Mixed Reload Design Using MOX and UOX Fuel Assemblies

Conference · Mon Jul 01 04:00:00 EDT 2002

OSTI ID:21064626

Ramon, Ramirez Sanchez J ^[1]; Perry, R T ^[2]

---

1. Instituto Nacional de Investigaciones Nucleares, Km 36.5 Carretera Mexico-Toluca, Ocoyoacac 52045, Edo. de Mexico (Mexico)
2. Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)

As part of the studies involved in plutonium utilization assessment for a Boiling Water Reactor, a conceptual design of MOX fuel was developed, this design is mechanically the same design of 10 X 10 BWR fuel assemblies but different fissile material. Several plutonium and gadolinium concentrations were tested to match the 18 months cycle length which is the current cycle length of LVNPP, a reference UO{sub 2} assembly was modeled to have a full cycle length to compare results, an effective value of 0.97 for the multiplication factor was set as target for 470 Effective Full Power days for both cycles, here the gadolinium concentration was a key to find an average fissile plutonium content of 6.55% in the assembly. A reload of 124 fuel assemblies was assumed to simulate the complete core, several load fractions of MOX fuel mixed with UO{sub 2} fresh fuel were tested to verify the shutdown margin, the UO{sub 2} fuel meets the shutdown margin when 124 fuel assemblies are loaded into the core, but it does not happen when those 124 assemblies are replaced with MOX fuel assemblies, so the fraction of MOX was reduced step by step up to find a mixed load that meets both length cycle and shutdown margin. Finally the conclusion is that control rods losses some of their worth in presence of plutonium due to a more hardened neutron spectrum in MOX fuel and this fact limits the load of MOX fuel assemblies in the core, this results are shown in this paper. (authors)

• Research Organization: The ASME Foundation, Inc., Three Park Avenue, New York, NY 10016-5990 (United States)
• OSTI ID: 21064626
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
BWR TYPE REACTORS
COMPARATIVE EVALUATIONS
CONTROL ELEMENTS
DESIGN
FISSILE MATERIALS
FUEL ASSEMBLIES
GADOLINIUM
MIXED OXIDE FUELS
MULTIPLICATION FACTORS
NEUTRON SPECTRA
PLUTONIUM
SHUTDOWN
URANIUM DIOXIDE