Edward J. Waller

Overview of hazard assessment and emergency planning software of use to RN first responders.

There are numerous software tools available for field deployment, reach-back, training and planning use in the event of a radiological or nuclear terrorist event. Specialized software tools used by CBRNe responders can increase information available and the speed and accuracy of the response, thereby ensuring that radiation doses to responders, receivers, and the general public are kept as low as reasonably achievable. Software designed to provide health care providers with assistance in selecting appropriate countermeasures or therapeutic interventions in a timely fashion can improve the potential for positive patient outcome. This paper reviews various software applications of relevance to radiological and nuclear events that are currently in use by first responders, emergency planners, medical receivers, and criminal investigators.

Combined hardware—software considerations for triage of internally contaminated personnel

Medical response to a radiological emergency involves first assessing, triaging and treating trauma, followed by determining potential hazard from radiological intake. A combined hardware-software strategy is required for this mission. The hardware strategy should consist of a dedicated detector suite capable of alpha, beta and gamma radiation detection, identification and quantification suitable for order of magnitude dose assessment. The hardware platform should provide a simple user interface suitable for field deployment. The software should provide first-on-the-scene responders with the ability to perform radiological triage in a mass casualty type event, physicians with the ability to assign treatment regimes, and long-term care medical personnel with information to provide continual risk reassessment of the patient taking into account toxicology of the decorporation therapy and dose aversion. The software should be rich in data, yet accessible through a simple user interface. Practicing in a radiological emergency exercise environment with the equipment is crucial to its efficacy in a real emergency.

Neutron production associated with radiotherapy linear accelerators using intensity modulated radiation therapy mode

A number of experiments were conducted on a Clinac 21EX radiotherapy accelerator using an IMRT treatment plan to determine neutron dose equivalent as a function of both patient dose delivered and machine workload. It was determined that IMRT mode is more neutron dose intensive as a function of patient dose when compared to a similar standard non-IMRT treatment. It was found that when the neutron production is normalized to workload, the measured neutron dose equivalents are similar. It is therefore recommended that neutron production be reported as a function of workload when considering IMRT treatment modes.

A neutron steam-quality meter for a fluidized bed plant

Abstract The design and testing aspects of a neutron scattering device for measuring the quality of steam in a pipe of a circulating fluidized bed plant are presented. The device employs a californium-252 source and a thermal neutron detector that measures the fluence of neutrons backscattered from the pipe. Neutronic and thermodynamic effects that may influence the performance of the device are investigated and a simple calibration process is proposed.

Intercomparison of Monte Carlo radiation transport codes to model TEPC response in low-energy neutron and gamma-ray fields

Tissue-equivalent proportional counters (TEPC) can potentially be used as a portable and personal dosemeter in mixed neutron and gamma-ray fields, but what hinders this use is their typically large physical size. To formulate compact TEPC designs, the use of a Monte Carlo transport code is necessary to predict the performance of compact designs in these fields. To perform this modelling, three candidate codes were assessed: MCNPX 2.7.E, FLUKA 2011.2 and PHITS 2.24. In each code, benchmark simulations were performed involving the irradiation of a 5-in. TEPC with monoenergetic neutron fields and a 4-in. wall-less TEPC with monoenergetic gamma-ray fields. The frequency and dose mean lineal energies and dose distributions calculated from each code were compared with experimentally determined data. For the neutron benchmark simulations, PHITS produces data closest to the experimental values and for the gamma-ray benchmark simulations, FLUKA yields data closest to the experimentally determined quantities.

The role of the health physicist in nuclear security.

AbstractHealth physics is a recognized safety function in the holistic context of the protection of workers, members of the public, and the environment against the hazardous effects of ionizing radiation, often generically designated as radiation protection. The role of the health physicist as protector dates back to the Manhattan Project. Nuclear security is the prevention and detection of, and response to, criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities, or associated activities. Its importance has become more visible and pronounced in the post 9/11 environment, and it has a shared purpose with health physics in the context of protection of workers, members of the public, and the environment. However, the duties and responsibilities of the health physicist in the nuclear security domain are neither clearly defined nor recognized, while a fundamental understanding of nuclear phenomena in general, nuclear or other radioactive material specifically, and the potential hazards related to them is required for threat assessment, protection, and risk management. Furthermore, given the unique skills and attributes of professional health physicists, it is argued that the role of the health physicist should encompass all aspects of nuclear security, ranging from input in the development to implementation and execution of an efficient and effective nuclear security regime. As such, health physicists should transcend their current typical role as consultants in nuclear security issues and become fully integrated and recognized experts in the nuclear security domain and decision making process. Issues regarding the security clearances of health physics personnel and the possibility of insider threats must be addressed in the same manner as for other trusted individuals; however, the net gain from recognizing and integrating health physics expertise in all levels of a nuclear security regime far outweighs any negative aspects. In fact, it can be argued that health physics is essential in achieving an integrated approach toward nuclear safety, security, and safeguards.

