SEMINARIO ENEA - CASACCIA Venerdì 12 marzo 2010 ore 10 Carlo Artioli Multi-physics parameters optimization of ADS core for transmutation

Int’l Conference on Peaceful Uses of Atomic Energy New Delhi, Sept 29-Oct 1 / ENEA-BO 12 Nov 009 Carlo Artioli Multi-physics parameters optimization of ADS core for transmutation IP-EUROTRANS International training course (ITC-9) on Accelerator–driven Transmutation System for European and Asian Young Scientists and Engineers Nuclear Technology and Education Center JAEA, Tokai, Ibaraki, Japan Dec. 1-4, 2009 Carlo Artioli IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

SIXTH FRAMEWORK PROGRAMME EURATOM Management of Radioactive Waste IP EUROTRANS EUROpean Reserch Programme for the TRANSmutation of high Level Nuclear Waste in an Accelerator Driven System (ADS) DM0DM1 … DM5 ManagementDesignNudatra WP1.1 WP1.2….. WP1.6 Reference Design Development and Assesment XT-ADS Remote Specifications of XT-ADS and EFIT Designs Handling Catalogue U-free Core design of the EFIT-Pb and of the Gas backup option Task ….. Task …. Task (ENEA, FZK, Ansaldo, CEA, Framatome ANP, NNC, CRS4) IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

EFIT Pb Main features EFIT Pb Main features Goal:fissioning MA, while producing energy Fuel:MA & Pu Oxide in inert matrix (MgO) Coolant:Lead, Tin=400 °C, Tout=480°C Power:several hundreds MW EUROTRANS DM1 Task 1.2.4: EFIT Core Design (European Facility for Industrial Transmutation,) VI FP, IP EUROTRANS concept developed for the transmutation of MAs IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Kmax =0.97 High amount of MA allowed in the core IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Main questions to be answered 2) In which way the burning capability has to be optimized? 3) What about the two goals: “burner” and “energy producer”? (should they be contradictory) 1)What exactly means “burning MA at best” ? IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Core size (MW) M A b a l a n c e K g ( M A ) / T W h 1)What exactly means “burning MA at best” ? (e.g.400) (e.g.65) E u r o / K g ( M A t r a n s m u t e d ) IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Power density roughly invariant Power size become geometrical size Core size (MW) MA balance Kg (MA) /TWh Lattice ruled by linear power rating and TH constraint 1)What exactly means “burning MA at best” ? IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Core size (MW) MA balance Kg (MA) /TWh 1)What exactly means “burning MA at best” ? fuel Pu MA Pu MA Pu MA IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Pu MA Pu MA Transmutation fission Small size, high enrichment Large size, low enrichment Small size = low MA reaction rate Large size = high MA reaction rate IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

e = Pu / (Pu+ MA) Pu MAFUEL Pu mass Balance MA mass balance Pu breeder Pu burner Kg/TWh Ex. - 60, +18 Ex. - 30, -12 Total balance ≈ - 42 kg / Twh th (from theor. 210 MeV/fission) e = Pu / (Pu+ MA) Pu MA FUEL Fission product Transmutations IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

A MA balance lower than -42 kg/TWh (e.g. -50) means that: - 42 have been actually fissioned and - the difference (e.g. 8) have been transmuted in new Pu A MA balance higher than -42 kg/TWh, e.g. -35, means that: - 35 have been actually fissioned and - the difference (e.g. 7) are fissions of Pu 1)What exactly means “burning MA at best” ? the system would act as Pu breeder the system would act as Pu burner IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

In both the cases: -Producing new Pu and -Burning Pu the system has not been optimized because there are “expensive” neutrons used not to fission MA. 1)What exactly means “burning MA at best” ? (Producing or fissioning Pu can be made in cheaper way in conventional reactor) The best ADS, as MA burner, shows a: - MA balance of -42 kg/TWh and (of course) - Pu balance of 0 kg/TWh IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

or considering the velocity of burning -42kg/h / TW the minimum cost of the power deployed 2) In which way the burning capability has to be optimized? 3) What about the to goals: “burner” and “energy producer”? (should they be contradictory) The best ADS, as MA burner, shows a: - MA balance of -42 kg/TWh and (of course) - Pu balance of 0 kg/TWh Since looking for a MA performance “better” than -42 kg/TWh is meaningless, the optimization leads to the minimum cost of the TWh which is the same optimization required for the energy production IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

