1 / 21

TRAMU@GSI M.-L. GIACRI-MAUBORGNE , D. RIDIKAS, J.-C. DAVID

Modeling of Photonuclear Reactions & Transmutation of Long-lived Nuclear Waste in High Photon Fluxes. TRAMU@GSI M.-L. GIACRI-MAUBORGNE , D. RIDIKAS, J.-C. DAVID DSM/DAPNIA/SPhN, CEA/Saclay, F-91191 Gif/Yvette, France M. B. CHADWICK, W. B. WILSON

nakia
Download Presentation

TRAMU@GSI M.-L. GIACRI-MAUBORGNE , D. RIDIKAS, J.-C. DAVID

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Modeling of Photonuclear Reactions & Transmutation of Long-lived Nuclear Waste in High Photon Fluxes TRAMU@GSI M.-L. GIACRI-MAUBORGNE, D. RIDIKAS, J.-C. DAVID DSM/DAPNIA/SPhN, CEA/Saclay, F-91191 Gif/Yvette, France M. B. CHADWICK, W. B. WILSON Los Alamos National Laboratory (T-16), Los Alamos, NM 87545, USA giacri@cea.fr

  2. Applications of photonuclear reactions • Production of RNB • Neutron production • Non-destructive characterization of nuclear waste • Detection of nuclear materials (235U, 239Pu) • Radioprotection of electron accelerators • Transmutation of nuclear waste

  3. TRAMU@GSI 9/5/03 giacri@cea.fr Contents • Development of a photonuclear cross section library for CINDER’90 evolution code : • use of the IAEA photonuclear evaluation library • use of HMS-ALICE and GNASH to complete the library • use of GSI fission model for photofission-yields • Example: transmutation in photon fluxes for 90Sr, 237Np and comparison with neutron fluxes

  4. TRAMU@GSI 9/5/03 giacri@cea.fr CINDER’90 CINDER’90 (LANL) – material evolution in neutron fluxes Photonuclear activation data library is needed to extend it for photon fluxes Similar efforts for proton induced activation will make CINDER a multi-particle activation code

  5. TRAMU@GSI 9/5/03 giacri@cea.fr HMS-ALICE : Light nuclides Cross sections of light nuclides are difficult to reproduce whatever the model In HMS-ALICE model for light nuclides needs to be improved

  6. TRAMU@GSI 9/5/03 giacri@cea.fr HMS-ALICE : Heavy nuclides Good agreement for 208Pb 181Ta not as good : total absorption cross section has a different shape Calculations for heavy nuclei are good enough to be use in CINDER’90

  7. TRAMU@GSI 9/5/03 giacri@cea.fr HMS-ALICE : Absorption cross sections HMS-ALICE model for absorption can not be employed for actinides - sum of two Lorentzians should be used Work is in progress to change the absorption model for actinides in HMS-ALICE

  8. TRAMU@GSI 9/5/03 giacri@cea.fr Photoabsorption new model

  9. TRAMU@GSI 9/5/03 giacri@cea.fr HMS-ALICE : Conclusion HMS-ALICE should be used with certain precaution for photonuclear reactions Our approach to prepare CINDER’90 library: • Use of the IAEA evaluations when available • Use of GNASH for nuclides of interest to get better accuracy • Complete the library with the HMS-ALICE predictions Next improvements in HMS-ALICE will focus on: • Total absorption cross section model (new parameterization) • Inclusion of photo-fission yields (GSI fission model)

  10. TRAMU@GSI 9/5/03 giacri@cea.fr GNASH : 235U and 239Pu Input: σabsfrom the IAEA evaluations Good agreement with experimental data for separate channels

  11. TRAMU@GSI 9/5/03 giacri@cea.fr GNASH : 237Np Data on σabsare inconsistent We fix this value according to the total integral, using the systematic from the IAEA for neighbor actinides We made a compromise between two experimental data to obtain a integral equal to 3.54 barn.MeV

  12. TRAMU@GSI 9/5/03 giacri@cea.fr GNASH : 237Np Photo-fission evaluation between the two experimental data Good agreement for photoneutron production

  13. TRAMU@GSI 9/5/03 giacri@cea.fr GNASH : Conclusions GNASH is a powerful tool for photonuclear data evaluations Good agreement with experimental data when the total absorption cross section is used as input Might be very time-consuming to use GNASH to build the entire library. However, it can be used to increase the accuracy of cross sections for some elements and actinides in particular

  14. PhotofissionYields TRAMU@GSI 9/5/03 giacri@cea.fr • Data • on the photofission of 235Uand238U with Bremsstrahlung spectra very limited • a few mass and charge distributions, some isotopic yields • P/V ratios, <LM> & <HM> • Calculation procedure • total absorption cross section (GDR parameterization) • fission-evaporation in competition (GSI model) • calculation of independent fission yields and residual nuclei

  15. Example: photofission of 235U TRAMU@GSI 9/5/03 giacri@cea.fr • both bremsstrahlung and monoenergetic photons are tried • 15 MeV photons are equivalent to 25 MeV bremsstrahlung

  16. Search for the systematic from (n,fiss) TRAMU@GSI 9/5/03 giacri@cea.fr n + 234Uorn + 235U at 6-8 MeVmight be a good combination More careful checks on charge and isotopic distributions to be done!

  17. Fission Yield : Conclusion TRAMU@GSI 9/5/03 giacri@cea.fr • we’ve got a working model for photofission(still in validation process) • preliminary results are encouraging but sensitivity due to different parameters still to be tested • in the near future we will provide for a number of actinides • fission cross-section predictions • mass, charge and isotopic distributions of FFs and residual nuclei • delayed neutron yields and time-dependence; and search for the systematic from neutron induced fission

  18. Decay Irradiation TRAMU@GSI 9/5/03 giacri@cea.fr Example : Transmutation of 90Sr 1 year irradiation in the flux of 1017.cm-2.s-1 7 years decay Results are in agreement with T. Matsumoto NIM A 268 (1988) 234-243 Total activity decreases by 30% compared to the natural decay of 90Sr The same result can be obtained with a flux of 1016 nth cm-2 s-1 At 1018.cm-2.s-1 activity is decreased ~20 times.

  19. TRAMU@GSI 9/5/03 giacri@cea.fr Example : Incineration by fission of 237Np 1 year irradiation as a function of flux intensity 5 %/year incineration: - 5x1016 .cm-2.s-1 - 7x1014 nth.cm-2.s-1 - 2x1015 nfast.cm-2.s-1

  20. Transmutation : Conclusion • Transmutation by photonuclear reaction does not create elements heavier than the initial nuclei • It tends to reduce the long term activity • Photon fluxes need to be one to two orders of magnitude higher than neutron fluxes

  21. TRAMU@GSI 9/5/03 giacri@cea.fr Conclusion and perspectives • Thanks to the photonuclear library (by now it includes ~600 isotopes), with CINDER’90 we can do activation analysis in photon fluxes • The library will be more precise by improving predictive power of HMS-ALICe • Fission yields still have to be added to the library • The integrality of the library still needs to be validated-tested by dedicated experiments

More Related