Assessment of soil contamination in the vicinity of a research reactor during the decommissioning process

Summary

The performance of a collimated in-situ gamma measurement system for the determination of radioactive inventories on places with strong local variations of contamination was assessed. The local inventories and the relaxation depths of ²⁴¹Am, ¹³⁷Cs and ⁶⁰Co at the investigated site were determined by the analysis of soil profiles. Distinct variations of inventories calculated from the analysis of soil profiles could be observed even for sampling sites close to each other. Average relaxation depths were established for the evaluation of the in-situ measurements. Additionally, the isotopic ratios of ²³⁸Pu/²³⁹⁽40⁾Pu and ²⁴¹Am/²³⁹⁽40⁾Pu were determined by alpha-spectrometry for the investigated site.