Study of Thorium-Plutonium Fuel for Possible Operating Cycle Extension in PWRs

Table 1

Control rod and boron worth, their limits, and the calculated values for the Th-MOX and the reference UOX core. For the Th-MOX core, the boron used for reactivity control is enriched to 60% in ¹⁰B instead of the usual 19.8% (natural isotopic composition), and stronger control rods are used.

Parameter	Limit	UOX-ref	Th-MOX
Min boron worth [pcm/ppm]	−15	−8.3	−8.7
Max boron worth [pcm/ppm]	−5	−6.2	−5.2
Min SDM [pcm]	2000	2559	3895
Max rod worth [pcm]	—	6505	7808