Experience of transportation of radioactive samples for analysis

Independent verification of the concentration of special nuclear materials in the input solution, plant discards and product samples constitutes an important element of the state system of accounting or international safeguards for a reprocessing plant. This requires that the samples collected at the reprocessing plant are sent to the referee laboratory for verification analysis. Safe handling procedures and packaging codes have been evolved and are being kept constantly reviewed. During the reprocessing campaigns carried out at Prefre, India, under IAEA safeguards, a number of samples from stipulated stages of the process were sent to the Agency in discrete consignments. It was observed that verification analysis at the Agency's Analytical Laboratory involves considerable delay due to various procedural and logistic constraints in the transportation and co-ordination. This delay has certain implications for the verification system, the most notable being the problem of ageing of the samples. The paper describes experience in various aspects of transportation of samples, highlighting detrimental effects of ageing on the determination of elemental and isotopic composition in such samples. Corrective measures to be taken to compensate for these detrimental effects are also described in the paper. (author)