[en] Nuclear fuel reprocessing has been carried out on an industrial scale in the United Kingdom since 1952. Two large reprocessing plants have been constructed and operated at Windscale, Cumbria and two smaller specialized plants have been constructed and operated at Dounreay, Northern Scotland. At the present time, the second of the two Windscale plants is operating, and Government permission has been given for a third reprocessing plant to be built on that site. At Dounreay, one of the plants is operating in its original form, whilst the second is now operating in a modified form, reprocessing fuel from the prototype fast reactor. This chapter describes the development of nuclear fuel reprocessing in the UK, commencing with the research carried out in Canada immediately after the Second World War. A general explanation of the techniques of nuclear fuel reprocessing and of the equipment used is given. This is followed by a detailed description of the plants and processes installed and operated in the UK

[en] The redox catalytic properties of ruthenium dioxide hydrate (RuO₂.xH₂O) were studied using a test system of Ce⁴⁺ in 0.5 mol. dm^-3 H₂SO₄. In powder form RuO₂.xH₂O appeared a poor redox catalyst unless bound to an inert support, such as titanium dioxide (TiO₂). This was attributed to the production of ruthenium tetraoxide (RuO₄), which was observed with RuO₂.xH₂O and a RuO₂.xH₂O-TiO₂ mixture but not with a TiO₂-bound RuO₂ catalyst. In the absence of a catalyst, or when TiO₂ or Al₂O₃ were used, no decay of the Ce⁴⁺ was observed (t > 200 h). (author)

[en] A membrane polarographic detector for deuterium (D₂-MPD) would offer a sensitive, selective and cheap method for the quantitative and continuous determination of deuterium in a closed system as well as in an open one. Only in the last decade has progress been made in the development of MPDs for gases other than oxygen. In a recent paper we describe how a two-electrode O₂-MPD (better known as a 'Clark electrode') could be modified to determine hydrogen and the results agreed with those obtained by other research groups. In this paper we report on what we believe is the first application of an MPD for the determination of deuterium. (author)

[en] Ruthenium dioxide hydrate is shown to be a poor redox catalyst for O₂ evolution from Ce⁴⁺, unless it is bound to an inert support such as titanium dioxide; this is attributed to the release of RuO₄ into the gas phase which was observed when ruthenium dioxide hydrate alone was used but not when it was bound to titanium dioxide. (author)

[en] The neurotensin receptor protein, solubilized with digitonin/asolectin from bovine cerebral cortex membranes, was purified to apparent homogeneity by affinity chromatography using immobilized neurotensin. The product exhibits saturable and specific binding of [3,11-tyrosyl-3,5-³H] neurotensin with an apparent affinity (K/sub d/ = 5.5 nM) comparable to that measured in intact membranes and crude soluble extracts. The affinity-purified material, after reduction with 100 mM dithiothreitol, in denaturing gel electrophoresis showed a single polypeptide of M/sub r/ 72,000. Under nonreducing conditions the apparent M/sub r/, however, was 50,000, suggesting the presence of intramolecular disulfide bonds. The purified neurotensin receptor was judged to be homogenous, in that (i) only a single polypeptide was detectable; and (ii) the overall purification was 30,000-50,000-fold, giving a specific neurotensin-binding activity close to the theoretical maximum

[en] The radiation dose to accompanying nurses, relatives and other patients in a nuclear medicine department waiting room was assessed at 5 min intervals by observing the seating arrangement. The total radiation dose to each person was calculated, using fixed values of dose rate per 100 MBq activity for radionuclides, and applying the inverse square law. Radioactive decay and attenuation effects due to intervening persons were also taken into account. The median radiation doses to accompanying nurses, relatives and other patients were 2.3, 2.0 and 0.2 μSv with maximum values of 17, 33 and 5 μSv respectively. In all cases, the radiation dose received by patients was less than 0.2% of the radiation dose resulting from their own investigation. Also, the maximum radiation dose received by an accompanying norse or friend was less than 1% of their appropriate annual dose limit. Similar values were obtained with calculations based on a 15 min time interval. The radiation doses received by those in a nuclear medicine department waiting room are small, and separate waiting room facilities for radioactive patients are unnecessary. (author)

[en] Clusters of four atomic vacancies were found in Au nanoparticle-embedded MgO by positron lifetime spectroscopy [Phys. Rev. Lett. 83, 4586 (1999)]. These clusters were also suggested to locate at the surface of Au nanoparticles by one-detector measurements of Doppler broadening of annihilation radiation. In this work we provide evidence, using two-detector coincidence experiments of Doppler broadening (2D-DBAR), to clarify that these vacancy clusters reside on the surfaces of Au nanoparticles. This work also demonstrates a method for identifying defects at nanomaterials interfaces: a combination of both positron lifetime spectroscopy, which tells the type of the defects, and 2D-DBAR measurements, which reveals chemical environment of the defects

[en] A Comment on the Letter by Hui Chen et al., Phys. Rev. Lett. 102, 105001 (2009).

[en] Nuclear fuel reprocessing has been carried out on an industrial scale in the United Kingdom since 1952. Two large reprocessing plants have been constructed and operated at Windscale, Cumbria and two smaller specialized plants have been constructed and operated at Dounreay, Northern Scotland. At the present time, the second of the two Windscale plants is operating, and Government permission has been given for a third reprocessing plant to be built on that site. At Dounreay, one of the plants is operating in its original form, whilst the second is now operating in a modified form, reprocessing fuel from the prototype fast reactor. This chapter describes the development of nuclear fuel reprocessing in the UK, commencing with the research carried out in Canada immediately after the Second World War. A general explanation of the techniques of nuclear fuel reprocessing and of the equipment used is given. This is followed by a detailed description of the plants and processes installed and operated in the UK. (author)

[en] A particularly bright and intense polarized slow positron beam could be formed from isotopically enriched ⁷⁹Kr produced at a reactor. After moderation with solid Ne, accumulation, compression, and bunching, this type of positron beam would enable a number of experiments including: (1) Long term storage of a neutral polarized electron-positron plasma in a cold box; (2) Pulsed e+ ACAR with a pulsed magnet to measure Fermi surfaces of paramagnetic metals; (3) Single shot measurements of positron annihilation in laser-imploding plasmas; (4) Study of a spin-polarized positronium gas at a density around that of ordinary air to produce a Ps Bose-Einstein condensate at room temperature; (5) High energy polarized positron channelling experiments to study polarized electron spatial wave functions in ferromagnets; and (6) Study of supersonic free expansion spin polarized BEC Ps jets formed from, for example, 10¹¹ m=1 triplet Ps atoms created within an open ended 1 μm diameter cylindrical cavity 100 μm in length.