日本福島事件顯示電廠在發生超過設計基準事故時既有之緊急替代設備及應變程序需要重新審視與修正，為此，台灣電力公司(TPC)及美國核能協會(NEI)先後研擬嚴重事故緊急應變策略，分別為斷然處置措施(URG)與彈性且多樣化處理策略(FLEX)，以應對此類極端事件。兩者主要宗旨為透過各式手段提供替代注水及電源供應設備，以維持電廠關鍵機組之功能，確保反應器處於安全狀態。
超過設計基準事故中，對電廠機組安全最具影響案例為長期喪失交流電源及喪失最終熱沉事件。此研究利用美國核管會開發之最佳估算熱水流系統程式TRACE建立馬鞍山三迴路壓水式電廠模型，除利用起動測試驗證輸入模式外，亦針對馬鞍山電廠一號機實際發生之全黑事故做模擬並與實際電廠數據進行比對。隨後參考WCAP-17601-P與NUREG-1953報告時序設定訂定假想長期喪失交流電源併反應器冷卻水軸封小破口洩漏事件，評估嚴重事故下電廠耐受能力及各個應變策略之事故緩和能力，再針對軸封破口流量及降壓時間做靈敏度分析，觀察軸封破口流量對反應槽進入迴流冷卻時間點之關聯性。
模擬結果顯示，馬鞍山電廠在長期喪失交流電源事件且反應器冷卻水泵有軸封洩漏約21gpm/loop發生時，有約60.89小時應對時間可對反應器進行補水，此外，儘管兩種應變策略皆可使電廠狀態維持穩定，斷然處置措施相較FLEX策略額外執行緊急降壓，可再降低軸封洩漏之冷卻水流量，並提早約6小時使反應器壓力槽回復滿水位。在靈敏度分析之模擬中，執行控制降壓可有效降低軸封洩漏率，並使ACC連結至RCS執行被動注水，無論破口流量為何，即時執行控制降壓皆可有效延長燃料護套達法定限值之時間。此研究成功建立方法分析斷然處置與FLEX策略之事故緩和能力，且模擬結果可作為電廠評估嚴重事故執行決策之參考資料。

After Fukushima accident, from many investigative reports, Beyond Design Basis External Event(BDBEE) may be longer than we have concerned. The emergency response guidelines of severe accident should be modified. To cope with such event, Taiwan Power Company(TPC) has developed a method called Ultimate Response Guidelines(URG), which gives operators the rights taking emergency steps to avoid the reactor core melting or the hydrogen accumulation inside the containment. Once either AC power or water supply can’t be restored in time, or there’s an earthquake and tsunami larger than safety shutdown, URG will be activated. The main action of URG including 2 steps depressurization, alternative water injection and containment venting. In addition, US NEI also developed a mitigation strategy called Diverse and Flexible Coping Strategy(FLEX) to tackle with such severe event. The main purpose of FLEX was to support key safety functions by providing multiple means of power and water supply, which can mitigate the consequence of beyond design basis external event.

In this study, TRACE code was used to evaluate the postulated ELAP event and compound severe accident in Maanshan nuclear power plant, determining the effectiveness of URG and FLEX. TRACE was developed by U.S. NRC, which was for NPP thermal hydraulic analysis, and was usually applied to analyze the transients or accidents at nuclear power plant. In addition, Maanshan nuclear power plant is a 2-units Westinghouse 3-loops PWR power station. Maanshan TRACE model has been built and verified by the comparison between FSAR data and Maanshan startup test data. Since there was a real SBO accident happened in unit 1 of Maanshan NPP in 2001, the accuracy and availability of the simulation results of Maanshan NPP TRACE model has also been compared with these data.


The scenario and assumptions of postulated ELAP event and compound severe accident in this study were referred to the WCAP-17601-P report and NUREG-1953 report. According to the results of simulation, it can be found that all cases with mitigation strategy in this study can keep RCS water level above TAF, ensuring the safety function of reactor. In sensitivity study, cooldown of RCS with control depressurization is very beneficial to the transients since not only can it reduce break flow from seal but also get accumulator makeup with RCS, which provides RCS vital coolant and increases bulk boron concentration for subcritical margin. This study successfully develops a method to analyze the mitigation capability of URG and FLEX strategy. The results can help evaluating the efficiency of mitigation strategy about NPP severe accident.

摘要 i
ABSTRACT ii
誌謝 iv
目錄 v
表目錄 vii
圖目錄 viii
名詞縮寫表 x
第一章 緒論 1
1.1 研究動機與目的 1
1.2. 論文架構與模擬案例簡介 4
1.3. 嚴重事故緊急應變策略介紹 5
1.3.1. 斷然處置介紹 5
1.3.2. FLEX策略介紹 6
第二章 文獻回顧 11
第三章 TRACE程式、馬鞍山電廠與輸入模式介紹 14
3.1. TRACE程式介紹 14
3.2. 馬鞍山電廠(核三廠)介紹 15
3.3. 馬鞍山電廠TRACE輸入模式介紹 17
3.4. 馬鞍山電廠318事故模擬與TRACE模型驗證 21
3.4.1. 馬鞍山電廠318全黑事故簡介 21
3.4.2. 馬鞍山電廠318全黑事故模擬方法 22
3.4.3. 馬鞍山電廠318全黑事故模擬結果 23
3.4.4. 馬鞍山電廠318全黑事故模擬之結論 27
第四章 馬鞍山電廠假想長期喪電事故緩和策略有效性分析 28
4.1. 假想長期喪電事件描述 28
4.2. ELAP分析案例初始條件與假設 30
4.2.1. ELAP事故無處置措施之初始假設條件 30
4.2.2. 救援案例一之初始假設條件 31
4.2.3. 救援案例二之初始假設條件 32
4.2.4. 救援案例三之初始假設條件 33
4.2.5. 救援案例四之初始假設條件 34
4.3. 假想ELAP事件模擬結果 35
4.3.1. 基本案例模擬結果 35
4.3.2. 救援案例一模擬結果 42
4.3.3. 救援案例二模擬結果 49
4.3.4. 救援案例三模擬結果 56
4.3.5. 救援案例四模擬結果 63
4.4. URG、FLEX緩和策略比較 70
第五章 假想電廠全黑暨破口複合型事故靈敏度分析 71
5.1. 假想複合型事故描述 71
5.2. 假想複合型事故模擬結果 74
5.3. 結果與討論 89
第六章 結論與建議 90
6.1. 結論 90
6.2. 建議 91
參考文獻 92

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