The JANUS Phase 1, Phase 2 and Phase 4 shielding experiments performed in the 90’s in the NESTOR reactor aimed to study deep neutron propagation in mild steel, stainless steel, sodium and boron carbide. Together with the other JANUS phases (up to Phase 9) they represent invaluable experimental database for improving nuclear data for fast reactor applications. Several detectors were used to measure reaction rates at different energy domains. These experiments are interpreted using multiple nuclear data for iron 56 and sodium 23 with the TRIPOLI-4® Monte-Carlo code. Discrepancies up to 30% are obtained between calculated reaction rates and experimental results, which points out that the nuclear data of iron, sodium as well as some other isotopes contained in stainless steel should be improved. The JANUS Phase 4 is inconclusive as it is similar to Phase 2 replacing some steel shields with boron carbide, but the introduced boron carbide zone is too small to give significantly different results.

在90年代在NESTOR反应堆中进行的JANUS 1期，2期和4期屏蔽实验旨在研究中子在低碳钢，不锈钢，钠和碳化硼中的深层传播。与其他JANUS阶段（直到第9阶段）一起，它们代表了宝贵的实验数据库，可改善快速反应堆应用的核数据。几个检测器用于测量不同能量域的反应速率。这些实验使用具有TRIPOLI-4®Monte-Carlo密码的铁56和钠23的多个核数据进行解释。计算出的反应速率与实验结果之间的差异最多可达到30％，这表明应改善不锈钢中所含铁，钠以及其他一些同位素的核数据。