Analysis of burnup performance and temperature coefficient for a small modular molten‑salt reactor started with plutonium  

作　　者：Xue‑Chao Zhao Yang Zou Rui Yan Xiang‑Zhou Cai 

机构地区：[1]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China [2]CAS Innovative Academies in TMSR Energy System,Chinese Academy of Sciences,Shanghai 201800,China [3]University of Chinese Academy of Sciences,Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Nuclear Science and Techniques》2023年第1期178-189,共12页核技术（英文）

基　　金：supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000);Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(No.JCYJ-SHFY-2021-003);the Chinese Academy of Sciences Special Research Assistant Funding Project.

摘　　要：In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched uranium or plutonium as the starting fuel.By exploiting plutonium as the starting fuel and thorium as the fertile fuel,the high-purity^(233)U produced can be separated from the spent fuel by fluorination volatilization.Therefore,the molten salt reactor started with plutonium can be designed as a^(233)U breeder with the burning plutonium extracted from a pressurized water reactor(PWR).Combining these advantages,the study of the physical properties of plutonium-activated salt reactors is attractive.This study mainly focused on the burnup performance and temperature reactivity coefficient of a small modular molten-salt reactor started with plutonium(SM-MSR-Pu).The neutron spectra,^(233)U production,plutonium incineration,minor actinide(MA)residues,and temperature reactivity coefficients for different fuel salt volume fractions(VF)and hexagon pitch(P)sizes were calculated to analyze the burnup behavior in the SM-SMR-Pu.Based on the comparative analysis results of the burn-up calculation,a lower VF and larger P size are more beneficial for improving the burnup performance.However,from a passive safety perspective,a higher fuel volume fraction and smaller hexagon pitch size are necessary to achieve a deep negative feedback coefficient.Therefore,an excellent burnup performance and a deep negative temperature feedback coefficient are incompatible,and the optimal design range is relatively narrow in the optimized design of an SM-MSR-Pu.In a comprehensive consideration,P=20 cm and VF=20%are considered to be relatively balanced design parameters.Based on the fuel off-line batching scheme,a 250 MWth SM-MSR-Pu can produce approximately 29.83 kg of ^(233)U,incinerate 98.29 kg of plutonium,and accumulate 14.70 kg of MAs per year,and the temperature reactivity coefficient can always be lower than−4.0pcm/K.

关 键 词：Molten salt fuel Incinerate plutonium 233U production Temperature reactivity coefficient 

分 类 号：TL426[核科学技术—核技术及应用]