초록

● 이중비균질 원자로심 모사능 개발
● 몬테칼로 순방향 계산 중 수반해 생산법 개발
● 몬테칼로 수반해 기반 민감도/불확실도 해석법 개발
● 몬테칼로 고유치 계산에 대한 히스토리 기반 진분산 계산법 개발

(출처 : 보고서 요약서 3p)

Abstract ▼

IV. Results of Project

We designed and developed the Fill Cell moudule for an exact double heterogeneity modeling in McCARD. Also, We applied the method for the weakly coupled fissile array problems varying the dominance ratio and the batch size. From the comparisons with the real variances e

IV. Results of Project

We designed and developed the Fill Cell moudule for an exact double heterogeneity modeling in McCARD. Also, We applied the method for the weakly coupled fissile array problems varying the dominance ratio and the batch size. From the comparisons with the real variances estimated by other methods, it was demonstrated that the history-based batch method can accurately predict the true variance

From the comparisons with the analytic solutions for the infinite homogeneous 2-group problems, we demonstrated that the MC estimates of the effective delayed neutron fraction, β_eff, and the prompt neutron generation time, Λ, agree well within 95% confidence intervals. For some critical facility problems, it is demonstrated that β_eff and β_eff/Λ weighted by Φ^*₀ agree well with the measurements within 3% errors, while the maximum error of β_eff/Λ from the use of Φ^*_S is 13%.

An algorithm for the first-order MC AWP technique in which the adjoint flux can be estimated in the course of the MC forward calculations has been presented. It has been shown that the first-order AWP method is identical to the first-order DOS method with the FSP taken into account. In order to confirm numerically the equivalence of the two first-order MC perturbation methods, the changes in k due to globally or locally induced ²³⁵U density changes in Godiva and ²³⁸U microscopic cross-section changes in Bigten were calculated. Also, contributions of ²³⁵U cross section uncertainties to the uncertainty of k, σ_XX(k), of the Godiva by nuclear data types were analyzed. It has been demonstrated that Dk’s and σ_XX(k)’s from the first-order AWP method are the same as those from the first-order DOS/FSP method and that σ_XX(k)’s from by the AWP method agree well with those from other S/U codes. This then leads us to conclude that the first-order AWP method is a useful alternative to the same order DOS/FSP method.

The depletion module in McCARD works in the same manner as the ORIGEN2 code. In the study, the nuclide, integrated into a group, is applied to the burnup matrix and the equation is solved by a burnup matrix module. Afterwards, the burnup matrix accelerated by Krylov subspace method is applied to the matrix exponential method. The modified model is added to MCCARD and the efficiency and accuracy are verified.

(출처 : SUMMARY 8~10p)

목차 Contents

• 표지 ... 1제 출 문 ... 2보고서 요약서 ... 3요 약 문 ... 4SUMMARY ... 7CONTENTS ... 11목차 ... 12제 1 장 연구개발의 목적 및 필요성 ... 15제 2 장 국내외 기술개발 현황 ... 17제 3 장 연구개발수행 내용 및 결과 ... 18 제 1 절 몬테칼로 이중비균질 모사 ... 18 1. 임의분포 연료입자 처리 모듈 개발 ... 18 2. 이중비균질 구조물 클래스 설계 및 입력법 ... 28 제 2 절 고성능 진분산 예측법 개발 ... 35 1. 몬테칼로 고유치 계산의 분산 바이어스 ... 35 2. 히스토리기반 진분산 예측법 ... 54 제 3 절 수반해를 이용한 섭동해석법 개발 ... 61 1. 몬테칼로 수반해 예측 ... 61 2. 수반해를 이용한 동특성인자 계산 ... 73 3. 수반해 기반 불확실도 해석법 개발 ... 76 제 4 절 연소방정식 해법 ... 97 1. 연소계산 모델 ... 97 2. 기존 연소계산 모델 방법론 ... 99 3. Krylov 부공간 근사법을 이용한 행렬지수함수 근사 ... 107제 4 장 목표달성도 및 관련분야에의 기여도 ... 110제 5 장 연구개발결과의 활용계획 ... 111제 6 장 참고 문헌 ... 112끝페이지 ... 119