How to get the : - MA balance of -42 kg/TWh and (of course) - Pu balance of 0 kg/TWh Pu MA Pu mass Balance MA mass balance Pu breeder Pu burner Kg/TWh Ex. - 60, +18 Ex. - 30, -12 Suitable e = Pu / (Pu+ MA) The burning performance depends on the mutual ratio between Pu and MA i.e. on the enrichment X kg/TWh of net Transmutations 42-X kg/TWh fissioned X kg/TWh fissioned FP, 42 kg/TWh IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

 k swing  INPUT to be supplied OUTPUT Pu and MA vectors Search of suited Pu/ (Pu+MA) Pellet composition Pu, MA dioxyde stechiometry and density; Matrix, density and fraction Definition of “enrich.” Pu/ (Pu+MA) Pin geometry definition ( diameter and other by guess ) Gas releases = f (T, BU) Fuel element definition Max linear power, TH (T max, conductivity law) Fuel density power Core density power K eff required Core definition Core size and power Verification and optimization Main statement: DESIGN  IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Which are the correlationships among the main core parameters (A-BAQUS graph) Matrix rate Current Power/size Performances Enrichment  k cycle IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

fuel Pu MA e = Pu / (Pu+ MA) Inert matrixPELLET %MgO = Matrix / (Matrix + fuel) MgO e (%) 50 %MgO 50 ( %fuel ) Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

e (%) e = Pu / (Pu+ MA) %MgO Pu MA Fission product Total balance 42 kg / Twhth Transmutations 50 FUEL ( %fuel ) Pu mass Balance MA mass balance Pu breeder Pu burner Kg/TWh Ex. - 60, +18 Ex. - 30, -12 Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli Approximation: No effect on the spectrum of the variation of the matrix fraction (in the range)

e (%) %MgO Pu mass Balance MA mass balance Pu breeder Pu burner Kg/TWh Pu MA  K swing (pcm/y) Fission Transmutations  k (pcm/y) 0 FUEL 50 e = Pu / (Pu+ MA) ( %fuel ) Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

e (%) %MgO Homog. Power density rather constant 50 ( %fuel ) Coolant volume fraction (depending on coolant velocity) Linear power rating (depending on the fuel) Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Homog. Power density rather constant IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

e (%) %MgO Homog. Power density rather constant decreasing %fuel (incr. %MgO) Increases the geometrical size (to adjust for criticallity) Increases the Core Power P (MW) Core Radius (cm) ( %fuel ) Coolant volume fraction (depending on coolant velocity) Linear power rating (depending on the fuel) Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Core Power Proton current  k swing Proton current range P (MW) Core Radius (cm) Subcriticality fixed! Enrichment constant I (mA) Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Which are the correlationships among the main core parameters IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

EFIT-Pb Technology constraints Fuel CERCER (Pu,MA)O 2-x -MgO inert matrix (or 92 Mo, 93%enriched) % VF of MgO>50% (to assure thermal conductivity); Linear power < W/cm (depending on %VF MgO). - FA residence time = 3 years (Pb corrosion is the most restricting condition) T limit for the fuel: ~ 1650 K (500 K below the inert matrix melting/disintegration) T limit for the cladding at nominal cond. (9Cr1MoVNb steel T91): 820 K Pb speed at 1 m/s (to limit corrosion effects) Active height = 90 cm (to limit the pressure drop) IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Maintain a low k eff swing during the cycle (no oversize of target and accelerator) Maximize the power density Decrease the form factors to flatten the coolant T out (Pb at 750 K and <820 K for the cladding) and to maximize the avg power density by use of 3-zones with increasing active fuel volume fraction along the core radius (enr. Is fixed): from inner to intermediate zone by increasing the fuel/matrix from 43% to 50% (but same pin diameter) from intermediate to outer zone by increasing the pin diameter (and same fuel/matrix %), FA dimensions are driven by the size of the spallation module, R target = 43.7 cm (to replace 19 FAs) Design choices, rationales and solutions Maximize MA fission. The enrichment is fixed to fulfil the “42-0” approach, i.e.: 1.42 kg/TWh th is true for any nuclear system (it comes from 210 MeV/fission) 2.what is the policy about Pu? The choice here is neither Pu production (not consistent with U-free) nor Pu reduction (net fission expensive in ADS) 3.the choice is then to dedicate all the fissions (directly or indirectly) to MAs: net balance is -42 kg/TWh th for MA and 0 kg/TWh th for Pu (which sustains in any case the reactivity, acting as a catalizer) IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Project parameters (as inputs) – Thermal power of some hundreds of MW (to be optimized) – Pb coolant for the proton target and the core (fast spectrum). Pb temp. for the core: T in =673 K, T out =753 K – External proton beam of 800 MeV up to 20 mA (windowless target) – Sub-critical level of k eff = 0.97 (to be verified a posteriori) – The fuel is U-free and uses Pu and MA vectors. MA come from the spent UO 2 (90%) and MOX fuel (10%) of a PWR (45 MWd/kgHM) with 30 cooling years. Pu from UO 2 with 15 cooling years (data from CEA). IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

