节块法部分插棒显式表示法及数值结果

Partial Inserted Rod Explicit Representation Method in Nodal Method and Numerical Result

Shanghai Branch, China General Nuclear Engineering Design Company, Shanghai 200030, China

摘要: 节块法在堆芯扩散计算程序中得到广泛应用，但由于采用较粗网格以加快计算速度，给计算结果带来锯齿效应。锯齿效应影响部分与堆芯扩散相关的计算结果。本文提出将部分插棒节块内的中子截面在节块法横向积分方程中进行显式表示的方法，即引入与节块轴向位置相关的截面阶跃函数。数值结果表明，该方法显著改善了锯齿效应引起的控制棒微分价值偏差，特别是基本完全消除了该效应对控制棒相关动力学问题的偏差。
- 节块法 ,
- 部分插棒 ,
- 显式表示法 ,
- 锯齿效应
Abstract: Nodal method is widespread used in reactor core diffusion code, but as nodal method adopting coarse mesh in order to speedup calculation, so it causes cusping effect. Cusping effect would affect some reactor core diffusion relevant calculation result. In this paper, the partial inserted rod intro-node cross section in nodal method transverse integration equation was explicitly represented, i.e. node axial position dependent cross section step function was introduced. Numerical results indicate the method greatly improves the control rod differential worth deviation of cusping effect, in particular nearly completely eliminates the control rod relevant kinetic problem’s deviation of this effect.
- nodal method ,
- partial inserted rod ,
- explicit representation method ,
- cusping effect

[1]	CHO N. Fundamentals and recent developments of reactor physics methods[J]. Nuclear Engineering and Technology, 2005, 37(1): 25-78.
[2]	ZIMIN V G, NINOKATA H, POGOSBEKYAN L R. Polynomial and semi-analytic nodal methods for nonlinear iteration procedure[C]∥PHYSOR-98. Long Island: [s. n.], 1998:994-1002.
[3]	SMITH K S. An analytic nodal method for solving the two-group, multidimensional, static and transient neutron diffusion equations[D]. USA: Massachusetts Institute of Technology, 1979.
[4]	CHAO Y A, HUANG P. Theory and performance of the fast-running multidimensional pressurized water reactor kinetics code, SPNOVA-K[J]. Nucl Sci Eng, 1989, 103: 415-419.
[5]	de LIMA Z R, MARTINEZ A S, da SILVA F C, et al. Correcting the cusping problem in three-dimensional transients through NEM modification[J]. Nucl Sci Eng, 2012, 170: 66-74.