Updated Tritium Breeding Requirement in Fusion Nuclear

Science Facility (FNSF)

Mohamed SawanUniversity of Wisconsin-Madison

Mohamed AbdouUCLA

With input from Scott Willms-LANL

FNST Meeting at UCLAAugust 18-20, 2009

1

Objective Determine the required TBR in the FNSF as a function of

fusion power and available external tritium supply

TBR determined for three options Required FNSF TBR to ensure it does not run out of

tritium fuel during its lifetime Required FNSF TBR to ensure that 5 kg of tritium is

available at end of ITER and FNSF operation for startup of DEMO

Required FNSF TBR to ensure that 10 kg of tritium is available at end of ITER and FNSF operation for startup of DEMO

Assume that ITER has priority over FNSF for using external tritium supply from CANDU reactors

2

Projected World-Wide CANDU Tritium (from Scott Willms, LANL)

3

Initial ITER Schedule

4

Assumptions:•2016 ITER start with 2020 D-T•2 kg working inventory that builds up over 2 years beginning 2018•At end of 20 ITER operation half of working inventory lost to waste

External Tritium Supply Available for FNSF(from Scott Willms, LANL)

5

Assumptions:•2016 ITER start with 2021 DT•2 kg working inventory that builds up over 2 years prior to DT•At end of 20 ITER operation half of working inventory lost to waste

FNSF Assumptions

6

2021 FNSF start (same time as DT start in ITER) 1 year HH followed by 1 year DD operation 3 years DT operation at 10% availability followed by 10 years DT

operation at 30% availability Fusion power in the range 50-400 MW considered A tritium inventory is maintained at all time during DT operation to

cover hold-up in chamber components, tritium processing system, and needed reserve

This working inventory is assumed to be 0.4 kg at 100 MW fusion power (scaling from ITER)

Working inventory scales linearly with fusion power and builds up over the 2 years preceding DT operation

At end of 15 year FNSF operation half of the working inventory is lost to waste with the rest added to supply available for DEMO

Tritium burn rate is 55.6 kg/GWy Tritium decays at rate of 5.5% per year

Total External Tritium Supply Required by FNSF (to cover burn, inventory, decay)

Has Strong Dependence on TBR and Pf

7

0

5

10

15

20

0 5 10 15

TBR=0TBR=0.5TBR=0.8TBR=1.0TBR=1.045

Years from start of FNSF operation

100 MW Fusion Power

0

5

10

15

20

0 5 10 15

50 MW100 MW150 MW200 MW300 MW400 MW

Years from start of FNSF operation

TBR=0.8

Tritium Inventory Available for DEMO at End of ITER and FNSF Operation Depends Strongly on TBR in FNSF

8

0

5

10

15

20

25

30

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045

Supply w/o fusionWith ITERFNSF- 0 TBRFNSF- 0.5 TBRFNSF- 0.8 TBRFNSF- 1.2 TBRFNSF- 1.4 TBR

Year

100 MW FNSF2016 ITER start2021 FNSF start

Required TBR in FNSF

9

TBR required to ensure that FNSF does not run out of tritium supply during its operation increases as fusion power increases

Incremental TBR required to provide a given additional tritium for DEMO is larger for lower fusion power FNSF

0.0

0.5

1.0

1.5

2.0

50 100 150 200 250 300 350 400

FNSF does not run out of T5 kg T available after ITER and FNSF10 kg T available after ITER and FNSF

Fusion Power of FNSF (MW)

2016 ITER start2021 FNSF start

Current ITER Schedule

10Start of DT operation delayed by 5 years

Expected External Tritium Supply Available for FNSF with Current ITER Schedule

11

With the current ITER start delay almost all tritium supply will be used by ITER and FNSF has to be self-sufficient in tritium in addition to providing initial startup inventory for DEMO

TBR required in FNSF will be higher than with previous ITER schedule0

5

10

15

20

25

30

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045

Supply w/o fusion

With old ITER schedule

With current ITER schedule

Year

Tritium Inventory Available for DEMO at End of ITER and FNSF Operation Reduced with Delayed ITER and FNSF

12

0

5

10

15

20

25

30

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045

Supply w/o fusionWith ITERFNSF- 0 TBRFNSF- 0.5 TBRFNSF- 0.8 TBRFNSF- 1.2 TBRFNSF- 1.4 TBR

Year

100 MW FNSF2016 ITER start2021 FNSF start

0

5

10

15

20

25

30

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045

Supply w/o fusionWith new ITER scheduleFNSF- 0 TBRFNSF- 0.5 TBRFNSF- 0.8 TBRFNSF- 1.2 TBRFNSF- 1.4 TBR

Year

100 MW FNSF2018 ITER start2026 FNSF start

Required TBR in FNSF is Higher with Delayed ITER and FNSF

13

0.0

0.5

1.0

1.5

2.0

50 100 150 200 250 300 350 400

FNSF does not run out of T5 kg T available after ITER and FNSF10 kg T available after ITER and FNSF

Fusion Power of FNSF (MW)

2016 ITER start2021 FNSF start

0.0

0.5

1.0

1.5

2.0

50 100 150 200 250 300 350 400

FNSF does not run out of T5 kg T available after ITER and FNSF10 kg T available after ITER and FNSF

Fusion Power of FNSF (MW)

2018 ITER start2026 FNSF start

Conclusions

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With the limited external supply and taking into account the initial ITER operating schedule (2016 start), any next step FNSF should provide significant part of its tritium need

With available external tritium supply, a small fusion power and a modest TBR are required for FNSF to have enough tritium for its operation

Another part of FNSF mission is to provide the initial tritium inventory needed for startup of DEMO. This increases the required TBR in FNSF. Incremental TBR required to provide a startup tritium inventory for DEMO is larger for low fusion power FNSF and large initial startup inventory for DEMO (significantly greater than 5 kg)

• To achieve this mission, FNSF can have a TBR that increases with time with possible extension of its operation at a higher TBR

With the current ITER start delay almost all tritium supply will be used by ITER and FNSF has to be self-sufficient in tritium in addition to providing initial startup inventory for DEMO