AMS of the Minor Plutonium Isotopes

Abstract

VERA, the Vienna Environmental Research Accelerator, is especially equipped for the measurement of actinides, and performs a growing number of measurements on environmental samples. While AMS is not the optimum method for each particular plutonium isotope, the possibility to measure 239Pu, 240Pu, 241Pu, 242Pu and 244Pu on the same AMS sputter target is a great simplification. We have obtained a first result on the global fallout value of 244Pu/239Pu = (5.7 ± 1.0) × 10−5 based on soil samples from Salzburg prefecture, Austria. Furthermore, we suggest using the 242Pu/240Pu ratio as an estimate of the initial 241Pu/239Pu ratio, which allows dating of the time of irradiation based solely on Pu isotopes. We have checked the validity of this estimate using literature data, simulations, and environmental samples from soil from the Salzburg prefecture (Austria), from the shut down Garigliano Nuclear Power Plant (Sessa Aurunca, Italy) and from the Irish Sea near the Sellafield nuclear facility. The maximum deviation of the estimated dates from the expected ages is 6 years, while relative dating of material from the same source seems to be possible with a precision of less than 2 years. Additional information carried by the minor plutonium isotopes may allow further improvements of the precision of the method.

Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

“…Similar values were found for other heavy ions [25] and also for a series of U and Pu runs for neutron capture cross section measurements of U and Th [26].…”

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

“…The 233 U/ 236 U atom ratio was determined in seven samples from different depths of a sediment core (3-47 cm) from the Irish Sea which was collected by the Federal Maritime and Hydrographic Agency, Germany. Previous work suggests that the core showed no good stratigraphy 14,56 but was probably mixed by environmental reworking. The 236 U/ 238 U ratios determined in the sediment samples ranged from 1.35Á10 À5 to 4.36Á10 À5 and thus, were considerably elevated compared with natural background (10 À14 -10 À1012 ) or global fallout (% 5Á10 À811 ).…”

“…Later emissions originated from the reprocessing of spent fuel from thermal Nuclear Power Plants showed 240 Pu/ 239 Pu ratios higher than 0.20 21 . Dating of the sediment core using its 241 Pu content resulted in a maximum age of 34.0 ± 0.4 years before 2010 56 and, therefore, an isotopic signature of high burn-up fuel from NPPs was expected. This has been confirmed by the high 240 Pu/ 239 Pu ratios ranging from 0.20 to 0.33 detected in the sediment core 14 .…”

Accelerator Mass Spectrometry of Actinides in Ground- and Seawater: An Innovative Method Allowing for the Simultaneous Analysis of U, Np, Pu, Am, and Cm Isotopes below ppq Levels

“…For this reason, the amount of Fe was limited to a maximum of 1.5 or 2 mg per sample, due to restrictions of the available accelerator beam time that is finally related to the detection efficiency. 27 In our method, therefore, a compromise had to be found between the minimum concentration of Fe which would allow an efficient coprecipitation of the actinides and the maximum amount of Fe that would not cause a too long measuring time.…”