[en] Radioactive tracers have been used to study the movement of water in several geothermal fields, including Wairakei and Broadlands, in New Zealand. This technique has been particularly useful in hot water reinjection investigations for detecting the invasion of reinjected water into the production zone. Iodine-131 has been used as the tracer and the methods and equipment used to inject, sample and measure it are described. The single well dilution method of estimating horizontal flow velocities was found to be useful as a preliminary step to multi-well testing. A number of tests in both fields are discussed, and some details of the results presented. Peak velocities as high as 17 m/hr were observed and tracer recoveries of over 10% obtained. Possible interpretation of some of the results in relation to available geological descriptions are made. The dominating influence of faulting on water movement, and the inadvisability of relying on distance alone to prevent cold water re-entering into a production field, is stressed

[en] The report summarises the radioactive tracer tests, using iodine-131 and bromine-82, made in the Wairakei geothermal field over the period 1978-80. Injection of tracer into three wells with strong cool water downflows at about 300-400m below ground level, produced strong rapid responses from the only deep wells feeding from about 800-1000m and lying in the south-westerly direction from the injection wells, i.e. parallel to the fault planes. Shallower wells, even though in some cases much closer to the injection well, reacted much more slowly. Velocities, as measured by peak arrival times, as high as 22m/h over 200m and 11m/h over 650m, were found. The flow patterns for the cool water feeds to the production area are discussed

[en] Two radioactive tracer tests using iodine-131 were made in conjunction with hot water reinjection tests on two wells in the Broadlands geothermal field. In each case, a return was detected to the production part of the field. In one case, as much as 30% of the water being discharged at the observation well was reinjected water. The underground flow velocity as measured by the tracer peak arrival time was 13m/day. In the other test the corresponding figures were 1% and 28 m/day. Flow paths in relation to known geological information are discussed

[en] The oceanic inventory for natural ¹⁴C is 19.6x10²⁹ atoms, an estimate similar to those found by other methods. The ¹⁴C produced from nuclear weapons (1972) is 550x10²⁶ atoms and 52% was in the oceans. From 1972 to 1985 132x10²⁶ atoms of bomb ¹⁴C were added. The nuclear power industry produces 0.5x10²⁶ atoms per year (17% of natural production rate). Most estimates by varying methods indicate an exchange time of carbon from atmosphere to ocean of about seven years or about 22 moles m^-2 yr^-1 for the surface ocean. The oceanic distribution generally has higher concentrations in low to mid latitudes, and low concentrations in the most southern regions, with the deep ocean retaining levels similar to those before nuclear testing

[en] A new combined radiation-chemotherapy protocol for the treatment of small cell lung carcinoma has produced unexpectedly severe normal tissue injury during radiation therapy. Thirteen of 23 patients who received radiation treatment plus combination chemotherapy [Vincristine, Adriamycin, Cyclophosphamide and VP16-213 (epipodophyllotoxin)] developed severe epithelial reactions from relatively low radiation doses. Prior experience with combination of radiation and chemotherapy leads us to implicate VP16-213 as the agent responsible for the enhanced radiation reactions

[en] The Institute of Nuclear Sciences accelerator mass spectrometry system has been used to determine the ages of a selection of spicules from crown of thorns starfish, collected at the Great Barrier Reef, Queensland. The measurements constitute a pilot study to determine the feasibility of using the technique to establish whether or not there is a periodicity in the invasion of The Great Barrier Reef by Crown of Thorns starfish

[en] Cholestyramine is a non-absorbable ion-exchange resin which specifically binds bile salts. We have treated seven patients with acute or chronic radiation-induced diarrhea that was refractory to the usual methods of control with cholestyramine. In each case, the diarrhea was controlled with cholestyramine. This observation supports previous experimental work with animals which indicated that bile salts contribute to the genesis of radiation-induced diarrhea. Cholestyramine is well-tolerated, but should not be administered with certain oral medications. The results of this small series are preliminary, but point the way toward a more extensive clinical trial to define the usefulness of cholestyramine in the treatment of refractory acute or chronic radiation-induced diarrhea

[en] A technique to make measurements of δ¹³C in atmospheric methane (δ¹³CH₄) to a precision of 0.02 per mille (1 sigma) is presented. Measurements of the mixing ratio and δ¹³CH₄ from Baring Head, New Zealand and Scott Base, Antarctica are reviewed for the period 1989 to 1998. The data show persistent but irregular seasonal cycles in δ¹³CH₄ ranging from 0.1-0.3 per mille superimposed on an increasing secular trend of about 0.04 per mille.year^-1 . In 1990/91 a 0.2 per mille positive anomaly appeared in this trend. The causes of the anomaly remain unresolved but, during 1992 when it disappeared, the decrease in δ¹³C was approximately coincident with a decrease in growth rate consistent with a decrease in biomass burning sources, which are relatively enriched in ¹³CH₄. δ¹³CH₄ data are also reported from large clean air samples collected every 2.5 deg. to 5 deg. of latitude on four voyages across the Pacific between New Zealand and the West Coast of the USA in 1996 and 1997. These data show that the inter-hemispheric gradient for δ¹³CH₄ was highly dependent on season, and varied from less than 0.1 per mille in June 1996 to more than 0.5 per mille in November 1996 with an estimated annual mean of 0.2-0.3 per mille. (author)

[en] Removal and disposal of neutron activated concrete from biological shields is the most significant operational task associated with research reactor decommissioning. During 1985 and 1986 Chem-Nuclear Systems, Inc. was the prime contractor for complete dismantlement and decommissioning of the Northrop Triga Reactor Facility and the Virginia Tech Argonaut Reactor. This paper discusses operational requirements, methods employed, and results of the concrete removal, packaging, transport and disposal operations for the Northrop Triga and Virginia Tech Reactor decomissioning projects. Methods employed for each are compared. Disposal of concrete above and below regulatory release limits for unrestricted use are discussed. This study concludes that activated reactor biological shield concrete can be safely removed and buried under current regulations

[en] Lower bound energy formulae for the N-fermion problem of the type used by Hall (Proc. Phys. Soc.; A91:16 (1967)) are considered in terms of a reduced density operator for the interparticle separation. In bounds of this type the N-body energy is bounded by a sum of eigen-energies of states of relative motion weighted by occupations for the relative states. It is shown that the wavefunctions of relative motion are subject to constraints and in particular must be zero when the particle separation is zero. This modifies the energy spectrum of the reduced Hamiltonian of relative motion and improves the lower bound due to Hall. The improvement is demonstrated for some simple model problems. Furthermore it is shown that the bounds of this type currently known do not exhibit saturation regardless of the interaction details. This leads to some speculation on improved lower bounds. (author)