Ensure Personnel Safety Research Articles

Safety Systems and Access Control in the National Ignition Facility

The National Ignition Facility (NIF) is the world's largest and most energetic laser system. The facility has the potential to generate ionizing radiation due to the interaction between the laser beams and target material, with neutrons and gamma rays being produced during deuterium-tritium fusion reactions. To perform these experiments, several types of hazards must be mitigated and controlled to ensure personnel safety. NIF uses a real-time safety system to monitor and mitigate the hazards presented by the facility. The NIF facility Safety Interlock System (SIS) monitors for oxygen deficiency and controls access to the facility preventing exposure to laser light and radiation from the Radiation Generating Devices. It also interfaces to radiation monitoring and other radiological monitoring and alarm systems. The SIS controls permissives to the hazard-generating equipment and annunciates hazard levels in the facility. To do this reliably and safely, the SIS has been designed as a fail-safe system with a proven performance record now spanning over 10 y. This paper discusses the SIS, its design, implementation, operator interfaces, validation/verification, and the hazard mitigation approaches employed in the NIF. A brief discussion of the Failure Modes and Effect Analysis supporting the SIS will also be presented. The paper ends with a general discussion of SIS do's and don'ts and common design flaws that should be avoided in SIS design.

A Survey of Wireless Communications and Propagation Modeling in Underground Mines

Mining and mineral exploration play important roles in the global economy. In mining operations, communication systems play vital roles in ensuring personnel safety, enhancing operational efficiency and process optimization. Over the period 1920-2012, this article surveys the evolution of wireless communications in underground mines, the developments of the underlying technology, and progress in understanding and modeling the underground wireless propagation channel. Current and future trends in technology, applications and propagation modeling are also identified. About ninety relevant references have been reviewed that consider: 1) the emergence of technology and applications, 2) analytical, numerical and measurement-based propagation modeling techniques, and 3) implications of the physical environment, antenna placement and radiation characteristics on wireless communication system design. Affected systems include narrowband, wideband/ultra-wideband (UWB) and multiple-antenna systems. The paper concludes by identifying open areas of research.

Online Monitoring of Substation Grounding Grid Conditions Using Touch and Step Voltage Sensors

A grounding grid of a substation is essential for reducing the ground potential rises inside and outside the substation during a short-circuit event. The performance of a grounding grid is affected by a number of factors, such as the soil conductivity and grounding rod corrosion. Industry always has a strong desire for a reliable and cost-effective method to monitor the condition of a grounding grid to ensure personnel safety and prevent equipments damage. In view of the increased adoption of telecom and sensor technologies in power industry through the smart grid initiative, this paper proposes an online condition monitoring scheme for grounding grids. The scheme monitors touch and step voltages in a substation through a sensor network. The voltages are created by a continuously-injected, controllable test current. The results are transmitted to a database through wireless telecommunication. The database evaluates the grid performance continuously by comparing the newly measured results with the historical data. Many of the limitations of the offline measurement techniques are overcome. Computer simulation studies have shown that the proposed scheme is highly feasible and technically attractive.

Predicting HCN gas generation in the SART process

The SART (Sulphidization, Acidification, Recycling and Thickening) process is a novel industrial technology used in gold mining to recover cyanide and copper from cyanide solutions. Since the operation of this process involves hydrogen cyanide (HCN) generation, the design of the process must provide full control on gaseous HCN evolution to ensure personnel safety. Even though gas extraction and scrubber systems play a fundamental role in the control and reduction of potentially dangerous HCN levels, currently there are no formal methods to estimate the HCN generation in the SART process in order to afford a robust design for the extraction and scrubber systems. The objective of the present work is to propose a general methodology to predict the generation of HCN gas in the SART process. For this purpose, a mathematical model was developed, supported by the phenomenology of the process and considering the system's operational conditions. This model considers the chemical equilibrium of HCN in solution, the liquid–gas phase equilibrium and the mass transfer phenomena between the liquid and gas phases. The results predicted by the model have indicated very low rates of HCN gas generation (1–12mg/hm2), showing HCN concentrations below 4ppm at the inlet of the scrubbing system under typical operational conditions. In addition, it was found that the generation of HCN gas is controlled by the liquid mass transfer resistance and, due to this reason, that the correct adjustment of operational parameters of the SART process can maximize the liquid mass transfer resistance, avoiding HCN volatilization.

MO‐E‐BRB‐06: Communicating Radiation Safety Procedures After Patient Death: Beyond Decay in Storage

Purpose: To discuss radiation safety issues that may arise in the event of death of patients who have received radiopharmaceutical therapy or a radioactive implant and to educate clinical medical physicists in specific procedures performed by pathology personnel, morgue personnel, funeral directors and crematory workers that present radiation safety risks to those workers. Also to provide guidance on lessons learned by the author in communicating appropriate radiation safety procedures to funeral professionals and working with state agencies that regulate funeral homes and crematories. Method and Materials: The author researched pathology, embalming, and cremation procedures and facilities and spent considerable time on‐site in such facilities to gain an understanding of the specific risks presented to personnel and safety precautions that are currently used (or not used). Results: The author prepared instructions to be provided to personnel in the event of the death of radiopharmaceutical therapy or radioactive implant patient to comply with state and federal radiation control regulations and ensure personnel safety. The author also provided education to local funeral directors and spoke on this subject at a state funeral directors conference. Conclusions: It is not a matter of “if” but rather “when” a clinical medical physicist at a facility performing radiopharmaceutical therapy or radioactive implant procedures will receive a call regarding radiation safety procedures for a deceased patient. It is preferable to be prepared with specific instructions and establish a relationship with your pathology laboratory, morgue, and local funeral professionals in advance than to flounder when the event occurs.

