U-235 isotopic characterization of natural and enriched uranium materials by using multigroup analysis (MGA) method at a defined geometry using different absorbers and collimators

YÜCEL H., Yeltepe E., Yuksel A. O., Dikmen H.

NUKLEONIKA, cilt.60, sa.3, ss.615-620, 2015 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 60 Sayı: 3
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1515/nuka-2015-0114
  • Dergi Adı: NUKLEONIKA
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.615-620
  • Anahtar Kelimeler: nuclear safeguards, enrichment measurements, uranium, multigroup analysis, enrichment meter principle, GAMMA-RAY, APPLICABILITY, SPECTROMETRY, DETECTORS, CODE
  • Ankara Üniversitesi Adresli: Evet

Özet

Characterization of nuclear materials is an important topic within the context of nuclear safeguards, homeland security and nuclear forensics. This paper deals with the performance of multigroup gamma-ray analysis (MGA) method using the X-and gamma-rays in the 80-130 keV region and enrichment meter principle (EMP) based on the analysis of 185.7 keV peak for a certain geometry using different absorbers and collimators. The results from MGA and those of EMP are compared. In particular, the effect of aluminum/lead absorbers and lead collimator on the enrichment determination of U-235 in natural and low enriched samples is investigated in a given source-detector geometry. The optimum diameter/height ratio for the Pb-collimator is found to be D-c/H-c = 1.4-1.6 in the chosen geometry. In order to simulate the container walls, ten different thicknesses of Al-absorbers of 141 to 840 mg.cm(-2) and six different thicknesses of Pb-absorbers of 1120-7367 mg.cm(-2) are interposed between sample and detector. The calibration coefficients (% enrichment/cps) are calculated for each geometry. The comparison of the MGA and EMP methods shows that the enrichment meter principle provides more accurate and precise results for U-235 abundance than those of MGA method at the chosen geometrical conditions. The present results suggest that a two-step procedure should be used in analyses of uranium enrichment. Firstly MGA method can be applied in situ and then EMP method can be used at a defined geometry in laboratory.