【摘要】 在堆用不锈钢包壳管内分别填装不同B/C比的B4C芯块及核级钠 ,以模拟快堆控制棒内的B4C/Na/S .S .三元体系 ,在堆外 5 5 0、65 0和 75 0℃下相互作用 82d。试验后的B4C芯块外观完整 ,未见掉角、龟裂或破碎 ;表面变得粗糙 ,失去原有的金属光泽 ,化学反应产物NaB5 O8等在表面沉积和粘附 ,并导致B4C芯块体积增大 ;芯块的微观结构和晶粒度试验前后无明显变化。包壳管内表面渗B、渗Na和渗C ,渗B和渗Na量均随温度升高和B/C比增大而增加 ,渗C则反之。Na和Na中杂质以及B4C与包壳间的化学反应产物为NaBO2 、Cr2 B、Fe2 B和Ni3 B。B化物的形成使包壳管内表面显微硬度显著增大。更多还原

【Abstract】 B 4C pellets with different B/C ratio and nuclear purity grade sodium were put into a stainless steel cladding tubes and the out of pile tests were carried out at 550,650 and 750 ℃. The test period is 82 d. After compatibility test, the appearance of B 4C pellets is integral, and crack or break are not found. However, the surfaces become rough and original metal luster is lost. The chemical reaction product NaB 5O 8 deposits and adheres to the surface of B 4C pellets. This results in the volume increasing of B 4C pellets. No considerable change in microstructure and grain size of B 4C pellets are observed. There are B、Na and C penetrate into cladding inner surface. The amount of B and Na penetration increases with the temperature and B/C ratio increasing, but C penetration is opposite. The chemical reaction products among Na, impurities in sodium, B 4C and cladding are NaBO 2, Cr 2B, Fe 2B and Ni 3B. The formation of the borides made increasing considerably in microhardness at the cladding inner surface.更多还原