高溫試驗反應器 (High Temperature engineering Test Reactor，簡稱 HTTR) 為第四代超高溫氣冷式反應器 (Very High Temperature gas-cooled Reactor，簡稱 VHTR) 的前身，用以測試此類型反應器的特性。HTTR 使用石墨作為緩速劑，氦氣作為冷卻劑，熱功率達 30 MW。HTTR的爐心由六角柱型的燃料柱與反射體所組成，根據燃料柱位置的不同，各別包含 31/33 根燃料棒，每根燃料棒由 14 個燃料單元堆疊而成，約莫 13,000 顆多層燃料球 (TRISO particle) 均勻分布其中。為了進一步強化多層燃料球的結構安全性，於燃料球核心與碳化矽之間增加一層碳化鋯材料，稱為 3S (safety, security, safeguard) TRISO particle。該層碳化鋯的主要功能為吸收氧原子，抑制一氧化碳的形成，降低燃料內部壓力，以減少結構破裂導致放射性物質從多層燃料球外洩的可能性。此論文將探討 3S 結構用於低濃縮度鈾 LEU 與 PuMA 兩種燃料的爐心中子特性，從有效中子增殖因數、中子能譜、徑向與軸向之中子通量、溫度係數、控制棒效能與燃耗進行特性分析。結果顯示 3S-TRISO particle 設計對中子特性無顯著影響。為了抑制起爐時的過溢反應度，並使運轉過程中的 keff 更加平穩，針對可燃毒物的種類與分布方式對中子特性帶來的影響進行分析，可燃毒物核種選擇 B 與 Gd-157，並與未加可燃毒物時的情形比較，可燃毒物分布方式分為原始設計的可燃毒物棒與將可燃毒物均勻散佈於 kernel 處兩種。計算結果顯示使用 Gd-157 分布於可燃毒物棒中與 B 散佈於 kernel 處較原始設計 B 分布於可燃毒物棒中更適合 LEU 燃料，前者僅需原始可燃毒物用量的一半 (2×10-4 atom/b-cm)，還可以延長燃料運轉週期，後者更僅需原始可燃毒物用量的 0.4 倍 (此時 B 中的 B-10 與 B-11 原子密度分別為 6.62×10-5 與 2.66×10-4 atom/b-cm)，大幅降低可燃毒物的成本，且兩者的溫度係數皆維持負值。PuMA 燃料方面，由於 B 與 Gd-157 主要吸收熱中子，兩者分布於可燃毒物棒中對中子能譜偏硬的 PuMA 來說皆不適合，而當 Gd-157 以 5 倍原子密度散佈於 kernel 處時 (此時 Gd-157 的原子密度為 8.28×10-4 atom/b-cm)，其吸收中子的機會上升，不僅抑低 PuMA 起爐時的過溢反應度，且運轉過程中 keff 隨時間的變化更加平緩，也使 HTTR 採用 PuMA 燃料的概念成為可能。

High temperature engineering test reactor (HTTR) is one of the most promising reactors belonging to GEN-IV high temperature gas-cooled reactor (HTGR). The 30 MWt reactor adopts graphite as moderator and helium as coolant. The HTTR core contains hexagonally prismatic fuel and graphite blocks. The fuel block consists of 31 or 33 fuel rods (depending on locations), each of which is made up of 14 stacking fuel compacts. Every fuel compact holds approximately 13,000 tiny tri-isotropic (TRISO) particles randomly distributed in a graphite matrix. The purpose of this dissertation was to assess the influence of using 3S (safety, security, safeguard) TRISO particles on the neutronics characteristics of LEU and PuMA fuel in HTTR. 3S-TRISO particles have an extra 10-μm-thick ZrC layer meant to reduce the possibility of fuel failure owing to the increase of internal pressure because of CO production. The result showed that 3S-TRISO particles influenced little on neutronics characteristics. Furthermore, in order to suppress the excessive reativity in the beginging of fuel cycle and flatten the effective multiplication factor (keff) during the operation period, the dissertation changed the allocation (rod and dispersion in the kernel) and material (Non-bp, B and Gd-157) of burnable poison (bp) and examined the neutronics characteristics. The neutronics characteristics such as neutron spectrum, spatial flux distribution, effective multiplication factor, temperature coefficient, and control rod worth were examined in depth after these changes. In the end, the dissertation concluded that the optimal options of bp in LEU fuel model were Gd-157 rods and B dispersing in the kernel, both of which used less amount of bp, suppressed the excessive reactivity in the beginning and flattened the keff. Moreover, the former model prolonged the operation period and lowered temperature coefficient. In terms of PuMA, the optimal model was Gd-157 dispersing in the kernel, which required only three tenths the amount of original HTTR did. The result saw the future of HTTR employing PuMA fuel.

