Conceptual Design of a Large, Passive Pressure-Tube Light Water Reactor
Author(s)
Hejzlar, P.; Todreas, N. E.; Driscoll, M. J.![Thumbnail](/bitstream/handle/1721.1/67640/ANP-021.pdf.jpg?sequence=3&isAllowed=n)
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Other Contributors
Advanced Nuclear Power Technology Program (Massachusetts Institute of Technology)
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Show full item recordAbstract
A design for a large, passive, light water reactor has been developed.
The proposed concept is a pressure tube reactor of similar design to
CANDU reactors, but differing in three key aspects. First, a solid
Sic-coated graphite fuel matrix is used in place of pin-rod bundles to enable
the dissipation of decay heat from the fuel in the absence of primary
coolant. Second, the heavy water coolant in the pressure tubes is replaced by
light water, which serves also as the moderator. Finally, the calandria
tank, surrounded by a graphite reflector, contains a low pressure gas
instead of heavy water moderator, and the normally-voided calandria is
connected to a light water heat sink. The cover gas keeps the light water out
of the calandria during normal operation, while during loss of coolant or
loss of heat sink accidents it allows passive calandria flooding. Calandria
flooding also provides redundant and diverse reactor shutdown. The entire
primary system is enclosed in a robust, free standing cylindrical steel
containment cooled solely by buoyancy-induced air flow, and surrounded by
a concrete shield building.
It is shown that the proposed reactor can survive loss of coolant
accidents without scram and without replenishing primary coolant
inventory, while the safe temperature limits on the fuel and pressure tube
are not exceeded. It can cope with station blackout and anticipated
transients without scram - the major traditional contributors to core
damage frequency - without sustaining core damage. The fuel elements
can operate under post-CHF conditions even at full power, without
exceeding fuel design limits. The heterogeneous arrangement of the fuel
and moderator ensures a negative void coefficient under all circumstances.
Although light water is used as both coolant and moderator, the reactor
exhibits high neutron thermalization and a large prompt neutron lifetime,
similar to DgO moderated cores. Moreover, the extremely large neutron
migration length results in a strongly coupled core with a flat thermal flux
profile, and inherent stability against xenon spatial oscillations.
Date issued
1994-06-01Publisher
Massachusetts Institute of Technology. Center for Advanced Nuclear Energy Systems. Advanced Nuclear Power Program
Other identifiers
DOE/ER/75785-4
Series/Report no.
MIT-ANP;TR-023