[en] This paper presents complex studies on establishment of derived emission limits for potential radionuclides emitted as gaseous and liquid effluents, during the decommissioning activities (2nd and 3rd phases) of a nuclear research reactor, cooled and moderated with distilled water, type VVR-S, owned by the IFIN-HH. In the present paper there are described: the analysis methods and equipment used, the methodologies for calculating doses and the Derived Emission Limits (DEL), the experimentally measured activities of the representative radionuclides found in gaseous and liquid effluents resulted from decommissioning activities, as well as the effective derived limits of liquid and gaseous effluents, applying the calculation methodologies, specific to critical categories of exposed subjects. A constraint effective dose limit for a person from the critical group of 50 μSv/year was considered in calculations. From the comparison of the two series of values, measured released activities and DELs, there has been concluded that for the gaseous effluents they comply with the DELs, while in the case of liquid effluents they are higher and consequently they must be treated as liquid radioactive wastes. - Highlights: • The DELs for gaseous and liquid effluents in decommissioning were studied. • The impact on the environment and critical group was assessed. • Gamma-ray spectrometry was used to determine the radionuclide composition. • Based on the dosimetry models, the values of conservative DELs were calculated. • The DELs are compliant for gases, not for liquids; require the treatment as rad-waste

[en] Full text: A decommissioning project is performed on the nuclear facility research reactor WWR-S Magurele-Bucharest to remove the radioactive and hazardous materials to avoid any risk to human health and the environment. The project involves four phases, namely: assessment, development, activity implementation and closeout. There are two major parts of the assesment phase: preliminary characterisation and the review and decision-making process. Characterisation is needed to develop project baseline data, which should include sufficient chemical, physical, and radiological characterisation to meet planning needs. Based on the conclusions of these studies, possible decommissioning alternatives will be considered, the best alternative chosen, final goal identified, risk assessments evaluated, and issues of regulations supporting assessment, land use considerations, financial problems, disposal availability, public involvement, and technology developments will be appropriately solved. After a decommissioning alternative is chosen, detailed engineering will begin following appropriate regulatory guidance. The plan requires characterisation information, namely: review of decommissioning alternatives; justification for the selected alternative; provision for regulatory compliance; predictions of personnel exposure, radioactive waste volume, and cost. Other activities are the following: scheduling, preparation for decommissioning operations, coordination, documentation, characterization, report, feasibility studies, Decommissioning Plan, project report day to day, radiological survey, airborne sampling records, termination survey of the site. Key concerns in operations are worker protection, health and safety program, review of planing work, work area assessment, work area controls, personal protection and monitoring, environmental protection: air quality, surface water, ground water, shipments, effluent sampling and monitoring, environmental monitoring, site release criteria. The final chemical and radiological surveys, as well as a Project Final Report, should be produced in the conclusion of the decommissioning project. Project stages are the following: 1. Documentation: - Urbanism licence from Ilfov Prefecture; - Feasibility study for 16 years and 3 months approved, for green-field stage decommissioning; - Technical documentation for building demolition for obtaining the Permission from Ilfov Prefecture - already obtained in December 2003; - Decommissioning Plan revision 5 - which develop immediate dismantling strategies (16 years and 3 months) - finished in December 2003; - MECT financing 'Technical Project' and 'Execution Documentation' (effected by CITON in 2004); - Decommissioning Plan revision 5 for IAEA Technical Assistance Contract ROM 04/029 2003-2006; 2. Preparing activities for starting the decommissioning process include: Clean-up activities, radiological characterisation, up-grading of storage conditions at nuclear spent fuel by air filtering, maintaining and monitoring of water parameters from water pools nuclear spent fuel storage, work protection and nuclear safety for Nuclear Reactor concerning ANL - USA agreement for September 2003 - September 2005 period with 1 year prolongation, 500 kUSD value. 3. Specific activities in preservation stage of Nuclear Reactor: surveillance, radiological monitoring, maintaining and improvement of nuclear surveillance, improvement of nuclear surveillance of AFR, and finally implementation of CNCAN disposition by license stipulation. (author)

[en] Full text: The superabsorbents obtained by gamma Co-60 processing with swelling capacity from 40g/g to 500g/g have been used in the: 1. land management; 2. toxic and hazardous materials in aqueous state management in emergencies situations; 3. deuterated and tritiated water accidentally spreading in various places. The hydrophilic absorbents obtained from rigid polyurethane reused from wastes have been used in the management of risks when petrol and derived - petroleum materials, all in liquid state, are spread on the soil, surface of water (rivers, lakes, sea etc.) or in work places. The absorbent capacity are min 4g/g and max 10g/g. All absorbents hydrophilic and hydrophobic are in bulk form or in pillows (40x40x10)cm, tubes (Φ = 30 cm (max), Length = 3 m (max)) with fast catching/ detaching systems for emergency situations. For the case of the forest and wood building fires ecological systems based on aqueous polymeric solutions and esters fatty acids have been prepared. (author)

[en] The objective of this work is to determine the amount of metakaolin as a replacement of cement in the recipe of mortars made with recycled concrete in order to obtain good mechanical characteristics. Currently, low-level radioactive waste (LLW) resulted from the decommissioning of nuclear facilities is pre-placed in cylindrical steel containers and solidified with cement mortar prepared with natural aggregates. The mortar matrices that fix the radioactive waste in the container must have optimal properties (good flow ability and no bleeding for fresh mortar and compressive and flexural strength as high as possible for hardened mortar) for the waste package to keep its properties as long as possible. In this study, a type of kaolin from Bulgaria (Senovo, Vetovo and Ruse regions) was heat treated at 700 C for 2 hours to be transformed into metakaolin. The resulted metakaolin was ground in a ball mill for 24 hours and used in the radioactive waste solidification mortar recipe. The experiments were done with mortars in the recipe of which the cement was partially replaced with metakaolin 5 - 30% wt. and fine natural aggregates, respectively. The bleeding of the fresh mortar and the values of compressive and flexural strength of the hardened mortar were measured. The additions in this study, as substitutes for cement in mortars prepared with recycled concrete, have the following effects: the presence of metakaolin eliminates the phenomenon of bleeding from fresh mortars, in the hardened mortar with metakaolin addition the flexural strength of the samples with the addition of 15% wt. metakaolin is close to the compressive strength of the reference mortar samples (8.6 MPa versus to 9.3 MPa), the compressive strength is higher for the sample with the addition of 5% wt. metakaolin versus reference mortar samples (51.9 MPa versus 50.3 MPa), the flexural and compressive strengths for samples with the addition of fine natural aggregates are below the values displayed by the OPC. Mortars with the addition of 5% wt. metakaolin and recycled concrete meet the requirements for compressive strength and can be used to solidify radioactive waste resulted from the decommissioning of RN VVR-S Magurele. (authors)