STAR Facility Tritium Accountancy

The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed

Radiometric techniques for the detection and assessment of tritium in aqueous media - a review

Tritium (3H) is one of the hardest isotopes to detect by most traditional radiometric means due to the low energy of the β− emission, (β−MEAN 5.67 keV, β−MAX 18.59 keV). The high mobility of the isotope in groundwater environments and subsequent entry into the food chain constitutes a radiation safety risk justifying assessment. Accordingly, there is a need to measure 3H accurately and efficiently, often in low concentrations, both in laboratory settings and on-line flow-cells for potential in situ measurement requirements. This review covers technologies developed to assess aqueous tritium-containing samples. Of the techniques reviewed, liquid scintillation counting (LSC) is the best performing means of aqueous 3H detection with a minimal detectable activity of 6 × 10−4 Bq L−1 for a 195-min counting time. LSC is also established as the industry standard and is the basis of the first, commercially-available, real-time 3H detection system. This review also covers the other means described in literature for the detection of tritium in aqueous samples, including the use of plastic and inorganic scintillators, imaging plates, both in off-line and on-line modes of operation. Whilst most of these techniques lag LSC in terms of technological maturity, several offer detection sensitivities that could rival LSC, without the need for the sample preparation and waste generation associated with LSC, and providing real-time in situ measurements

Comparatioions of two methods for HPGe detector efficiency calibration for charcoal canister radon measurement

The charcoal canister method of radon concentration estimation according to US EPA protocol 520/5-87-005, is the most widely used method of screening. This method is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. For the purpose of gamma spectrometry, appropriate efficiency calibration of the measuring system must be performed. The most usual method of calibration is using standard canister, a sealed canister with the same matrix and geometry as the canisters used for measurements, but with the known activity of radon. In absence of standard canister, a different method of efficiency calibration has to be implemented. This paper presents the results of efficiency calibration using EFTRAN efficiency transfer software. Efficiency was calculated using soil matrix cylindrical secondary reference material as a starting point. Calculated efficiency is then compared to the one obtained using standard canister and applied to a realistic measurement in order to evaluate the results of the efficiency transfer.2nd International Conference on Radiation and Applications in Various Fields of Research (RAD), May 27-30, Niš, 2014

A New 76Ge Double Beta Decay Experiment at LNGS

This Letter of Intent has been submitted to the Scientific Committee of the INFN Laboratori Nazionali del Gran Sasso (LNGS) in March 2004. It describes a novel facility at the LNGS to study the double beta decay of 76Ge using an (optionally active) cryogenic fluid shield. The setup will allow to scrutinize with high significance on a short time scale the current evidence for neutrinoless double beta decay of 76Ge using the existing 76Ge diodes from the previous Heidelberg-Moscow and IGEX experiments. An increase in the lifetime limit can be achieved by adding more enriched detectors, remaining thereby background-free up to a few 100 kg-years of exposure.Comment: 67 pages, 19 eps figures, 17 tables, gzipped tar fil

Sensitivity of standard and stacked RADFET dosimeters

Radiation Sensing Field Effect Transistors (RADFETs), also known as MOSFET dosimeters, are discrete p-channel MOSFETs with the gate oxide engineered for increased radiation sensitivity. RADFETs are small, require very little or no power during operation, read-out is simple and non-destructive, and their electronic signal is suitable for integration with the electronics systems. For these reasons RADFETs have found applications in quality assurance of radiotherapy, dose monitoring in high energy physics laboratories, accidental personal dosimetry, and space. Lower dose applications, such as e.g. occupational personal dosimetry and radiology, are currently out of reach owing to inherent sensitivity limits of the standard RADFET technology. Tyndall National Institute has been involved in RADFET research and development, fabrication, and commercialisation for several decades and has acquired significant experience in the technology and applications. This paper presents Tyndall recent efforts in RADFET manufacturing and characterisation for different applications and discusses possible approaches towards increased sensitivity of the technology, including standard and stacked RADFETs.Fourth International Conferenceon Radiation and Applications in Various Fields of Research, RAD 2016, May 23-27, 2016, Niš, Serbi