Federal Radiological Monitoring Research Articles

Uncertainty Analysis of Consequence Management Data Products.

An interlaboratory effort has developed a probabilistic framework to characterize uncertainty in data products that are developed by the US Department of Energy Consequence Management Program in support of the Federal Radiological Monitoring and Assessment Center. The purpose of this paper is to provide an overview of the probability distributions of input variables and the statistical methods used to propagate and quantify the overall uncertainty of the derived response levels that are used as contours on data products due to the uncertainty in input parameters. Uncertainty analysis results are also presented for several study scenarios. This paper includes an example data product to illustrate the potential real-world implications of incorporating uncertainty analysis results into data products that inform protective action decisions. Data product contours that indicate areas where public protection actions may be warranted can be customized to an acceptable level of uncertainty. The investigators seek feedback from decision makers and the radiological emergency response community to determine how uncertainty information can be used to support the protective action decision-making process and how it can be presented on data products.

Analysis of Radionuclide Deposition Ratios from the Fukushima-Daiichi Incident.

This paper will examine deposition patterns of four radionuclides following the Fukushima-Daiichi accident. For nearly 13 d following the event, fission products were released into the environment through planned venting procedures and hydrogen explosions. To assist the government of Japan (GOJ) in the assessment of the releases, the National Nuclear Security Administration's Consequence Management Response Team (CMRT) deployed and took nearly 3 mo of measurements using airborne radiation sensors, fixed monitors, high purity germanium (HPGe) detectors, and health physics survey equipment. From the HPGe detector in-situ results gathered by the CMRT and GOJ teams, the depositions of Cs, Cs, Cs, and I were examined as a function of latitude and longitude. Deposition ratios were calculated to express how each radionuclide was deposited relative to Cs. In addition, the first 30 d of results were compared to the isotopic ratios listed in the Federal Radiological Monitoring and Assessment Center (FRMAC) Dose Assessment Manual Volume 2 Nuclear Power Plant default scenario. This was completed to analyze how the default FRMAC values compared with actual measurements. For Cs:Cs and Cs:Cs (1 wk after shutdown), the ratios were 0.969 ± 0.025 and 0.13 ± 0.007, respectively. These were significantly different from the FRMAC default values of 1.6 and 0.4, but they were of the same order of magnitude. Spatially, larger ratios with high uncertainties were recorded near Tokyo, over 200 km from the accident site. The I to Cs ratios, as expected, decayed exponentially over time but were significantly higher than FRMAC values. Six ratios were greater than 20 within 10 d after shutdown compared to the FRMAC default value of 9.9. In addition, the highest ratios were located less than 75 km to the southwest of the plant. Comparing all the isotopic ratios to the FRMAC manual illustrated differences between the default values and the actual field results. This is at least partly due to the fact that the FRMAC default values are based on an average between a pressurized water reactor and boiling water reactor release. These results of the comparison illustrate that the Assessment Manual default values should only be used when no other data are available.

EFRMAC Overview: Data Management and Enabling Technologies for Characterization of a Radiological Release.

The eFRMAC enterprise is a suite of technologies and software developed by the U.S. Department of Energy National Nuclear Security Administration's Office of Emergency Response to coordinate the rapid data collection, management, and analysis required during a radiological emergency. This enables the Federal Radiological Monitoring and Assessment Center assets to evaluate a radiological or nuclear incident efficiently to facilitate actions to protect public health and the environment. This document identifies and describes eFRMAC methods including: (1) data acquisition, (2) data management, (3) data analysis, (4) product creation, (5) quality control, and 6) product dissemination.

Adapting the U.S. Domestic Radiological Emergency Response Process to an Overseas Incident

The earthquake and resulting tsunami in Japan led to a radiological release from the Fukushima Daiichi Nuclear Power Plan, which in turn resulted in the rapid activation and deployment by the U.S. Department of Energy National Nuclear Security Administration (DOE/NNSA) emergency response teams. These teams and those from other federal agencies are typically coordinated through the Federal Radiological Monitoring and Assessment Center (FRMAC) when responding to radiological incidents in the U.S. FRMAC is the body through which the collection, analysis, and assessment of environmental radiological data are coordinated and products released to decision makers. This article discusses DOE/NNSA’s role in the U.S. response to the Fukushima accident as it implemented its components of FRMAC in a foreign country, coordinated its assets, integrated with its federal partners, and collaborated with the Government of Japan. The technical details of the various data collections and analyses are covered in other articles of this issue.

