) mixture, and
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failure to remove 200 gram accumulations from the
glovebox.
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