Mitigation of Anticipated Transients Without Scram in the ESBWR
- GE Energy (United States)
The ESBWR has robust ATWS performance due to the use of passive systems. The heatup of the suppression pool is minimized and the ATWS can be managed at high pressure. ATWS prevention/mitigation features of ESBWR include: An Alternate Rod Insertion (ARI) system that utilizes sensors, logic and valves that are diverse and independent of the Reactor Protection System RPS, Electrical insertion of Fine Motion Control Rod Drives (FMCRDs) that utilize sensors and logic which are diverse and independent of the RPS, Automatic feedwater run-back under conditions indicative of an ATWS An automatic Standby Liquid Control System (SLCS) with a capacity equivalent to 5.42 E-3 m{sup 3}/sec (86 gpm) of 13-weight percent sodium penta-borate solution. The boron is supplied by 2 accumulators and injection is triggered by Squib valves. The boron solution is piped inside the reactor to the core bypass, and discharges at several distribution points in high velocity jets. Several other ESBWR features help to mitigate an ATWS. The large steam volume in the chimney results in a reduced vessel pressurization rate. The isolation condensers terminate suppression pool heatup while there is still steam generation occurring in the core. Analysis with the TRACG computer code shows the ESBWR safety valve capacity is effective in limiting the pressure in the reactor vessel pressure. The automatic FW reduction reduces water level and core flow, which in turn reduces power to approximately one-quarter of the initial value. Finally the reactor is brought sub-critical by boron injection into the core bypass region from two Standby Liquid Control System accumulators. The results show that the mitigation systems are adequate to meet the acceptance criteria without operator action. (authors)
- Research Organization:
- The ASME Foundation, Inc., Three Park Avenue, New York, NY 10016-5990 (United States)
- OSTI ID:
- 20995689
- Resource Relation:
- Conference: 14. international conference on nuclear engineering (ICONE 14), Miami, FL (United States), 17-20 Jul 2006; Other Information: Country of input: France
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evaluation of BWR emergency procedure guidelines for BWR ATWS using RAMONA-3B code
ESBWR - Robust design for natural circulation and stability performance effectiveness