Application of the Basic Standards in Radiation Safety

The BSS set out detailed requirements for practices and interventions to protect workers, patients and the general public from radiation exposure. They also recommend procedures for ensuring the safety of sources, for accident prevention, for emergency planning and preparedness and for mitigating the consequences of accidents. Although the majority are of a qualitative nature, the BSS also establish many requirements expressed in terms of restrictions or guidance on the dose that may be incurred by people. The range of doses spreads over four orders of magnitude, from ones that are so minute that they should be exempt from the requirements to doses that are large enough to make intervention almost mandatory.

Organizational requirements

National governments usually have the responsibilities for enforcing radiation safety standards, generally through a system that includes a regulatory authority. In addition, governments usually provide for certain essential services for radiation protection and safety and for interventions that exceed or that complement the capabilities of regulators. The BSS can only be effectively applied when such a national infrastructure is firmly in place. In addition to legislation and regulations, the essential elements are:

A Regulatory Authority. This should be empowered to authorize and inspect, and to enforce the legislation and regulations. It must have sufficient resources, including adequate numbers of trained personnel. There must be arrangements for detecting any build up of radioactive substances in the general environment, for disposing of radioactive waste and preparing for interventions, particularly during emergencies, that could result in exposure of the public.

Education, training and public information. There must be adequate arrangements and resources for these, as well as for the exchange of information among specialists. There must also be appropriate means of informing the public, its representatives and the information media about health and safety concerns.

Facilities and services for radiation protection and safety must be well established at the national level. These include laboratories for personal dosimetry and environmental monitoring, and calibration and intercomparison of radiation measuring equipment; they could also include central registries for radiation dose records and information on equipment reliability.

Management requirements

To ensure radiation safety, the BSS promotes development of:

• A Safety Culture - that encourages a questioning and learning attitude to protection and safety, and discourages complacency.
• Quality Assurance Programmes - that provide, as appropriate, adequate assurances that the specified requirements related to protection and safety are satisfied.
• Control of Human Factors - limiting, as far as practicable, the contribution of human error to accidents and other events that could give rise to exposures. This can be achieved by ensuring that all personnel on whom protection and safety depend are appropriately trained and qualified.
• Qualified experts - made available for providing advice on the observance of the BSS.

Technical requirements

The BSS promotes sound technical planning and implementation through the following:

Security of sources. Radiation sources must be kept secure so as to prevent theft or damage.

Defence in depth. A multilayer system of protection and safety provisions commensurate with the radiation hazards involved is applied to sources, so that a failure at one layer is compensated for or corrected by subsequent layers.

Good engineering practice. This reflects approved codes and standards, and must be supported by reliable management and organization to ensure protection and safety throughout the life of the sources.

Verification of safety. Protection and safety measures for sources must be made in a way that they can be regularly monitored and verified for compliance. In addition, records should be kept of the results of monitoring and verification.

Transport

Additionally, radioactive substances have to be transported in accordance with the IAEA Regulations for the Safe Transport of Radioactive Material and with any applicable international convention.

Under the BSS, interventions apply to the following: Emergencies, where protective action is needed to reduce or avert temporary radiation exposures, including accidents at nuclear installations (for which emergency plans or procedures have been activated). Chronic exposure situations requiring remedial action to reduce or avert long-term radiation exposure. This includes exposure to radon in buildings and exposure to radioactive residues from past events.

        

Exposure resulting from	Basis	Equivalent period of global exposure to average natural background
Nuclear weapons testing	All past tests	2- 3 years
Apparatus and substances used in medicine	One year of pracitce at the current rate	90 days
Severe accidents	Accidents to date	20 days
Nuclear power generation (under normal operating conditions)	Total nuclear generation to date. One year of practice at the current rate	1 day
Occupational activities	One year of occupational activities at the current rate	8 hours

The table presents the UNSCEAR summary of the relative radiological impact from some practices as well as from severe accidents that required intervention. The levels of radiation exposure are expressed as equivalent periods of exposures to natural resources.