1. Summary of Nuclear Input for Safety Analysis for the DCLL TBM -update-
Mahmoud Z Youssef
UCLA
Contents:
- Nuclear Heating and Tritium Production During Operation
- Activation and After Heat levels at shutdown and at several times thereafter (after reaching conservative fluence level of 0.3 MWa/m2)
- Information (in digital form) were sent to INL (B. Merrill) for further safety analysis
Presented at ITER-TBM Meeting, UCLA, February 14-15, 2007

2. total TBM thermal power of 0.872 MW
Nuclear Heating
Component
Nuclear Heating (MW)
First Wall
0.082
Side Walls
0.036
Top/Bottom Walls
0.011
Flow Channel Divider
0.012
Radial Ribs
0.017
Back Wall
0.071
Front Pb-17Li Channel
0.253
Back Pb-17Li Channel
0.146
Total
0.628
Power density in Be PFC W/cm3
Peak power density in FS structure 8.2 W/cm3
Peak power density in Pb-17Li W/cm3
Peak power density in SiC FCI W/cm3
Adding surface heating at FW results in
total TBM thermal power of MW
Nuclear Energy multiplication is 1.006

3. Tritium Production
Tritium generation rate in the TBM is 2.1x1017 atom/s (1.02x10-6 g/s) during a D-T pulse with 500 MW fusion power
0.3 MWa/m2 average FW fluence corresponds to 4700 hr at full power. Neill Taylor recommended using this number for safety analysis. It was used by EU
Total tritium production is 17.3 g
Tritium production in the Be PFC is 1.4x10-9 g/s  g total
Peak tritium production rate in LiPb is 2.94x10-8 kg/m3s during the D-T pulse

4. Assumptions/data used in the Activation/Afterheat calculations
Average NWL at TBM= 0.78 MW/m2
TBM has the dimension of 62 cm toroidal x 200 cm poloidal x 100 cm radial (including 69.5 back shield)
Average NWL in ITER =0.57 MW/m2
A pulse is composed of 400 s on and 1800 sec off
Number of pulses to reach a fluence of 0.3 MWa/m2 at average NWL=0.57 MW/m2 is pulse
Structure (F82H) and SiC inserts are irradiated during a pulse and allowed to decay during the 1800 dwell time. This is repeated times.
For LiPb breeder in addition to the above irradiation scenario, within each pulse it is irradiated for 36 sec and un-irradiated for 20 sec

11. The waste disposal rating (WDR)
depends on the level of the long-term activation.
For the F82H structure: Nb-94 (T1/2=2.03x104 y),
Mn-53 (T1/2=3.7x106 y),
Ni-59 (T1/2=7.5x104 y), and
Nb-91(T1/2=6.8x102 y)
For Pb-17Li breeder: Pb-205 isotope (T1/2=1.52x107 y)
For SiC insert: C-14 (T1/2=5730 y)
Be-10 (T1/2=1.51x106 y)
The WDR was evaluated according to the Nuclear Regulatory Commission (NRC) 10FR61and Fetter waste disposal concentration limits.
The limits given are based on the assumption that all solid components are crushed before being disposed (no voids).
The WDR values according to the conservative limits of Fetter are:
For F82H structure: x10-2
For Pb-17Li breeder: x10-3
For SiC insert are: 2.1x10-4,
The WDR values are much lower than unity and therefore these materials are qualified for shallow land burial according to the Class C limits.