The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

Abstract

Portions of this document 1118y be illegible in electronic image productsL fmaos are produced from the best available original dOCUXtlent FOREWORDThe purpose of the New Mexico Environmental Evaluation Group (EEG) is to conduct an independent technical evaluation of the Waste Isolation Pilot Plant (WIPP) Project to ensure the protection of the public health and safety and the environment. The WIPP Project, located in southeastern New Mexico, is being constructed as a repository for the disposal of transuranic (TRU) radioactive wastes generated by the national defense programs. The EEG was established in 1978 with funds provided by the U.S. Department of Energy (DOE) to the State of New Mexico. Public Law 100-456, the National Defense Authorization Act, Fiscal Year 1989, Section 1433, assigned EEG to the New Mexico Institute of Mining and Technology and conhued the original contract DE-AC04-79AL10752 through DOE contract DE-AC04-89AL58309. The National Defense Authorization Act for Fiscal Year 1994, Public Law 103-160, continues the authorization.EEG performs independent technical analyses of the suitability of the proposed site; the design of the repository, its planned operation, and its long-term integrity; suitability and safety of the transportation systems; suitability of the Waste Acceptance Criteria and the generator sites' compliance with them; and related subjects. These analyses include assessments of reports issued by the DOE and its contractors, other federal agencies and organizations, as they relate to the potential health, safety and environmental impacts from WIPP. Another important function of EEG is the independent environmental monitoring of background radioactivity in air, water, and soil, both on-site and off-site. EXECUTIVE SUMMARYAlpha continuous air monitors (CAMs) will be used at the Waste Isolation Pilot Plant (WIPP) to measure airborne transuranic radioactivity that might be present in air exhaust or in work-place areas. WIPP CAMs are important to health and safety because they are used to alert workers to airborne radioactivity, to actuate air-effluent filtration systems, and to detect airborne radioactivity so that the radioactivity can be confined in a limited area.In 1993, the Environmental Evaluation Group (EEG) reported that CAM operational performance was affected by salt aerosol, and subsequently, the WIPP CAM design and usage were modified. In this report, operational data and current theories on aerosol collection were reviewed to determine CAM quantitative performance limitations. Since 1993, the overall CAM performance appears to have improved, but anomalous alpha spectra are present when samplingfilter salt deposits are at normal to high levels.This report shows that sampling-filter salt deposits directly affect radon-thoron daughter alpha spectra and overall monitor efficiency. Previously it was assumed that aerosol was mechanically collected on the surface of CAM sampling filters, but this review suggests that electrostatic and other particle collection me...

Use of Alpha Spectroscopy for Conducting Rapid Surveys of Transuranic Activity on Air Sample Filters and Smears

“…here utilized air filters taken from relatively low airborne dust environments. If filter loading were to become so egregious that the spectral shape from the alpha spectrometry were substantially distorted, all TRU estimates would become biased in a spectrally dependent way (Bartlett and Walker 1996). One way to avoid the occurrence of obtaining biased TRU estimates would be to use the previously established spectral quality requirements for the algorithm developed by Bartlett (1993).…”

Impact of the Coarse Indoor Non-radioactive Aerosols on the Background Radon Progenies’ Compensation of a Continuous Air Monitor

“…On the other hand, mass measurements show a large amount of collected non-radioactive aerosols. Experiments have been conducted by several authors to appreciate the effect of the aerosol mass deposit on the nuclear measurement (Bartlett and Walker 1996; Geryes and Monsanglant-Louvet 2011; Hogue et al 2018; Hoover and Newton 1998; Huang et al 2002; Moore et al 1993; Seiler et al 1988). The experiments showed the influence of the amount of material on the nuclear, especially alpha, measurement, which is significantly degraded, and the result given by the CAM got worse with the aerosol mass accumulation on the sampling filter.…”