Evaluation of Repurposing Archetypal Preventive Radiological/Nuclear Detectors for the Consequence Management Mission.

In the first hours or days after an unplanned release of radioactive material to the environment, the radiation detection instruments most widely available to local first responders may be those currently fielded for interdiction missions. This study investigated how such preventative radiological/nuclear detection instruments could perform if repurposed for consequence management missions. A representative sample of three archetypes (body-worn, human-carried, and other/large-detection-volume equipment) encompassed six categories: personal radiation detector, extended-range personal radiation detector, personal emergency radiation detector, radioisotope identification device, human-portable detector/backpack, and vehicle-mounted large-detection-volume detector. Overall 19 models of equipment were included in the study. Laboratory evaluations were designed to assess the capabilities of the instruments in four consequence management missions: exposure rate, integrated exposure, radiation survey, and contamination screening. As applicable, the evaluations included measurement of exposure rate, integrated exposure, overrange response, and angular response. The results were compared to benchmarks from the American National Standards Institute N42.49A. The performance of the instruments for initial screening for contamination was assessed by an automated radioactive source moving past the detectors at various speeds and distances. The results demonstrate that if the equipment is used in accordance with the mission analysis and categories and within the original equipment manufacturer specifications, it is possible to achieve sufficient accuracy to estimate and document doses to responders, plan entries into contaminated areas, detect contamination, and protect the public until such time as outside resources arrive with sufficient numbers of standard health physics instruments and personnel dosimetry to replace the preventative radiological/nuclear detection instruments. This evaluation campaign was conducted to complement the National Council on Radiation Protection and Measurements Report 179, Guidance for Emergency Response Dosimetry.

How Prepared Are the Public and Responders for Nuclear Terrorism?

The theme of the 2017 Annual Meeting of the National Council on Radiation Protection and Measurements was "Assessment of National Efforts in Emergency Preparedness for Nuclear Terrorism: Is There a Need for Realignment to Close Remaining Gaps?" In the "Guidance, Training and Exercises: Emergency Responders" session, speakers explored our level of public and responder preparedness and the challenges to being adequately prepared. There were three themes expressed from the perspective of emergency responders. The federal government is effective at creating guidance and a systematic preparedness process but not so effective at engaging and implementing guidance and processes at the state and local level for technical hazards like radiation. Second, preparedness at the local level is driven by local leadership and champions who see the problem through a "different lens." These champions often have to overcome significant institutional, political, and social barriers associated with preparing for radiological events. Finally, there is a limit to the amount of general preparedness and public information that can be absorbed in the absence of a perceived threat. Occasionally, events lead to a heightened concern that offers a window of opportunity for a "learning moment."

Updated Emergency Response Guidance for the First 48 h after the Outdoor Detonation of an Explosive Radiological Dispersal Device.

ABSTRACT: This paper updates portions of the guidance originally published in 2006 based on the interpretation of subsequent experiments simulating explosive aerosolization from a radiological dispersal device and three-dimensional modeling of a high-rise urban-canyon type environment and wind field. These new data increase confidence about the predicted range of radioactive ballistic fragments that could endanger first responders and the public. The results of the most recent complete set of experiments indicate that the previously recommended initial hazard boundary corresponding to the potential for acute health effects can be reduced from 500 m to 250 m. This revised recommendation is independent of the total activity of the radioactive material. The assessment of the potential range and effects of dispersal from small particles as aerosol remains unchanged from the guidance issued in 2006. New recommendations are offered on sheltering versus evacuation and how to conduct the initial field measurements so as to make early decisions on protecting the public and responders, and providing coherent data for an assessment scientist to make a first estimate of the source term in the device.

Environmental measurements in an emergency: this is not a drill.

Emergency responders from the Department of Energy are trained regularly to assess the environmental consequences of a radiological or nuclear incident. While drills and exercises are highly effective tools in rehearsing for an emergency, the accidents at the Fukushima Daiichi Nuclear Power Plants presented real-world complexities that are difficult or impossible to simulate in such training. Customarily, the modeled hypothetical event used to create a drill or exercise data set is simple, well defined, and closely resembles conventional assumptions about the type of that event. Consequently, the modeling performed by players from the outset closely resembles the planner's hypothetical event. This approach also entails idealized, uniform data in the simulated plume and ground deposition scenarios created for the drill that match the modeling closely. The real-world event that occurred in Japan sharply deviated from the simple picture ordinarily created for drills and exercises that typically involve a release of radioactivity that is of short duration, a single puff with constant meteorology, or simple deviation such as a wind shift to bifurcate the plume. In the very early stages, accurate plume and deposition model predictions were difficult to produce due to the lack of field monitoring data and other information. In contrast to drills and exercises where plant monitoring data is available, there was much less plant monitoring data, essentially no reactor state information, and the meteorological conditions and releases were much more complex. Inevitably, the measurements in Japan were not homogeneous, thus presenting technical challenges to assessors tasked with ensuring the quality of the finished assessments and data products for government officials, the responder community, and the public. In this paper, examples of some operational real-world complexities are considered. Procedures, measurements, or radiological assessments from the Fukushima response are not in the purview of this paper.

The ALARA principle in the context of a radiological or nuclear emergency.

Traditionally, the concept of As Low As Reasonably Achievable (ALARA) has been applied to the workplace and to protect the public. The goals are to minimize small incremental exposures on a daily basis or per specific task, and on a yearly basis, thereby to keep the total annual dose equivalent as far below regulatory limits as practical. In an extreme emergency caused by radiological or nuclear terrorism, or a large scale radiological accident, it is proposed that the same principles can be applied to protect First Responders against potentially large exposures.

Realistic radiological dispersal device hazard boundaries and ramifications for early consequence management decisions.

If dispersal occurs from an explosive radiological dispersal device, first responders need to know what actions they need to take to protect life and property. Many of the decisions required to minimize exposure will be made during the first hour. To help the first responder decide what countermeasures to employ, Sandia National Laboratories has established realistic hazard boundaries for acute and sub-acute effects relevant to radiological dispersal devices. These boundaries were derived from dispersal calculations based on the aerosolization behavior of devices tested in the Sandia Aerosolization Program. For 20 years, the Sandia Aerosolization Program has performed explosive and non-explosive aerosolization tests relevant to radiological dispersal devices. This paper discusses (1) the method and technical bases used to establish hazard boundaries and the appropriate actions that apply within those areas and (2) whether large-scale evacuations or sheltering in place are appropriate responses to a radiological dispersal device event.

Emergency response guidance for the first 48 hours after the outdoor detonation of an explosive radiological dispersal device.

Strategies and decisions to protect emergency responders, the public, and critical infrastructure against the effects of a radiological dispersal device detonated outdoors must be made in the planning stage, not in the early period just after an attack. This contrasts with planning for small-scale types of radiological or nuclear emergencies, or for a large-scale nuclear-power-type accident that evolves over many hours or days before radioactivity is released to the environment, such that its effects can be prospectively modeled and analyzed. By the time it is known an attack has occurred, most likely there will have been casualties, all the radioactive material will have been released, plume growth will be progressing, and there will be no time left for evaluating possible countermeasures. This paper offers guidance to planners, first responders, and senior decision makers to assist them in developing strategies for protective actions and operational procedures for the first 48 hours after an explosive radiological dispersal device has been detonated.