Within-Pin Reaction Rate Distributions: CASMO-4 and HELIOS Compared Against Tomographic Measurements at the PROTEUS Reactor
Within-Pin Reaction Rate Distributions: CASMO-4 and HELIOS Compared Against Tomographic Measurements at the PROTEUS Reactor
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引脚内反应速率分布：CASMO-4 和 HELIOS 与 PROTEUS 反应堆的断层扫描测量结果进行比较
DOI：
10.13182/nse05-a2499
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发表时间：
2005
影响因子：
1.2
通讯作者：
R. Chawla
中科院分区：
文献类型：
--
作者：
C. P. Fauchère;M. Murphy;F. Jatuff;R. Chawla
在Paul Scherrer研究所进行的先进轻水堆堆芯分析工具的扩展验证计划LWR PROTEUS项目的框架内，采用两种程序计算了西屋SVEA-96+沸水堆燃料组件零燃耗销钉的总裂变率（Ftot）和238 U（C8）俘获率的径向内部变化，CASMO-4和HELIOS。虽然CASMO-4和HELIOS预测的Ftot分布非常一致，但C8分布显示出显著的不一致性（20 - 30%）。计算结果与实验结果进行了比较，使用单光子发射计算机断层扫描几个SVEA-96+针在零功率反应堆PROTEUS辐照。这些比较证实了UO 2引脚内Ftot分布的预测形状，并清楚地表明，C8的HELIOS引脚内预测比CASMO-4结果更可靠。这是很重要的伽玛射线自吸收修正的推导时，针集成的反应速率是使用伽玛扫描技术来确定。因此，使用CASMO-4型针内分布将导致C8和C8/Ftot推导出的绝对自吸收校正针积分值存在3%至4%的差异。对于相对的C8分布，差异会小得多，即，如果包含可燃吸收剂的引脚参与，高达~1%。
Abstract In the framework of the LWR-PROTEUS project—an extended validation program for advanced light water reactor core analysis tools conducted at the Paul Scherrer Institute—the radial, internal variations of the total fission rate (Ftot) and the capture rate in 238U (C8) have been calculated for zero-burnup pins of a Westinghouse SVEA-96+ boiling water reactor fuel assembly using two codes, namely, CASMO-4 and HELIOS. While Ftot distributions predicted by CASMO-4 and HELIOS are in good agreement, C8 distributions show significant inconsistencies (20 to 30%). The calculations are compared with experimental results obtained using single photon emission computerized tomography for several SVEA-96+ pins irradiated in the zero-power reactor PROTEUS. The comparisons confirm the predicted shape of the Ftot distributions within UO2 pins and clearly indicate that HELIOS within-pin predictions for C8 are more reliable than CASMO-4 results. This is important for the derivation of gamma-ray self-absorption corrections when pin-integrated reaction rates are to be determined using the gamma-scanning technique. Thus, the use of CASMO-4-type within-pin distributions would lead to 3 to 4% discrepancies in the absolute, self-absorption-corrected pin-integrated values deduced for C8 and hence for C8/Ftot. For relative C8 distributions, the discrepancy would be much smaller, namely, up to ~1% if pins containing a burnable absorber are involved.