Investigations of the use of natural organic matter as a remediation material

Industrial activities and accidental releases often introduce a large amount of inorganic and organic contaminants to the environment. Humic substances interact strongly with metals and organic pollutants. In this study, this property was exploited in order to establish new remediation materials in two environmental applications and in one pharmaceutical application. The two remediation materials under investigation were sludge and sediment, ST sludge and CE sludge, respectively. The first application aimed at investigating the use of the remediation materials to remove arsenic, iron, and uranium from the industrial effluents. The main results were the release of iron from ST sludge inhibited its usage as remediation material whereas CE sludge showed excellent performance. The extractions were both rapid and efficient. The second application studied the extraction of organic contaminants. The objective of this study was to find a new remediation material for removal of organic contaminants. The remediation materials showed similar and excellent performance on extraction of chlorinated anilines, phenols and benzenes. The third application investigated the extraction of iodine species from urine. It aimed at determining whether the radioactive iodine can be extracted from the urine and thereby concentrated into a smaller volume of solid. Even though the extraction percentages from urine were not as promising as from deionised water and synthetic urine, scientific interest was raised and further investigations on the effect of the composition of urine and solubility of sludges for the extraction of iodine species were recommended. The outcome of the presented study was interesting both scientifically and economically. The promising extraction results for arsenic, iron and uranium indicate that the CE sludge is ready to be tested in a field study. The extraction of organic compounds by both remediation materials was also promising. However, further studies on permeability and solubility were recommended

Development of 3H, 14C, 41Ca, 55Fe, 63Ni radiochemical analysis methods in activated concrete samples

Development of H-3, C-14, Ca-41, Fe-55 and Ni-63 radiochemical analysis methods were carried out independently by two laboratories using both inactivate and activated concrete samples. Two preliminary radioanalytical procedures for the non-volatile radionuclides (Ca-41, Fe-55, Ni-63) and one Thermal oxidation method for the volatile radionuclides (H-3, C-14) were developed. The difficulties in the method development and analysis of results are discussed.Peer reviewe

Intercomparison exercise on difficult to measure radionuclides in spent ion exchange resin

A need for method validation in radiochemical analyses of decommissioning waste is a challenging task due to lack of commercial reference materials. Participation in an intercomparison exercise is one way for a laboratory to assess their performance and validate their analysis results. A three-year project within the Nordic Nuclear Safety Research (NKS) community was initiated in order to carry out intercomparison exercises on difficult to measure (DTM) radionuclides in real decommissioning waste. Both Nordic and Non-Nordic laboratories participated. This paper reports the results from the final year of the project focusing on beta- and gamma emitter (i.e., easy to measure, ETM) analysis in spent ion exchange resin. The assigned values were derived from the participants' results according to ISO 13528 standard and the performances were assessed using z scores. The results showed generally good performances for both DTMs and ETMs.Peer reviewe

Determination of C-14, Fe-55, Ni-63 and gamma emitters in activated RPV steel samples : a comparison between calculations and experimental analysis

Determination of C-14, Fe-55, Ni-63 and gamma emitters in two different types of activated reactor pressure vessel (RPV) steel samples were carried out. The gamma emitters were analysed using HPGe detectors with ISOCS and standard geometry calibrations. Two radioanalytical procedures for the C-14, Fe-55, Ni-63 analysis were developed using inactive samples and activated samples were analysed using modified procedures. A Monte Carlo code was used for the modelling of the activation results. The obtained measured and calculated results were comparable.Peer reviewe

Intercomparison exercise on difficult to measure radionuclides in activated steel : statistical analysis of radioanalytical results and activation calculations

This paper reports the results obtained during an intercomparison exercise for the determination of difficult to measure radionuclides in activated reactor pressure vessel (RPV) steel samples. In total, eight laboratories participated analysing 14C, 55Fe and 63Ni activity concentrations in RPV steel. In addition, some laboratories also analysed 60Co activity concentrations. Corresponding activity concentrations were also determined using activation calculations. Robust statistical techniques were utilised for the analysis of the results according to ISO 13528 standard. The results showed good agreement for 55Fe and 63Ni results whereas 14C results had significant differences. 60Co results were in quite good agreement.Peer reviewe