English

Rarely do rock pile characterization methods allow for examination and sampling of the undisturbed interior of large rock piles in-situ. The regrading of the Goathill North (GHN) rock pile at the Molycorp Questa mine, New Mexico provided a unique opportunity to examine and sample the undisturbed, interior of a large rock pile through the construction of trenches cut into the rock pile as earth-moving progressed. Weekly during the regrading of the GHN rock pile, contractors excavated a trench to allow for sampling of rock pile material. Trenches typically had four benches, which were 1.5 m wide and did not exceed 1.2 m in height, to give an overall slope of 1.4 horizontal to 1.0 vertical within the trench. Each trench extended for a length sufficient to explore site conditions, maintain the regraded 2:1 slope, and ensure personnel safety. Once excavated, trench walls and benches were surveyed using a differential global positioning system. For every trench, maps and logs of each bench were created to describe the different mine soil units, including the thickness, dip and extent of the units. Units were defined based on color, grain size, stratigraphic position, and other physical properties that could be determined in the field. Units were correlated between benches and to both sides of each trench, and several units were correlated downward through the series of successively excavated trenches. The field sampling crew began sampling within each of the identified units after the unit boundaries were identified and mapped. The following in situ measurements were taken along either the horizontal or vertical surfaces of each exposed bench and along the base of the trench: sand cone (density), tensiometer (matric suction), gravimetric moisture content, grain size, infiltration, and nuclear gauge measurements (density, moisture content). Gravimetric water content samples were collected at the locations selected for the measurement of matric suction and infiltration tests. Samples were collected from each defined unit for geochemical, geotechnical (including shear box tests, slake durability tests), biological, and electron microprobe analyses. Channel sampling for pyrite reserve modeling was performed in short 1.5-m long horizontal slots using a rock hammer to chip material to be placed into a sample bag. Additional material from selected layers was collected for potential weathering-cell tests in the future. Typically, paste pH increases with distance from the outer, oxidized zone (west) towards the interior, unoxidized zone (east) of the GHN rock pile.

Transmission Line, Railroad and Pipeline Common Corridor Study

The sharing of common corridors by electric power transmission lines, pipelines and rail-road facilities is becoming more commonplace. However, such corridor sharing can result in undesired coupling of electromagnetic energy from the power lines to the paralleling facilities. The principal concerns are with respect to both personnel safety and equipment operational compatibility. Induced interfering voltages and currents can result from either magnetic or electrostatic induction from the power line circuits. The induction can occur during either the normal steady-state operation of the power system or during a fault. The situations that give rise to problems, as well as the candidate mitigation measures, depend on the susceptibilities, the excitation parameters and the interaction between the electromagnetically coupled components of the common corridor. This paper presents the results of a recently completed study of a utility common corridor in southern Arizona. A detailed analysis of the voltages and currents induced into the pipeline and rail facilities was performed using a computer program developed during the study. Alternate forms of mitigation were investigated to ensure personnel safety and operational compatibility where likely problems were predicted.

Computerized Analysis of Power Systems and Pipelines Proximity Effects

This paper describes the computerized analysis which was conducted to ensure personnel safety and pipeline integrity during power system faults occuring near the Trans Quebec & Maritimes gas pipeline. The pipeline section considered was constructed in the vicinity of two Hydro-Quebec power substations and a number of high voltage transmission line structures. The effects of electromagnetic induction and through-earth conduction caused by currents originating from Hydro-Quebec facilities during ground fault conditions are examined and their impact on the gas pipeline are quantified.

Transmission Line, Railroad and Pipeline Common Corridor Study

The sharing of common corridors by electric power transmission lines, pipelines and rail-road facilities is becoming more commonplace. However, such corridor sharing can result in undesired coupling of electromagnetic energy from the power lines to the paralleling facilities. The principal concerns are with respect to both personnel safety and equipment operational compatibility. Induced interfering voltages and currents can result from either magnetic or electrostatic induction from the power line circuits. The induction can occur during either the normal steady-state operation of the power system or during a fault. The situations that give rise to problems, as well as the candidate mitigation measures, depend on the susceptibilities, the excitation parameters and the interaction between the electromagnetically coupled components of the common corridor. This paper presents the results of a recently completed study of a utility common corridor in southern Arizona. A detailed analysis of the voltages and currents induced into the pipeline and rail facilities was performed using a computer program developed during the study. Alternate forms of mitigation were investigated to ensure personnel safety and operational compatibility where likely problems were predicted.

On some methods for the mass production of Po-?-Be neutron sources

Some methods for the preparation of Po-α-Be neutron sources are discussed in this paper. A detailed description is given of one of the “wet” methods of preparing Po-α-Be sources, which consists in the preparation of a uniform mixture of polonium and beryllium by passing a solution of polonium nitrate through beryllium powder, followed by the drying and grinding of the mixture obtained. A method for obtaining polonium nitrate free from copper contamination is described. The method described is not suitable for the mass production of sources because of the high neutron activity accompanying the main technological operation. For the mass production of sources a “dry” method is recommended which is a modification of the method proposed by Brean and Hertz. Copper powder mixed in with a known amount of Po210 is weighed out into containers which are then filled with beryllium powder. When the hermetically shut containers are heated, the polonium volatilizes and is distributed uniformly throughout the mixture. With this method it is possible to prepare sources with a yield of (2.1±0.2) · 106 neutrons/sec per 1 curie of Po210 under conditions which ensure personnel safety.