Current Levels of Pu Isotopes and ¹³⁷Cs at the Former Soviet Union's Semipalatinsk Nuclear Test Site

Abstract

This paper is a report on our survey of residual radioactivity in the soil of the Semipalatinsk nuclear test site in the former USSR. The soil was sampled at approximately 30 sites along the roads connecting Kurchatov City, ground zero for the first USSR nuclear test, Balapan, Degelen Mountain and Salzhal settlement. The radioactivity levels of 137 Cs, 238 Pu and 239 -240 Pu as well as the ^Pu/^'Pu atomic ratios in the soil were determined. Although ,37 Cs was within typical environmental levels except for an area near ground zero, 239 ' 240 Pu was at elevated levels contaminated with weapons-grade plutonium in all areas we visited.

SPATIAL DISTRIBUTION OF SOIL CONTAMINATION BY 137Cs AND 239,240Pu IN THE VILLAGE OF DOLON NEAR THE SEMIPALATINSK NUCLEAR TEST SITE: NEW INFORMATION ON TRACES OF THE RADIOACTIVE PLUME FROM THE 29 AUGUST 1949 NUCLEAR TEST

“…activity ratios ranged from 0.25 to as high as 5.68, while most of the data were from 0.90 -2.0. These values were similar to those observed around Dolon by some other researchers Yamamoto et al 1998), and were several tens of times higher than the global fallout values of 0.02-0.03. Anomalously high 239,240 Pu/ 137 Cs activity ratios in some soil samples might be due to the presence of hot particles containing much more plutonium than 137 Cs.…”

“…The resulting two solutions were combined and 242 Pu was added to the mixed solution as a yield tracer. The plutonium was radiochemically separated and purified using an anion-exchange resin column method (Yamamoto et al 1996(Yamamoto et al , 1998. The purified plutonium was electroplated onto a polished stainless steel disc, and its activities were determined by alpha-ray spectrometry.…”

What Anthropogenic Radionuclides (90Sr and 137Cs in Atmospheric Deposition, Surface Soils and Aeolian Dusts Suggest for Dust Transport over Japan

“…Similarly, the 90 Sr produced via 90 Kr (T 1 / 2 : 32.3 sec) by the nuclear detonations would disperse more extensively than U and Pu, which are fissile bomb materials. This fact, that the close-in fallout of 137 Cs was small compared to Pu, was also observed for the Kazhakstan case (Yamamoto et al, 1998). Therefore, it is deduced that the local contamination of the Sahara and Taklamakan areas by 90 Sr and 137 Cs due respectively to the French and Chinese nuclear tests seems to be insignificant.…”

DETERMINATION OF 240Pu/239Pu ISOTOPIC RATIOS IN HUMAN TISSUES COLLECTED FROM AREAS AROUND THE SEMIPALATINSK NUCLEAR TEST SITE BY SECTOR-FIELD HIGH RESOLUTION ICP-MS

“…Long-lived radionuclides such as 137 Cs and plutonium isotopes have been measured for soil samples from various areas (Yamamoto et al 1996a(Yamamoto et al , 1996b(Yamamoto et al , 1998(Yamamoto et al , 1999(Yamamoto et al , 2001(Yamamoto et al , 2002(Yamamoto et al , 2004a(Yamamoto et al , 2004bSakaguchi et al 2004Sakaguchi et al , 2006. Unlike 137 Cs, the inventories of 239,240 Pu for most of the sites we visited were several to a few hundred times higher than those (40 -120 Bq m Ϫ2 ) for global fallout observed in Japan.…”