[en] This paper demonstrates the development and usage of the devices designed for non- destructive radiological characterization of radioactive waste. All ..systems are based on gamma-spectrometry and are divided into two categories - stable and mobile. Stable ones involve only measurement in fixed detector - package configuration. They are used for assessment of packaged waste, mainly in drums. Mobile ones are flexible and allow measurement of a wide range of objects from various positions and can be also transported to arbitrary location. The calibration of such systems is performed by means of appropriate software which allows computation of full-energy peak efficiency in various configurations. (authors)

[en] This study validates two methods used for full-energy peak efficiency calibration of a device developed by ENVINET a.s. The device is based on gamma spectrometry. The device is designed to determine activity in a drum with radioactive waste in various matrices. The full-energy peak efficiency is the ratio between the number of counts detected in net peak area to the number of photons of given energy emitted from the drum. The calibration has to be performed for various types of matrices and for homogeneously distributed activity in the volume. A special drum which allows validation of calibration methods described in section B was developed. The first method is based on Monte Carlo simulation of the whole system. The second method is called shell-method and is based on line source which is placed to various positions in the drum which is rotated during the acquisition. The summed spectrum from all positions is used for calibration so that the detector sees activity as homogeneously spread in a volume. (authors)

[en] This study validates two methods used for full-energy peak efficiency calibration of a device developed by ENVINET a.s. The device is based on gamma spectrometry. The device is designed to determine activity in a drum with radioactive waste in various matrices. The full-energy peak efficiency is the ratio between the number of counts detected in net peak area to the number of photons of given energy emitted from the drum. The calibration has to be performed for various types of matrices and for homogeneously distributed activity in the volume. A special drum which allows validation of calibration methods described in section B was developed. The first method is based on Monte Carlo simulation of the whole system. The second method is called shell-method and is based on line source which is placed to various positions in the drum which is rotated during the acquisition. The summed spectrum from all positions is used for calibration so that the detector sees activity as homogeneously spread in a volume. (authors)

[en] Safeguards by design is a complex step-by-step interactive decision process involving various stake-holders and design choices to be made over a certain period of time. The resulting plant design should be a compromise among economical, safety, security and safeguards implementation constraints. Access to technology and equipment, as well as to the nuclear fuel cycle, determines the basic choices that the designer has to make. Once the boundary conditions for a given facility have been fixed, the designer still faces the challenge of setting several design and operational parameters that will require various trade-offs . Concerning safeguards, these can be seen in three groups, i.e. those related to the general design and its intrinsic proliferation resistance; those related to the specific lay-out and planning; those related to the actual safeguards instrumentation, its effectiveness and efficiency. The paper aims at describing a model for a phased, or 'layered' approach to safeguards-by-design, focusing on the example of off-load reactors.