Program - Brookhaven National Laboratory

source SINQ (Swiss Spallation Neutron Source) at PSI in 2006. The MEGAPIE target was 5.35 meter
long and filled with 87 litres of LBE. It was irradiated with 575 MeV protons for 123 days, starting from
August 21st 2006, receiving a total charge close to 3 Ah [3]. To determine the radionuclide inventory of
this target, an extensive sampling program was performed in the hot cells of PSIs’ Hotlab, starting in
May 2011 and ending in the beginning of 2012. In total 74 samples from different positions in the target
were taken, 30 from LBE/steel interfaces and the LBE/cover gas interface in order to study enrichment
effects at these positions and the remaining samples comprising the bulk LBE. All samples were measured
by γ-spectrometry without prior chemical separation, analyzed and compared with activation calculations
of Zanini et al. [4]. The radionuclides that were definitely identified by γ-spectrometry are 60Co, 101Rh, 102Rh, 108mAg, 110mAg, 133Ba, 172Hf/Lu, 173Lu, 194Hg/Au, 195Au and 207Bi. For some of these nuclides,
such as 207Bi, 194Hg/Au, 101Rh and 102Rh, the activities can be easily evaluated from the γ-spectrometry
results obtained without prior chemical separation, while other nuclides that were unambiguously identified
require chemical separation from the matrix before they can be quantified ( 108mAg, 110mAg, 195Au). There
are certainly also a large number of additional nuclides that will be only detectable after chemical separation
like the long-lived 129I, 36Cl or the α-emitting 208−210Po and 148Gd. To present the general results on the
radionuclide inventory and distribution in the MEGAPIE target in a concise way, we focus on 207Bi, 194Au and 173Lu as leading nuclides. Here, 207Bi represents the target material itself. 194Au represents noble
metals that have a high solubility and low chemical reactivity in the eutectic, while 173Lu represents the
rare earth elements that are highly reactive and sensitive to oxidation. 207Bi is homogeneously distributed
in the target, whereas 194Au and 173Lu are inhomogeneously distributed. While 194Au is found in varying
amounts in all of the samples that have been analysed, 173Lu is only found in samples from the LBE/steel
and LBE/cover gas interfaces and not in the bulk LBE, indicating strong separation effects. Moreover,
the separation of 129I and 36Cl from the residue by distillation in a N2-stream was performed for about 30
samples. The activity of these nuclides will be studied by Accelerator Mass Spectrometry (AMS). First
results should be available by the end of 2012. Furthermore, the separation and analysis of α-emitting
208/209/210Po from LBE by deposition onto a silver disc was started. First results indicate that 208−210Po is not homogeneously distributed in the target.
[1] D. Gorse-Pomonti, V. Russier, Journal of Non-Crystalline Solids, 353, 3600-3614 (2007) [2] A. Y.
Konobeyev, U. Fischer, L. Zanini, Nuclear Instruments and Methodes in Physics Research Section A, 605,
224 (2009) [3] L. Zanini, S. Dementjev, F. Gröschel et al., Journal of Nuclear Materials, 415, 367-377 (2011)
[4] L. Zanini, J.-C. David, A. Konobeyev, S. Panebianco, N. Thiolliere, Neutronic and Nuclear Post-Test
Analysis of Megapie, PSI-Report No. 08-04, Paul Scherrer Institute, Villigen, Switzerland, December 2008.
KE 4 2:40 PM
Measured and Calculated Iron Filtered Neutron Spectra Using Different Data Libraries for
Calculation
B. Jansky, Z. Turzik, E. Novak, M. Kostal
Research Centre Rez, Czech Republic
L.A. Trykov, A.I. Blokhin
Institute of Physics and Power Engineering, Obninsk, Russia
The Iron filtered leakage neutron spectra measurements have been done on the following benchmark assemblies:
reactor Iron filtered beam of the thickness 67 cm at PTB Braunschweig (Germany) and of the
thickness 120 cm at NRI Rez on LWR-15 reactor (Czech Republic). The leakage neutron spectra from
Iron spheres with diameter of 30, 50, 100 cm with the Cf-252 neutron source placed into the centre of
iron sphere were measured. Neutron spectra were measured also on reactor pressure vessel model of the
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