摘要 ii
Abstract iii
誌謝 iv
目錄-------------------------------------------v
表目錄-----------------------------------------viii
圖目錄-----------------------------------------xi
第一章 緒論-----------------------------------1
1.1 前言---------------------------------------1
1.2 高溫氣冷式反應器的發展-----------------------2
1.2.1 模組式高溫氣冷式反應器介紹-----------------3
第二章 文獻回顧--------------------------------8
2.1 HTTR 概述----------------------------------8
2.2 HTTR 反應器元件介紹-------------------------12
2.2.1 燃料柱------------------------------------14
2.2.2 控制棒導管柱------------------------------20
2.2.3 輻射偵檢柱--------------------------------24
2.2.4 替換型反射體------------------------------25
2.2.5 永久型反射體------------------------------26
2.3 3S-TRISO 燃料元件介紹-----------------------27
2.3.1 3S-TRISO 多層燃料球與反應器介紹------------27
2.3.2 計算與評估方法----------------------------31
2.4 可燃毒物燃耗計算分析-------------------------34
2.4.1 UWB1 燃耗程式介紹-------------------------35
2.4.2 Gd 作為可燃毒物的實際情形------------------35
2.4.3 單一核種可燃毒物評估-----------------------36
2.4.4 單一核種可燃毒物反應度分析------------------37
2.4.5 複合可燃毒物反應度分析---------------------38
2.4.6 複合可燃毒物於三種運轉週期的表現------------39
2.4.7 複合可燃毒物的原子密度評估------------------41
2.5 研究動機------------------------------------44
第三章 程式介紹--------------------------------46
3.1 MCNP6 與 MCNPX 介紹-------------------------46
3.2 截面資料庫介紹-------------------------------47
3.3 臨界計算介紹---------------------------------49
3.4 燃耗計算介紹---------------------------------50
第四章 HTTR 模型的建立與 ZrC 應用----------------52
4.1 HTTR 模型的建立------------------------------52
4.1.1 靈敏度測試---------------------------------54
4.1.2 臨界驗證計算-------------------------------55
4.2 Pu 系列燃料比較------------------------------60
4.2.1 有效增殖因數-------------------------------62
4.2.2 中子能譜-----------------------------------62
4.2.3 控制棒效能---------------------------------63
4.2.4 溫度係數-----------------------------------64
4.3 ZrC 對中子特性的影響--------------------------65
4.3.1 中子能譜-----------------------------------66
4.3.2 中子通量-----------------------------------67
4.3.3 熱中子比例---------------------------------71
4.3.4 有效增殖因數-------------------------------73
4.3.5 控制棒效能---------------------------------78
4.3.6 溫度係數-----------------------------------80
第五章 可燃毒物對 LEU 與 PuMA 燃料中子特性的影響--82
5.1 不同可燃毒物種類對 LEU 燃料的影響-------------82
5.2 不同可燃毒物分布方式對 LEU 燃料的影響---------92
5.3 不同可燃毒物種類對 PuMA 燃料的影響------------104
5.4 不同可燃毒物分布方式對 PuMA 燃料的影響--------110
第六章 結論-------------------------------------118
參考文獻-----------------------------------------120

1. "GenIV International Forum 2007 Annual Report," Forum, GenIV International.
2. 吳宗鑫與張作義, 先進核能系統和高溫氣冷堆，第一版, 北京: 清華大學出版社, 2004.
3. M. Edenius, Studies of the Reactivity Temperature Coefficient in Light Water Reactors, Goteborg, Sweden: Chalmers University of Technology, 1976.
4. “Upgraded Core Design of a Small-sized High Temperature Gas-cooled Reactor Suitable for Application in Emerging Countries,” Kazakhstan, 2012.
5. J. Bess, N. Fujimoto, B. Dolphin, S. L. and A. Zukeran, Evaluation of the Start-up Core Physics Test at Japan's High Temperature Engineering Test Reactor (Fully-Loaded Core), INL/EXT-08-14767 REV.2, Idaho National Laboratory, 2010.
