用過核子燃料最終處置場緩衝材料之 熱-水耦合實驗及模擬

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題名:	用過核子燃料最終處置場緩衝材料之熱-水耦合實驗及模擬
作者:	蔡家恩;TSAI,CHIA-EN
貢獻者:	土木工程學系
關鍵詞:	深層地質處置;緩衝材料;熱-水耦合效應;熱傳導係數;時域反射法;有限元素分析;Deep Geologic Disposal;Buffer Material;Thermal-Hydro coupling;Thermal Conductivity;Time Domain Reflectometry;Time Domain Reflectometry;Finite Element Method
日期:	2016-07-27
上傳時間:	2016-10-13 12:09:19 (UTC+8)
出版者:	國立中央大學
摘要:	本研究針對用過核子燃料最終處置場緩衝材料之熱-水(T-H)耦合行為進行實驗與模擬之相關研究，亦針對瑞典核子燃料與廢棄物管理公司(Svensk Kärnbränslehantering AB, SKB)所提之文獻進行驗證，因此研究內容主要分為四個部分，首先於實驗上使用ASTM D5334之試驗方法量測緩衝材料於不同乾密度下之熱傳導係數，選用乾密度為1.4-1.7g/cm3，並針對溫度範圍27-80℃之小型試體溫度分佈進行量測，輔以有限元素分析程式ABAQUS進行熱傳模擬驗證，使用實驗所得之參數代入加以模擬進行驗證；第二部份則使用時域反射法（Time Domain Reflectometry, TDR）進行緩衝材料含水量變化量測，且針對TDR感測器進行溫度校正、感測器率定、偏心共線與偏心不共線影響評估，並建立SPV200膨潤土之介電常數與體積含水量之關係曲線，最後提出分層含水量之計算方法；第三部分整合前兩部分試驗建立緩衝材料T-H耦合效應之小型即時監測系統，以求得溫度分佈及含水量之歷時關係演變；最後研究部分根據瑞典SKB TR-09-04報告內所提出之點、線、複合熱源解析解運算，輔以MATLAB程式建立解析解之控制方程式之程式設計與建立有限元素之數值解模擬進行驗證，計算時間為500年之歷時演變，並定義文獻所提之熱衰函數進行驗算，以作為後續研究之參考。熱傳導試驗之試驗結果顯示緩衝材料之熱傳導係數隨溫度上升而增加，且試驗參數應用於有限元素進行溫度分佈模擬驗證上有一致性結果，意即試驗與模擬分析之間有相當的可信度。再者由於SPV200膨潤土為高塑性黏土，其體積含水量與視介電常數率定公式與既有文獻差異甚大，顯示建立SPV200視介電常數與含水量關係曲線相當重要；視介電常數受溫度有一定影響，其視介電常數亦為溫度之函數並隨著溫度上升而增加；TDR感測器之偏心共線與偏心不共線配置量測比對，對視介電常數計算上沒有太大差異而忽略；而分層含水量目前已可得到解析度1 cm之3層水平面歷時之體積含水量變化。最後關於TR-09-04報告之熱衰函數驗算，其設定初始熱原為1700W，計算熱衰函數與文獻完全符合，可提供後續各熱源計算，而數值解之模型建立與解析解方程式計算出特定點位之溫度歷時曲線結果相接近，顯示數值解有限元素分析模擬準確度相當高。 ;Deep geological disposal has been recognized internationally as a feasible means for final disposal of high-level radioactive wastes. This involves the use of engineered barrier system covering the canister to prevent leakage of waste. The near field of the underground repository includes engineered barriers such as the canister, buffer, backfill from the inside to out, and surrounding earth. The first issue to be dealt with at the repository after deposition of the spent nuclear fuel (SNF) is the temperature field generated by heat decay of SNF. The heat spreads out by the heat transfer properties of the buffer material, causing temperature increase of the buffer and thus affecting the disposition performance. Furthermore, after a period of time of deposal, groundwater intrudes into the near field and affects the cushioning material in many ways. This study investigated the thermal-hydro coupling effects of the buffer material. The study can be divided into four main topics. The first involved experimental testing on buffer material using ASTM D5334 standard method to determine the thermal conductivity of buffer material at different temperatures and dry densities. The range of dry density of buffer is 1.4-1.7 g/cm3, and the temperature was set to 27-80℃for experiments. supported by the finite element analysis simulation program ABAQUS. The results obtained from the use of these experimental parameters will be simulated for further verification. The second part adopted the time domain reflectometry (TDR) method to determine the volumetric moisture content of buffer material via pre-calibrations for temperature effect and the probe constant. The third part integrates the former two parts’ experiments to establish a monitoring system for the thermal-hydro coupling effects in order to observe their time history. Lastly, computations of the point, line, and complex heat source analytic solutions were implemented according to the Swedish SKB TR-09-04 report, as a reference and cross-reference to future research. The thermal test results show the thermal conductivity of the buffer material rises with the increase of temperature. In the model tests, the experimental measurements were matched well by the finite element simulation, indicating credibility of the simulation analysis for future applications. In moisture measurements using TDR, the apparent dielectric constant was found to be influenced by temperature and moisture content, thus the relation between the apparent dielectric constant and temperature or water content for buffer material has been established.
顯示於類別:	[土木工程研究所] 博碩士論文

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