Towards the application of electrokinetic remediation for nuclear site decommissioning.

Contamination encountered on nuclear sites includes radionuclides as well as a range of non-radioactive co-contaminants, often in low-permeability substrates such as concretes or clays. However, many commercial remediation techniques are ineffective in these substrates. By contrast, electrokinetic remediation (EKR), where an electric current is applied to remove contaminants from the treated media, retains high removal efficiencies in low permeability substrates.

Determination of ¹³⁵Cs and ¹³⁷Cs in environmental samples: A review.

Radionuclides of caesium are environmentally important since they are formed as significant high yield fission products ((135)Cs and (137)Cs) and activation products ((134)Cs and (136)Cs) during nuclear fission. They originate from a range of nuclear activities such as weapons testing, nuclear reprocessing and nuclear fuel cycle discharges and nuclear accidents. Whilst (137)Cs, (134)Cs and (136)Cs are routinely measurable at high sensitivity by gamma spectrometry, routine detection of long-lived (135)Cs by radiometric methods is challenging.

Calixarene-based extraction chromatographic separation of ¹³⁵Cs and ¹³⁷Cs in environmental and waste samples prior to sector field ICP-MS analysis.

Advances in the sensitivities achievable by sector field inductively coupled plasma mass spectrometry (ICP-SFMS) offer the prospect of low-level measurement of shorter and longer lived radionuclides, thus expanding options for environmental and radioactively contaminated land assessment. In ICP-SFMS, the critical requirement for accurate detection is the effective chemical separation of isobaric and polyatomic interferences prior to sample introduction. As instrumental detection limit capability improves, accurate radionuclide determination requires highly effective separation materials that combine high analyte selectivity with subsequent quantitative analyte recovery compatible with ICP-SFMS detection.

Using thermal evolution profiles to infer tritium speciation in nuclear site metals: an aid to decommissioning.

Understanding the association and retention of tritium in metals has significance in nuclear decommissioning programs and can lead to cost benefits through waste reduction and recycling of materials. To develop insights, a range of metals from two nuclear sites and one non-nuclear site were investigated which had different exposure histories. Tritium speciation in metals was inferred through incremental heating experiments over the range of 20-900 °C using a Raddec Pyrolyser instrument.

Determination of precise ¹³⁵Cs/¹³⁷Cs ratio in environmental samples using sector field inductively coupled plasma mass spectrometry.

Recent advances in sector field inductively coupled plasma mass spectrometry (ICP-SFMS) have led to significant sensitivity enhancements that expand the range of radionuclides measurable by ICP-MS. The increasing capability and performance of modern ICP-MS now allows analysis of medium-lived radionuclides previously undertaken using radiometric methods. A new generation ICP-SFMS was configured to achieve sensitivities up to 80,000 counts per second for a 1 ng/L (133)Cs solution, providing a detection limit of 1 pg/L.

Identification and quantification of radionuclides in contaminated drinking waters and pipeline deposits.

There is broad international interest, particularly with Homeland Security and first-responder organizations, in developing a range of effective, robust, and rapid analytical tools to identify terrorist assaults. Accidental or intentional radionuclide contamination of drinking water supplies would have significant public health, social, political, and financial implications even where the real risk might be small given public perception. Rapid identification and assessment of the magnitude of any contamination is critical in managing any threat and ultimately in allaying public and regulator concerns and in steering subsequent remediation operations.

Determination of carbon-14 in environmental level, solid reference materials.

An intercomparison exercise to determine the (14)C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection.

Marine bacterioplankton can increase evaporation and gas transfer bymetabolizing insoluble surfactants from the air-seawater interface.

Hydrophobic surfactants at the air-sea interface can retard evaporative and gaseous exchange between the atmosphere and the ocean.While numerous studies have examined the metabolic role of bacterioneuston at the air-sea interface, the interactions between hydrophobic surfactants and bacterioplankton are not well constrained. A novel experimental design was developed, using Vibrio natriegens and (3)H-labelled hexadecanoic acid tracer, to determine how the bacterial metabolism of fatty acids affects evaporative fluxes.