Rancho Seco
Rancho Seco
December 2000
The Subsurface Multi-spectral Contamination Monitor (SMCM) developed by Shonka Research Associates was used at the Rancho Seco Generating Station to perform a comprehensive survey in support of the partial site release of designated areas of the site outside the Industrial Area. The survey was to support a report to the Nuclear Regulatory Commission (NRC) to determine the boundary of any impacted areas using the criteria of "indistinguishable from background." The purpose of the survey, as conveyed by the Sacramento Municipal Utility District (SMUD) staff, is to support consideration of placement of a gas-fired plant on the Rancho Seco site.
Highlights of the survey include:
- 100% scan of 76 acres (308,000 m2) of land within the Rancho Seco Owner Controlled Area were surveyed in less than 3 weeks time
- All survey areas were verified to be non-impacted with no contamination in excess of background detected
- Over 80,000 gamma spectra were collected and processed during the survey project
- Achievement of sensitivities between one and two orders of magnitude less than the Derived Concentration Guidelines Levels required
- Completed performance tests consisting of repeated grids, grids "salted" with check sources, and a grid intentionally placed in a known contaminated effluent area. These tests verified the capabilities of the system.
Additional measurements were also made inside of the industrial area to provide information about radiological conditions in the vicinity of the Independent Spent Fuel Storage Installation (ISFSI), prior to its loading with spent reactor fuel.
Contact:
John Newey, Sacramento Municipal Utility District (SMUD)
