CAJ | 학술논문

COSINE软件包组件程序是二维、多群输运计算程序，主要用于压水堆组件和单棒的计算，生成少群均匀化常数和核素的核子密度供堆芯程序使用。组件程序的输运计算模块在完成第一阶段两步均匀化方法开发的基础上，为提高程序的先进性和更好满足未来设计需求，现进行开发第二阶段基于特征线（MOC）方法的一步均匀化技术。在输运计算中直接考虑组件的精细构造，消除了两步均匀化方法中由栅元均匀化引入的近似。本文基于MOC方法的输运模块采用循环特征线方法，在方向求积组中的每一个辐角方向内都有一组平行的特征线扫过整个组件区域，每一种栅元类型对应一种特征线几何处理方式。循环特征线方法可确保在二维几何中栅元间的特征线都是完全相接且栅元边界完全满足反射条件。MOC方法在计算精度上减少了近似，且理论上可处理任意几何，但由于大量的存取数据，导致计算时间相对较长。为此，程序使用粗网有限差分（CMFD）技术对MOC计算进行加速，有效地节省了计算时间。在程序开发过程中，测试与验证是开发过程中的重要部分且严格执行质保体系。通过对C5G7基准题比较，数值验证了输运模块的可行性。
COSINE연건포조건정서시이유、다군수운계산정서，주요용우압수퇴조건화단봉적계산，생성소군균균화상수화핵소적핵자밀도공퇴심정서사용。조건정서적수운계산모괴재완성제일계단량보균균화방법개발적기출상，위제고정서적선진성화경호만족미래설계수구，현진행개발제이계단기우특정선（MOC）방법적일보균균화기술。재수운계산중직접고필조건적정세구조，소제료량보균균화방법중유책원균균화인입적근사。본문기우MOC방법적수운모괴채용순배특정선방법，재방향구적조중적매일개복각방향내도유일조평행적특정선소과정개조건구역，매일충책원류형대응일충특정선궤하처리방식。순배특정선방법가학보재이유궤하중책원간적특정선도시완전상접차책원변계완전만족반사조건。MOC방법재계산정도상감소료근사，차이론상가처리임의궤하，단유우대량적존취수거，도치계산시간상대교장。위차，정서사용조망유한차분（CMFD）기술대MOC계산진행가속，유효지절성료계산시간。재정서개발과정중，측시여험증시개발과정중적중요부분차엄격집행질보체계。통과대C5G7기준제비교，수치험증료수운모괴적가행성。
The lattice code in COSINE package is a two-dimensional and multi-group transport code which is mainly used for pressurized water reactor (PWR) assemblies or pin cells analysis .It is used to calculate few group constants and nuclei densities for the core code . As an improvement of the first phase code which using two-step homogenization method ,the one-step homogenization technique based on M OC method is under developing to satisfy the design need in future .In the new technique ,the fine structure of lattice was directly considered ,so it could eliminate the error introduced by two-step homogenization method .In this paper ,the cyclic characteristic method was employed to trace the neutron transfer w hich could make sure the characteristic passes through the geometry of the problem and assigns cell types to each individual cell .T he cyclic tracking approach also could ensure perfect reflection in two dimensions problem . T he M OC method could reduce the approximate and handle the complex geometry problem theoretically .However ,the MOC method had disadvantage of low calculation efficiency for large storage in processing . T he coarse mesh finite difference (CM FD ) was used to accelerate the MOC method in this paper .In the development of LATC ,the quality assurance (QA) process was implemented strictly to ensure the quality of code . The C5G7 benchmark was used as an example to verify the LATC code .The results show that the transport module in LATC is feasible .