Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (6): 60601-060601.doi: 10.11889/j.0253-3219.2016.hjs.39.060601

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Using the neutron balance method to access the feed fuel requirements for CANDLE

YANG Kun1,2, CHEN Jingen1, CAI Xiangzhou1   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-03-09 Revised:2016-03-21 Online:2016-06-10 Published:2016-06-12
  • Supported by:

    Supported by Strategic Priority Program of Chinese Academy of Sciences (No.XDA02010000)

Abstract:

Background: CANDLE (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy produced) is a burnup strategy for Breed-and-Burn (B&B) reactors in which the effective neutron multiplication factor at an equilibrium state is equal to unity. The radius and fuel volume fraction of such a core play a very important role in the B&B mode of operation. However, using the Monte Carlo method to model a full CANDLE core for optimization costs too much computational effort and time. Purpose: This study aims to assess the validity of neutron balance analysis with a simplified 1D model for determination of the maximum burnup (BU) attainable in a CANDLE mode, and then apply this 1D methodology to optimize the configurations of feed fuel and core radii for a sodium-cooled core to sustain the CANDLE mode. Methods: When the maximum achievable BU of feed fuel equals the maximum burnup of the CANDLE feed fuel at equilibrium state, the keff value of the core is equal to unity. The neutron balance method with the 1D approach for various core radii and fuel volume fractions of feed fuel can provide a quick way to scope the optimized configuration. Results: Neutron balance analysis with the 1D approach can provide a reasonable estimation of the maximum attainable BU of feed fuel in a CANDLE reactor, despite a small inaccuracy due to the spectrum difference between the 1D and the full core models. A small size of core and a low fuel volume fraction of feed fuel display a small value of the maximum attainable BU, which implies that it is disadvantageous to sustain a CANDLE mode. However, a too big size of core or high fuel volume fraction of feed fuel may lead to keff>1 at equilibrium state. With the above considerations and optimization, we present a suitable core geometry and its fuel fraction to ensure the stable B&B mode of operation at equilibrium state (keff=1). Conclusion: The neutron balance calculation with 1D approach can save much computational time, and the optimized configurations of feed fuel to sustain a CANDLE mode are proposed based on this methodology.

Key words: CANDLE reactor, Neutron balance method, Optimized configuration, Monte Carlo method

CLC Number: 

  • TL329+.2