Aspects of severe accidents in transmutation systems
The different types of transmutation systems under investigation include accelerator-driven (ADS) and critical systems. To switch off an accelerator in case of an accident initiation is quite important for all accidents. For a fast ADS the grace times available for doing so, depend strongly on the total heat capacity and the natural circulation capability of the primary coolant. Cooling with heavy metal Pb/Bi has considerable advantages in this regard compared to gas cooling. Moreover it allows passive ex-vessel cooling with natural air or water circulation. In the remote likelihood of fuel melting, oxide fuel appears to mix with the Pb/Bi coolant. Fast critical systems that are cooled by Pb/Bi will automatically shut off if the flow or heat sink is lost. Reactivity accidents can be limited by a low total control rod worth. High Temperature Reactors can achieve only incomplete burning of actinides. If an accelerator is added to increase burn up, a fast spectrum region is needed, which has a low heat capacity.
Bibliographic Reference: An oral report given at: The 6th OECD/NEA Information Exchange Meeting. Organized by: CIEMAT-European Commission. Held at: Madrid (ES), 11-13 December, 2000
Record Number: 200013171 / Last updated on: 2001-03-20
Original language: en
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