Radioanalytical data quality objectives and measurement quality objectives during a Federal Radiological Monitoring and Assessment Center response

During the early and intermediate phases of a nuclear or radiological incident, the Federal Radiological Monitoring and Assessment Center (FRMAC) collects environmental samples that are analyzed by organizations with radioanalytical capability. Resources dedicated to quality assurance (QA) activities must be sufficient to assure that appropriate radioanalytical measurement quality objectives (MQOs) and assessment data quality objectives (DQOs) are met. As the emergency stabilizes, QA activities will evolve commensurate with the need to reach appropriate DQOs. The MQOs represent a compromise between precise analytical determinations and the timeliness necessary for emergency response activities. Minimum detectable concentration (MDC), lower limit of detection, and critical level tests can all serve as measurements reflecting the MQOs. The relationship among protective action guides (PAGs), derived response levels (DRLs), and laboratory detection limits is described. The rationale used to determine the appropriate laboratory detection limit is described.

Dose Assessment for Reentry or Reoccupancy and Recovery of Urban Areas Contaminated by a Radiological Dispersal Device: The Need for a Consensus Approach

Should an attack occur in an urban area with a Radiological Dispersal Device (RDD), guidance is available on the acceptable total dose equivalent for reentering the contaminated zone, and there is an accepted methodology for plume projection in the model used by the Federal Radiological Monitoring and Assessment Center (FRMAC). After initial characterization of the impact of the plume caused by an RDD, there will be considerable pressure from the public to allow them to return and quickly collect their belongings, and, eventually, to reoccupy residences and to reopen businesses. The FRMAC procedures principally deal with early and intermediate phase dose assessment, but do include late phase assessment procedures. However, the late phase assessments do not include complex geometries, such as the internal structure of buildings. This paper identifies areas where more specificity is needed to rapidly provide assessments to health officials and senior decision-makers. In this regard, there is no national consensus method to calculate projected dose inside buildings after an RDD event that addresses selecting the exposure pathways, scenarios, key parameters, etc. Therefore, to demonstrate an approach that exemplifies some of the technical and policy issues, which are unresolved, four exposure scenarios (residential, industrial, public park, park worker) were evaluated to determine the level of contamination that would deliver a dose equivalent of 10 mSv in the first year, excluding exposure during the first 4 d (emergency phase). In addition, the retrieval of personal belongings was simulated by assessing a 1-h exposure for the residential and industrial scenarios. RESRAD-BUILD was used to calculate the surface concentration of 60Co, 90Sr, 137Cs, 192Ir, 226Ra, 238Pu, 241Am, and 252Cf that would lead to a 10 mSv reference dose for these exposure periods. These example studies are intended to provide insights and guidance on how a municipal health agency can begin to develop a response plan, and to understand how the assessment process will determine the dose impacts resulting from an RDD event. The model's predictions heavily depend on the choice of the model's parameters; for several key ones, there are large uncertainties about their appropriate values. To avoid having to make hasty decisions during an emergency after an RDD attack, this analysis demonstrates that a detailed protocol for calculating dose should be developed prospectively so that decision-makers already are fully familiar with the process and its ensuing products.

U.S. NATIONAL RESPONSE ASSETS FOR RADIOLOGICAL INCIDENTS

The federal government has had the ability to respond to incidents of national significance for decades. Since 11 September 2001, there have been enhancements to existing federal assets and the creation of new federal assets. This presentation will provide an overview of the more significant federal assets. Pivotal to a response of national significance is the U.S. Department of Energy (DOE) Federal Radiological Monitoring and Assessment Center, which organizes and coordinates federal agency monitoring activities during an emergency. DOE manages the Federal Radiological Monitoring and Assessment Center during the emergency phase, and the Environmental Protection Agency (EPA) manages the response during the recovery phase once the emergency is terminated. EPA monitoring teams provide support during both the emergency and recovery phases of an emergency. Other DOE teams are available to respond to major nuclear power plant events, transportation accidents, or terrorism events involving the use of radiological materials, including the Radiological Assistance Program, the Aerial Measuring System, the National Atmospheric Release Advisory Center, and the Radiation Emergency Assistance Center/Training Site. For incidents involving a nuclear weapon, an improvised nuclear device, or a radiological dispersal device, DOE assets such as the Nuclear Emergency Support Team and the Accident Response Group could provide capabilities for weapon or device search, recovery, and removal. The Radiological Triage System harnesses the weapons scientists and engineers at the DOE national laboratories to provide gamma spectroscopy interpretation for agencies responding to an incident. In recent years, National Guard Weapons of Mass Destruction-Civil Support Teams have been created to support state and local response to terrorism events. The Civil Support Teams normally come under direct control of the state and can respond without requiring authorization from the U.S. Department of Defense (DoD). Changes brought about by the events of September 11 also extend to changing federal response policy and planning. Therefore, the Catastrophic Incident Response Annex to the National Response Plan is discussed. DoD also provides specifically designated radiological response capabilities that can be utilized within the guidelines of the National Response Plan. While optimally designed to support military missions, these resources also help provide for a well-equipped set of national assets to temporarily support and augment the local, state, and federal civil agencies that have primary authority and responsibility for domestic disaster assistance. The military's role in domestic emergencies is well defined in military regulations, as well as the national plan.

