Status of the WAND (Waste Assay for Nonradioactive Disposal) project as of July 1997

The WAND (Waste Assay for Nonradioactive Disposal) system can scan thought-to-be-clean, low-density waste (mostly paper and plastics) to determine whether the levels of any contaminant radioactivity are low enough to justify their disposal in normal public landfills or similar facilities. Such a screening would allow probably at least half of the large volume of low-density waste now buried at high cost in LANL`s Rad Waste Landfill (Area G at Technical Area 54) to be disposed of elsewhere at a much lower cost. The WAND System consists of a well-shielded bank of six 5-in.-diam. phoswich scintillation detectors; a mechanical conveyor system that carries a 12-in.-wide layer of either shredded material or packets of paper sheets beneath the bank of detectors; the electronics needed to process the outputs of the detectors; and a small computer to control the whole system and to perform the data analysis. WAND system minimum detectable activities (MDAs) for point sources range from {approximately}20 dps for {sup 241}Am to approximately 10 times that value for {sup 239}Pu, with most other nuclides of interest being between those values, depending upon the emission probabilities of the radiations emitted (usually gamma rays and/or x-rays). The system can also detect beta particles that have energies {ge}100 keV, but it is not easy to define an MDA based on beta radiation detection because of the greater absorption of beta particles relative to photons in low Z-materials. The only radioactive nuclides not detectable by the WAND system are pure alpha emitters and very-low-energy beta emitters. At this time, operating procedures and quality assurance procedures are in place and training materials are available to operators. The system is ready to perform useful work; however, it would be both possible and desirable to upgrade the electronic components and the analysis algorithms