Mitja Majerle for the “Energy Plus Transmutation” collaboration

   Subcritical reactor  Wider choice for reactor fuel ( 238 U, 232 Th)   Transmutation of nuclear waste Increased safety Accelerator  Protons or light ions of energy around 1 GeV   Very high powers (tens, hundreds of MeW) Stability of the beam Spallation reaction

    C.Rubbia at CERN (protons on lead block) MUSE Cadarache (reactor k eff =0.95 with (d,t) source) TRADE Casaccia (reactor coupled with cyclotron) MEGAPIE at PSI (target research)

  Until today:  cross-section measurements on 660 MeV protons     Lead+parafine (GAMMA-2) Lead target (PHASOTRON) Energy Plus Transmutation Lead in graphite block (GAMMA-MD) Future:  Subcritical Assembly Dubna (SAD)

    Lead target + 660 MeV protons Activation detectors (Au, Al, Bi) 129 I samples Focus – spatial distribution of fast neutrons

     Lead target + nat U blanket Protons (0.7-2 GeV), deuterons (1.6-2.52 GeV) Activation detectors (Al, Au, Bi, Cu, In, Ta, Y) Solid state nuclear track detectors ( 235 U, 238 U, nat Pb) Fast neutrons in uranium

     Lead target + graphite moderator Deuterons 1.6 GeV Activation detectors (Al, Au, Bi, Cu, In, Ta, Y) Solid state nuclear track detectors ( 235 U, 238 U, nat Pb) Fast neutrons in graphite

    Monoisotopic materials (Au, Al, Bi, In, Ta, Y, …) Activation during the irradiation  (n,xn), (n, g ), (n, a ) reactions, but also (p,pxn),..

Activity measurement after the irradiation Activity a number of produced isotopes n (n,xn), (n, g ), … g HPGe detector

     Irradiator material (Pb, 235 U, 238 U) + plastic, mica … (n,f) reactions - fission fragments leave tracks in plastic Chemical etching Track counting with microscope Tracks a number of fissions chemical etching n n,fission tracks

   MCNPX, FLUKA -> spectral fluence   Spallation Transport of particles Spectral fluence folded with cross-sections = number of produced isotopes or fissions -> experimental values Experiment / calculations inside 30%:   Cross-sections or Monte-Carlo codes ?

by A. Potapenko

MCNPX calculated spectrum of neutrons

1E-1 1E-3 1E-5 1E-7 1E-9 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 1E-2 1E-1

Neutron bin energy [MeV]

1E+0 1E+1 1E+2 1E+3

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

0 Na-24 Au-196 Au-194 Au-192 Au-191 10 20 30

Position along the target [cm]

40 Phasotron experiment at 660 MeV : measurement/FLUKA calculation.

Detectors are placed on top of the target along its length.

50 4 3 2 1 0 0 5 10

Radial distance [cm]

15 Au-196 Au-194 Au-192 Energy plus transmutation at 1.5 GeV: Measurement / MCNPX calculation.

Detectors are placed in radial direction In the first gap.

    (n,xn) reaction in energy range 10-100 MeV Materials in detectors: Al, Au, Bi, Cu, In, Ta, Y Other : 127 I, 129 I Higher x reactions – n,3n-n,10n – few measurements     (n,f) reactions in energy range 10-1000 MeV Materials : Pb, 235 U, 238 U Other heavy materials : Au, W, Bi, Th For materials other than U few measurements

    Monte-Carlo predictions of XADS within 30% with the experiment –better accuracy needed for real ADS Mostly (n,xn) and (n,f) cross-sections in energy range 10-1000 MeV are needed Cross-sections that we need can be used also for monitoring neutron fluxes at other experiments, in reactors ...

Currently we work on some measurements inside EFNUDAT (Ondrej Svoboda talk)