Measurement of isotopic uranium in water for compliance monitoring by liquid scintillation counting with alpha/beta discrimination
A simple and inexpensive method is described for analysis of uranium (U) activity and mass in water by liquid scintillation counting using [alpha]/[beta] discrimination. This method appears to offer a solution to the need for an inexpensive protocol for monitoring U activity and mass simultaneously and an alternative to the potential inaccuracy involved when depending on the mass-to-activity conversion factor or activity screen. U is extracted virtually quantitatively into 20 ml extractive scintillator from a 1-[ell] aliquot of water acidified to less than pH 2. After phase separation, the sample is counted for a 20-minute screening count with a minimum detection level of 0.27 pCi [ell][sup [minus]1]. [alpha]-particle emissions from the extracted U are counted with close to 100% efficiency with a Beckman LS6000 LL liquid scintillation counter equipped with pulse-shape discrimination electronics. Samples with activities higher than 10 pCi [ell][sup [minus]1] are recounted for 500-1000 minutes for isotopic analysis. Isotopic analysis uses events that are automatically stored in spectral files and transferred to a computer during assay. The data can be transferred to a commercially available spreadsheet and retrieved for examination or data manipulation. Values for three readily observable spectral features can be rapidly identified by data examination and substituted into a simple formula to obtain [sup 234]U/[sup 238]U ratio for most samples. U mass is calculated by substituting the isotopic ratio value into a simple equation. The utility of this method for the proposed compliance monitoring of U in public drinking water supplies was field tested with a survey of drinking water from Texas supplies that had previously been known to contain elevated levels of gross [alpha] activity. U concentrations in 32 samples from 27 drinking water supplies ranged from 0.26 to 65.5 pCi [ell][sup [minus]1], with seven samples exceeding the proposed Maximum Contaminant Level.
- Research Organization:
- Texas Univ., Houston, TX (United States). School of Public Health
- OSTI ID:
- 6760895
- Country of Publication:
- United States
- Language:
- English
Similar Records
Optimization of screening for radioactivity in urine by liquid scintillation.
Determination of uranium in drinking water using a PERALS spectrometer
Related Subjects
540230* -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
ACTINIDE ISOTOPES
ACTIVITY LEVELS
ALPHA DETECTION
CHARGED PARTICLE DETECTION
COUNTING TECHNIQUES
DETECTION
DRINKING WATER
FEASIBILITY STUDIES
HYDROGEN COMPOUNDS
ISOTOPES
LIQUID SCINTILLATION DETECTORS
MEASURING INSTRUMENTS
MONITORING
OXYGEN COMPOUNDS
RADIATION DETECTION
RADIATION DETECTORS
RADIATION MONITORING
SCINTILLATION COUNTERS
SCINTILLATION COUNTING
URANIUM ISOTOPES
WATER