Impact of design options on natural circulation performance of the AFR-300 advanced fast reactor.
The AFR-300, Advanced Fast Reactor (300 Mwe), has been proposed as a Generation IV concept. It could also be used to dispose of surplus weapons grade plutonium or as an actinide burner for transmutation of high level radioactive waste. AFR-300 uses metallic fuel and sodium coolant. The design of AFR-300 takes account of the successful design and operation of EBR-II, but the AFR-300 design includes a number of advances such as an advanced fuel cycle, inspectability and improved economics. One significant difference between AFR-300 and EBR-II is that AFR-300 is considerably larger. Another significant difference is that AFR-300 has no auxiliary EM pump in the primary loop to guarantee positive core flow when the main primary pumps are shut down. Thus, one question that has come up in connection with the AFR-300 design is whether natural circulation flow is sufficient to prevent damage to the core if the primary pumps fail. Insufficient natural circulation flow through the core could result in high cladding temperatures and cladding failure due to eutectic penetration of the cladding by the metal fuel. The rate of eutectic penetration of the cladding is strongly temperature dependent, so cladding failure depends on how hot the cladding gets and how long it is at elevated temperatures. To investigate the adequacy of natural circulation flow, a number of pump failure transients and a number of design options have been analyzed with the SASSYS-1 systems analysis code. This code has been validated for natural circulation behavior by analysis of Shutdown Heat Removal Tests performed in EBR-II. The AFR-300 design includes flywheels on the primary pumps to extend the pump coastdown times, and the size of the flywheels can be picked to give optimum coastdown times. One series of transients that has been run consists of protected loss-of-flow transients with various values for the combined moment of inertia of the pump, the motor and the flywheel giving coastdown times from 70 seconds to 586 seconds. In this transient series both the main pump motors and the pony motors lose power. Another series of loss-of-flow cases involved staggered failures of the pony motors. The main pump motors fail, the reactor scrams, and the pumps coast down to pony motor speed. Then at various times the pony motors are assumed to fail. If the pony motors fail at the wrong time, then the resulting transient can be more severe than if the pony motors failed at the same time as the main motors. A third series of cases involved a reactor scram followed by failure of both the main pump motors and the pony motors at various times. For all of these cases, satisfactory natural circulation behavior can be obtained if the right design options are used.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 795871
- Report Number(s):
- ANL/RAE/CP-106808; TRN: US0201628
- Resource Relation:
- Conference: International Congress on Advanced Nuclear Power Plants (ICAPP), Hollywood, FL (US), 06/09/2002--06/13/2002; Other Information: PBD: 7 Mar 2002
- Country of Publication:
- United States
- Language:
- English
Similar Records
Validation of the HOTCHAN code for analyzing the EBR-II core following an unprotected loss of flow
SAS4A/SASSYS-1 Commercial Grade Dedication Example Report for a Generic Sodium Pool-Type Fast Reactor Application