A New Seismic Data System for Determining Nuclear Test Yields At the Nevada Test Site

Characterizing and managing groundwater contamination associated with the 828 underground nuclear tests conducted at the Nevada Test Site are among the most challenging environmental remediation issues faced by the U.S. Department of Energy. Although significant long-term stewardship and risk management issues are associated with underground nuclear tests on the Nevada Test Site, of possible equal concern are a smaller number of underground nuclear tests conducted by the United States, 12 total, at eight sites located off the Nevada Test Site. In comparison to the Nevada Test Site, the U.S. Department of Energy has minimal institutional controls at these “offsite test areas” (Offsites) to serve as risk barriers. The corrective action and closure strategy under development for the Central Nevada Test Area and proposed recommendations [1] concerning long-term stewardship for this and the other Offsites illustrate long-term stewardship and risk management strategies applicable to underground nuclear test areas in the United States. The groundwater flow and transport model for the Central Nevada Test Area, site of the 1968 Faultless underground nuclear test, is the first model accepted by a U.S. state regulator (the Nevada Division of Environmental Protection) for an underground nuclear test area. Recommendations for the Central Nevada Test Area and other Offsites include developing decision support models to evaluate the impacts of future changes of land and water uses on previous decisions involving groundwater-use restrictions. Particularly for the Offsites in arid states such as Nevada, New Mexico, and Colorado, it is difficult to envision all future demands on subsurface resources. Rather than trying to maintain complex flow and transport models to evaluate future resource-use scenarios, decision support models coupled with original contaminant flow and transport models could be used as scoping tools to evaluate the sensitivity of previously established resource-use boundaries. This evaluation will determine if the previously established boundaries are still adequate for proposed new land and resource uses or if additional data collection or modeling will be necessary to make technically sound decisions. In addition, previously developed Data Decision Analyses, used to quantitatively evaluate the costs and benefits of different data collection activities conducted during the site characterization phase, could be maintained as a long-term stewardship tool to identify new data collection efforts, if necessary as indicated by a decision support model.

Evaluation of the Transient Hydrologic Source Term for the Cambric Underground Nuclear Test at Frenchman Flat, Nevada test Site

10.2172/907859 ◽

2006 ◽

Cited By ~ 1

Author(s):

S Carle ◽

R Maxwell ◽

G Pawloski ◽

D Shumaker ◽

A Tompson ◽

...

Keyword(s):

Source Term ◽

Test Site ◽

Nuclear Test ◽

Nevada Test Site

Recovery and Calibration of Legacy Underground Nuclear Test Seismic Data from the Leo Brady Seismic Network

Seismological Research Letters ◽

10.1785/0220190341 ◽

2020 ◽

Vol 91 (3) ◽

pp. 1488-1499 ◽

Cited By ~ 2

Author(s):

Brian A. Young ◽

Robert E. Abbott

Keyword(s):

United States ◽

Seismic Data ◽

Test Site ◽

The United States ◽

Seismic Network ◽

Nevada Test Site ◽

Data Format ◽

Weight Lift ◽

Poles And Zeros ◽

Full Waveforms

Abstract The Leo Brady Seismic Network (LBSN, originally the Sandia Seismic Network) was established in 1960 by Sandia National Laboratories to monitor underground nuclear tests (UGTs) at the Nevada National Security Site (NNSS, formerly named the Nevada Test Site). The LBSN has been in various configurations throughout its existence, but it has generally been comprised of four to six stations at regional distances (∼150–400 km) from the NNSS with approximately evenly spaced azimuthal coverage. Between 1962 and the end of nuclear testing in 1992, the LBSN—and a sister network operated by Lawrence Livermore National Laboratories—was the most comprehensive United States source of regional seismic data of UGTs. Approximately 75% of all UGTs performed by the United States occurred in the predigital era. At that time, LBSN data were transmitted as frequency-modulated (FM) audio over telephone lines to a central location and recorded as analog waveforms on high-fidelity magnetic audio tapes. These tapes have been in dry temperature-stable storage for decades and contain the sole record of this irreplaceable data; full waveforms of LBSN-recorded UGTs from this era were not routinely digitized or otherwise published. We have developed a process to recover and calibrate data from these tapes. First, we play back and digitize the tapes as audio. Next, we demodulate the FM “audio” into individual waveforms. We then estimate the various instrument constants through careful measurement of “weight-lift” tests performed prior to each UGT on each instrument. Finally, these coefficients allow us to scale and shape the derived instrument response of the seismographs and compute poles and zeros. The result of this process is a digital record of the recorded seismic ground motion in a modern data format, stored in a searchable database. To date, we have digitized tapes from 592 UGTs.

Sorption--desorption studies of Nevada Test Site alluvium and leaching studies of nuclear test debris

10.2172/6791117 ◽

1978 ◽

Cited By ~ 4

Author(s):

K Wolfsberg

Keyword(s):

Test Site ◽

Nuclear Test ◽

Nevada Test Site