Pressurized water reactor inherent core protection by primary system thermohydraulics
Current light water reactors (LWRs) depend for the protection of core integrity on a multitude of active systems and components, such as instrumentation, cables, electronic logics, relays, actuators, etc., and on human judgment. This approach to safety has led to a complex and expensive plant design in which all parts of the plant where these systems are present must be protecte against damage due to, e.g., earthquake. It has also failed to persuade the public about the safety of the reactors because of the existing (but very small) probability of multiple failures leading to core meltdown. With the process inherent ultimate safety (PIUS) approach, this dependence on active systems is eliminated. The safety is now no longer a result of their intervention but is built into the thermohydraulics of the primary system itself. The PIUS primary system response to a number of severe anticipated transients without scram (ATWS) is described, as studied by means of a specially devel oped computer simulation program. The method is shown by which the thermohydraulic self-protection properties of the primary system terminates these ATWS transients, which could have severe consequences in a conventional LWR, with neither the core nor the rest of the plant suffering any damage (beyond the initial failure assumed). This has important economic consequences. The surveillance and control systems used to run the plant and the buildings in which they are housed can be designed as for a fossil plant, since they no longer have the ultimate responsibility for nuclear safety. The ensuing design simplification pays for the more expensive pressure vessel and primary system. Inherent safety is obtained as a bonus.
- Research Organization:
- AB ASEA-ATOM, Vasteras
- OSTI ID:
- 6134600
- Journal Information:
- Nucl. Sci. Eng.; (United States), Vol. 90:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
PWR TYPE REACTORS
PRIMARY COOLANT CIRCUITS
REACTOR PROTECTION SYSTEMS
REACTOR SAFETY
ATWS
COST BENEFIT ANALYSIS
HEAT TRANSFER
HYDRAULICS
MELTDOWN
PRESSURE VESSELS
REACTOR ACCIDENTS
REACTOR CONTROL SYSTEMS
ACCIDENTS
CONTAINERS
CONTROL SYSTEMS
COOLING SYSTEMS
ENERGY SYSTEMS
ENERGY TRANSFER
FLUID MECHANICS
MECHANICS
REACTOR COMPONENTS
REACTOR COOLING SYSTEMS
REACTORS
SAFETY
WATER COOLED REACTORS
WATER MODERATED REACTORS
220900* - Nuclear Reactor Technology- Reactor Safety
210200 - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled