API PUBL 7103:1997 pdf download.Management and <Disposal Alternatives for Naturally Occurring Radioactive Material (NORM).Wastes in Oil Production and Gas Plant Equipment
Natural radioactivity occurring at trace concentrations in undergmund formations and in oil and gas production streams occasionally accumulates in surface equipment to exceed background levels. The accumulations are dominated by radium and its decay products in sludges and pipe scales, and by thin lead-210 deposits on interior surfaces of gas plant equipment. Such accumulations of naturally-occurring radioactive materials (NORM) have mainly been noted in recent years, and appropriate methods and alternatives for their disposal are not well characterized. NORM concentrations vary h m predominantly background levels that require no special precautions to elevated levels that occasionally are similar to levels in uranium mili tailings. This report presents radiological analyses of disposal alternatives that will protect against elevated radiation exposures and facilitate cost- effective precautions that are proportionate to any hazards posed by the NORM.
Four waste forms were considered in the safety analyses, including sludges, scales, production equipment, and gas-plant equipment. Sludges were characterized by relatively low radium contents, ranging from background to several hundred picocuries per gram (pcilg), and a moderate radon emanation coefficient of 22%. They also have a moderate leach fraction of io4. Scales were characterized by occasionally higher radium contents, ranging from background to several thousand pCi/g. Their radon emanation coeffiaent is typically low (5961, as is their leach hction (loJ). Production equipment contains residual deposits of sludges or scales with identical radiological properties. Ln options such as burial, however, NORM in equipment cannot be as concentrated or compacted as in the separated scales, and thus it has different exposure properties. Gas-plant equipment contains only the long-lived radon daughters dominated by lead-210, and thus has very Werent radiation, leaching, and exposure risk properties. Lead-210 occurs in extremely thin deposits that are plated onto the inside surfaces of selected gas-plant equipment.
Other disposition alternatives for equipment containing NORM include release for general use, release for re-use within the petroleum industry, storage in an oil-field equipment yard, and release for smelting. General use involves incorporation of pipe with NORM scales in the indoor environment. Reuse in the oii industry is a null alternative, leading only to delayed disposal. Storage involves worker handling and refurbishing of the equipment. Release for smelting involves smelter emissions and incorporation of the NORM into metal consumer products such as fsing pans and piping.