P. Ivanov

Study of the 111In-DTPA complex by the electromigration method.

The electrophoretic behavior of the 111In-DTPA radiopharmaceutical has been investigated. The stability constant, diffusion coefficient and effective charge of the complex as well as the temperature dependence of the electrophoretic mobility were determined. No-carrier-added 111In with high specific activity was used in the electrophoretic experiments in ultramicroconcentrations (10(-9)M).

Development of an optimised method for analysis of 90Sr in decommissioning wastes by triple quadrupole inductively coupled plasma mass spectrometry

The ongoing development of an optimised procedure for the measurement of 90Sr in decommissioning samples using the latest generation triple quadrupole inductively coupled plasma mass spectrometry (ICP-QQQ-MS) is presented. The procedure incorporates digestion, and separation from interferences using a combination of wet chemical and instrument-based separation using the ICP-QQQ-MS reaction cell. The key factors under study are the procedural time and limits of detection achievable compared to existing radiometric techniques.

Development of a method for rapid analysis of Ra-226 in groundwater and discharge water samples by ICP-QQQ-MS

A novel and rapid method has been developed for pre-concentration and measurement of 226Ra in groundwater and discharge water samples using the latest generation triple quadrupole inductively coupled plasma mass spectrometry (ICP-QQQ-MS). Cation exchange and extraction chromatography are capable of pre-concentration factors of ~200 based on 1L samples. The sensitivity and interference removal capability of ICP-QQQ-MS was assessed from spiked groundwaters, with the introduction of He collision gas required to minimise instrument background in high-matrix samples. The technique developed is potentially capable of detecting 226Ra activities as low as 5mBqL-1 when combined with pre-concentration prior to measurement.

Cyclotron production and radiochemical purification of 88,89Zr via α-particle induced reactions on natural strontium

The radionuclides (88)Zr and (89)Zr have been produced by cyclotron irradiation of (nat)SrO with 35 MeV α-particles at a beam current of 15 μA. The thick source production yield of (89)Zr is ~3.1 MBq μA(-1) h(-1). A two-step radiochemical purification utilising anion-exchange chromatography in hydrochloric and hydrofluoric acids has been developed to separate (88,89)Zr from the target material, natural strontium, the target substrate, aluminium, and long-lived (88)Y.

Development of the NPL gamma-ray spectrometer NANA for traceable nuclear decay and structure studies.

We present a brief report on the progress towards the construction of the National Nuclear Array (NANA), a gamma-ray coincidence spectrometer for discrete-line nuclear structure and decay measurements. The proposed spectrometer will combine a gamma-ray energy resolution of approximately 3% at 1MeV with sub-nanosecond timing discrimination between successive gamma rays in mutually coincident decay cascades. We also review a number of recent measurements using coincidence fast-timing gamma-ray spectroscopy for nuclear structure studies, which have helped to inform the design criteria for the NANA spectrometer.

Development of NANA: A Fast-Scintillator, Coincidence Gamma-ray Array for Radioactive Source Characterisation and Absolute Activity Measurements at the UK National Physical Laboratory

A multi-detector modular coincidence gamma-ray spectrometer is being designed and constructed for use at the UKs National Physical Laboratory (NPL) for use in direct measurement and metrological standardisation of nuclear decay activities. In its first generation, the NPL National Nuclear Array (NANA) will consist of twelve individual halide scintillation detectors placed in a high-efficiency geometry around a well-defined central point source position. This brief conference paper provides details of the measured detector module and coincidence energy and timing responses for the LaBr3(Ce) detectors which will be used in the NANA array. Preliminary GEANT4 simulations of the arrays full energy peak efficiency and expected gamma-ray coincidence response are also presented.

The behaviour of 226Ra in high-volume environmental water samples on TK100 resin

Accurate, low-level measurement of 226Ra in high volume water samples requires rapid pre-concentration and robust separation techniques prior to measurement in order to comply with discharge limits and drinking water regulations. This study characterises the behaviour of 226Ra and interfering elements on recently developed TK100 (Triskem International) extraction chromatography resin. Distribution coefficients over a range of acid concentrations are given, along with an optimised procedure that shows rapid pre-concentration and separation of 226Ra on TK100 resin is achievable for high volume (1 L) water samples without the need for sample pre-treatment.

Isolation and purification of protactinium-231

Protactinium-231 is one of the lesser known actinides, yet the measurement of this radionuclide is central to dating studies in both paleoclimate and nuclear forensics measurements; furthermore, it is important as the immediate parent nuclide of the 227Ac decay chain. In this paper, we present the preparatory work for an upcoming CCRI(II) supplementary comparison of this radionuclide. The material used in this work was of poorly known provenance, and it was necessary to carry out a chemical purification of this material prior to use. A new extraction chromatography resin, TK 400, which has been developed for the separation of 231Pa, was tested at NPL. The aims of the work were achieved; the recovery of 231Pa was ~85%, the decay products were recovered in good yield (~95%) and stable element impurities were removed.

Behavior of zirconium and hafnium ions in ultramicroconcentrations investigated by horizontal zone electrophoresis in free electrolyte

The electrophoresis of zirconium and hafnium ions in aqueous solutions was investigated. No-carrier-added 88Zr and 175Hf have been used in microconcentrations (10-11M). The complexation of zirconium and hafnium with DTPA has been investigated in a large pH interval. The stability constants of the Zr-DTPA and Hf-DTPA complexes were determined for the first time by the method of horizontal zone electrophoresis in free electrolyte. The electrophoretic behavior of Zr(IV) and Hf(IV) ions in nitric acid solutions has also been studied.

Evaluation and requirements for scale factors from EMRP project MetroDECOM (ENV 54)

The EMRP project MetroDECOM was concerned with research addressing all aspects of nuclear decommissioning in order to deliver integrity and cost-effectiveness in support of clearance and disposal processes as well as improving safety and accuracy. One of the work packages was focused on the characterisation of materials present on decommissioning. Within this work package, work on scaling factors was aimed at applying the principles set out in ISO 21238:2007 to the measurement of contaminated areas in decommissioning sites. In this paper, we report the progress made under MetroDECOM in identifying decommissioning matrices of specific relevance to nuclear decommissioning within the EU and selecting priority hard-to-measure radionuclides for further study.