Abstract
An investigation of the utilization of TRistructural-
ISOtropic (TRISO)-coated fuel particles for the burning
of plutonium/neptunium (Pu/Np) isotopes in typical
Westinghouse four-loop pressurized water reactors is
presented. Though numerous studies have evaluated the
burning of transuranic isotopes in light water reactors
(LWRs), this work differentiates itself by employing
Pu/Np-loaded TRISO particles embedded within a silicon
carbide (SiC) matrix and formed into pellets, constituting
the fully ceramic microencapsulated (FCM) fuel concept
that can be loaded into standard LWR fuel element
cladding. This approach provides the capability of Pu/Np
burning and, by virtue of the multibarrier TRISO particle
design and SiC matrix properties, will allow for greater
burnup of Pu/Np material, plus improved fuel reliability
and thermal performance. In this study, a variety of
heterogeneous assembly layouts, which utilize a mix of
FCM rods and typical UO2 rods, and core loading
patterns were analyzed to demonstrate the neutronic
feasibility of Pu/Np-loaded TRISO fuel. The assembly and
core designs herein reported are not fully optimized and
require fine-tuning to flatten power peaks; however, the
progress achieved thus far strongly supports the conclusion
that with further rod/assembly/core loading and
placement optimization, Pu/Np-loaded TRISO fuel and
core designs that are capable of balancing Pu/Np
production and destruction can be designed within the
standard constraints for thermal and reactivity performance
in pressurized water reactors.
