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XYLENE POWER LTD.

OTTENSMEYER PLAN DETAIL

By Charles Rhodes, P.Eng., Ph.D.

OTTENSMEYER PLAN DETAIL:
This web page sets out sequential detail relating to implementation of fuel processing in the Ottensmeyer Plan. For an overview of the Ottensmeyer Plan please review Ottensmeyer Plan.
 

COMMENT:
In the below material flow chart ZrCl4 distillation is used to extract most of the zirconium from the fission products contained in one of the pyro process discharge streams. This extracted zirconium is recycled into the blanket rod cladding and the core rod material. To the extent that this zirconium extraction process is imperfect a small fraction of the zirconium remains mixed with the fission product chlorides in the 300 year fission product storage and a small fraction of the fission products in the pyro process fission product discharge stream is fed back into blanket rod cladding and the core rod material.
 

"LOCAL" AND "REMOTE":
To minimize transportation costs the selective uranium oxide extraction and some blanket rod reprocessing is performed at the FNR site. The term "local" refers to the FNR site. The term "remote" refers to the core rod reprocessing site which for certainty of public safety should be remote from any urban population. A suitable core rod processing site is Chalk River, Ontario.
 

CANDU SPENT FUEL SELECTIVE URANIUM OXIDE EXTRACTION AND BLANKET ROD REPROCESSING AT FNR SITE:
1. From the spent CANDU fuel inventory that has been out of a CANDU reactor for at least 10 years withdraw spent CANDU fuel bundles as required and transport these bundles to the spent CANDU fuel bundle store on the FNR site.

2. Withdraw a spent CANDU fuel bundle and/or neutron irradiated blanket rods from the local spent CANDU fuel bundle/ irradiated blanket rod store.

3. Chop up the spent CANDU fuel bundle into small pieces.

4. Dissolve the spent CANDU fuel bundle pieces and recycled blanket rod and control rod pieces in HNO3.

5. Remove the undissolved zirconium and send it to the local zirconium store.

6. Cool the solution.

7. Grow and then physically extract urynal nitrate hexahydrate [UO2(NO3)2-6H2O] crystals from this solution.

8. Heat the [UO2(NO3)2-6H2O] crystals to realize a total of about 97.55% of the spent CANDU fuel weight as pure uranium oxide and a residue of about 2.45% of spent CANDU fuel weight (fission products + TRUs + uranium oxide). Note that for blanket rod and control rod reprocessing as opposed to spent CANDU fuel reprocessing the residue weight fraction may be much higher at about 7%.

9. Send the residue (fission products + TRUs + uranium oxide + zirconium) to the new core rod oxide material store at the remote site.

10. Condense and recycle the nitric acid.

11. Dissolve the nearly pure UO2 in newly condensed nitric acid.

12. Cool the solution.

13. Grow and physically extract urynal nitrate hexahydrate [UO2(NO3)2-6H2O] crystals from this solution.

14. Heat the [UO2(NO3)2-6H2O] crystals to realize a total of about 97.55% of the spent CANDU fuel weight as high purity pure uranium oxide.

15. Send the pure UO2 to the local Pure UO2 store.

16. Send the (fission products + TRUs + uranium oxide + zirconium) residue to the new core rod oxide material store at the remote site.

17. Withdraw sufficient pure UO2 from the pure UO2 store for blanket rod and control rod fabrication.

18. Reduce the UO2 to metallic uranium.

19. Send the oxide for electrolytic recovery.

20. Melt the pure uranium.

21. Form a 90% uranium 10% zirconium alloy.

22. Cast the uranium-zirconium alloy blanket rods.

23. Cast the uranium-zirconium control rods.

24. Send the uranium-zirconium blanket rods to the local new blanket rod store.

25. Send the uranium-zirconium control rods to the local new control rod store.

26. Draw passive fuel tube components from the local tube store, local new blanket rod store, local sodium store.

27. Assemble the passive fuel tubes. Ensure that there is enough contained sodium in each fuel tube to fully absorb the F, Cl, Br and I nuclear fission products.

28. Send the assembled blanket type fuel tubes to the local finished passive fuel tube store.
 

FUEL BUNDLE ASSEMBLY AND LOADING:
29. Draw fuel bundle components from their respective stores.

30. Assemble active fuel bundles and paswive fuel bundles. Use an assembly jig that has sets of parallel steel sheets at 90 degrees to each other to position fuel tubes on the bottom grating. Weld the shroud to the bottom grating.

