MIGRATION MECHANISMS OF PLUTONIUM, OTHER ACTINIDES AND FISSION PRODUCTS AT A LEGACY TRENCH DISPOSAL SITE

Date

Nov 5, 2015

Time

2:00 PM - 3:30 PM

Speaker

T.E. Payne Australian Nuclear Science and Technology Organisation

Language

en

Main Topic

Physik

Other Topics

Physik

Host

Dr. Brendler

Description

The Little Forest Legacy Site (LFLS), located on the urban fringes of the city of Sydney, Australia, was used to dispose of low level radioactive waste in shallow trenches during the 1960s. According to operational records, various radionuclides were disposed, including both plutonium and uranium. The total amount of Pu disposed was a few grams, with 239Pu being the isotope most commonly mentioned in available disposal records. This presentation will summarise the available information on the distribution of radionuclides at the site, and contrasts the behaviour of the various radionuclides, particularly the relative importance of different pathways and mechanisms. One of the main findings from the project has been the identification of a mechanism known as “bathtubbing” which has caused significant quantities of radionuclides (particularly Pu and Am) to be present in surface soils near the trenches. Bathtubbing is a process by which the former trenches, which are located in a low-permeability clay-rich surface layer, fill with water during major rainfall episodes and overflow at the ground surface. As a result, it appears that the plutonium primarily moves in surface pathways rather than through groundwater.

Last modified: Nov 5, 2015, 8:59:41 AM