Nitride Fuel and Pyrochemical Process

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Nitride Fuel and Pyrochemical Process
Developments for Transmutation of Minor
Actinides in JAERI
Masahide Takano, Mitsuo Akabori, Kazuo Minato,
Yasuo Arai Japan Atomic Energy Research Institute
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
2
Content
gtBackground gtPROMINENT program gtFabrication of MA
nitrides Carbothermic synthesis of
(Pu,Am,Cm)N (Pu,Am,Cm,Zr)N gtProperty
Measurements of MA nitrides Hydrolysis
Evaporation behavior of AmN
(Am,Zr)N gtPyrochemical process Pu
nitridation in Pu-Cd alloy gtIrradiation test
(Pu,Zr)N PuNTiN gtConclusion
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
3
Nitride fuel cycle - background
gt JAERI has proposed double strata fuel cycle for
MA transmutation, based on U-free nitride
fuel, ADS, and pyrochemical reprocessing.
gt Expected on nitride fuel Good
thermal properties, Mutual solubility
among MA nitrides, High heavy metal
density
gt We have studied on Fuel fabrication
technology Property measurements
Irradiation behavior Pyrochemical
process
gt Experiments on MA nitride
Limitation in facility, apparatus, handling,
material amount, High purity inert
atmosphere required
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
4
PROMINENT program
gt Started Nov. 2002, five year program
gt Development and demonstration of elemental
technology for nitride fuel cycle in
laboratory scale
gt JAERI, Osaka Univ, MMC, NDC, JAPC
PROMINENT Property Measurements, Pyrochemical
Process and Irradiation Experiments Needed for
Nitride Fuel Cycle Technology.
Research areas in PROMINENT program
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
5
Fabrication of MA nitrides (1)
(Pu,Am,Cm)N
gt PuAmCm(Zr) nitrides
3040 mg scale
gt Starting materials
243Am2O3, (240Pu,244Cm)O2, ZrO2 amorphous carbon
gt Fabrication method
(Pu,Am,Cm,Zr)N
Carbothermic reduction of oxides mixture
MOx xC 1/2N2 MN xCO
Nitridation N2 1300 ºC Decarburization N24H2
1500 ºC
gt Analyses
X-ray diffraction N,O,C analyses
Process temperature and CO gas release
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
6
Fabrication of MA nitrides (2)
Composition of the oxides and carbon mixtures
Expected product
(Pu,Am,Cm)N
(Pu,Am,Cm,Zr)N
Mixture weight (mg)
31.40
37.58
Pu/Am/Cm/Zr molar ratio
0.45 /0.34 /0.21 /0
0.14 /0.10 /0.06 /0.70
C/O molar ratio
1.3
2.0
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
7
Fabrication of MA nitrides (3)
gt (Pu,Am,Cm)N Single phase solid solution
0.4956nm (0.4960 nm by Vegards law) No
oxide phase Low carbon content (lt0.05 wt)
(Pu,Am,Cm,Zr)N
gt (Pu,Am,Cm,Zr)N Double phases with NaCl
structure different (Pu,Am,Cm)/Zr
ratio Low oxygen content (0.15 wt)
High carbon content (1.3 wt)
remained as carbonitride
(Pu,Am,Cm)N
XRD profiles of products
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
8
Property measurements (1) Hydrolytic behavior
gt MA nitrides are reactive with moisture
gt Hydrolysis of AmN and (Am,Zr)N observed in
ambient air
gt AmN reacted with moisture to form Am(OH)3
gt (Am0.1Zr0.9)N retained the phase over 1000h
AmN
Am(OH)3
Am2O3
Weight gain of AmN, (Am,Zr)N and (Dy,Zr)N in air
and moist N2
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
9
Property measurements (2) Evaporation behavior
gt Am has high vapor pressure
gt Evaporation behavior of AmN (Am,Zr)N in
He gas flow
AmN Am(g) 1/2N2
gt Evaporation rate constant, k (s-1)
v -(dN/dt) kN
gt AmN retained the phase while heating, no
metallic phase
Arrhenius plots of k
gt k of AmN in (Am,Zr)N depressed
gt Selective evaporation of AmN on (Am,Zr)N
change in composition
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
10
Property measurements (3) New apparatus
gt Apparatus for thermal property measurements
installed
gt Designed for nitrides and small sized samples
gt Thermal diffusivity laser flash method
sample diameter 35 mm installed in Ar
atmosphere
gt Specific heat capacity drop calorimeter
sample sealed in Pt capsule
gt Thermal expansion high temp. XRD
installed in Ar atmosphere
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
11
Pyrochemical process of nitride fuel
gt Anodic dissolution of PuN in LiCl-KCl
eutectic salt examined
gt Recovery of Pu into liquid Cd cathode
demonstrated with high current efficiency
gt Pu in Pu-Cd alloy converted to PuN
gt Experiments on Am-containing nitride will
start soon at TRU-HITEC
Schematic diagram of pyrochemical process for
nitride fuel
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
12
Nitridation of Pu in Pu-Cd alloy
gt N2 bubbling process
U in U-Cd 100 recovery
Pu in Pu-Cd only 10 recovery
decrease in Pu activity in Pu-Cd
gt Nitridation-distillation combined process
(a) N2 bubbling process
Pu 99 recovery
PuN with high purity obtained
973K
Pu-Cd (12wt Pu)
Recovered PuN
(b) Nitridation-distillation combined process
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
13
Irradiation test ongoing
gt Basic irradiation behavior of U-free
nitride fuel
(Pu,Zr)N
gt (Pu,Zr)N PuNTiN pellets Pu 20wt,
He-bond
gt Irradiation ongoing at JMTR
PuNTiN
Linear power 40kW/m Target burnup 20 at of Pu
gt Irradiation of (Pu,Np,Zr)N pellet scheduled
at JOYO with JNC
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004
14
Concluding remarks
gt (Pu,Am,Cm)N and (Pu,Am,Cm,Zr)N synthesized
by carbothermic reduction of the oxides
Mutual solubility among PuN-AmN-CmN was
demonstrated.
gt Hydrolysis and evaporation behavior of AmN and
(Am,Zr)N studied
AmN was chemically and thermodynamically
stabilized by formation of solid solution
with ZrN.
gt Pu nitridation in Pu-Cd alloy investigated
Simultaneous nitridation-distillation
process yielded high purity PuN.
OECD/NEA 8th Information Exchange Meeting on
Actinide and Fission Product Partitioning
Transmutation, Las Vegas, USA, 9-11 Nov. 2004