Nuclear Techniques in National Security Studies on Contraband Detection

The Federal Radiological Monitoring and Assessment Center (FRMAC) is authorized by the Federal Radiological Emergency Response Plan to coordinate all off-site radiological response assistance to state and local governments, in the event of a major radiological emergency in the United States. The FRMAC is established by the U.S. Department of Energy, National Nuclear Security Administration, to coordinate all Federal assets involved in conducting a comprehensive program of radiological environmental monitoring, sampling, radioanalysis, quality assurance, and dose assessment. During an emergency response, the initial analytical data is provided by portable field instrumentation. As incident responders scale up their response based on the seriousness of the incident, local analytical assets and mobile laboratories add additional capability and capacity. During the intermediate phase of the response, data quality objectives and measurement quality objectives are more rigorous. These higher objectives will require the use of larger laboratories, with greater capacity and enhanced capabilities. These labs may be geographically distant from the incident, which will increase sample management challenges. This paper addresses emergency radioanalytical capability and capacity and its utilization during FRMAC operations.

Federal Radiological Monitoring and Assessment Center: The analytical response

A performance comparison of a CdTe and a CdZnTe detector when exposed to uranium samples of various isotopic enrichments has been performed. These high-resolution detectors can assist in the rapid determination of uranium isotopic content of illicit material. Spectra were recorded from these “room temperature' semiconductor detectors with a portable multi-channel analyzer, both in the laboratory and in a field environment. Both detectors were operated below ambient temperature using the vendor supplied thermoelectric coolers. Both detectors had nominally the same active volume (18 mm 3 for the CdZnTe and 25 mm 3 for the CdTe detector) and resolution (i.e., <1.0 keV resolution FWHM at 59.5 keV). Spectra of samples of known isotopic content were recorded at fixed geometries. An evaluation of potential signature g-rays for the detection of enriched uranium was completed. Operational advantages and disadvantages of each detector are discussed.

Development of a Rapidly Deployed Department of Energy Emergency Response Element

The Federal Radiological Emergency Response Plan (FRERP) directs the Department of Energy (DOE) to maintain a viable, timely, and fully documented response option capable of supporting the responsible Lead Federal Agency in the event of a radiological emergency impacting any state or United States territory (e.g., CONUS). In addition, the DOE maintains a response option to support radiological emergencies outside the continental United States (OCONUS). While the OCONUS mission is not governed by the FRERP, this response is operationally similar to that assigned to the DOE by the FRERP The DOE is prepared to alert, activate, and deploy radiological response teams to augment the Radiological Assistance Program and/or local responders. The Radiological Monitoring and Assessment Center (RMAC) is a phased response that integrates with the Federal Radiological Monitoring and Assessment Center (FRMAC) in CONUS environments and represents a stand-alone DOE response for OCONUS environments. The FRMAC/RMAC Phase I was formally "stood up" as an operational element in April 1999. The FRMAC/RMAC Phase II proposed "stand-up" date is midyear 2000.

Federal Radiological Response in the United States

Under the Federal Radiological Emergency Response Plan (FRERP), the Federal Radiological Monitoring and Assessment Center (FRMAC) coordinates all federal off-site radiological assistance to state and local governments in the event of a major radiological emergency in the United States. In response to a major radiological emergency, the FRMAC is established by the US Department of Energy to coordinate all federal assets involved in conducting a comprehensive programme of environmental monitoring, sampling, radioanalysis, quality assurance, and dose assessment. This programme includes: (i) aerial radiological monitoring -fixed-wing and helicopter; (ii) field monitoring and sampling; (iii) radioanalysis mobile and institutional laboratories ; (iv) radiation detection instrumentation calibration and maintenance; (v) environmental dosimetry; and (vi) integrated programme of Quality Assurance. The structure, assets, and operations of the FRMAC programme are discussed.