行波堆深燃耗的计算特点

行波堆属于新概念堆型,卸料燃耗深度可达400 GWd/tHM,是现有快堆的3~4倍、压水堆的6~8倍,较高的卸料燃耗深度对堆芯物理分析工具计算正确性提出挑战。基于此,以KYLIN-1程序为基础,从能谱、裂变产物核素重要性、燃耗计算误差累积等方面探究行波堆深燃耗计算特点。对典型行波堆六角形组件分析结果表明:低富集度铀组件寿期初、末能谱差别较大,采用单一权重谱制备的多群截面库用于其燃耗计算时,无限增殖系数偏差较大；为保证行波堆深燃耗计算的正确性,燃耗链应包含重要的70种裂变产物核素；行波堆深燃耗计算时,由于燃耗步增多累积的误差较小,无限增殖系数偏差每燃耗步约为0.001%。

High burnup calculation characteristics of traveling wave reactor

The traveling wave reactor (TWR) is an innovative nuclear system, whose discharge burnup is 400 GWd/tHM, about three to four times of existing fast reactor and six to eight times of pressurized water reactor. High discharge burnup forces the present codes to face the great challenges in precision.This paper studies the high burnup calculation characteristics of traveling wave reactor from energy spectrum, importance of fission production and calculation error accumulation of fuel consumption by KYLIN-1 code. The analysis results of typical traveling wave reactor hexagonal assembly show that the low enriched uranium assemblies have different energy spectra at beginning and end of life, which cause big calculation error ofkinf by existing code system. To ensure the correctness of the traveling wave reactor burnup calculations, the burn chain should contain 70 kinds of important fission product nuclides. The calculation error accumulation of fuel consumption is small when the burnup step is increased. The calculation error ofkinf is about 0.001% each burnup step.