NORM in Norway [ENG]

[a story apparently paradoxical of “nuclear repositories” in a “100% renewable” Country]

This article was originally published in Italian on the 7th of July, 2015.

Electricity production in Norway is almost 100% renewable: about 97% is hydropower, the rest comes from natural gas (just under 2%) and wind (just over 1%), “a little bit” from biomass and waste incineration; “traces” of production from solar, coal and oil are also present.

So there are no nuclear power plants in Norway. There has been a few discussions in recent years, chasing some innovative ideas based on the use of thorium; but for now, everything is silent – or rather, it is on the paper at proposal level. There are, instead, two research reactors still operating, the heavy water boiling reactor (HBWR) at Halden and the JEEP II at Kjeller; while two other are “retired” since long time, JEEP I and NORA. (As a mere curiosity the “retired” JEEP I coming into operation in 1951 was the first reactor operating in Europe, outside the borders of Great Britain and France, and the Soviet bloc.)

As in virtually all developed countries, nuclear technology finds application in Norway also in the medical field (e.g. radio-diagnostic and radio-pharmacology) and in the industrial field (e.g. NDT, and the treatment and storage of radioactive waste). Monitoring of all these activities is in accordance with international regulations and it is up to Statens strålevern, namely the Norwegian Radio Protection Authority (NRPA).

Fig.1On the left, the map of the main "workplaces" of NRPA. On the right, top, pit storage of spent fuel from JEEP II at Kjeller; bottom, again at Kjeller, spent fuel storage of the two "retired" reactors, JEEP I and NORA. At Halden's site spent fuel is stored in the same reactor building. — Fig.1 On the left, the map of the main “workplaces” of NRPA. On the right, top, pit storage of spent fuel from JEEP II at Kjeller; bottom, again at Kjeller, spent fuel storage of the two “retired” reactors, JEEP I and NORA. At Halden’s site spent fuel is stored in the same reactor building.

In January 2011 IFE’s inventory [1] recorded a total of some 18 tons of irradiated material (inclusive of the fuel inside the reactors still operating) – a volume easy to manage, even taking into account concrete and various structures with which this fuel is “packed”; since, for example, the density of U²³⁸ metallic is about 19 t/m³.

Thus, it would appear that there is not a lot of work for the NRPA. Actually, in Norway radioactive wastes offer volumes far more interesting, soon as you move from the storage of spent nuclear fuel to that of Naturally-Occurring Radioactive Materials (NORM).

Although, in fact, it does not use large amounts of oil for electricity generation, Norway is one of the largest oil producers in the world (just under 3% of the total, in 2013). And oil extraction – like any other mining activity, refining or processing of raw materials – involves a variety of by-products, some of which are radioactive, as they contain radioisotopes that abound in the Earth’s crust [2]. Natural gas extraction is going great too; indeed, in many respects even better than oil: before the European embargo to Russia, Norway was the second largest supplier of natural gas to the EU [3].

Fig. 2“Natural radioisotopes”. Thorium and Uranium series: starting from Th232 and U238 two distinct decay chains generate in Nature two series of radioactive elements. These radionuclides are concentrated in different ways in the different materials constituting the Earth's crust. — Fig. 2 “Natural radioisotopes”. Thorium and Uranium series: starting from Th232 and U238 two distinct decay chains generate in Nature two series of radioactive elements. These radionuclides are concentrated in different ways in the different materials constituting the Earth’s crust.

Since January 1st, 2011, a new regulation is in force for which the treatment and management of radioactive waste – as well as monitoring and contrast to radioactive pollution – are under the same regulatory framework of all other pollutants and hazardous waste (cf. Pollution Control Act, 1981). The regulation provides, among other things, two sets of criteria that define radioactive waste: for example, all the wastes containing ≥ 1 Bq/g by source Ra²²⁶ have to be considered as radioactive, whereas only radioactive wastes containing ≥ 10 Bq/g by source Ra²²⁶ have to be disposed of in a repository equipped for the purpose, and definitively stored. All wastes with levels of radioactivity between 1 and 10 Bq/g (from Ra²²⁶) can be handled and disposed by any company that owns a license for the management of hazardous wastes. Management of other radioactive wastes requires a license issued ad hoc by the NRPA.

The largest quantity of wastes containing naturally occurring radioactive isotopes (NORM) and with activity levels from Ra226 ≥ 10 Bq/g comes from the Oil&Gas industry. Therefore, all this material, properly treated, shall flow into a final repository.

Fig. 3“He who seeks finds”. A small photo gallery showing some places where NORMs usually lurk and concentrate in the various phases that characterize oil and gas extraction. — Fig. 3 “He who seeks finds”. A small photo gallery showing some places where NORMs usually lurk and concentrate in the various phases that characterize oil and gas extraction.

