Tanker Ships Recycling – Naturally Occurring Radioactive Material
GMS Trader Kiran Thorat highlights – Naturally Occurring Radioactive Material (NORM)
We had an in-depth discussion on hot water washing, de-mucking, gas-freeing operations for cargo and slop tanks of trading tankers.
In addition, Floating Production Storage and Offloading (FPSO) units and Floating Storage and Offloading (FSO) vessels are typically converted from existing tankers, although some are purpose-built in rare cases.
FPSOs are utilized globally in offshore oil fields for hydrocarbon production and processing, as well as crude oil storage. They are anchored to the seabed using various mooring systems, such as turret or spider mooring arrangements. The operational lifespan of an FPSO typically ranges from 20 to 30 years, during which they remain stationed in a fixed location. These vessels are equipped with advanced machinery for the separation and treatment of crude oil, condensate, gas, and water following extraction from the Earth’s crust.
The presence of Naturally Occurring Radioactive Material (NORM) is a potential consideration, depending on the geographical location of the oil field.
International Atomic Energy Agency (IAEA) explains about NORM. Natural resources such as oil and natural gas extracted from the Earth’s crust contains various amounts of natural radioactivity. When these resources are extracted and processed, their natural state can be modified which may result in the enhancement of the natural radioactivity content originally present. Such enhancement can sometimes be high enough to cause harm to the workers and surrounding environment if they are not controlled properly.
World Nuclear Association defines NORM as Radioactive Materials which occur naturally and where human activities increase the exposure of people to ionizing radiation.
NORM is usually present in oilfields located in Middle East, Gulf of Mexico and North Sea. Radioactive isotopes of Uranium – 238, Thorium – 232 and their decay products such as Radium – 226 and Radon – 222 are possibly present in NORM
As explained above there are chances of finding NORM on FPSO vessel’s cargo tanks, slop tanks, piping, and pumping systems. There is possibility of accumulating / scaling up of NORM at various locations, such as production tubulars, wellheads, separator vessels, Gas treatment tanks and other processing machinery. NORM can accumulate in the form of scale and sludge. And if it is not handled properly as per guidelines of IAEA and local authorities then it will certainly affect tank cleaning staff, ship’s staff, and yard workers.
It is very critical to appropriately deal with the NORM when FPSOs are brought for recycling. Ship recycling yards in Indian sub-continent don’t have adequate infrastructure to control NORM contaminated equipment and facility for NORM waste handling and disposal. Therefore, Ship Recycling Facility Plan (SRFP) clearly mentions that any vessel which will be recycled in yards should be brought to the yard NORM free.
It is the shipowner’s responsibility to ensure that the FPSO vessel is free from Naturally Occurring Radioactive Material (NORM). The vessel should undergo a survey conducted by a reputable agency to assess the presence of NORM. A NORM Survey Report, along with a NORM-Free Certificate, must be provided. These documents will be reviewed by local authorities at the recycling destination.
The shipowner should proactively plan and take necessary actions to decontaminate any materials containing NORM on board the vessel well in advance of the vessel’s scheduled recycling.
For more information or any clarification, please write to bd@gmsinc.net
with thanks, credit to: https://www.gmsinc.net/article/tanker-ships-recycling-naturally-occurring-radioactive-material-issue-5
