36 research outputs found
Technical Support for Improving the Licensing Regulatory Base for Selected Facilities Associated with the Front End of the Fuel Cycle
Pacific Northwest Laboratory (PNL) was asked by the NRC Office of Nuclear Material Safety and Safeguards (NMSS) to determine the adequacy of its health, safety and environmental regulatory base as a guide to applicants for licenses to operate UF{sub 6} conversion facilities and fuel fabrication plants. The regulatory base was defined as the body of documented requirements and guidance to licensees, including laws passed by Congress, Federal Regulations developed by the NRC to implement the laws, license conditions added to each license to deal with special requirements for that specific license, and Regulatory Guides. The study concentrated on the renewal licensing accomplished in the last few years at five typical facilities, and included analyses of licensing documents and interviews with individuals involved with different aspects of the licensing process. Those interviewed included NMSS staff, Inspection and Enforcement (IE) officials, and selected licensees. From the results of the analyses and interviews, the PNL study team concludes that the regulatory base is adequate but should be codified for greater visibility. PNL recommends that NMSS clarify distinctions among legal requirements of the licensee, acceptance criteria employed by NMSS, and guidance used by all. In particular, a prelicensing conference among NMSS, IE and each licensee would be a practical means of setting license conditions acceptable to all parties
Opening up the Pandora's box of sustainability league tables of universities: a Kafkaesque perspective
The aim of this paper is to explore the institutional impact of sustainability league tables on current university agendas. It focuses on a narrative critique of one such league table, the UK's ‘Green League Table', compiled and reported by the student campaigning NGO, ‘People & Planet’ annually between 2007 and 2013. Through a Kafkaesque perspective, this paper offers the proposition that such league tables could be acting as an institutional hegemonic mechanism for social legitimacy, through the desire by universities to show that environmental issues are effectively under control. Espoused eco-narratives of the ‘carbon targets imperative’ and ‘engagement' can serve as a form of deception, by merely embracing the narrative as a rhetorical device. Moreover, they can serve the exclusive, particularistic self-interests of a growing legion of ‘carbon managers’, ‘sustainability managers’ and ‘environmental managers' in satisfying the neo-liberal institutional drive from their vice chancellors
The calibration system for the photomultiplier array of the SNO+ experiment
A light injection system using LEDs and optical fibres was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. Large volume, non-segmented, low-background detectors for rare event physics, such as the multi-purpose SNO+ experiment, need a calibration system that allow an accurate and regular measurement of the performance parameters of their photomultiplier arrays, while minimising the risk of radioactivity ingress. The design implemented for SNO+ uses a set of optical fibres to inject light pulses from external LEDs into the detector. The design, fabrication and installation of this light injection system, as well as the first commissioning tests, are described in this paper. Monte Carlo simulations were compared with the commissioning test results, confirming that the system meets the performance requirements
Impact of repairs on embodied carbon dioxide expenditure for a reinforced-concrete quay
Studies on structural repair using life-cycle analysis are still lacking the environmental impact of repair actions. This research work shows that the choice of the best repair option for reinforced-concrete structures is a function of long-term environmental impact, considering the longevity of maintenance intervention and embodied carbon dioxide expenditure. The purpose of this work was to assess the lifetime of a quay superstructure exposed to an aggressive marine microenvironment by using a probabilistic performance-based approach and then to select the best repair option for its reinforced-concrete structures. The comparison is made for reinforced-concrete service life using three different concrete types and two different corrosion inhibitors. Longevity and embodied carbon dioxide were predicted for the expected number of repair actions per 100 years. It is shown that concretes may have a higher impact at the outset, although they result in a much lower impact across the service life of the structure
Steel fibre reinforced concrete for elements failing in bending and in shear
Discrete steel fibres can increase significantly the bending and the shear resistance of concrete
structural elements when Steel Fibre Reinforced Concrete (SFRC) is designed in such a way that fibre
reinforcing mechanisms are optimized. To assess the fibre reinforcement effectiveness in shallow structural
elements failing in bending and in shear, experimental and numerical research were performed. Uniaxial
compression and bending tests were executed to derive the constitutive laws of the developed SFRC. Using a
cross-section layered model and the material constitutive laws, the deformational behaviour of structural
elements failing in bending was predicted from the moment-curvature relationship of the representative cross
sections. To evaluate the influence of the percentage of fibres on the shear resistance of shallow structures, three
point bending tests with shallow beams were performed. The applicability of the formulation proposed by
RILEM TC 162-TDF for the prediction of the shear resistance of SFRC elements was evaluated. Inverse
analysis was adopted to determine indirectly the values of the fracture mode I parameters of the developed
SFRC. With these values, and using a softening diagram for modelling the crack shear softening behaviour, the
response of the SFRC beams failing in shear was predicted.Fundação para a Ciência e a Tecnologia (FCT
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Precision white-beam slit design for high power density x-ray undulator beamlines at the Advanced Photon Source
A set of precision horizontal and vertical white-beam slits has been designed for the Advanced Photon Source (APS) X-ray undulator beamlines at Argonne National Laboratory. There are several new design concepts applied in this slit set, including: grazing-incidence knife-edge configuration to minimize the scattering of X-rays downstream, enhanced heat transfer tubing to provide water cooling, and a second slit to eliminate the thermal distortion on the slit knife edge. The novel aspect of this design is the use of two L-shaped knife-edge assemblies, which are manipulated by two precision X-Z stepping linear actuators. The principal and structural details of the design for this slit set are presented in this paper
The Use of Process Monitoring Data for Nuclear Material Accounting Summary Report
A study was conducted for the Nuclear Regulatory Commission (NRC) as part of a continuing program to estimate the effectiveness of using process monitoring data to enhance strategic special nuclear material (SSNM) accounting in nuclear facilities. Two licensed fuel fabrication facilities with internal scrap recovery processes were examined. The loss detection sensitivity, timeliness, and localization capabilities of the process monitoring technique were evaluated for single and multiple (trickle) losses. The impact of records manipulation, mass and isotopic substitution, and collusion between insiders as methods for concealing diversion were also studied
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Beamline standard component designs for the Advanced Photon Source
The Advanced Photon Source (APS) has initiated a design standardization and modularization activity for the APS synchrotron radiation beamline components. These standard components are included in components library, sub-components library and experimental station library. This paper briefly describes these standard components using both technical specifications and side view drawings