1. E n v i r o n m e n t a l s o l u t i o n s f o r t h e e n e r g y i n d u s t r y
Assessment, Treatment and Management of NORM in the Norwegian Oil and Gas Industry
Per Varskog, Norse Decom AS, Norway
Helge Aamlid, Statoil ASA, Norway

2. LSA scale types
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3. LSA scale composition
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4. LSA scale activity
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5. Identification of LSA Scale
Identification of LSA Scale can easily be done in the field using hand-held instruments.
It is developed a method for using the same instruments for quantitative determination and classification of LSA Scale.
The method requires that the 226Ra : 228Ra isotope ratio is known, but if performed correctly the method is reliable within %.
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6. Where to find LSA scale Oil production Gas production
Production tubulars
Christmas trees
Risers
Oil-water separators
Topside tubes before oil-water separation
Water discharge system
Gas production
Anywhere in the system from the risers to the flares
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7. HSE Considerations Offshore Onshore Dose rates rarely above 7.5 µSv/h.
Focus on ”open system” situations:
Pulling of production tubulars.
Maintenance e.g. on separators.
Handling for transport to shore.
Handling for reinjection of waste.
Transport to shore.
Onshore
Classification.
Cleaning of equipment.
Recovery and Storage of LSA Scale.
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8. HSE Measures
Incorporation of LSA Scale procedures in the corporate HSE systems
The procedures include:
Administrative issues.
Identification and classification.
Use of protective equipment.
Controlled Areas.
Conditioning and Transport.
The typical doses to workers may be considered to be low: 0.05 mSv/year and 0.8 mSv/year for offshore and onshore workers, respectively.
The radiation protection measures are almost entirely connected to avoiding internal exposure through inhalation (or digestion).
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9. Waste handling
LSA Scale is handled according to the same principles as all other waste in the industry i.e. in a ”cradle-to-grave” perspective with focus on highest possible degree of reuse and recycling.
Therefore, LSA Scale contaminated equipment is cleaned by high-pressure water jetting facilitating recycling of the component steel and minimisation of the NORM waste.
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10. Decommissioning
LSA Scale contaminated equipment is identified prior to dismantling.
The equipment is thereafter dismantled in a separate waste stream.
After cleaning the equipment is either reused or sent to recycling in a steel smelter.
A decommissioning project is not completed before all waste streams are closed. Currently no proper final storage solution exist for LSA Scale either in Norway or UK.
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11. End solutions for LSA scale
In common terms ”repository” means ”facility for eternal storage (of waste)”.
For a LSA Scale repository eternity is 10 × 1600 years.
A LSA Scale repository should satisfy the following criteria:
The material should be chemically stable.
The repository should withstand weathering.
The repository including the area should have an sustainable owner.
The repository concept must be likely to be accepted by future generations.
3 examples of final storage for LSA scale in Norway and UK :
Storage of 70 tons of LSA scale in KLDRA Himdalen (Norway).
Storage of material from 44 drums from Brent Spar at Drigg.
Storage of unknown amounts of LSA scale in an ”unconstriceted repository” in UK: the bottom sediments of Aberdeen harbour.
If the radioactive substances in LSA scale is utilised, the material is not waste but a resource.
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12. LSA Scale Repository
It has been decided by the Norwegian government that the LSA scale repository is to be located at Sløvåg, Gulen municipality.
The repository will be situated in a rock cavern with a capasity of at least tons of chemically stabilised material.
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13. The Sløvåg Repository Concept
Sea Water
Fresh Water
Ground Water Stream
Repository Tunnel
Fly Ash Repository
Concrete injected rock
Surrounding Rock
Concrete Filled
Concrete containers
HDPE Drums with LSA scale
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14. 238U radioactive decay series
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15. Radium
226Ra is a longlived alpha emitter (half life 1600 years) originating from the 238U series.
228Ra is an beta emitter with a half life of 5.75 years originating from the 232Th series.
Radium is a Group II element. Chemical properties are therefore similar to those of calcium, strontium and barium.
Radium in the oil industry originates as a co-precipitate with Group II elements, usually barium sulphate.
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16. Activity and mass
Original definition of radioactivity : 1 Curie  activity of 1 gram radium 1 Curie = 37 Giga Bequerels (GBq)
Total amount of present LSA scale: 300 tons ~ 7 GBq ~ 0.2 gram radium
Relation to half life: Normal LSA scale isotope ratios: 226Ra : 228Ra = : 1 (activity) 226Ra : 228Ra = 830 : 1 (mass)
Relation to mass: Sulphate scale with 30 Bq/g 226Ra: Mass ratio Ba : Ra = 6  108 Radium content : 2 ppb
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