Groundwater Monitoring and Control Before Decommissioning of the Research Reactor VVR-S from Magurele-Bucharest
- National Institute of Physics and Nuclear Engineering-Horia Hulubei - IFIN-HH, Bucharest-Magurele, Romania, POBox MG-6, 077125, Ilfov (Romania)
The research reactor type VVR-S (tank type, water is cooler, moderator and reflector, thermal power- 2 MW, thermal energy- 9. 52 GW d) was put into service in July 1957 and, in December 1997 was shout down. In 2002, Romanian Government decided to put the research reactor in the permanent shut-down in order to start the decommissioning. This nuclear facility was used in nuclear research and radioisotope production for 40 years, without events, incidents or accidents. Within the same site, in the immediate vicinity of the research reactor, there are many other nuclear facilities: Radioactive Waste Treatment Plant, Tandem Van der Graaf heavy ions accelerator, Cyclotron, Industrial Irradiator, Radioisotope Production Center. The objectives of this work were dedicated on the water underground analyses described in the following context: - presentation of the approaches in planning the number of drillings, vertical soil profiles (characteristics, analyses, direction of the flow of underground water, uncertainties in measurements); - presentation of the instrumentation used in analyses of water, soil and vegetation samples - analyses and final conclusions on results of the measurements; - comparison of the results of measurements on underground water from drillings with the measurements results on samples from the town and the system of drinking water - supplied from the second level of underground water. According to the analysis, in general, no values higher than the Minimum Detectable Activity were detected in water samples (MDA) for Pb{sup 212}, Bi{sup 214}, Pb{sup 214}, Ac{sup 228}, but situated under values foreseen in drinking water. Distribution of Uranium As results of the Uranium determination, values higher than 0,004 mg/l (4 ppb) were detected, values that represent the average contents in the underground water. The higher values, 2-3 times higher than background, were detected in the water from the drillings F15, F12, F5, F13, drillings located between RWTP (Radioactive Waste Treatment Plant) - the 300 m{sup 3} tanks and the Spent Filters Storage (SFS). At south of this area, on the leaking direction of the underground water layer, in the drillings F1, F2, F3, F18 and at east, in F6, F7, the natural Uranium values are within the background for the underground-water. Distribution of Radon For the Radon determination with RAD 7 equipment, water samples were taken from the same piezo-metrical drilling, 2 or 4 times during of six months period, and then, the average contents were calculated, which varied between 0,35 - 2,1 Bq/l. The values higher than 1,1 -1,2 Bq/l were detected in the water taken from the drillings located in the northern part (F10, F11) and in the eastern part (F6, F8) of the Institute fences (around of the radioactive waste storage facilities). The concentrations of 0,3 - 0,5 Bq/l are in the underground-water layer 'intercepted' by the piezo-metrical drillings (F1, F2, F3) located near the Nuclear Reactor. Concentration of heavy metals: 0.04-0.08 mg/l Pb in F5, F14, F7, F8 exceeding MCA-Maximum Admissible Concentration (0.01 mg/l) for Pb, and for Zn in F5, F7, F8, F14 are 0.2-0.5 mg/l situated under MCA , and 0.18 mg/l in F18, in accordance with tendency of decreasing of concentration of contaminants. After 50 years of deploying nuclear activities on the site the underground water quality is in very good condition. Taking into consideration the direction of the underground water flow, it results that, only in the area of underground pipe, around of the research reactor and radioactive waste treatment plant, the quality of water is influenced, and remediation actions are not necessary. Based on measurements executed in F18, the water quality is the same with any other part of the region. During the decommissioning of the Research Reactor, the samples from 18 drillings will be analysed monthly, and the contents of the heavy metals, Pb and Zn, will be monitored carefully, together with all the factors: air, soil, vegetation, subsoil, water surface and underground water. A great attention will be paid to the dismantlement of the underground structures, the 30 m{sup 3} tank, that collects all the liquid radioactive waste from the reactor, the pipes that connects this tank to the other two 300 m{sup 3} tanks, from RWTP, the ventilation ducts between the Spent Filters Storage and reactor's stack, in order to prevent contamination of surface and underground water. Engineering Absorbent Barriers will be used both for hydrophilic substances and for hydrophobic substances, tents will be used for preventing the spread of possible contaminants from the pipes and tanks, owing to the precipitation or wind, and the tanks and pipes will be drained to eliminate the spills. Since we are dealing with a multinuclear facility site, the on site and off site Monitoring Program of Institute will be properly upgraded, taking into account the values of the derived emission limit approved by Regulatory Body, before, during and after the completion of the works with impact on underground water. In another work will be presented radiological map of land associated of decommissioning project (on surface, at 0.15 m and 0.30 m in depth of soil) and estimation of migration rate in soil up to ground water level. Applying these measures, taking account of the radiological status at the beginning of the project, will mean savings and a good protection of the environment in completing the decommissioning project.
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, Illinois 60526 (United States)
- OSTI ID:
- 21144213
- Resource Relation:
- Conference: DD and R 2007: ANS Topical Meeting on Decommissioning, Decontamination, and Reutilization 2007, Chattanooga, TN (United States), 16-19 Sep 2007; Other Information: Country of input: France; 4 refs; Related Information: In: Proceedings of the 2007 ANS Topical Meeting on Decommissioning, Decontamination, and Reutilization - DD and R 2007, 336 pages.
- Country of Publication:
- United States
- Language:
- English
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