報告書番号

380017

タイトル（和文）

高速増殖炉における熱流動の研究に関する調査報告

タイトル（英文）

RESEARCH ON THE THERMAL HYDRAULIC PHENOMENA IN THE FAST BREEDER REACTOR

概要 （図表や脚注は「報告書全文」に掲載しております）

高速増殖炉（ＦａｓｔＢｒｅａｄｅｒＲｅａｃｔｏｒ）の特徴の１つに，炉心での核分裂により発生する熱を輸送する冷却材として，中性子減速能が低く，しかも熱伝導性の良好な液体ナトリウムを使用することがあげられる。そのため，ナトリウムの取り扱い技術や計測器，あるいは主要機器において，軽水炉と違った新しい問題が派生する。ここでは，そのうちから，とくに水理学的な側面から見た冷却材の熱流動現象に焦点をあて，その特徴と問題点の指摘を行った。また，ＦＢＲによる発電方式は，エネルギー源としてのウランの有効な利用形態と考えられている。そのため，ＦＢＲの原理とわが国を初め諸外国での研究・開発状況を文献，資料にもとづき軽水炉との比較のもとでとりまとめた。

概要 （英文）

THE DEVELOPMENT OF THE FAST BREEDER REACTOR(FBR)IS NEEDED TO RESPOND THE INCREASING ENERGY DEMAND IN THE WORLD. IN JAPAN,THE CONSTRUCTION OF THE PROTOTYPE REACTOR,MONJU, WILL START IN THE NEAR FUTURE. THE CONCEPTUAL DESIGN AND THE BASIC RESEARCH AND DEVELOPMENTS FOR THE DEMONSTRATION REACTOR WITH ABOUT ONE MILLION KILOWATTS OFELECTRICITY HAVE BEEN CONDUCTED BY THE ELECTRIC COMPANIES, MANUFACTURER CONSORTIUM AND OUR INSTITUTE. THE MOST IMPORTANT JUDGEMENT FOR THE DESIGN OF THE DEMONSTRATION REACTOR IS WHETHER THE LOOP-TYPE OR THE TANK-TYPE REACTOR WILL BE SUITABLE. IN THE LOOP-TYPE REACTOR,THE LAYOUT OF PIPINGS IS SO COMPLICATED TO ACCOMODATE THE THERMAL EXPANSION AND TO MAKE THE COMPACTNESS. THE PIPE WALL IS SO THIN TO REDUCE THE THERMAL STRESS AND THERMAL SHOCK. THE PIPINGS ARE ALSO HANGED BY HANGERS SO AS TO EXPAND FREELY AND FIXED BY OIL-DAMPERS AGAINST THE SEISMIC FORCE. IN THISWAY,THE INTERACTION BETWEEN THE HIGH VELOCITY COOLANT AND THE COMPLICATEDLY CURVED PIPING WITH LARGE DIAMETER AND THIN WALL COMES INTO QUESTION IN THE DESIGN OF THE COOLANT SYSTEMS FOR THE LARGE LOOP-TYPE FBR. INTHE TANK-TYPE DEMONSTRATION REACTOR,THE VESSEL IS SUPPORTED SO AS TO EXPAND DOWNWARDS AND CONTAINS THE COOLANT OF 4000CUB.M IN VOLUME,SIX INTERMEDIATE-HEAT-EXCHANGERS(IHXS),FOUR PUMPS AND OTHER PRINCIPAL COMPONENTS. THEREFORE,THE SEISMIC AND THERMO-HYDRAULIC DESIGN ARE THE MOST IMPORTANT SUBJECTS FOR SUCH LARGE VESSEL WITH THE THIN WALL,THE LARGE VOLUME OF COOLANT AND MANY COMPONENTS. FROM THE VIEWPOINT OF HYDRAULICS,IT SHOULD BE ESTIMATED WHICH FLOW PATTERNS WILL BE DOMINATING AMONG THE COMPONENTS,HOW MUCH THE MIXING OF COOLANT WILL GENERATE AND HOW STEEPLY THE THERMAL SHOCK WILL ACT ON THE VESSEL WALL DURING STEADY OPERATION ANDIN CASE OF EMERGENCY.

報告者

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