Ranstad radiological survey 2010-08-15 Karin von Kronhelm
Agenda 1. Background 2. Decommissioning process 3. Measurment programme 4. Results 2010-09-20
Background 2010-09-20
2010-09-20 The site in Ranstad
Service and process buildings within the site 2010-09-20
2010-09-20 Building for milling
2010-09-20 The leaching building
Decommissioning process 2010-09-20
Decommissioning process steps Decommissioning plan Radiological survey, phase 1 • Additional measurements, as needed • Clearance of materials • Clearance of buildings • Other business use alternatively demolition Goal In the long term the facility in Ranstad, including the remaining buildings, could continue to be used and further developed as a small scale, of the district requested, viable industrial area. The area should be adapted to its surroundings and add value to the district. In addition, it provides a natural environment that enables development of rural livelihoods. 2010-09-20
Measurement programme 2010-09-20
Expected nuclide inventory Ranstad – the Swedish uranium mine and processing plant - Natural uranium, shale, with the whole decay chain - Chemically processed uranium with part of the decay chain broken - Uranium contaminated processing waste from nuclear fuel factories 2010-09-20
Risk for radioactive contamination • Risk Examples • Without risk Administration building Garage Mechanical work shop Power station except bottom floor • Small risk Laboratory building Waste water treatment • Risk Milling building Leaching building Ion-exchange building 2010-09-20
Compilation of different parts of the programme Scint i ruta SV101G12 4,50E+01 • Systematical measurements 4,00E+01 3,50E+01 – Floors and walls 3,00E+01 • Smear tests and scintillation measurments Beta (cps) 2,50E+01 – Ventilation 2,00E+01 • Smear tests in the systems 1,50E+01 – Drains 1,00E+01 S3 • Material samples in floor drains and wash basins 1 2 Rad 3 4 5 S1 6 7 8 Kolumn • Scanning of loose equipment and horizontal surfaces – Horizontal surfaces • Smear tests and scintillation instrument – Loose equipment • Smear tests and scintillation instrument • Complementing measurements – Material samples for analysis – Water samples – Radon monitoring – Depth of contamination – Gamma spektrometric measurement/ISOCS – Background level 2010-09-20
Compilation of measured data Systematical measurements – Average for each square cps alfa and cps beta/gamma – Spread between min and max in a square – Loose contamination, alfa och beta – Content • 13 buildings • 510 rooms • 2 748 walls • 434 service systems (ventilation, floor drains, wash basins) • 241 800 scintallation measurements • 8 000 smear test samples 2010-09-20
Compilation of measured data, cont. • Scanning – Peak value cps, alfa and beta/gamma – Loose contamination alfa and beta • Material samples – Nuclide specific activity concentration Bq/g • Gamma spectrometric measurements/ISOCS – Nuclide specific activity kBq/m 2 2010-09-20
2010-09-20 Data management
Results 2010-09-20
Background level • Measurements outside Mätplats Min Max Medel – Within the facility Bakgrund plats 1 6,95 9,65 8,42 Bakgrund plats 2 6,20 9,65 7,02 – Nearby farm • In each building Bakgrundsmätningar i byggnader inom Ranstadsverket. – Influence of the building material Byggnad Min, cps Max, cps Medel, cps • Site specific influences Lakverket 12,00 16,9 14,0 Kontors/laboratoriebyggnaden 8,60 14,8 11,2 – Radon Sovringsverket 13,6 18,3 16,0 – Blue concrete/light concrete NVIA 6,65 10,00 8,0 Ångcentralen 8,25 11,9 10,0 2010-09-20
Administration building/laboratory 2010-09-20
Results from the building for milling, bottom floor 2010-09-20
Depth of contamination Uppmätt aktivitet efter dammsugning, skrapning och slipning i sovringsverket. Rutans id Uppmätt Efter damm- Efter Uppskattat medel sugning/ slipning inträngningsdjup Totalbeta cps skrapning cps mm Totalbeta cps 1–2 SV101G160 25 22 18 SV101G26 19 19 15 1–2 SV101G158* 21 17 SV101G20 38 36 18 1–2 SV101G21 48 28 20 1–2 SV101G157 48 48 20 1–2 SVK3G11 60 60 20 2–3 SV116G12 41 41 21 1–2 SV116G30 23 23 18 1–2 SV116G62 43 40 19 1–2 SV201G10 21 21 16 1–2 SV201G20 29 24 19 1–2 SV301G12 23 23 17 1–2 * Eftersom bakgrundvärde uppmättes redan efter första dammsugningen genomfördes ingen slipning 2010-09-20
Gamma spectrometric nuclide specific results Golv- Golv- Golv- Golv- Golvbrunnar brunnar brunnar/ brunnar brunnar vattenlås SV401 SV111 SV408 SV201, SV101, SV405 SV301 SV406, SV507 SV404, SV205 SV505 Bq/g Bq/g Bq/g Bq/g Bq/g K-40 3,3 E-1 <9,0E-2 4,7 E-1 4,3 E-1 6,0 E-1 Cs-137 7,2 E-2 1,1 E-2 Sönderfallskedja U-238 U-238 2,4 E0 < 8,0 E-1 1,9E0 3,0 E0 <9,9 E-1 Ra-226 5,8 E-1 9,7 E-2 1,3 E0 1,4 E0 1,3 E0 Pb-210 3,8 E-1 8,1 E-1 7,4 E-1 Sönderfallskedja U-235 U-235 9 E-2 <2,3 E-2 9,2 E-2 1,3 E-1 7,2 E-2 Pa-231 <1,5 E-1 <1,9 E-1 <1,7E-1 <2,0 E-1 9,0 E-2 Ac-227 <2,4 E-2 <3,5 E-2 <3,8 E-2 6,1 E-2 4,4 E-2 Sönderfallskedja Th-232 Th-228 1,3 E-2 <9,5 E-3 2,0E-2 2,5 E-2 2,1 E-2 Ra-228 <2,5 E-2 <1,8 E-2 <2,0E-2 2,2 E-2 2,3 E-2 2010-09-20
Summary • With a few exceptions the radioactivity measurements are at background levels or slightly above. The number of hot spots is very limited • The nuclide specific results for material samples from most buildings indicated natural uranium in equilibrium. • The highest activity concentrations were found in the building for the leaching process. • In the building for milling the highest activity was measured in that part of the building were the material had been handled wet. Increased activity concentrations were observed also on old process equipment. • In the building for the leaching process uranium with a broken decay chain was found including low enriched uranium as well as traces of artificial nuclides. • In many of the office and sanitary areas in the different buildings the measurement results were influenced by the presence of blue porous concrete in the building material. • The depth of the contamination is in general very small. Exception could be were cracks have been observed, in porous material and in areas where water could have penetrated the building structures 2010-09-20
2010-09-20
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