Workers in Nuclear Installations (Nuclear Fuel Cycle)

Workers in nuclear installations of are special concern from an occupational radiation protection standpoint. The process of taking uranium ore from the earth and converting it into useable fuel and then its further disposal is laborious task with many challenges from an occupational radiation protection standpoint. Each point in the nuclear fuel cycle exposes workers to different forms of radiation that must be accounted for. The Information System on Occupational Exposure (ISEO) provides a forum for radiation protection professionals from nuclear electricity licensees and national regulatory authorities worldwide to share dose reduction information, operational experience and information to improve the optimization of radiological protection at nuclear power plants.

What do I need to know?

What sort of exposure you will receive as a worker depends on what point of the nuclear fuel cycle you are working in. Regardless of what facility a worker is in, the IAEA has laid forth requirements for protection and safety in both General Safety Requirements Part 3 (GSR Part 3) and Specific Safety Requirements Part 4 (SSR-4) pertaining to general radiation protection requirements and specific safety requirements relevant to different nuclear fuel cycle facilities.  

“The design of a nuclear fuel cycle facility shall ensure that radiation doses to workers and other personnel at the facility and to members of the public do not exceed the dose limits, and that doses are kept as low as reasonably achievable in operational states for the entire lifetime of the facility, and that they remain below acceptable limits and as low as reasonably achievable during, and following, accident conditions.” – SSR-4 Requirement 8.

Additionally,

“The operating organization shall establish and implement a radiation protection programme… The operating organization shall ensure that the radiation protection programme is in compliance with the requirements of GSR Part 3” SSR-4 Requirement 67.

Therefore, the same protections afforded to workers dealing with radiation in other industries still apply here in the nuclear fuel cycle.

Does the facility I work at matter?

Depending on what point in the nuclear fuel cycle a worker is in, it will affect the types of radiation the worker may be exposed to. For example, a worker in the mining and milling portion of the nuclear fuel cycle will be exposed to radionuclides found in the earth such as K40, Uranium, and Thorium, but also Radon (a decay product of thorium) that can build up in the air without proper ventilation. Breathing in radon is a primary form of radiation exposure for workers in ANY enclosed mining process, let alone uranium mining.

For conversion and enrichment facilities, “… in normal operation, the main characteristic that needs to be taken into account in the development of measures for radiation protection is that the external and internal dose rates are relatively low. It is required to put in place emergency arrangements for criticality incidents, which are the only events in which a high external dose rate would be encountered.” – SSG-5 Paragraph 7.23.

In fuel fabrication facilities, “…the main radiological hazard for both the workforce and members of the public is from the inhalation of airborne material containing uranium compounds. Insoluble compounds of uranium such as the uranium oxides UO2 and U3O8 pose a particular hazard because of their long biological half-lives (and therefore effective half-lives) and their typically relatively small particle size (typically a few micrometres in diameter) when encountered in uranium fuel fabrication facilities.” SSG-6 Paragraph 7.21.

For waste disposal facilities, “The relevant principles and requirements for radiation protection are also established in the Fundamental Safety Principles (SF-1) and the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (GSR Part 3), respectively.” However, “The main radiation protection principle involved in decisions concerning remedial actions or changes to operating plans and procedures at an operating facility is the principle of optimization.” (SSG-14) Meaning that because exposure to radiation is an inevitability at these facilities, operators should make sure to ensure the methods and training performed at this facility minimizes dose to employees as low as reasonably achievable.

As for nuclear fuel cycle facility radiation programmes, operators should still be including normal methods such as dose monitoring, dose record keeping, and dose optimization.

Responsibilities

Organisations/employers are responsible for:

• Devising, implementing, and regularly reviewing their Radiation Protection Programme.
• regulatory compliance.
• Development a training programme that provides the appropriate level of training and information specific to the worker`s job assignments and also general radiation protection information.
• Induction and ongoing training of workers, including contractors.
• Appropriate dosimetry arragements.
• Record keeping.

Workers are responsible for:

• Following any applicable rules and procedures for protection and safety as specified by the employer, registrant or licensee.
•  Using properly the monitoring equipment and personal protective equipment provided.
• Cooperating with the employer, registrant or licensee with regard to protection and safety, and programmes for workers’ health surveillance and programmes for dose assessment.
• Providing to the employer (and registrant or licensee, where appropriate) information on work history relevant to developing an effective protection and safety programme for the worker (and others).
• Communicating perspectives on job specific radiation risks gained from education and training, and otherwise cooperating with regard to developing and executing an effective protection and safety programme.
• Following radiation protection practices specified in local rules, procedures and in the Radiation Protection Programme, including the proper use of monitoring and personal protective equipment as described in those rules and procedures.
• Complying with legitimate instructions of the employer or designated Radiation Protection Officer.
• Participation in radiation protection training.
• Reporting to the employer or designated Radiation Protection Officer identified circumstances jeopardizing protection and safety of the worker or others.
• Abstaining from any wilful action that could put the worker or others in situations not in compliance with the requirements for protection and safety.
• Accepting such information, instruction and training in protection and safety as will enable them to conduct their work in accordance with the requirements of [GSR Part 3].”

Dose Limits

The GSR Part 3 requires annual limits for public and occupational exposure to ionising radiation: 1 mSv for the members of the public and 20 mSv for workers who are occupationally exposed. Despite this, there are different definitions of who is “occupationally exposed” and who should wear personal dosimeters.

References

• Fundamental Safety Principles, IAEA Safety Standards No. SF-1, IAEA, Vienna (2006) 
• Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards, IAEA Safety Standards Series No. GSR Part 3, IAEA, Vienna (2014) 
• Occupational Radiation Protection, IAEA Safety Standards Series No. GSG-7, IAEA, Vienna (2018) 
• Safety of Uranium Fuel Fabrication Facilities, IAEA Safety Standards Series No. SSG-6, IAEA, Vienna (2010)
• Geological Disposal Facilities for Radioactive Waste, IAEA Safety Standards Series No. SSG-14, IAEA, Vienna (2011) 
• Safety of Conversion Facilities and Uranium Enrichment Facilities, IAEA Safety Standards Series No. SSG-5, IAEA, Vienna (2010) 
• Establishing the Safety Infrastructure for a Nuclear Power Programme, IAEA Safety Standards Series No. SSG-16, IAEA, Vienna (2012)