Ranstad radiological survey 2010-08-15 Karin von Kronhelm Agenda - - PowerPoint PPT Presentation

Ranstad radiological survey

2010-08-15 Karin von Kronhelm

2010-09-20

Agenda

1. Background 2. Decommissioning process 3. Measurment programme 4. Results

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Background

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The site in Ranstad

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Service and process buildings within the site

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Building for milling

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The leaching building

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Decommissioning process

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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.

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Measurement programme

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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

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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

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Compilation of different parts of the programme

• Systematical measurements

– Floors and walls

• Smear tests and scintillation measurments

– Ventilation

• Smear tests in the systems

– Drains

• Material samples in floor drains and wash basins
• 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

1 2 3 4 5 6 7 8 S1 S3 1,00E+01 1,50E+01 2,00E+01 2,50E+01 3,00E+01 3,50E+01 4,00E+01 4,50E+01 Beta (cps) Kolumn Rad

Scint i ruta SV101G12

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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

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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/m2

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Data management

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Results

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Background level

• Measurements outside

– Within the facility – Nearby farm

• In each building

– Influence of the building material

• Site specific influences

– Radon – Blue concrete/light concrete

Bakgrundsmätningar i byggnader inom Ranstadsverket. Byggnad Min, cps Max, cps Medel, cps Lakverket 12,00 16,9 14,0 Kontors/laboratoriebyggnaden 8,60 14,8 11,2 Sovringsverket 13,6 18,3 16,0 NVIA 6,65 10,00 8,0 Ångcentralen 8,25 11,9 10,0

Mätplats Min Max Medel Bakgrund plats 1 6,95 9,65 8,42 Bakgrund plats 2 6,20 9,65 7,02

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Administration building/laboratory

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Results from the building for milling, bottom floor

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Depth of contamination

Uppmätt aktivitet efter dammsugning, skrapning och slipning i sovringsverket.

Rutans id Uppmätt medel Totalbeta cps Efter damm- sugning/ skrapning Totalbeta cps Efter slipning cps Uppskattat inträngningsdjup mm SV101G160 25 22 18 1–2 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

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Gamma spectrometric nuclide specific results

Golv- brunnar Golv- brunnar/ vattenlås Golv- brunnar Golv- brunnar Golvbrunnar SV401 SV111 SV408 SV201, SV301 SV101, SV405 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

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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

• bserved 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

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