Determination of 240Pu/239Pu Ratio in Environmental Samples Based on the Measurement of Lx/alpha-ray Activity Ratio

Abstract

The determination of the 240Pu /239Pu isotopic ratio in environmental samples has been attempted by the measurement of the Lx/alpha-ray activity ratio using a Ge- LEPS (low-energy photon spectrometer) and a surface-barrier Si detector. By this method, interesting data were obtained for various samples collected from Thule , Greenland, Bikini Atoll and Nagasaki, as well as for some soils collected from near and off-site locations of atomic power stations.

Plutonium isotopes concentration in seawater and bottom sediment off the Pacific coast of Aomori sea area during 1991–2005

“…Muramatsu et al (2001) and Yamada et al (2007) reported that this higher atom ratio was likely due to close-in fallout Pu originating from the Pacific Proving Grounds (PPGs). For example, the 240 Pu/ 239 Pu atom ratio in soil from Bikini Island was reported to be 0.338 AE 0.0051 (Komura et al, 1984). The 240 Pu/ 239 Pu atom ratio could be lowered by mixing in the sea with Pu isotopes which were deposited directly from the atmospheric environment and transported by rivers and winds through weathering processes from the land (Kim et al, 2003(Kim et al, , 2004Okubo et al, 2008;Yamada and Nagaya, 2000;Yamada et al, 2007;Zheng and Yamada, 2004, 2005a.…”

240Pu/239Pu mass ratio in environmental samples in Finland

“…The nuclear emulsion technique (Sloth and Studier, 1958), internal conversion electron spectroscopy (Shiokawa et al, 1989), and simultaneous counting of alpha particles and U L-shell X-rays (Hisamatsu and Sakanoue, 1984;Komura et al, 1984) have been utilized in measuring the separate activities of 239 Pu and 240 Pu in environmental samples. In addition, thermal neutron activation analysis together with alpha spectrometry has been used for determining the 238 Pu/ 239þ240 Pu activity ratio (Matsunami et al, 1983), as well as high-resolution alpha spectrometry with spectral deconvolution methods (Amoudry and Burger, 1984;Mitchell et al, 1997).…”

240Pu/239Pu atom ratios in seawater from Sagami Bay, western Northwest Pacific Ocean: sources and scavenging

“…The inventory of anthropogenic long-lived radionuclides in the water column is one of the useful parameters for delineating accumulation and transport processes in the environment (Krey et al, 1976;Koide et al, 1985;Kelley et al, 1999) and that of w0.33 from the Bravo shot fallout (Komura et al, 1984). The horizontal tick marks plotted below the vertical distributions indicate the depth of the bottom.…”

“…The atom ratio of 240 Pu/ 239 Pu depends upon the specific weapons design and test yield (Warneke et al, 2002). Komura et al (1984) reported the 240 Pu/ 239 Pu atom ratio of 0.338 AE 0.051 in Bikini Island soil, and that of 0.318 AE 0.033 in hemp-palm leaves of fishing floats which were used by the No. 5 Fukuryu-Maru (Lucky Dragon) and exposed to fallout from the ''CASTLE-Bravo'' shot.…”

“…The atom ratio of 240 Pu/ 239 Pu depends upon the specific weapons design and test yield (Warneke et al, 2002). The average atom ratios of 240 Pu/ 239 Pu from global stratospheric fallout are 0.176 AE 0.014 (Krey et al, 1976) or 0.180 AE 0.014 (Kelley et al, 1999) based upon soil samples' data, whereas those from close-in tropospheric fallout are 0.33e0.36 (Diamond et al, 1960;Komura et al, 1984;Koide et al, 1985;Buesseler, 1997). Studies on the atom ratios of 240 Pu/ 239 Pu in marine sediments recently have clarified the existence of close-in fallout plutonium originating from the PPG in the western North Pacific Ocean and its marginal seas (Kim et al, 2003;Lee et al, 2004Lee et al, , 2005Yamada, 2004, 2005;Wang and Yamada, 2005).…”