本研究係以先前針對BWR型球墨鑄鐵內襯之研發結果，選定最佳之合金設計及製程條件來研製PWR型全斷面縮尺型(1250 mm長度)球墨鑄鐵內襯，並進行各項相關之試驗及檢驗，測試結果顯示金相組織、拉伸性質、尺寸(包含球墨鑄鐵內襯之直徑、鋼鐵方管之管道深度、管道平直度及偏心度等)及鑄件品質(UT & PT檢驗)均能夠符合相關規格之要求。此外，本研究亦比較BWR型與PWR型球墨鑄鐵內襯之金相組織與拉伸性質之差異並分析其原因。
The disposal canisters are used for permanently storing the spent nuclear fuels. The disposal canisters consist of two major parts; the ductile cast iron insert and the copper outer shell. The ductile cast iron insert which is part of the multiple barrier system is to provide the mechanical strength to withstand the pressures of the overlying rock and future shear loading. The primary
purpose of this research is to develop the casting technology for the production of the PWR-type pilot small scale ductile cast iron insert (1250 mm in length) that can meet the specifications of microstructure, tensile properties, dimensions and casting quality.
Based upon the research results obtained in the development of the BWR-type ductile cast iron insert, the optimal alloy design and production conditions were attained and were used to cast the PWR-type pilot small scale ductile cast iron insert (1250 mm in length). The results of microstructure analyses, tensile properties test, dimensions measurements (including the outer diameter of the ductile cast iron canister, and the depth, straightness and eccentricity of the steel cassette) and casting quality all meet their respective specification. In addition, comparisons in microstructures and tensile properties between BWR-type and PWR-type ductile cast iron inserts were performed, and the differences were analyzed.
Keywords: Disposal canister, Ductile cast iron insert, PWR-type steel cassette, Microstructure, Tensile property