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Table 1. Core performance of MA and I transmutation ADS
with proton beam power of 30 MW (1.5 GeV and 20 mA)
Core
Thermal power
K eff
Core height/diameter (cm)
Fuel compositions
Initial heavy metal loading (kg)
Transmutation of MA (kg/300 days) 250
Blanket
Thickness (cm)
NaI/(NaI+ZrH) (%)
Initial iodine loading (kg)
Transmutation of I (kg/300 days)
800 MW
0.95
100/115
60%MA + 40%Pu
4 000
Axial
25
50
765
35
Radial
16
40
839
22
An analysis of beam trip transient was made for the accelerator-transmutation plant [5]. Transient
of the primary coolant temperature, the water/stream temperature, the water/steam pressure, the
turbine flow rate were required at a time of 380 s after beam trip to prevent from overcooling. The
maximum temperature swing was 185°C in lead-bismuth, and 82°C for in water/steam for the case
when beam recovered at a time of 370 s. The temperature change during beam trip transient is shown
in Figure 2.
3. Scenario studies of ADS introduction in future fuel cycle
The effect of ADS on MA transmutation: transmutation performance by ADS has been studied
by assuming the existence of MA of 100 tons. As the MA transmuter, we selected the ADS system
with 800 MW thermal power with a 1.5 GeV and 20 mA proton beam, and with the core having an
effective neutron multiplication factor of 0.95. With the assumption of a load factor of 80%, the net
MA transmutation rate becomes approximately 250 kg/y. The system inventories of MAs in ADS fuel
cycle will be reduced from around 80 tons in 2050 to 20 tons in 2100, and will be minimised in 2150.
MA of 100 tons , that is, will be transmuted during 120 years.
Dependence of MA and iodine build-up on fuels, burn-up and cooling times: the amount of the
MAs produced in LWRs with UO 2
/ MOX fuels and an FBR with MOX fuel have been investigated
for various conditions such as fuel compositions, burn-up and cooling time duration as shown in
Table 2. For the UO 2
-LWRs, MA build-up increases slightly with increasing burn-up. The MA buildup
quantities for full MOX fuelled LWR are more than three times for the UO 2
fuelled LWRs. In
addition, MOX-FBR produces about two times MA comparative with UO 2
-LWR.
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