New results of experimental studies of fission products release from spent nuclear fuel of the icebreaker ?Lenin? reactor dumped in the Kara Sea

[Emily]

http://www.radioprotection.org/inde...doi&doi=10.1051/radiopro/20116468s&Itemid=129

<table class="idline" border="0" width="100%"><tbody><tr><td class="gen" valign="top">Issue </td><td width="10">
</td><td> Radioprotection
Volume 46, Number 6, 2011
ICRER 2011 ? International Conference on Radioecology & Environmental Radioactivity: Environment & Nuclear Renaissance
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</td></tr><tr><td class="gen"> Page(s) </td><td>
</td><td>S363 - S369</td></tr><tr><td class="gen">Section</td><td>
</td><td>Mechanisms and Models</td></tr><tr><td class="gen">DOI</td><td>
</td><td>http://dx.doi.org/10.1051/radiopro/20116468s</td></tr><tr><td class="gen">Published online</td><td>
</td><td> 09 January 2012 </td></tr></tbody></table>
The new results of experimental studies of fission products release from spent nuclear fuel of the icebreaker ?Lenin? reactor dumped in the Kara Sea

V. Soyfer¹, V. Goryachev¹, A. Salyuk¹, O. Dudarev¹, D. Andreev², A. Gaiduchenko², I. Barabanov³ and E. Yanovich³
¹ I. Il?ichev Pacific Oceanological Institute, FEB RAS, 690041 Vladivostok, Russia
² National Research Centre ?Kurchatov Institute?, 123182 Moscow, Russia
³ Institute for Nuclear Research RAS, 117312 Moscow, Russia

Abstract
The new technologies were developed for spent nuclear fuel (SNF) condition operative monitoring and search for the lost objects with SNF at the sea bottom using Kr-85. The new paradigm of sea radioecology based on extensive research was proposed. The investigations include a preliminary experimental study of kinetics of fission products (Kr-85 and Cs-137) release from SNF, a subsequent expedition to the Arctic, as well as modeling radionuclides transfer in a near-bottom layer by means of fractal formalism using hydrological data on the expedition area [1,2]. Series of original experimental studies on Kr-85 and Cs-137 release from SNF during corrosion in sea water were conducted in 2002?2010. Time dependence of fission products (FP) release was measured in laboratory under conditions typical of a near-bottom water layer in the Novaya Zemlya Basin. Another important result was received during the expedition to the Arctic in the fall of 2000. The H-3 anomaly was recognized in the surface layer of the Kara Sea in the Novaya Zemlya Basin (228 ? 9.1 TU vs.10?15 TU in the Arctic on average!). This anomaly is located 100 miles south from the dumped reactor of atomic icebreaker ?Lenin?. So it can be caused by SNF from the reactors of icebreaker ?Lenin? or nuclear submarine K-140.
? Owned by the authors, published by EDP Sciences, 2011
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3. CONCLUSION
Experimental research was carried out in order to understand processes which control radioactive pollution of the sea environment. The experimental studies include investigation of fission products release during UO2 corrosion process. Total fission products release from containers with SNF fragment was measured in laboratory during 2800 days of the experiment. Experimental conditions simulate fission products release from the fuel of dumped nuclear icebreaker ?Lenin? reactor. Released quantities of Cs-137 from the fuel fragment were about 28% for pure sea water and about 3% for water with silt from the Novaya Zemlya Basin. For Kr-85 these values were about 10 and 15% of the initial accumulated amount. Kr-85 release rate exceeded Cs-137 release rate in few ten times in the beginning of the experiment (first tens of days). However, Kr-85 release reached saturation after 800?900 days of the experiment, while Cs-137 release rate remained almost constant during more than 8 years of the corrosion experiment.
Tritium background measurements were carried out using the samples of Arctic water. The water was sampled from the Arctic surface layer along the Northern Sea cruise during one expedition for the first time. Fission products from spent nuclear fuel were recognized on a shelf of the Arctic as a result of anthropogenic or natural accidents. Abnormal high tritium concentration was discovered in the south of the Novaya Zemlya Basin in the Kara Sea (more than 200 TU vs. 6?15 TU on shelf of other
Arctic seas!). The anomaly is located at 200 km to the south of dumping regions of unloaded reactors from the nuclear icebreaker ?Lenin? and atomic submarine K-140. So this anomaly can be caused by
release of fission products from SNF of these reactors [11]. The abnormal sample was investigated by two independent methods.
Acknowledgments
The authors are grateful to Ph Dr. I. Semiletov (POI FEB RAS Vladivostok) for skilled expedition organization.
Work is supported RFBR (Grant 10-05-00366).

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