[en] The Bureau of International Recycling (BIR) speaks as the unified voice of the international recycling industry on a world level, promoting free-trade in non-hazardous recyclables and the increased usage of recycled goods. In October 1998, BIR presented its 'Guide to Radioactivity' to its members in order to explain the basics of radioactivity, to help determine what actions material recyclers should take and to provide an initial contact guide for summoning expert help. The Guide was promulgated together with a survey questionnaire; initial results of this survey have been collated. BIR members do not trade in radioactive materials and do not wish to receive hazardous radioactive contaminated materials. Furthermore it is very uncommon to find this unwelcome and unwanted material. The burden of handling contaminated materials should not rest on the recycling industry alone, however, as the hazards associated with processing contaminated materials are potentially extreme, recyclers have a role to help safeguard both their workforce and subsequent customers. Some BIR members have invested in in-plant detection equipment of various types from a variety of suppliers to detect contamination from 'lost' sources or from naturally occurring radioactive materials (NORM). Strict State control on sources in use would be very welcome to limit these ' losses'. Not all BIR members are in a position to provide or operate detection equipment; therefore, BIR would welcome States providing detection and control at sea ports and at border checkpoints on railways and roads. Some states have proposed permitting requirements for the handling of radioactive contaminated materials and have tried, inappropriately, to impose on the mainstream recycling industry, permits designed for the specialist decontamination or decommissioning industry. Current discussions on applying the transport of dangerous goods regulations would lead to unnecessary and impracticable additional restraints to facilitating impracticable additional restraints to facilitating proper disposal. A more reasoned approach would be to draw up a binding code of practice to avoid disincentives to detection and subsequent appropriate action. Free of charge disposal routes would recognise that the recycling industry should not have to bear the costs resulting from lack of government/institutional controls. As the mainstream recycling industry never intends to purchase or sell radioactive contaminated metallurgical scrap, provisions to prohibit purchase and sales would not be constructive, and could lead to court actions, furthering disincentives to co-operation. International understanding of the basic scientific issues needs improvement. A clear distinction must be made between the very specialised decontamination industry and the normal recycling industry that does not want to process radioactive contaminated material There is a need to determine and harmonise the standards and measurement techniques of radiation. If a standard for 'below regulatory concern' could be internationally accepted, materials certified as such would be regarded as formal commercial materials. As detection systems become more effective and sensitive, this is the most important criteria to resolve. The misunderstanding and misuse of information related to radioactive contaminated metallurgical scrap is of great concern because the recycling industry could suffer from adverse and unfair publicity which would damage co-operation and damage markets for recyclables. BIR members' efforts are directed at environmentally sound materials recycling and the detection of this unwanted material is providing a service and safeguard to customers and to society as a whole. (author)

[en] A description is given of the influence on the design of the containment structure to meet the recent safety requirements in the UK of specified external hazards. Methods of preliminary design for the case of aircraft impact are described to enable structural sizes to be determined. (author)

[en] The Bureau of International Recycling (BIR) is an international trade federation representing the world's recycling industry, covering, in particular, ferrous and non-ferrous metals, paper and textiles. This paper sets out the concerns of the worldwide recycling industry about radioactive material appearing in scrap metal. The involvement of BIR over the last decade in the international discussions on this matter is described and the views on the way forward are presented. (author)

[en] Full text: There is considerable evidence that the amount of sediment reaching the Great Barrier Reef (GBR), Australia, has increased since agricultural development commenced in the 1870’s. This sediment is having deleterious effects on freshwater and marine ecosystems. However, identifying the primary source and processes driving the increased sediment delivery has been challenging due to the large size and diversity of adjacent catchments. This study was the first of its kind in Australia to compare long-term (~100 to >10,000 year) erosion rates derived from terrestrial cosmogenic nuclides (TCN’s; ¹⁰Be) with contemporary erosion rates obtained by monitoring sediment fluxes over ~5-10 years. This study was conducted in the Burdekin catchment, which is the largest source of contemporary sediment to the Great Barrier Reef lagoon. Following rigorous testing of the assumptions for this technique, the ratio of these two data sets provided a measure of the accelerated erosion factor (AEF) for the major sub-basins in the Burdekin catchment. Results show that three out of five of the major sub-catchments in the Burdekin basin have AEF’s greater than 1.0. In the Bowen and Upper Burdekin sub-catchments, the AEF is 7.47 (± 3.71) and 3.64 (± 0.5), respectively. This suggests that erosion rates in these sub-basins are well above the natural background erosion rates, which is largely to be due to the relatively high slopes, higher rainfall and intensive land use (grazing and mining) compared to other parts of the catchment. This study has important implications for how GBR water quality targets are set and evaluated. Without an understanding of the natural susceptibility of a catchment to erosion, resources for remediation may be incorrectly allocated to areas that appear to be producing high sediment yields, when in fact they have landscape attributes that generate large volumes of sediment even in the absence of land use change (e.g. agriculture). Remediating catchments with high AEF’s to reduce erosion and sediment delivery is likely to take several decades, and will require a range of approaches including pasture and rangeland management, as well as targeted erosion control in highly gullied landscapes. (author)