31. Send the assembled fuel bundles to the local fuel bundle store.

32. Draw fuel bundles from the local fuel bundle store as required for reactor fuelling.

33. Load the fuel bundles into the reactor zone of the sodium pool.

34. Slip a 15 inch square steel float over the indicator tube.
 

REACTOR OPERATION:
34. Run the reactor. While the reactor is running neutrons are net emitted by core rods and are net absorbed by blanket rods.

35. After each year in the reactor zone move (1 / N) of the fuel bundles to the liquid sodium pool perimeter zone, where N is the number of years per fuel cycle (typically N = 30).

36. After a fuel bundle has been in the perimeter cooling zone for ~ 10 years extract the fuel bundle.
 

FUEL RECYCLING:
37. Disassemble the fuel bundle. Sort the fuel bundle into its fuel tube, control rod and conventional steel components.

38. Send the conventional steel components to interim storage prior to metal recycling.

38A. Send the control rod material to the irradiated blanket rod store for recycling with the blanket rod material.

39. Disassemble the fuel tubes in an argon atmosphere at a temperature above the melting point of sodium.. Physically sort each fuel tube assembly into its fuel tube material, blanket rod, core rod, liquid sodium, sodium salt and inert gas components. Each of these components is processed differently.

40. Vent the inert gas to the atmosphere.

41. Send the core rods to the irradiated core rod store on the remote site to enable later core rod reprocessing.

42. Send the blanket rods to the irradiated blanket rod store to enable later blanket rod reprocessing.

43. Send the liquid sodium to sodium recycling.

44. Send the sodium salts to a dedicated container for long term storage. This container will store the long lived Cl-36 and I-129 fission products.

45. Send the fuel tube material to interim storage prior to metal recycling. Note that the used fuel tube material may require additional processing to remove surface residue.
 

CORE ROD PROCESSING AT REMOTE SITE:
For reasons of public safety in the face of a terrorist attack the core rod reprocessing is performed at a remote site such as Chalk River. The core rod reprocessing actually consists of many parallel but physically separate material streams so that there is no danger of accidental formation of a critical mass.

45A. Draw core rod oxide material from the remote site core rod oxide material store.

46. Reduce core rod oxide material to metallic material. Use either Na, Mg or Al to avoid introduction of Ca into the process. Neutron activation of stable isotopes of Na, Mg and Al lead to other stable isotopes.

47. Separate the Na2O, Al2O3 or MgO from the metallic fuel.

48. Electrolytically recycle the Na, Al or Mg. Note that the released oxygen is not radioactive. Even O-19 will fully decay to stable F-19 by about 300 seconds after neutron absorption.

49. Pyro process core rod metallic material to reject fission products and zirconium.

50. Send high atomic weight elements from pyroprocessing to the remote high atomic weight core material store.

51. Send the fission products + zirconium to the zirconium recovery process.

52. Dry chlorinate the fission products plus the zirconium to form a spectrum of chlorides.

53. Distil these chlorides at about 331 degrees C to selectively remove ZrCl4.

54. Send the remaining chlorides to 300 year storage.

55. Determine the weight of fission products headed for 300 year storage.

56.Transmit the weight of fission products going into 300 year storage back to steps #16 and #45 so that the material inventories in the stores remain nearly stable.

57. Reduce the ZrCl4 with sodium to obtain NaCl + Zr.

58. Electrolytically separate the NaCl into Na and Cl. Send the recovered Na and Cl to the appropriate stores.

59. Send the extracted zirconium to the remote zirconium store.

60. Draw zirconium from the remote site zirconium store.

61. Draw high atomic weight elements from the remote high atomic weight element store.

62. Combine the high atomic weight elements from step #61 and the zirconium from step #60 above.

63. Cast the core rods.

64. Send the core rods to the core rod store on the FNR site. The transport of reprocessed core rods must be safely done in a manner such that no matter what transportation accident occurs the core rods cannot form a critical mass.

65. Ship any surplus zirconium from the remote Zr store to the local Zr store to minimize the overall process zirconium requirement.
 

CORE TYPE TUBE ASSEMBLY AT FNR SITE:
66. Draw tubes, end plugs, core rods, blanket rods and sodium from their respective stores.

67. Assemble the core type tubes. Ensure that there is enough contained sodium to fully absorb the F, Cl, Br and I fission products.

68. Send core type fuel tubes to the local fuel tube store.
 

This web page last updated October 28, 2016

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