Dates back to 1981 the discovery of levels of radioactivity “out of the norm” (i.e. average values above those expected for the natural background) in deposits (scale, sands and sludge) of by-products from North Sea oil and natural gas production. The specific activity of the solid dry material varies from the natural radioactive background level to several hundreds of Bq/g (from Ra²²⁶ and Ra²²⁸) [4]. For workers involved in the different operations of handling and treatment/cleaning of equipment or contaminated waste the doses are usually very low (maximum estimated value: 0.2 mSv/year) – well below the standard limit of dose for exposed workers (20 mSv/year). The main problem is the disposal of this type of radioactive waste, considering the amount of surfaces to be cleaned, and harvesting and treating of waste (i.e. moderate levels of radioactivity, but large quantities to be disposed of).

Tab. 1In Oil & Gas industry, NORM are categorized according to the type of scale/slag. This is due to the fact that during extraction activities NORM wastes originate from particular compounds (e.g. Ra226 tends mainly to concentrate in barium sulfate or calcium carbonate, Pb210 in steel, etc.). — Tab. 1 In Oil & Gas industry, NORM are categorized according to the type of scale/slag. This is due to the fact that during extraction activities NORM wastes originate from particular compounds (e.g. Ra226 tends mainly to concentrate in barium sulfate or calcium carbonate, Pb210 in steel, etc.).

Fig. 4 Some other details on scales, sludge, various deposits, decontamination and disposal of NORM in the Norwegian Oil&Gas production chain. Industry insiders often name such kind of NORM Low Specific Activity Scale (abbreviated: LSA Scale).

Since 2008, Norway features a storage place ready to receive the large amounts of NORM wastes coming from the Oil&Gas industry, both domestic and European (for some detail see Fig. 5 and 6, and their captions). The repository is located in Sløvågen, Gulen, Sogn og Fjordane county, at Stangeneset industrial site, and currently is able to contain little more than 7000 tons of NORM wastes, suitably and definitively stored. However, according to most estimates, the amount of wastes will increase significantly in the future due to the decommissioning of offshore facilities.

Fig. 5Sløvågen, Gulen, Sogn og Fjordane county, Norway. Final repository for NORM wastes from Oil&Gas industry at the Stangeneset industrial site. Disposal has being operating since 2008. 600 tons of wastes were stoked by 2011, out of a total capacity of 7000 tons. The stocking rate is about 50 tons/year at present day. The repository is designed to receive all the NORM wastes from whole Europe that are destined to final repository. — Fig. 5 Sløvågen, Gulen, Sogn og Fjordane county, Norway. Final repository for NORM wastes from Oil&Gas industry at the Stangeneset industrial site. Disposal has being operating since 2008. 600 tons of wastes were stoked by 2011, out of a total capacity of 7000 tons. The stocking rate is about 50 tons/year at present day. The repository is designed to receive all the NORM wastes from whole Europe that are destined to final repository.

Fig. 6Receiving, moving and stocking of materials at Gulen repository. — Fig. 6 Receiving, moving and stocking of materials at Gulen repository.

That’s why while using Gulen’s repository a search for new locations is already going on. Similar problems affect the management of low radioactivity NORM wastes as well.

This is the case of Langøya Island [5], managed by NOAH AS (Norsk Avfallshåndtering AS – literally Norwegian Corporation for waste treatment), which is going toward an environmental restoration.

As can be easily noticed from pictures in Fig. 7, the island doesn’t offer an amazing sight at present, due to the fact that after being used as a quarry for decades (chalk extraction), since 1985 Langøya has been converted to special waste disposal. Most part of it are NORM ashes [6], from manufactury and urban solid waste combustion from Norway, Sweden and Denmark. The island also hosts some facilities devoted to treatment of the waste destined to disposal. One of the core duties of NOAH on the island is in fact to transform the incoming wastes in materials that are environmentally safe for disposal in the quarry. And as far as we understood [7], part of the waste is treated to be recycled as construction material.

Fig. 7“Before the healing”. Langøya Island, in the Oslo fjord, located between Sweden and Norway, is 3 km long and 500 m width at most. Pictures are taken in different years, as can be noticed from some morphological changes. Despite heavy exploitation, vegetation and wildlife persist, encouraging a future restoration of the environment. — Fig. 7 “Before the healing”. Langøya Island, in the Oslo fjord, located between Sweden and Norway, is 3 km long and 500 m width at most. Pictures are taken in different years, as can be noticed from some morphological changes. Despite heavy exploitation, vegetation and wildlife persist, encouraging a future restoration of the environment.

NOAH experts calculated that, given the actual filling rate and the likely future increase, the island will be unusable in 10 years, and they put all the future expectations on the old chalk mines at Brevik (Dalen mines).

Down there a new disposal for high radioactive NORM wastes could see the light.