B: pellet with different fractions of matrix, T out A: reduction of coolant volume fraction (larger pin) Radial flattening by increasing fuel volume fraction T outmax Coolant volume fraction Increasing fuel volume fraction Outer zone , DP P lin T out IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Flattening Techniques StructuralC o o l a n t F u e l Pu+MA Matrix StructuralC o o l a n t F u e l Pu+MA Matrix Reference Intermediate zone Outer zone by different pin size and same matrix % Inner zone by different matrix% and same pin PD fuel =max; P lin =max; T out =max Pin “size” to obtain the same max PD but Tout should be unacceptable StructuralC o o l a n t F u e l Pu+MA Matrix PD fuel =max; P lin =max; T out =max PD fuel < max; P lin < max; T out =max IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Inner, Intermediate & Outer FA Design Inner and Intermediate : Outer: Same pin & pitch;  MgO VF (57%, 50%) > Pin  - Same MgO VF (50%) IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Cylindrised vertical section & H3D model 384 MWth core IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Hom. Power density at midplane Maximum allowed, corresponding to linear power rating 207 and 180 W/cm (calculations: M. Sarotto) IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

BOC Monte Carlo Calculations (calculations Carlo Petrovich) k eff  Neutron source (S) (neutrons/proton)  0.08 M = all fission neutrons / S  0.25 k S = M / (M+1)  Proton current13.2 mA To be considered in optimization step: reducing the core/spallation size the efficiency will be increased IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

 Pu / Pu (BOC)  -0,7%  MA / MA (BOC)  -13,9% 3 years BU = 78,28 MWd / kg (HM) BU -40,17 kg (MA) / TWh Total E = 10,0915 TWh th -1,74 kg (Pu) / TWh MA and Pu balances IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Pu, MA vectors evolutions  Pu / Pu (BOC)  -0,7%  MA / MA (BOC)  -13,9% 3 years BU = 78,28 MWd / kg (HM) BU -40,17 kg (MA) / TWh Total E = 10,0915 TWh th -1,74 kg (Pu) / TWh MA and Pu balances The Pu and MA vectors evolve in the time toward equilibrium configurations; this implies: - Calculation of the enrichment with the equilibrium vectors - Enrichment resettings in the transitory phase IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Power size optimization criterion: minimum cost / kg of fissioned Minor Actinides minimum cost per MW deployed. cost / MW deployed = f (core size, accelerator size) - Core term:decreases increasing the power (if power density is const.); - Accelerator term: decreases increasing the power, but the target loses efficiency. Present criterion: The largest size core acceptable within the current spallation module design (max power: 11.2 MW). IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

3 approaches Starting M a i n p a r a m e t e r s Performancies point ( kg/TWh) (- 42 TRU)  Kzero reactivity swing ≈ 0 e  k cycle P(MW) i (800 MeV) (%) (pcm) (MW) (mA) 400MW P = 400 MW 42-0  Pu ≈ 0 IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

3 different approaches Graphical extimations IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

3 approaches Starting M a i n p a r a m e t e r s Performancies point ( kg/TWh) (- 42 TRU)  Kzero reactivity 50 ~0 275 ~ 7~ -36 MA swing ≈ 0 ~ -6 Pu e  k cycle P(MW) i (800 MeV) (%) (pcm) (MW) (mA) 400MW P = 400 MW 27 ~ ~ ~ - 65 MA ~ +23 Pu 42-0  Pu ≈ ~ ~ ~ - 41 MA ~ -1 Pu IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

“42-0 Concept” Main conclusions -Conceptual “42-0” design leads to the best MA burner in the sense that each fission is devoted to an “atom” of MA, no matter the kind of ADS -The doubble goal, to be a burner and a producer of energy, are not in conflict -Both can be reached minimizing the cost of the unit of energy produced in the “42-0” concept IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

“EFIT-Pb” Conclusions The “42-0” strategy has been the fundamental approach for the neutronic design of the EFIT core. Simultaneously a low k eff swing is obtained (small current excursion). MA fission (about 120 kg/year) via an U-free lead-cooled ADS as EFIT (384 MW th ) is viable, as the core is concerned: acceptable max T for fuel and cladding in nominal conditions and transients. The safety analysis (including sub-criticality level choice) has anyway to be completed. Use of CERMET fuel (Mo matrix instead of MgO), qualification of fuel, steel in Pb environment, cost/benefits ratio are to be investigated. IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli

Multi-physics parameters optimization of ADS core for transmutation IP-EUROTRANS International training course (ITC-9) on Accelerator–driven Transmutation System for European and Asian Young Scientists and Engineers Nuclear Technology and Education Center JAEA, Tokai, Ibaraki, Japan Dec. 1-4, 2009 Carlo Artioli IP-EUROTRANS International Training Course (ITC-9) Dec. 1-4, 2009 JAEA, Tokai, Ibaraki, Japan Carlo Artioli