次锕系核素在铅冷快堆中的嬗变性能
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摘要
乏燃料中大部分次锕系(minor actinides,MA)核素半衰期较长,对环境具有长期放射性危害。分离-嬗变技术将次锕系核素从高放废液中分离出来,并通过反应堆嬗变为短寿命或稳定核素,从而消除其放射性危害。为研究次锕系核素与燃料均匀混合、制成嬗变棒和做燃料芯块镀层装载方式下在铅冷快堆中的嬗变特性,采用MCNP和SCALE程序进行模拟计算。结果表明,三种方式下~(237 )Np、~(241 )Am、~(243 )Am和混合次锕系核素使有效增殖因数k_(eff)降低,而~(244 )Cm和~(245 )Cm使k_(eff)升高,且~(245 )Cm可使k_(eff)大幅度增加。不同质量的混合次锕系核素装载后,三种方式下堆芯k_(eff)都随装载量的增加而降低,降低幅度由小到大分别为嬗变棒、均匀混合和镀层。不同次锕系核素装载量以均匀混合方式在堆芯经过550d辐照后,~(237 )Np、~(241 )Am和~(243 )Am嬗变率均为正值,其中~(241 )Am嬗变率最大,而~(244 )Cm和~(245 )Cm嬗变率均为负值,~(245 )Cm增加明显,总的次锕系核素嬗变率为14%,可为次锕系核素在铅冷快堆中嬗变性能评价提供参考。
The half-life of most of minor actinides in spent fuel is longer and has longterm radioactive hazards to the environment.Partitioning-transmutation technology can eliminate radioactive hazard by separating minor actinides from the high level waste and transmuting into short-life or stable nuclide in the reactor.MCNP and SCALE are used to simulate transmutation characteristics of minor actinides in lead-cooled fast reactor.The three loading methods are as follows,the homogeneous mixing of minor actinides with fuel,forming transmutation rods and fuel pellets coating.The results show that~(237 )Np,~(241 )Am,~(243 )Am and mixed minor actinides make the k_(eff)decrease,simultaneous loading of ~(244)Cm and ~(245)Cm make k_(eff)increase,and ~(245)Cm significantly increase k_(eff).After loading mixed minor actinides with different mass,the core k_(eff )decrease with the increase of loading,and the decreasing range from small to large are transmutation rod,uniform mixing and coating,respectively.The loading of different minor actinides is irradiated by uniform mixing in the core after 550days,~(237 )Np,~(241 )Am and ~(243 )Am transmutation rate are always positive,the ~(241 )Am transmutation rate is the largest,while~(244)Cm and ~(245)Cm transmutation rate are negative,~(245)Cm increases significantly,the total transmutation rate of minor actinides is about 14%.It can provide reference for minor actinides transmuted in the lead cooled fast reactor.
The half-life of most of minor actinides in spent fuel is longer and has longterm radioactive hazards to the environment.Partitioning-transmutation technology can eliminate radioactive hazard by separating minor actinides from the high level waste and transmuting into short-life or stable nuclide in the reactor.MCNP and SCALE are used to simulate transmutation characteristics of minor actinides in lead-cooled fast reactor.The three loading methods are as follows,the homogeneous mixing of minor actinides with fuel,forming transmutation rods and fuel pellets coating.The results show that~(237 )Np,~(241 )Am,~(243 )Am and mixed minor actinides make the k_(eff)decrease,simultaneous loading of ~(244)Cm and ~(245)Cm make k_(eff)increase,and ~(245)Cm significantly increase k_(eff).After loading mixed minor actinides with different mass,the core k_(eff )decrease with the increase of loading,and the decreasing range from small to large are transmutation rod,uniform mixing and coating,respectively.The loading of different minor actinides is irradiated by uniform mixing in the core after 550days,~(237 )Np,~(241 )Am and ~(243 )Am transmutation rate are always positive,the ~(241 )Am transmutation rate is the largest,while~(244)Cm and ~(245)Cm transmutation rate are negative,~(245)Cm increases significantly,the total transmutation rate of minor actinides is about 14%.It can provide reference for minor actinides transmuted in the lead cooled fast reactor.
引文
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[8]Wiese H W.Actinide transmutation properties of thermal and fast fission reactors including multiple recycling[J].Journal of Alloys and Compounds,1998,271(273):522-529.
[9]Takeda T.Detailed calculations of minor actinide transmutation in a fast reactor[C].US:AIPPublishing LLC,2015:179-196.
[10]Zhang H,Chen H,Chen C,et al.Burnup optimization of small natural circulation lead cooled fast reactor[J].Annals of Nuclear Energy,2017,103:424-430.
[2]周培德.MOX燃料模块快堆的嬗变研究[J].核科学与工程,2002,22(3):261-267.Zhou Peide.Study on transmutation of MOX fuel in module fast reactor[J].Nuclear Science and Engineering,2002,22(3):261-267(in Chinese).
[3]Liu B,Wang K,Tu J,et al.Transmutation of minor actinides in the pressurized water reactors[J].Annals of Nuclear Energy,2014,64:86-92.
[4]赵鹏程.小型自然循环铅冷快堆SNCLFR-100一回路主冷却系统热工安全分析[D].安徽:中国科学技术大学,2016.
[5]Alemberti A,Smirnov V,Smith C F,et al.Overview of lead-cooled fast reactor activities[J].Progress in Nuclear Energy,2014,77:300-307.
[6]Gauld I C.Development and applications of a prototypic SCALE control module for automated burnup credit analysis[R].[S.l.]:Office of Scientific&Technical Information Technical Reports,2001.
[7]Liu B,Hu W C,Wang K,et al.Transmutation of MA in the high flux thermal reactor[J].Journal of Nuclear Materials,2013(437):95-101.
[8]Wiese H W.Actinide transmutation properties of thermal and fast fission reactors including multiple recycling[J].Journal of Alloys and Compounds,1998,271(273):522-529.
[9]Takeda T.Detailed calculations of minor actinide transmutation in a fast reactor[C].US:AIPPublishing LLC,2015:179-196.
[10]Zhang H,Chen H,Chen C,et al.Burnup optimization of small natural circulation lead cooled fast reactor[J].Annals of Nuclear Energy,2017,103:424-430.