Discharge bumup

Totally (as of 1/11/97) 36 reactor core reloads have been carried out at peak discharge bumup of 10% h.a. and experimental fuel bumup of 11.8% h.a. 

Core reactivity is controlled by means of chemical poison dissolved in the coolant, burnable poison rods and control rod assemblies. Soluble boron and burnable poison rods are utilized for shutdown and fuel bumup reactivity control. Control rod assemblies (37 clusters) are used for power regulation and hot shutdown. The core consists of 3 regions with enrichments of 2.4%, 2,67 % and 3. 0%, It has a negative temperature coefficient of reactivity. The core has a fuel cycle of 12 to 16 months with a discharge bumup of 30,000 MWd/tU. 

Fuel material. Natural UO2 Fuel inventoiy (tons of heavy metal) 881 of U Average core power density (kW/litre). 8.2 kW/L Average ftiel power density (kW/kgU) 23.5 kW/kgU Maximum linear power (W/m) 57 kW/m of fiiel rod Average discharge bumup (MWd/t) 7500 MWd/t of U Initial enrichment (wt%) 0.711 wt%... 

Fuel inventory (tones of heavy metal) 4.67 tonnes (initial core) Average core power density (kW/liter) 6.6 W/cc Average discharge bumup (MWd/t) 121,000 Initial enrichment or enrichment range (Wt%) 15.5% (AVG)... 

The dose fields associated with RU are higher than those associated with natural uranium. The isotopic composition and activity of unenriched RU UO2 powders depend inter alia on the reactor type, initial enrichment and discharge bumup of the PWR fuel, the time between spent PWR fuel discharge and reprocessing, the route chosen to convert the UNL to UO2, and the delay until fuel fabrication. 

Discharge bumup of fhe fuel should be more than 20 MWd/kg HE. 

MK-III, average core discharge bumup, (118 500 in an irradiation test assembly) MK-III, limit average bumup for fuel pin, in irradiation test assembly)... 

The fuel rods are designed to satisfy the fuel rod design criteria for rod bumup levels up to the design discharge bumup using the extended bumup design methods described in the Extended Bumup Evaluation report (Reference 6.9). 

Average discharge bumup Up to 60 GWd/t U with the current U.S. limit on lead rod (62GWd/tU) Upto70GWdAU with increased limit on lead rod (75 GWd/t U) Up to 120 GWd/t heavy metal... 

The operational cycle can be extended by raising the fuel enrichment and the discharge bumup of the fuel. The fuel cycle cost may also be reduced by... 

From these considerations, the target average discharge bumup of the Super LWR is provisionally determined as about 45,000 MWd/t, which is expected to be easily attainable with the current LWR fuel experiences. 

The gas plenum of the fuel rod may be placed in the upper part of the fuel rod or the lower part of the fuel rod. If the gas plenum is placed in the upper part of the fuel rod, its temperature is assumed to be equal to that of the outlet coolant, which is assumed to vary from 400 to 600°C. If the gas plenum is placed in the lower part of the fuel rod, its temperature is assumed to be equal to that of the inlet coolant (280°C). For the core average discharge bumup of 45,000 MWd/t, the fuel rod subject to the analysis is assumed to have a bumup of 62,800 MWd/t (fuel rod average) with peak pellet bumup of 71,700 MWd/t. The core is assumed to have fuel of three cycles with operation periods of 500 days/cycle. The average linear heat generation rates of the fuel rod in the first, second, and third cycles are assumed to be 285.6, 249.3, and 176.7 W/cm, respectively, as shown in Fig. 2.98 [34],... 

Average fuel assembly discharge bumup around 70 MWd/kgHM... 

Among them, the high power density is of most interest because it allows for reducing the size of the RPV, containment, and reactor building. Core average power densities of PWRs, BWRs, and the Super LWR are about 100, 50, and 60 W/cm, respectively. The average fuel assembly discharge bumup of... 

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