在聚变堆中嬗变^（237）Np的研究

TRANSMUTATION OF ACTINIDE 237Np WITH A FUSION REACTOR

研究了在聚变堆中嬗变长寿命的锕系元素￣（２３７）Ｎｐ，以及转换￣（２３７）Ｎｐ成为可裂变燃料￣（２３９）ｐｕ的物理可行性。探讨了在嬗变包层中￣（２３７）Ｎｐ的浓度、￣（２３９）ｐｕ的中于增殖率、中子壁负载的变化以及嬗变区厚度与￣（２３７）Ｎｐ嬗变率的关系。给出的研究计算结果表明，在１个聚变功率为２００ＭＷ，中子壁负载为１．０ＭＷ／ｍ２的聚变堆包层中，实现年嬗变￣（２３７）Ｎｐ约３．５ｔ，年平均产钚量约２０ｋｇ是可行的。

The use of fusion reactors to transmute fission reactor wastes into stable species is an attrac-tive concept.In this paper,the feasibility of transmutation of the long-lived actinide radioactivewaste 237Np with a fusion reactor or a hybrid reactor has been investigated.A new waste manage-ment concept of burning HLW(High LeveI Waste),utilizing released energy and converting237Np into fissile fuel 239pu through transmutation has been adopted.The detailed neutronics anddepletion calculation of waste inventories was carried out with a modified version of one-dimen-sional neutron transport and burnup calculation code system BISON 1.5 in this study. The trans-mutation rate of Np with relationship to neutron wall loading,Pu and Np concentrations in thetransmutation zone have been explored ;and relevent results are given。It was shown that 237Np transmutation rates of l.55 tons in a fusion reactor and 4.55 tons ina hybrid reactor per FPY(full power year)are feasible with a fusion power of 200 MW and a neu-tron wall loading of l.0 MW/m2.The calculation results also show that it will not be difficult toachieve an effective half-life for 237Np of lesq than 2.98 year and a 239pu production rates of about20 kg per FPY with the type of system studied.The calculation results show that it is unpracticalto produce a large amount of fissile fuel 239pu by transmutating Np。The reasons are discussed inthis paper.It was found that reasonable Pu concentration in transmutation zone could obviouslyimprove the transmutation rate of Np.