Search - OECD Nuclear Energy Agency

Figure 6. FP target configuration
a) Plate Type for I-129 b) Rod Type for I-129
Table 3 shows the results of evaluations. The higher transmutation rate for both 99 Tc and 129 I are
achieved in Type B than Type A. The loading amount of 129 I for Type B is reduced by 30% compared
to that of Type A. However, there is not much difference between two types in terms of the total
amount of the transmuted 129 I. In addition, the pin power peaking is kept within an acceptable range in
both types.
Table 3. Performance of FP Targets in the HYPER System
Target
configuration
Type A
Initial loading
(kg)
Transmuted
(kg/yr)
Transmutation
rate(%/yr)
99
Tc 901.8 54.2 6.01
129
I 129.72 13.12 10.09
Pin power
peaking
1.211
Type B
99
Tc 901.8 57.8 6.41
129
I 93.8 13 13.90
1.232
As mentioned before, the support ratio of the HYPER is expected to be about ~5. In terms of
material balance, the HYPER system is desired to have the support ratio for 99 Tc and 129 I similar to that
of TRU. The optimised configuration Type B can transmute 57.8 kg, 13 kg of 99 Tc and 129 I,
respectively. In general, LWR (1.0 GWth) produces about 8.826 kg of 99 Tc and 2.721 kg of 129 I a year.
The HYPER system itself generates about 7.9 kg and 2.3 kg of 99 Tc and 129 I due to the TRU
transmutation. As results, the net support ratios of the HYPER are estimated to be 5.7 and 4.0 for 99 Tc
and 129 I, respectively. The fission product support ratios are very close to that of TRU in the HYPER
system.
6. Safety factor evaluation
As mentioned, the localised thermal flux increases the pin power peaking of TRU assemblies.
The target configuration is optimised to minimise such an impact. Figures 7 and 8 represent the
neutron energy spectrum for the target configuration of Type A and B. The energy spectrum for the
485