Session: 04-01: SMRs, Advanced Reactors and Fusion

Paper Number: 131299

131299 - Analysis of Smr Reactor Coolant System in Apros 

Abstract: 

The reactor coolant system (RCS) is the primary system of the nuclear power plant primary cycle. The majority operating pressurized water reactors (PWR) nuclear power plant in the world apply separate arrangement. The reactor pressure vessel, reactor coolant pumps and natural cycle steam generators are connected by reactor coolant pipes. But some small module (SMR) reactors use integrate reactor vessel and once through steam generator, which has the advantages of good economics, compact structure and modular construction. The primary circuit reactor coolant system doesn't contain any pipe element, therefore the possibility of a loss of coolant accident is eliminated.

Take the world’s 1^st SMR under construction-the Chinese ACP100 SMR in Hainan Changjiang for example. The reactor coolant system (RCS) mainly consists of 4 reactor coolant pumps (RCP), 16 once through steam generators which located inside the reactor pressure vessel (RPV), a pressurizer and related instrument devices. The reactor coolant of primary side flows into 16 once through steam generators, transfers heat to the secondary side feedwater. Then the reactor coolant leaves once through steam generators and flow into the reactor core to provide cooling. 4 reactors coolants pumps provide driving force to the reactor coolant in the process.

The characteristic of the ACP100 SMR differs widely from the tradition nuclear power plant. Thus, a reactor coolant system model of SMR that contains both process and control elements is developed. The reactor power control, pressurizer control, pressurizer level control, as well as secondary side feedwater control logic is built according to the realistic design. In order to achieve the most accurate and realistic simulation results, a three-dimensional reactor core APROS model which includes fuel elements, control elements, neutronics nodes and thermal hydraulic nodes is developed.

The ACP100 reactor coolant model and simulated to study its behavior under both steady and transit condition, including both 3D-core neutronics and thermal hydraulic results. Several simulations of the steady states at full-power and reduce-power operation were performed and compared with the design reference data. Steady states analysis is conducted under different power load and both force/natural cycle. Analysis of Transient condition including increasing/decreasing power load and force/natural circulation switching is also conducted to acquire dynamic neutronics and thermal hydrate parameter. The reactor core power distribution, fuel temperature, hot side and cold side temperature of reactor coolant, pressurizer pressure/level as well as secondary side steam temperature are recorded and analyzed. With the 3D core, process and control system model, it is capable to calculate numerous physical properties. This makes it possible to study the behavior the whole power plant with one single simulation model. Reference and guidance can be provided for system optimization and safety analysis.

 

Presenting Author: Ye Zhu NPIC

Presenting Author Biography: Process engineer in Nuclear Power Institute of China.

Authors:

Ye Zhu NPIC
Wang Xinbo NPIC
Liao Xianwei NPIC
Cai Zhiyun NPIC
Liu Minghao NPIC