SNETP ESNII Generation IV reactors, related fuel cycle and disposal issues

Transcription

1 IGD-TP 5th Exchange Forum SNETP ESNII Generation IV reactors, related fuel cycle and disposal issues M. Sepielli SNETP Governing Board IGDTP-SNETP IEG Kalmar (Sweden), October 27-30, 2014

2 Optimum use of natural resources Nuclear waste minimization Minimum impact on the environment Safety / Economics / Non proliferation

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4 Fuel Sytem Options in GEN IV Fast Reactors Table 1 Priority table. Items indicated in red are priority for the different fuel types. UPuO x UPuC UPuN GFR 100W/cm Tclad 800 C Tfuel 1100 C Pu: 15-20% Priority : 3 SiC+liner % Am >95%dth Priority : 1 SiC+liner % Am 80-85%dth vs open/closed porosity 5% < M2C3 < 15% Priority : 2 SiC+liner % Am 80-85%dth N/M: 1.0 and > 1.0 LFR ~400W/cm Tclad ~500 C Tfuel C T91 SFR 500W/cm Tclad 620 C Tfuel 2400 C (O) and 1400 C (C) Pu: 15-20% Priority : % Am >95%dth O/M 1,96 1,98 2,00 Priority : 2 T Ti % Am 80-85%dth Priority : 1 ODS - 15/ % Am >95%dth O/M 1,90 1,95 1,98 Priority : 2 ODS - 15/ % Am 80-85%dth Priority : 3 ODS - 15/ % Am 80-85%dth ENEN_Seminar, U. of Psa, Nov. 2007

5 GEN IV Fuel Characteristics Reactor concept GFR SFR LFR Power density (MWth/m 3 of fuel element) Linear power (W/cm) C/N : 100 O: 500 C : idem M: 500 Burn up (at%) And dose dpasic dpa dpa Pin geometry: - pellet - int. clad - ext.clad (2mm hole) idem Temperature clad in/out at PPN ( C) Max. temp. 850/ / Fuel Carbide or nitride Oxide, carbide, or metallic Fuel temp ( C) C/N: 1100 O: 2400 C: 1400 Nitride (or metallic) idem Melting temp. UPuO2: 2740 C, UPuN : 2720 C (dissoc. ~1800 C), UPuC : 2325 C. ENEN_Seminar, U. of Psa, Nov. 2007

6 GEN IV Reactor Concepts Reactor concept GFR LFR MSR SFR SCWR VHTR Coolant Helium Pb or Pb-Bi Molten salt Sodium Supercritical Helium water Spectrum (F fast, F F T F T/F T T thermal) Thermal efficiency (%) Thermal power (MW) ~ ~ ~ Power density (MWth/m 3 ) Pressure (bar) Temperature core 490 / / / / / / 1000 inlet/outlet ( C) Fuel Carbide or nitride Nitride, Oxide Molten salt (fluorides) Oxide, carbide, or Oxide (UO 2, MOX) Oxide or oxi-carbide (or metallic) metallic Fuel burnup (at%) > 10 Fuel cycle Closed Closed Closed Closed Closed Open ENEN_Seminar, U. of Psa, Nov. 2007

7 ENEN_Seminar, U. of Psa, Nov GEN IV Fuel&Structural Materials

8 ENEN_Seminar, U. of Psa, Nov GEN IV Fuel&Structural Materials

9 SNETP pillars and IV Generation Technologies ESNII

10 Fast reactors and closed loop fuel cycle FROM SNE TP TO IGD TP

11 Radiotoxicity drop with Gen IV Partitioning U Pu AM III gen reactor Short lived radwaste Long lived residuals Or ADS? Fast reactor IV gen Fuel Fabrication U-Pu-AM U nat U depl Radiotoxicity Fission products Short lived radwaste Exhaust fuel Long lived waste Geological repository Natural barriers ~ years Natural uranium ~430 years 1 O O Surface repository Artificial barriers 0, Years

12 Single component radiotoxicity decay 12

13 Reprocessing schemes and resulting waste 13

14 The main reprocessing methods presently used: Co extraction New extraction Uranium extraction (UREX) Electrochemical processing

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16 Block diagram of the pyrochemical process for metal fuel

17 Schematic illustration of the pyrochemical process for oxide fuel

18 Electrorefining of metal fuel MA: Minor Actinides RE: Rare Earths NM: Noble Metals AM : Alkaline Metals AEM: Alkaline Earth Metals

19 Electrorefining of nitride fuel

20 Electroreduction of oxide fuel (USA, Japan, Korea) (anode made of platinum wire (left) or graphite (right)

21 Properties UPO 2 UPC UPN Density, g/cm HM Density, g/cm T melt, C Thermal conductivity, 2, W/mK PUREX compatible Yes No yes

22 Electroreduction of oxide fuel (Russian method)

23 Conditioning of chloride salt wastes from pyroprocesses with different matrices SODALITE SAP MURATAITE PYROCHLORE

24 LiCl KCl SODALITE matrix Melting 773 K Ar glove-box Al 2 Si 2 O. 7 2H 2 O NaOH Kaolinite Freezing room temp. Mixing Crushing Heating Simulated Salt Waste Mixing Nepheline Glass frit Nepheline NaAlSiO 4 SODALITE Air Outline of sodalite synthesis from kaolinite through nepheline

25 SODALITE matrix Kaolinite + NaOH Synthesis of nepheline 700 C Nepheline 700 C

26 SODALITE matrix Mixing and grinding of nepheline with LiCl KCl

27 SODALITE matrix Components used for labo. scale Pressureless Consolidation experiments Alumina crucible Internal vessel Steel rod, ab. 280 g 38.0 mm Mix of nepheline, salt waste and glass frit between alumina crucible and internal vessel

28 SAP matrix Transparent hydrogels Products obtained after Products obtained after each of the three main steps for preparation of SAP matrix

29 SODALITE matrix Assembly of the components Final consolidation product 32.9 mm Assembly of the components for thermal treatment at 925C for 7 hours

30 SAP matrix Sources of Si Al P TEOS, Tetraethyl orthosilicate or tetraethoxysilane, Si(OCH 2 CH 3 ) 4 Aluminum (III) chloride, AlCl 3 Phosphoric Acid, H 3 PO 4

31 SAP matrix Outline of SAP synthesis by a conventional sol gel process

32 MURATAITE matrix Octahedral framework in the structure of Mu-5: arrangement of pyrochlore clustera formed by corner sharing of Ti1O6 and Ti4O6 octahedra (a); linkage of pyrochlore clusters by Ti3O6 octahedra (b); whole framework as combination of linked pyrochlore clusters and murataitelike framework formed by Ti2O6 and Ti5O6 octahedra ; murataite-like framework (d)

33 Evaluation of long term behaviour of conditioned salt wastes Static leaching tests up to 150 days Assessment of the main parameters which influence fission products release (ph, temperature, contact time) Determination of the interactions between host matrix and individual fission elements

34 Issues from SNETP SRIA in fuel reprocessing Advanced reprocessing for MA separation, using hydro and pyro metallurgical processes (UE Projects ACSEPT > SACSESS) Conversion process from separation to refabrication Synthesys of new fuel and performance assessment in reprocessing Irradiation behaviour of MA bearing MOX and carbide fuels, dedicated PIE programmes Industrial implementation of P&T&RF laboratories

35 General SRIA issues from new waste to geological disposal Increasing fuel burn up, most of TRU / MA Reducing FP asmuch aspossible Reducing of Pu towards non proliferation Improve stability of chemical and physical form GD with more relaxed requirements in terms of volumes and masses, easy conditioning and storage, safety and economics Locating in depth