New tests have been carried out on the START and EPICUR test benches as part of the STEM programme dedicated to radioactive releases and mitigation thereof. The STEM project was set up by IRSN under the auspices of the OECD and aims to better understand the behaviour of fission products in nuclear facilities which are likely to be released into the environment in the event of a severe accident.
For the START facility, one of the aims of the tests (test ST7) was to quantify the impact of the quantity of water vapour in the carrier gas on the quantity of gaseous ruthenium transported, and another (test ST8) was to show the potential volatilization of ruthenium deposits with a high level of water vapour in the gas stream. The results are being analysed.
For the EPICUR facility, test AER4 aimed to characterise, under the effects of irradiation, the production of volatile iodine from Cesium iodide aerosols (Csl) deposited on a specimen of Epoxy resin which represents the internal coatings of PWR containments. Initial analysis of this test is showing interesting results: the higher dose rate produces faster reaction kinetics and volatilized chemical species that are different from those in previous tests. The second test (AER5) continued with the same objective as previous AER tests, with an initial Csl concentration 100 times weaker. Volatilization turned out to be much lower than expected, and post-test analyses are expected to confirm this result. The next test series will take place in 2014.
The EPICUR facility
The Environment and Chemistry Experimental Research Laboratory (L2EC)
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