A mobile robotic platform for generating radiation maps

The use of mobile robots to collect the sensor readings required to generate radiation maps has the significant advantage of eliminating the risk of exposure that humans would otherwise face by collecting the readings by hand. In this work, a mobile robotic platform designed specifically to collect this information to synthesize radiation maps is presented. Details of the design are discussed, focusing in particular on the physical map generating capabilities of this new platform that are necessary to enable the generation of the radiation maps. The physical maps are generated using a laser range finder based implementation of Simultaneous Localization and Mapping (SLAM).

MEDECOR—A MEDICAL DECORPORATION TOOL TO ASSIST FIRST RESPONDERS, RECEIVERS, AND MEDICAL REACH-BACK PERSONNEL IN TRIAGE, TREATMENT, AND RISK ASSESSMENT AFTER INTERNALIZATION OF RADIONUCLIDES

After a radiological dispersal device (RDD) event, it is possible for radionuclides to enter the human body through inhalation, ingestion, and skin and wound absorption. From a health physics perspective, it is important to know the magnitude of the intake to perform dosimetric assessments. From a medical perspective, removal of radionuclides leading to dose aversion (hence risk reduction) is of high importance. The efficacy of medical decorporation strategies is extremely dependent upon the time of treatment delivery after intake. The “golden hour,” or more realistically 3–4 h, is optimal when attempting to increase removal of radionuclides from extracellular fluids prior to cellular incorporation. To assist medical first response personnel in making timely decisions regarding appropriate treatment delivery modes, it is desirable to have a software tool that compiles existing radionuclide decorporation therapy data and allows a user to perform simple diagnosis leading to optimized decorporation treatment strategies. In its most simple application, the software is a large database of radionuclide decorporation strategies and treatments. The software can also be used in clinical interactive mode, in which the user inputs the radionuclide, estimated activity, route of intake and time since exposure. The software makes suggestions as to the urgency of treatment (i.e., triage) and the suggested therapy. Current developments include risk assessment which impacts the potential risk of delivered therapy and resource allocation of therapeutic agents. The software, developed for the Canadian Department of National Defence (DND), is titled MEDECOR (MEdical DECORporation). The MEDECOR tool was designed for use on both personal digital assistant and laptop computer environments. The tool was designed using HTML/Jscript, to allow for ease of portability amongst different computing platforms. This paper presents the features of MEDECOR, results of testing at a major NATO exercise, and future development of this tool into MEDECOR2.

A portable neutron device for void-fraction measurement in a small-diameter pipe

Abstract A technique for measuring the void fraction of the flow of boiling-water in a small-diameter pipe using an isotopic neutron source is presented. The method relies on measuring the thermalization of fast neutrons incident on the pipe. The incident-neutron energy is optimized so that a linear and flow-regime-independent relationship between the void fraction and the neutron-detector response is obtained. The optimum energy is obtained by controlled moderation of the energy spectrum of the isotopic source. The detector and pipe are housed together in a cadmium chamber to increase the signal-to-noise ratio. Results obtained in static experiments using lucite rods, and in a dynamic air-water flow system, are shown to compare favourably with the actual void fraction.

Design of a hybrid computational fluid dynamics-monte carlo radiation transport methodology for radioactive particulate resuspension studies.

AbstractThere are numerous scenarios where radioactive particulates can be displaced by external forces. For example, the detonation of a radiological dispersal device in an urban environment will result in the release of radioactive particulates that in turn can be resuspended into the breathing space by external forces such as wind flow in the vicinity of the detonation. A need exists to quantify the internal (due to inhalation) and external radiation doses that are delivered to bystanders; however, current state-of-the-art codes are unable to calculate accurately radiation doses that arise from the resuspension of radioactive particulates in complex topographies. To address this gap, a coupled computational fluid dynamics and Monte Carlo radiation transport approach has been developed. With the aid of particulate injections, the computational fluid dynamics simulation models characterize the resuspension of particulates in a complex urban geometry due to air-flow. The spatial and temporal distributions of these particulates are then used by the Monte Carlo radiation transport simulation to calculate the radiation doses delivered to various points within the simulated domain. A particular resuspension scenario has been modeled using this coupled framework, and the calculated internal (due to inhalation) and external radiation doses have been deemed reasonable. GAMBIT and FLUENT comprise the software suite used to perform the Computational Fluid Dynamics simulations, and Monte Carlo N-Particle eXtended is used to perform the Monte Carlo Radiation Transport simulations.