[en] The assessment of the safety of nuclear reactors has necessitated the study of the effect of missiles on reinforced concrete structures. A programme of experimental work has been initiated within the United Kingdom to resolve the problem of design for the shear stresses produced by the impact loading. The basic scale of the experiments has been chosen to be 1/25th and both hard and soft missiles have been employed. The missiles are launched by a compressed air gun towards a vertical, circular, reinforced concrete target, high speed cine photography and deflection gauges being employed to record the missile behaviour and response of the target. Hard missiles have initially been plane circular discs and soft missiles have been developed to simulate the scaled load/time characteristic of a MRCA impacting at a velocity of 215 m/s. Targets of different overall thickness and varying amounts of reinforcement have been tested. A theoretical analysis of the impact phenomena has also been carried out using computer programs based on finite difference methods (Dynamic Relaxation and PISCES 2DL). The paper outlines the experimental work performed and discusses the analytical assessment by comparison with the test results. (Auth.)

[en] The assessment of the safety of nuclear reactors has necessitated the study of the effect of missiles on reinforced concrete containment structures. Two simple theoretical calculational methods have been developed to provide basic information. The first is based on a crude energy balance approach in which that part of the kinetic energy of the missile which is transferred into the containment structure, is absorbed only as bending strain energy. To determine the energy transferred into the structure it is assumed that during the loading the target does not respond. The energy input to the structure is thus equal to the kinetic energy it will possess immediately the impulse has been removed. The boundary of the responding zone is defined by the distance travelled by the shear stress wave during the time in which the impact force increases to the load at which the shear capacity reaches the ultimate shear resistance. The second method is based on the equation of motion for an equivalent one-degree-of-freedom system assuming that only the peak value of deflection is important and that damping can be ignored. The spring stiffness of the equivalent system has been based upon the stiffness of the actual disc configuration responding in the flexural mode only. The boundaries of the disc have been defined by using the elastic plate formulae and equating those positive and negative moments which will produce a specified yield line pattern which may be inferred from plastic plate formulae. The equation of motion is solved to indicate how the quantity of reinforcement included in the structure may modify the peak deflection. By limiting the ductility ratio of the reinforcement to some prescribed level it is possible to indicate the quantity of reinforcement w

[en] Plutonium fallout from atmospheric nuclear-weapons testing in the 1950s and 1960s constitutes an artificial tracer suitable for the study of recent soil erosion and sediment accumulation rates. Traditionally ¹³⁷Cs has been the fallout isotope of choice for such studies, but the plutonium isotopes confer a number of advantages, which can be realised using the ultra-sensitive detection technique of Accelerator Mass Spectrometry (AMS). As a first application of plutonium to a whole-of-basin study, Pu has been measured in both soil and sediment across the catchment of the Herbert River, which is one of the major rivers draining into Australia's Great Barrier Reef Lagoon. Its catchment includes undisturbed areas as well as regions of pasture and sugar cultivation. The Pu measurements allow the relative contributions of surface and gully erosion from the different land use areas to be determined, and permit the discharged material to be apportioned between the relevant sources.

[en] Highlights: • Review of suspended particulate matter (SPM) along the ‘ridge-to-reef’ continuum • Water clarity threshold tolerance limits of corals and seagrasses related to SPM • Links SPM terrestrial sources, transport, transformations, fate and ecological effects • Tools and guidance for prioritised SPM management from ridge-to-reef - Abstract: Studies documenting the effects of land-derived suspended particulate matter (SPM, i.e., particulate organic matter and mineral sediment) on marine ecosystems are typically disconnected from terrestrial studies that determine their origin, transport and fate. This study reviews sources, transport, transformations, fate and effects of SPM along the ‘ridge-to-reef’ continuum. We show that some of the SPM can be transported over long distances and transformed into large and easily resuspendible organic-rich sediment flocs. These flocs may lead to prolonged reductions in water clarity, impacting upon coral reef, seagrass and fish communities. Using the Great Barrier Reef (NE Australia) as a case study, we identify the latest research tools to determine thresholds of SPM exposure, allowing for an improved appreciation of marine risk. These tools are used to determine ecologically-relevant end-of-basin load targets and reliable marine water quality guidelines, thereby enabling enhanced prioritisation and management of SPM export from ridge-to-reef.

[en] Following atmospheric nuclear weapons testing in the 1950s and 1960s significant quantities of ¹³⁷Cs and ^239+240Pu were deposited worldwide. In recent decades, ¹³⁷Cs has been commonly used as a tracer of soil erosion and sedimentation, particularly in the Northern Hemisphere where atomic deposition was three times as great as in the Southern Hemisphere. The relatively short 30-year half-life of this isotope means that its sensitivity as a tracer is rapidly decreasing. In contrast, with half-lives of 24,110 and 6561 years, the sensitivity of the two plutonium isotopes remains essentially the same as when it was deposited. Here we use the technique of Accelerator Mass Spectrometry to demonstrate the potential of anthropogenic Pu as an alternative to ¹³⁷Cs as a tracer of soil transport in Australia. We measure an average ¹³⁷Cs/^239+240Pu activity ratio of 27.3 ± 1.5 and an average ²⁴⁰Pu/²³⁹Pu atom ratio of 0.149 ± 0.003, both slightly lower than the global average