HTR Fuel Waste Management: TRISO separation and acid-graphite intercalation compounds preparation

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• 作者：Fabrice Guittonneau ; Abdesselam Abdelouas ; Bernd Grambow
• 刊名：Journal of Nuclear Materials
• 出版年：2010
• 出版时间：15 December 2010
• 年：2010
• 卷：407
• 期：2
• 页码：71-77
• 全文大小：1173 K

文摘

Considering the need to reduce waste production and greenhouse emissions and still keeping high energy efficiency, various 4th generation nuclear energy systems have been proposed. As far as graphite-moderated reactors are concerned (future high temperature fast or thermal reactors), one of the key issues is the large volumes of irradiated graphite encountered. With the objective to reduce volume of waste in the HTR concept, it is very important to be able to separate the fuel from low level activity graphite representing a large volume. The separated TRISO particles can then be reprocessed for waste separation or disposed off in geological repository. In addition, preparation of acid-GICs from the separated graphite may constitute a way to recycle this waste.

We used HTR-type compact fuel with ZrO₂ TRISO particles to test two separation methods: low (H₂SO₄ + H₂O₂) and high (H₂SO₄ + HNO₃) temperature acid treatments. In both cases the TRISO separation was complete but some TRISO layers oxidized at high temperature. At low temperature, the desegregation of graphite grains is facilitated by intercalation of sulfuric acid between the graphene layers. The acid-GIC obtained consists of pure phases of high quality suggesting their potential industrial recycling.