However, as reported by media, local population doesn’t like the idea so far. Still a lot of work ahead, and few time, to win the resistance of the public opinion with the right argumentations, that means with feasible benefits for the local communities.

Fig. 8“After the healing”. How NOAH experts envisage their island in the future, once the disposal will be closed and the environmental restoration completed. — Fig. 8 “After the healing”. How NOAH experts envisage their island in the future, once the disposal will be closed and the environmental restoration completed.

Notes:

[1] Institute for Energy Technology. Source: Strålevern Rapport – Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management.

[2] Besides those already mentioned, other industries producing NORM wastes are: coal burning, metallurgy, Rare Earths manufactory, fertilizers production, construction materials production, recycle. Thus the acronym TENORM (Technologically Enhanced NORM) is often used to identify those material whose radioactivity is augmented due to higher concentration of radionuclides resulting from transformation and industrial processing. NORM wastes result from non-industrial sectors too: Radon exposition in residential sector, commercial flights, etc. For more details, please have a look at what reported by WNA here.

[3] Concerning oil extraction it seems the peak was reached in Norway in 2001. Natural gas has still good perspectives. More details here and here.

[4] Based on samples from solid deposits and scales (see Fig. 4), collected from Norwegian offshore platforms, the average value of radioactivity concentration (from Ra²²⁶ and Ra²²⁸) is close to 25 Bq/g: results range from few Bq/g to few hundreds of Bq/g – to be noticed that the upper limit of the range is still significantly smaller of values reported in other studies concerning offshore platforms in the USA (e.g. 3700 Bq/g) and onshore extraction in Syria (e.g. 1000 Bq/g).

In the following few notes about the most cited radionuclides in this article:

Ra²²⁶ has half-life of 1600 years, it’s an alpha emitter from the U²³⁸ series (see Fig. 2);
Ra²²⁸has half-life of 5.75 years, it’s a beta emitter from the Th²³² series;
a generic measure of the radioactivity of a certain material doesn’t give any information about the radio-toxicity of the material itself (e.g. a barium sulfate scale can present 23 MBq/t as a sum of the specific activity of all the radionuclides that it contains). However when the activity of the Radio is monitored a precautionary/conservative approach is assumed, being Radio’s radionuclides the most active in nature (shortest half-life), the most diffused and with the most dangerous emissions in case of food chain contamination and/or prolonged exposure.

[5] Island located in the Re Municipality, Oslofjord, Norway – not to be confused with the homonym island located in the Tjøme Municipality, and neither with the other homonym but bigger island in the Vesterålen archipelago.

[6] Fly ash, is a by-product of coal combustion in thermoelectric power plants and falls in the NORM category, but with radioactivity levels from Ra²²⁶ lower than 10 Bq/g.

[7] Most of the information we found on this topic were in Norwegian.

Main sources:

Astrid Liland, NRPA, “Advances in NORM Management in Norway and the Application of the ICRP Publication 103 Recommendations”. First ICRP Symposium, 24-26 October 2011, Bethesda, USA.

Liland A. et al., “Advances in NORM management in Norway and the application of ICRP’s 2007 recommendations”, 2012 Oct-Dec; 41(3-4):332-42. doi: 10.1016/j.icrp.2012.06.021. Epub 2012 Aug 22.

Cowie M. et al., “NORM management in the oil and gas industry”, 2012 Oct-Dec; 41(3-4):318-31. doi: 10.1016/j.icrp.2012.06.008. Epub 2012 Aug 22.

Per Varskog, Norse Decom AS, “Exposure to radiation in an underground NORM repository”. Dresden, 2010.

Per Varskog, Norse Decom AS, “Norway’s disposal site for oil industry NORM”.

Strand T., “NORM in the Norwegian Oil and Gas Industry – Activity Levels, Occupational Doses and Protective Measures”.

Weers A.W. et al., “Current Practice of Dealing with Natural Radioactivity from Oil and Gas Production in EU Member States”. Report EUR 17621, Directorate-General Environment, Nuclear Safety and Civil Protection, European Commission, Luxembourg (1997).

Strand T. et al., “Deposits of Naturally Occurring Radioactivity in the Production of Oil and Natural Gas”. Norwegian Radiation Protection Authority Report 1997:1, p. 136 (1997).

MacArthur A., “Development and Operation of a NORM Processing and Disposal Facility for the U.S. Oil and Gas Industry”. 19^thAnnual National Conference on Radiation Control, May 18-21, 1987, Boise, Idaho, USA. Conference on Radiation Control Program Directors, CRCPD Publ. 88-2, Frankfort, KY, USA, 1988.

Al-Masri M.S., Suman H., “NORM Waste Management in the Oil and Gas Industry: the Syrian Experience”. J. Radioanalytical and Nuclear Chemistry 256(1): 159-162, 2003.