The effectiveness of denaturing plutonium with a 238Pu heat spike was evaluated as a safeguards deterrent for light water reactor (LWR) fuel. The following aspects were examined:
- the percentage of 238Pu denaturant required to sufficiently protect reactor-grade plutonium from national and subnational diversion attempts
- the production rate of denaturant in LWRs
- logistics requirements.
Calculations were also performed to determine the impact of 238
Pu precursors on fuel reactivity and economics. Results indicate that a 5% by weight denaturant is sufficient to produce desired safeguards effects in reactor-grade plutonium. Reactivity calculations show that a maximum increase in uranium enrichment from 3.2 to 3.7% is required to compensate for additions of 237
Np and 236
U in first-cycle fuel. Required modifications of a standard PUREX plant are estimated to result in an overall increase in reprocessing costs of ∼5%, which does not have a significant impact on reprocessing economics.