0

Full Content is available to subscribers

Subscribe/Learn More  >

Verification Test of Clearance Automatic Laser Inspection System for Surface Contamination Measurement

[+] Author Affiliations
Michiya Sasaki, Haruyuki Ogino, Takeshi Ichiji, Takatoshi Hattori

Central Research Institute of Electric Power Industry, Komae, Tokyo, Japan

Paper No. ICEM2009-16109, pp. 209-216; 8 pages
doi:10.1115/ICEM2009-16109
From:
  • ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management
  • ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management, Volume 2
  • Liverpool, UK, October 11–15, 2009
  • Conference Sponsors: Nuclear Engineering Division and Environmental Engineering Division
  • ISBN: 978-0-7918-4408-3 | eISBN: 978-0-7918-3865-X
  • Copyright © 2009 by ASME

abstract

Recently, a clearance automatic laser inspection system (CLALIS) has been developed for clearance measurement of scrap metals and concrete debris. It utilizes three-dimensional laser scanning, gamma-ray measurement and Monte Carlo calculation, and its outstanding detection ability has been verified. In Japan, when an object is removed from a radiation-controlled area, the activity level must be lower than the surface contamination density standard of 4 Bq/cm2 for beta and gamma emitters, which is one-tenth of the surface contamination density limit. According to the clearance inspection report published by the Nuclear Safety Commission of Japan, the activity level of waste must be compared with not only the clearance level but also the surface contamination density standard for clearance inspection. To demonstrate that CLALIS can also be used for the measurement of surface contamination, a verification test was carried out using actual metal waste samples of various shapes, sizes and activity levels at Kashiwazaki-Kariwa Nuclear Power Station of Tokyo Electric Power Company. As a result, it was clarified that CLALIS gives a conservative value for surface contamination compared with the conventional GM survey meter measurement. This because the activities of metal waste samples were estimated using the total count rate, a fixed average surface area of 100 cm2 and the conservative source position assumed in the Monte Carlo calculation for the calibration factor. In a nuclear power plant, the actual judgment of whether an object can removed from a radiation-controlled area is based on whether the result of surface contamination measurement is lower than the detection limit, which is significantly lower than 4 Bq/cm2 . According to this criterion, CLALIS provides an almost identical judgment to the GM survey meter, which means that CLALIS can be used as a rational clearance monitor to carry out clearance level and surface contamination inspections in a single radiation measurement. The prospective detection limit for CLALIS at nuclear power plants is also discussed and compared with that for the conventional surface contamination monitors.

Copyright © 2009 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In