Transmutation of Actinides in CANDU Reactors B. Hyland G. Dyck A. - PowerPoint PPT Presentation

Transmutation of Actinides in CANDU Reactors B. Hyland G. Dyck A. Morreale R. Dworschak

Outline • Introduction to CANDU reactors • Motivation for transmutation of actinides • Transmutation of actinides in CANDU – Group-extracted TRU in MOX – Separated Am/Cm in targets

The CANDU Reactor On-power Fuelling Heavy Water Moderator – Good neutron economy Simple fuel bundle CANDU fuel channel

37-element bundle

Motivation • Increase capacity of long-term geological disposal • YM final, total cost: $96 billion • Technical capacity limited by decay heat load

What’s Contributing to the Heat Load? FP’s at short times Actinides at long times *Data for Russian VVER B.R. Bergelson, A.S. Gerasimov, and G.V. Tikhomirov

Transmutation Scenarios • Two transmutation scenarios were examined • Group-extracted TRU in MOX • Separated Am/Cm in targets

TRU MOX Scenario LWR, 45 MWd/kg • WIMS-AECL lattice cell calculations Cool 30 years • RFSP full-core calculations Group extraction • 45 MWd/kg exit burnup for MOX MOX

30 year cooled SNF Initial TRU MOX Compostion, Initial TRU Content, 653 g/bundle g/kg initial TRU Initial TRU Content, 3.3% % by volume Pu-238 +163 13 Pu-239 -77 563 Pu-240 -1.8 201 Pu-241 +65 30 Pu-242 +176 38 Pu Total -39 845 Np Total -52 47 Am-241 -90 100 Am total -64 108 Cm total +3700 0.6 Total MA -45 155 Total TRU -40 1000 Change in actinide composition (%) at discharge burnup

Decay Heat from Actinides MOX 200.0 180.0 Once through PWR without CANDU 160.0 140.0 % decay heat 120.0 100.0 80.0 60.0 40.0 20.0 0.0 10 100 1000 10000 100000 Time (years)

Nuclide Contribution to Heat Load Time Frame of Main Contribution % Difference Nuclide to Heat Load Pu-238 Less than 100 years +163 Cm-244 Less than 100 years +2641 Am-241 Less than 1000 years -90 Pu-239 1000-100,000 years -77 Pu-240 1000-100,000 years -1.8

Full-Core Calculation Input fuel composition Lattice cell calculation: WIMS Cross-sections, Depletion Full-Core Calculation: RFSP Full-core Parameters, Dwell Time, Burnup

Am and Cm Target Channels • 30 target channels Am and Cm in IMF 0.9% Fissile RU

Important Criteria • Support ratio : • % transmutation • Residence time

Fuel Bundle Designs CANFLEX 43 elements 21 elements 24 elements 30 elements

22 20 Support Ratio, GWe LWR: GWe CANDU 18 16 14 12 10 8 6 4 2 0 0 10 20 30 40 50 60 70 80 90 100 Destruction of Americium (%)

100 % per Initial Amount of AmCm Total Am + Cm + Pu 90 80 Total Am + Cm 70 60 Am-241 Total Am 50 Total Pu 40 30 20 Total Cm 10 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Residence Time (years) Total Am + Cm + Pu Am + Cm All Am All Cm All Pu Am-241 Am-243 Cm-242 Cm-244 Pu-241 Pu-239 Pu-240 Pu-242

Results Input Exit % Change kg/CANDU kg/CANDU Am 373 112 -70 Cm 9 68 +700 Total Am + 382 180 -53 Cm • 21-element bundle • 26% initial concentration • Support ratio 2.5 GWe LWR : 1 GWe CANDU • Residence time for AmCm = 5.7 years

Full-Core Calculation Input fuel composition Lattice cell calculation: WIMS* Cross-sections, Depletion Full-Core Calculation: RFSP Full-core Parameters, Dwell Time, Burnup * Calculations done with a developmental version of WIMS-AECL

Summary • CANDU reactors have unique features which allow them to effectively transmute transuranics • TRU in MOX – We can burn 40% of TRU – Reduce heat load by 40% at 1000 y • Am/Cm targets – We burn 70% of Am (53% or Am+Cm) – Reduce heat load by 70% at 1000 y • Provide a significant increase in geological repository capacity. • Full-core calculations indicate that both fuel cycles are feasible

30 year cooled — No Burn 1.E+02 237Np 239Np TotalNp 1.E+01 Thermal Power (W)/kg ITRU 238Pu 239Pu 240Pu 1.E+00 241Pu 242Pu 1.E-01 TotalPu 241Am 243Am 1.E-02 TotalAm 242Cm 244Cm 1.E-03 245Cm TotalCm TotalTRU 1.E-04 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 Time (years)

Decay Heat from Actinides, MOX 1.E+02 237Np Total TRU 239Np TotalNp Once Through LWR 1.E+01 238Pu Thermal Power (W)/kg ITRU 239Pu 240Pu 1.E+00 241Pu 242Pu TotalPu 1.E-01 241Am 243Am TotalAm 1.E-02 242Cm 244Cm 245Cm 1.E-03 TotalCm 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 TotalTRU No Burn Time (years)

The Calculation • WIMS-AECL used to calculate neutron fluxes • ORIGEN-S used for the depletion calculation • MOX: burned to 45 GWd/t • Assumed 3% neutron leakage

MOX, Pu Isotopes 120 100 % per initial TRU 238Pu 239Pu 80 240Pu 60 241Pu 242Pu 40 TotalPu TotalTRU 20 0 0 10 20 30 40 50 Burnup (MWd/kg)

MOX, Minor Actinides 16 14 237Np 241Am 12 % per intial TRU 243Am 10 TotalAm 8 242Cm 244Cm 6 TotalCm 4 Total MA 2 0 0 10 20 30 40 50 Burnup (MWd/kg)

Group Extracted TRU MOX, Cm 3 2.5 % per initial TRU 2 Total Cm 242Cm 1.5 243Cm 244Cm 245Cm 1 0.5 0 0 10 20 30 40 50 Burnup (MWd/kg)

Am Mass Flow 2.5 GWe LWR Decay for 30 years Separate Am, Cm 21 kg/year 27 kg/year 90 kg/year 63 kg/year destroyed

Full-Core Results Time- Refueling NU Fuel Average Ripple Max 6600 7100 7300 Channel Power (kW) Max. Bundle 790 845 935 Power (kW) • Avg. burnup for RU is 12.2 MWd/kg • 3.7 channels/day, 11 bundles/day