Upload
urit
View
37
Download
0
Tags:
Embed Size (px)
DESCRIPTION
MA and LLFP Transmutation Performance Assessment in the MYRRHA eXperimental ADS. E. Malambu , W. Haeck, V. Sobolev and H. Aït Abderrahim SCK·CEN, Boeretang 200, Mol, Belgium. P&T: 8th IEM, Las Vegas, Nevada, USA. November 9-11, 2004. Contents. Introduction: MYRRHA-XADS - PowerPoint PPT Presentation
Citation preview
MA and LLFP Transmutation Performance Assessment in
the MYRRHA eXperimental ADS
P&T: 8th IEM, Las Vegas, Nevada, USA
November 9-11, 2004
E. Malambu, W. Haeck, V. Sobolev and H. Aït Abderrahim
SCK·CEN, Boeretang 200, Mol, Belgium
Contents
1. Introduction: MYRRHA-XADS
2. Typical core configuration for MA and LLFP transmutation studies
3. MA and LLFP targets loading
4. Computational tools
5. Geometrical model features
6. Target irradiation conditions
7. Preliminary results
8. Conclusions
1. Introduction
Since 1998, the Belgian nuclear research Centre, SCK·CEN, is developing the MYRRHA ADS project.
In 2004, SCK•CEN is finalizing the pre-design phase of MYRRHA.
In the framework of the EC FP6 IP-EUROTRANS project, SCK•CEN is willing to adapt the design options of MYRRHA to fit out the objectives of the ETD/XT-ADS project (experimental demonstration of the technological feasibility of Transmutation in an ADS).
2.Typical core configuration for MA and LLFP transmutation
studies
3. MA and LLFP targets composition
4. Computational tools
MCNPX 2.5.e code used to: Define the sub-critical core configuration such as:
Keff-value close to 0.95
Total power close 50 MWth
Calculate neutron fluxes and spectra at each burn-up step through the ALEPH code flowchart
Libraries: JEF2.2 (MCB) combined to LA150n for Pb, Bi and steel elements); LA150h for protons.
ALEPH code (coupling MCNPX and ORIGEN2.2) to carry out the MA evolution calculation
4. Computational tools (cont’d) ALEPH
MCNPX calculates the spectrum in cells to be burned in an arbitrary group structure
The spectra are used to calculate reaction rates outside MCNPX using data read directly from ENDF files
The updated library is used to calculate new material compositions and densities
This entire process is repeated until the entire burn up history is calculated
MCNPX
calculate multigroup spectra
ORIGEN 2.2
burn up calculation
ORIGEN LIBRARY
use data directly from ENDF files preprocessed by NJOY
99.90
NEW MCNP(X) INPUT
update densities and composition
5. Geometrical model features:MYRRHA MODEL for MCNPX
calculations
5. Geometrical model features (cont’d):Modelled details of various
assemblies
6. Irradiation conditions
Irradiation history: One-year operational period 3 cyclesCycle time-span 90 (EFP) daysShutdown between cycles 30 days
Neutron flux :Constant level assumed over 30 days sub-
cycles Cycle-and-volume averaged neutron flux
MA targets in channel A: 3.17·1015 n/cm²sMA targets in channel D: 2.78·1015 n/cm²s99Tc targets : 1.08·1015 n/cm²s
7. Preliminary results:Core physics static parameters
7. Preliminary results (cont’d)
Neutron spectra in MOX fuel and MA assemblies
7. Preliminary results (cont’d)Neutron spectrum in 99Tc target
7. Preliminary results (cont’d)99Tc incineration
Mass incinerated: 431 grams (1.75% of initial mass)
Burnout half-life (T1/2=Ln(2)/a ): 13.9 yrs vs T1/2 = 2.11 x 105 yrs for natural decay
99Tc
Irradiation history
7. Preliminary results (cont’d)
Mass evolution of Am, Pu and Cm in MA targets
7. Preliminary results (cont’d) Time-evolution of Am mass
7. Preliminary results (cont’d) Time-evolution of Pu mass
7. Preliminary results (cont’d) Time-evolution of Cm mass
8. CONCLUSIONS
The fast spectrum available in the MYRRHA sub-critical core is very efficient for the transmutation of (Pu, Am) targets due to a better fission-to-absorption ratio than in fast reactors
The incineration of Cm pre-requires a Partitioning step to separate Cm and Am
The incineration of long-lived fission products, such as the 99Tc, in a resonance capture region is demonstrated.
Further studies are underway to enhance the epithermal tail of the neutron spectrum by optimizing the target design and choosing more appropriate spectrum softening materials.