龍門電廠主蒸汽閥門關閉之預期暫態未急停分析

ATWS Analysis of Lungmen ABWR MSIV Closure Transient

何愛玲(Ai-Ling Ho)

指導教授 ： 施純寬 ； 王仲容

國立清華大學/原子科學院/核子工程與科學研究所/碩士(2013年)

摘要

本論文主要的目的，是針對龍門電廠主蒸汽閥門 ( MSIVs ) 關閉之預期暫態未急停 ( ATWS ) 事件，建立TRACE/PARCS結合模式，根據FSAR第十五章第E節 「 ATWS Performance Evaluation 」 做各個設定點與動作設定，並做分析，希望能驗證在因MSIVs關閉所引起的ATWS暫態下，龍門ABWR的設計及FSAR中所敘述的動作設定，的確具有緩和ATWS暫態的作用。

ABWR在ATWS分析上分為三部分：替代插棒系統 ( ARI ) 啟動、微調控制棒驅動機構 ( FMCRD ) 啟動、備用硼液注入 ( SLCS ) 。ARI啟動及FMCRD啟動暫態分析的部分，比較控制棒未插入時的爐心功率，反應爐功率明顯因控制棒插入後而下降，顯示本論文所建立之ATWS的TRACE/PARCS結合模式，確實具有分析ATWS之ARI啟動及FMCRD啟動暫態分析的能力；SLCS注入分析的部分，由於現有的龍門核電廠PMAXS檔中，沒有包含計算爐心硼濃度負反應度的參數，因此，本論文中，SLCS分析是由點中子動力法來計算爐心功率。

龍門核電廠MSIVs關閉之ATWS的分析結果，驗證龍門ABWR的設計及FSAR中所敘述的動作設定，的確具有緩和ATWS暫態的作用，符合10CFR50.62法規要求。並顯示控制棒是否能成功插入爐心，對反應爐的暫態影響很大。若控制棒能成功插入，反應爐功率將會因控制棒的插入而快速下降，至安全停機範圍。但，若是所有控制棒插入皆失效，反應器必須等待約300秒後才會注入備用硼液。期間，RIP的跳脫，可增加爐心空泡分率、增加負反應度，有效降低部分爐心功率。300秒後，注入的備用硼液使爐心功率下降，至安全停機範圍。RVs開關頻率因爐心功率下降而減緩，限制了經由RVs開啟所排入抑壓池的蒸汽量。

關鍵字

龍門核電廠 ； 主蒸汽閥門關閉 ； 預期暫態未急停

並列摘要

The objectives of this thesis are to establish the TRACE/PARCS coupling model for the ATWS analysis of Lungmen ABWR MSIV closure transient, and to verify that the design of Lungmen ABWR and a multitude of equipment and procedures described in FSAR, Chapter 15E ATWS Performance Evaluation, do have ability to mitigate the ATWS transient.

There are three parts in ATWS analysis: ARI, FMCRD initiation and SLCS injection. In ARI and FMCRD initiation case, the core power, compared with that in control rod failing case, decreases obviously after control rod run-in. That is, the TRACE/PARCS coupling model established in this thesis indeed have ability to analyze the ARI and FMCRD initiation transient. In SLCS injection case, PARCS can not calculate the reactivity of boron without having the state variable IC ( Impurity of Coolant ) in PMAXS file. Thus, we substitute PARCS for point kinetics model.

According to the results in ATWS analysis of Lungmen ABWR MSIVs closure transient, the design of Lungmen ABWR and a multitude of equipment and procedures described in FSAR are verified to have ability to mitigate the ATWS transient. And it also shows the importance of control rod. Reactor power will decrease rapidly as control rod run-in. If the ARI and FMCRD run-in fail simultaneously, the peak reactor power would still be controlled by pressure, RVs, void fraction and RIP rotation speed. However, the reactor core shutdown will then rely on the SLCS injection after 300sec.

並列關鍵字

Lungmen ABWR ； MSIV Closure ； ATWS ； TRACE ； PARCS

參考文獻

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