6. T. Furusawa, M. Shinozaki, S. Hamamoto and Y. Oota, Cooling System Design and Structure Integrity Evaluation, Nucl. Eng. Des. 233, 2004.
7. M. Goto, S. Ueta, J. Aihara, Y. Inaba, Y. Fukaya, Y. Tachibana and K. Okamoto, Development of Security and Safety Fuel for Pu-burner HTGR, ICONE25, 2017.
8. M. Goto, et al., Conceptual Study of a Plutonium Burner High Temperature Gas-cooled Reactor with High Nuclear Proliferation Resistance, Global 2015, Paris, France,September 20-24, 2015.
9. T. Kim, et al., A Feasibility Study of Reactor-based Deep-burn Concepts, ANL-AFCI-155, 2005.
10. K. Verfondern, et al., Coated Particle Fuel for High Temperature Gas Cooled Reactors, Nucl. Eng. Technol., 39[5], p.603, 2007.
11. K. Kunitomi, et al., Japan's Future HTR-the GTHTR300, Nucl. Eng. Des., 233, p.309, 2004.
12. J. Aihara, et al., Code-B-2 for Stress Calculation for SiC-TRISO Fuel Particles, JAEA-Data/Code 2012-030, 2012.
13. M. Zeman, R. Škoda and J. Závorka, EPR: Burnable Absorber Optimization, London, 2018.
14. M. T. Loh, M. J. Driscoll and D. D. Lanning, The Use of Burnable Poison to Improve Uranium Utilization in PWRs, 1982.
15. M. Lovecký, J. Jiříčková and R. Škoda, Assessment of Burnable Absorber Fuel Design by UWB1 Depletion Code, Acta Polytechnica CTU Proceedings 4:43–49, 2016.
16. D.G. Cacuci, Handbook of Nuclear Engineering, London: Springer, 2010.
17. E.E. Lewis, Fundamentals of Nuclear Reactor Physics, Boston: Academic Press, 2008.
18. M.B. Chadwick, ENDF/B-VII. 1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data. Nucl. Data Sheets. 107, 2011.
19. Edwin Humphrey Uguru, S.F.Abdul Sani, Mayeen Uddin Khandaker, Mohamad Hairie Rabir and Julia Abdul Karim, A Comparative Study on the Impact of Gd2O3 Burnable Neutron Absorber in UO2 and (U,Th)O2 Fuels, Nuclear Engineering and Technology.
20. 吳炘融, 球床型高溫氣冷式反應器, 國立清華大學核子工程與科學研究所, 2017.
21. Jeong, Chang and S.H.H, Jeong, Estimation of the Fission Products, Actinides and Tritium of HTR-10, Nuclear Engineering and Technology Vol. 41, pp. 729-738, 2009.
22. J.S. Hendricks, G.W. McKinney, M.L. Fensin, M.R. James, R.C. Johns, J.W. Durkee, J.P. Finch, D.B. Pelowitz, L.S. Waters and M.W. Johnson, MCNPX 2.6.0 Extensions, LA-UR-08-2216, Los Alamas National Laboraty, 2008.
23. Bazant and Martin Z., “Pebble Flow Experiments for Pebble Bed Reactors,” 2nd International Topical Meeting on High Temperature Reactor Technology, Beijing, CHINA, 2004.
24. W. W. Engle Jr., Cross Section Processing Codes and Data Bases (AMPX), Oak Ridge, USA: Oak Ridge National Laboratory, 1980.
25. B. Zohuri, Spatial Effects in Modeling Neutron Diffusion: One-group Models, 2017.
26. X-5 Monte Carlo Team, Monte Carlo N–Particle Transport Code System Including MCNP6.1, MCNP5-1.60, MCNPX-2.7.0 and Data Libraries, Los Alamos, New Mexico: Los Alamos National Laboratory.
27. K. Kunitomi, Y. Sun, S. Ball, H.L. Brey and M. Methnani, Evaluation of High Temperature Gas Cooled Reactor Performance: Benchmark Analysis Related to Initial Testing of the HTTR and HTR-10, IAEA-TEDOC-1382, International Atomic Energy Agency, 2007.
28. C.Y. Li, R.J. Sheu and J.H. Liang, Neutronic Analyses of the HTTR Core Fueled with Plutonium and Minor Actinides, Chengdu, China: ICONE21, 2013.
29. 李俊諺, 高溫研究反應器, 工程與系統科學系, 2012.