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Management of Commercially Generated Radioactive Waste - U.S. ...

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6.170<br />

A waste processing facility would be located at the repository site where spent fuel<br />

would be dissolved and prepared for injection, either directly as a dilute acidic liquid or<br />

as a neutralized grout. The prepared waste would be transferred by piping to the injection<br />

well field. Dilute acid waste, if used, would be injected into porous sandstone having<br />

shale caprock at depths <strong>of</strong> approximately 1,000 m. Neutralized grout would be injected into<br />

a shale formation having natural or induced fractures at depths <strong>of</strong> approximately 500 m. TRU<br />

waste would require an alternative disposal concept.<br />

Liquid high-level waste resulting from a reprocessing fuel cycle would be transferred<br />

directly to the waste preparation facility, colocated with the reprocessing plant. TRL'<br />

waste would be packaged and emplaced using an alternative disposal concept (Table 6.2.1).<br />

6.2.1.8 Transmutation<br />

Transmutation would function as an ancillary waste treatment process for the conversion<br />

<strong>of</strong> selected long-lived waste isotopes to shorter-lived isotopes potentially reducing the<br />

time during which repository integrity must be maintained. The process would be operated<br />

in conjunction with a waste management system using a suitable alternative disposal concept<br />

for disposal <strong>of</strong> radioactive waste, including transmutation products (Table 6.2.1). Because<br />

transmutation is a waste treatment process and not a disposal alternative, it cannot be<br />

assessed in terms <strong>of</strong> containment, barriers and remoteness in the same manner as these terms<br />

are applied to repositories.<br />

At a processing plant spent fuel would be dissolved and uranium and plutonium separated<br />

for recycle. Reprocessing wastes would be transferred to an adjacent partitioning facility<br />

where long-lived waste isotopes would be partitioned from the reprocessing waste stream.<br />

The residual waste streams, stripped <strong>of</strong> long-lived isotopes, would be processed for disposal<br />

using a suitable disposal concept. The isotopes selected for transmutation would be com-<br />

bined with recovered plutonium and uranium and shipped to a MOX-FFP.<br />

At the fuel fabrication plant the plutonium-uranium-waste isotope mixture would be fab-<br />

ricated into MOX fuel assemblies following addition <strong>of</strong> sufficient enriched uranium to<br />

achieve the desired end-<strong>of</strong>-cycle reactivity. TRU waste from the fuel fabrication plant<br />

would be sent to a colocated waste purification facility for recovery <strong>of</strong> waste actinides.<br />

Recovered actinides would be returned to the fuel fabrication facility for incorporation<br />

into MOX fuel; the residual waste would be processed for disposal using a suitable alterna-<br />

tive waste disposal concept (Table 6.2.1).<br />

The MOX fuel, containing the waste isotopes for transmutation, would be shipped in<br />

shielded casks to power reactors where a portion <strong>of</strong> the waste isotopes would be transmuted<br />

to stable or shorter-lived isotopes. Transmuted isotopes would be partitioned for disposal<br />

during the subsequent reprocessing cycle. Repeated recycles would be required to achieve<br />

nearly complete transmutation <strong>of</strong> the long-lived isotopes.<br />

Implementation <strong>of</strong> transmutation as an actinide waste treatment process requires that<br />

spent fuel be reprocessed to recover the actinides and that the actinides be recycled for<br />

transmutation, mandating a reprocessing-type fuel cycle.

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