Filter Media Recommendation Review

The original filter recommended by PNNL for the RASA is somewhat difficult to dissolve and has been discontinued by the manufacturer (3M) because the manufacturing process (substrate blown microfiber, or SBMF) has been superceded by a simpler process (scrim-free blown microfiber, or BMF). Several new potential filters have been evaluated by PNNL and by an independent commercial lab. A superior product has been identified which provides higher trapping efficiency, higher air flow, is easier to dissolve, and is thinner, accommodating more filters per RASA roll. This filter is recommended for all ground-based sampling, and with additional mechanical support, it could be useful for airborne sampling, as well

Representative Atmospheric Plume Development for Elevated Releases

An atmospheric explosion of a low-yield nuclear device will produce a large number of radioactive isotopes, some of which can be measured with airborne detection systems. However, properly equipped aircraft may not arrive in the region where an explosion occurred for a number of hours after the event. Atmospheric conditions will have caused the radioactive plume to move and diffuse before the aircraft arrives. The science behind predicting atmospheric plume movement has advanced enough that the location of the maximum concentrations in the plume can be determined reasonably accurately in real time, or near real time. Given the assumption that an aircraft can follow a plume, this study addresses the amount of atmospheric dilution expected to occur in a representative plume as a function of time past the release event. The approach models atmospheric transport of hypothetical releases from a single location for every day in a year using the publically available HYSPLIT code. The effective dilution factors for the point of maximum concentration in an elevated plume based on a release of a non-decaying, non-depositing tracer can vary by orders of magnitude depending on the day of the release, even for the same number of hours after the release event. However, the median of the dilution factors based on releases for 365 consecutive days at one site follows a power law relationship in time, as shown in Figure S-1. The relationship is good enough to provide a general rule of thumb for estimating typical future dilution factors in a plume starting at the same point. However, the coefficients of the power law function may vary for different release point locations. Radioactive decay causes the effective dilution factors to decrease more quickly with the time past the release event than the dilution factors based on a non-decaying tracer. An analytical expression for the dilution factors of isotopes with different half-lives can be developed given the power law expression for the non-decaying tracer. If the power-law equation for the median dilution factor, Df, based on a non-decaying tracer has the general form Df=a〖×t〗^(-b) for time t after the release event, then the equation has the form Df=e^(-λt)×a×t^(-b) for a radioactive isotope, where λ is the decay constant for the isotope

A General Investigation of Optimized Atmospheric Sample Duration

ABSTRACT The International Monitoring System (IMS) consists of up to 80 aerosol and xenon monitoring systems spaced around the world that have collection systems sensitive enough to detect nuclear releases from underground nuclear tests at great distances (CTBT 1996; CTBTO 2011). Although a few of the IMS radionuclide stations are closer together than 1,000 km (such as the stations in Kuwait and Iran), many of them are 2,000 km or more apart. In the absence of a scientific basis for optimizing the duration of atmospheric sampling, historically scientists used a integration times from 24 hours to 14 days for radionuclides (Thomas et al. 1977). This was entirely adequate in the past because the sources of signals were far away and large, meaning that they were smeared over many days by the time they had travelled 10,000 km. The Fukushima event pointed out the unacceptable delay time (72 hours) between the start of sample acquisition and final data being shipped. A scientific basis for selecting a sample duration time is needed. This report considers plume migration of a nondecaying tracer using archived atmospheric data for 2011 in the HYSPLIT (Draxler and Hess 1998; HYSPLIT 2011) transport model. We present two related results: the temporal duration of the majority of the plume as a function of distance and the behavior of the maximum plume concentration as a function of sample collection duration and distance. The modeled plume behavior can then be combined with external information about sampler design to optimize sample durations in a sampling network

A General Investigation of Optimized Atmospheric Sample Duration

ABSTRACT The International Monitoring System (IMS) consists of up to 80 aerosol and xenon monitoring systems spaced around the world that have collection systems sensitive enough to detect nuclear releases from underground nuclear tests at great distances (CTBT 1996; CTBTO 2011). Although a few of the IMS radionuclide stations are closer together than 1,000 km (such as the stations in Kuwait and Iran), many of them are 2,000 km or more apart. In the absence of a scientific basis for optimizing the duration of atmospheric sampling, historically scientists used a integration times from 24 hours to 14 days for radionuclides (Thomas et al. 1977). This was entirely adequate in the past because the sources of signals were far away and large, meaning that they were smeared over many days by the time they had travelled 10,000 km. The Fukushima event pointed out the unacceptable delay time (72 hours) between the start of sample acquisition and final data being shipped. A scientific basis for selecting a sample duration time is needed. This report considers plume migration of a nondecaying tracer using archived atmospheric data for 2011 in the HYSPLIT (Draxler and Hess 1998; HYSPLIT 2011) transport model. We present two related results: the temporal duration of the majority of the plume as a function of distance and the behavior of the maximum plume concentration as a function of sample collection duration and distance. The modeled plume behavior can then be combined with external information about sampler design to optimize sample durations in a sampling network

Siting the International Linear Collider at Hanford

Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facility

Siting the International Linear Collider at Hanford

Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facility

The science case for 37Ar as a monitor for underground nuclear explosions

A new calculation of the production of 37Ar from nuclear explosion neutron interactions on 40Ca in a suite of common sub-surface materials (rock, etc) is presented. Even in mineral structures that are relatively low in Ca, the resulting 37Ar signature is large enough for detection in cases of venting or gaseous diffusion driven by barometric pumping. Field and laboratory detection strategies and projected sensitivities are presented

A Discussion of Procedures and Equipment for the Comprehensive Test Ban Treaty On-Site Inspection Environmental Sampling and Analysis

This paper is intended to serve as a scientific basis to start discussions of the available environmental sampling techniques and equipment that have been used in the past that could be considered for use within the context of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) on-site inspections (OSI). This work contains information on the techniques, equipment, costs, and some operational procedures associated with environmental sampling that have actually been used in the past by the United States for the detection of nuclear explosions. This paper also includes a discussion of issues, recommendations, and questions needing further study within the context of the sampling and analysis of aquatic materials, atmospheric gases, atmospheric particulates, vegetation, sediments and soils, fauna, and drill-back materials

A Discussion of Procedures and Equipment for the Comprehensive Test Ban Treaty On-Site Inspection Environmental Sampling and Analysis

This paper is intended to serve as a scientific basis to start discussions of the available environmental sampling techniques and equipment that have been used in the past that could be considered for use within the context of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) on-site inspections (OSI). This work contains information on the techniques, equipment, costs, and some operational procedures associated with environmental sampling that have actually been used in the past by the United States for the detection of nuclear explosions. This paper also includes a discussion of issues, recommendations, and questions needing further study within the context of the sampling and analysis of aquatic materials, atmospheric gases, atmospheric particulates, vegetation, sediments and soils, fauna, and drill-back materials