Rääf C, Holm E, Rabesiranana N, Garcia-Tenorio R, Chamizo E
Medical Radiation Physics, ITM, Malmö, Lund University, Sweden.
Department of Radiation Physics, Sahlgren Academy at the University of Gothenburg, Gothenburg, Sweden.
J Environ Radioact. 2017 Oct;177:91-99. doi: 10.1016/j.jenvrad.2017.06.011. Epub 2017 Jun 17.
This study examined the Pu and Pu activity concentration and the Pu/Pu atomic ratio in peat bogs sampled in 2012 from marshlands in central Madagascar. The purpose was to investigate the presence of plutonium isotopes, Pu, from the 1964 satellite failure carrying a SNAP-9A radiothermal generator. With an average Pu/Pu activity ratio of 0.165 ± 0.02 (decay corrected to 1964), the peat bogs in Madagascar exhibit similar values as the ones found in the southeastern African continent, except they are one order of magnitude higher than expected (0.025) from global fallout in the Southern Hemisphere. The Pu/Pu atomic ratio showed a distinct decrease for layers dating back to the mid-1960s (down to 0.069 compared with an anticipated ratio of 0.17 for global fallout), indicating that the SNAP-9A failure also resulted in an elevated deposition of Pu. The obtained results demonstrate that further Pu analysis in Madagascar and in southeastern continental Africa is necessary to fully account for the regional Pu deposition from the SNAP-9A event.
本研究检测了2012年从马达加斯加中部沼泽地采集的泥炭沼泽中钚（Pu）及其活度浓度，以及Pu/Pu原子比。目的是调查1964年搭载SNAP - 9A放射性同位素热电发生器的卫星故障所产生的钚同位素Pu的存在情况。马达加斯加的泥炭沼泽中Pu/Pu活度比平均为0.165±0.02（衰变校正至1964年），与在非洲大陆东南部发现的情况相似，但比南半球全球沉降预期值（0.025）高一个数量级。对于可追溯到20世纪60年代中期的地层，Pu/Pu原子比明显下降（降至0.069，而全球沉降预期比值为0.17），这表明SNAP - 9A故障还导致了Pu沉降增加。所得结果表明，有必要对马达加斯加和非洲大陆东南部进行进一步的Pu分析，以全面了解SNAP - 9A事件导致的区域Pu沉降情况。
