Airborne radioactive material

BS 5243 General principles for sampling airborne radioactive materials. 

Sampling and measuring methods of airborne radioactive materials... 

As can be seen in Figure 1, radon itself and its polonium daughter products are alpha emitting nuclides, while the isotopes of lead and bismuth produced are beta/ gamma emitters. The short half-lives of the daughter products prior to Pb (Table 2) result in the rapid production of a mixture of airborne radioactive materials which may attain equilibrium concentrations within a relatively short time. The half-life of °Pb is 22 years and at this point in the decay chain any activity inhaled is largely removed from airways in which it is deposited before any appreciable decay occurs. 

D. A Description of Radiation annd Radiobiological Hazards from the Cloud of Airborne Radioactive Material... 

For purposes of emergency planning, EPA-520/1-75-100 provides Protective Action Guides (PAGs) for exposure to airborne radioactive materials, contaminated foodstuff or water, and contaminated property or equipment. (Ref. 6)... 

Protective Action Guides for Exposure to Airborne Radioactive Materials ... 

AIRBORNE RADIOACTTVITY AREA - Some applications involving radioactive materials result in the generation of airborne radioactive materials in excess of those permitted by the standards of the NRC, or of the equivalent state agency in an agreement state. Should such an operation exist, the boundaries of the room, enclosure, or operating... 

AR527 4.20 Constraint on releases of airborne radioactive materials to the environment for licensees other... 

Radioactive needles contaminated with infectious agents or blood should be autoclaved as described above, and then incinerated on site or shipped to a low-level radioactive waste site. To prevent injuries, it is important that hypodermic needles and other sharps be kept in waste containers that are puncture-resistant, leak-proof, and closable from the point of discard through ultimate disposal. To prevent airborne radioactive materials, destruction of needles by grinding or a similar means is not recommended. 

OSHA requires the designation of restricted areas to protect individuals from radiation exposure. The term unrestricted area refers to any area access not controlled by the employer for purposes of protection of individuals from exposure to radiation. No employer can possess, use, or transport radioactive material within a restricted area that causes individuals to experience airborne radioactive material exposure in excess of limits specified in Table 1, Appendix B to 10 CFR 20. When monitoring exposure, make no allowance for the use of protective clothing or equipment, or particle size. 

Airborne radioactive material—Any radioactive material dispersed in the air in the form of dust, fumes, mists, aerosols, vapors, or gases. 

No new design requirements were established by the NRC as a result of this and other work related to control room habitability in an accident. However, more specific review procedures were incorporated in SRP Sections 6.4.1 and 9.4.1 (Reference 2), including the habitability review provisions of TMI Action Plan Item III.D.3.4 (Reference 1) regarding analyses of toxic gas concentrations and operator exposures from airborne radioactive material and direct radiation, to ensure more effective implementation of existing requirements. 

Generic Safety Issue (GSI) C-10 in NUREG-0933 (Reference 1) is concerned with the effectiveness of various containment spray solutions in removing airborne radioactive materials present in the containment after a loss-of-coolant accident (LOCA). Also of concern is the possible damage to equipment in the containment caused by the solutions in an inadvertent actuation of the spray system. 

Canadian Standards Association (CSA). 1991. Guidelines for Caladating Radiation Doses to the Public from a Release of Airborne Radioactive Material under Hypothetical Accident Conditions in Nuclear Reactors, CAN/CSA-N288.2-M01, Toronto. 

Bioassay measurements are subsequently taken at periodic intervals and at termination to detect if unsuspected intakes have occurred. If an intake is suspected, additional special monitoring should be used. An intake may be suspected if the individual has entered an airborne radioactive material area, has contamination on the face or nose, other skin contamination, or other unusual event. 

The primary purpose of anti-C clothing is to prevent skin contamination and the spread of contamination. In most instances, the use of anti-C clothing precedes the use of respirators. It is more common for areas to be contamination areas, indicating that there are surfaces and structures in the area with removable contamination, than it is for an area to be an airborne radioactive material area. Any airborne radioactive material area is automatically a contamination area because it is not possible to have a high concentration of airborne radioactive material without having removable contamination on the surfaces and structures in that area. 

No employer shall possess, use, or transfer radioactive material in such a manner as to cause any individual within a restricted area, who is under 18 years of age, to be exposed to airborne radioactive material in an average concentration in excess of the limits specified in Table II of Appendix B to 10 CFR Part 20. For purposes of this paragraph, concentrations may be averaged over periods not greater than 1 week. 

If applicable, appropriate limits should be established on the operability of ventilation systems where such systems have been provided for the purpose of controlling airborne radioactive material within stated limits in support of a safety system. 

C Building. The 117-N filter building used charcoal filters to absorb airborne radioactive materials emitted from N Reactor. The filters were transported to the 190-C building where the spent charcoal was removed and taken to the 200 East burial ground. New charcoal was then added and the filter was placed back in the 117-N building. 

For all operational states and DBAs, adequate provision shall be made in the design, on the basis of a consistent radiation protection programme and in accordance with the radiation protection objective (see para. 205 of Ref. [1], quoted in para. 2.2), for shielding, ventilation, filtration and decay systems for radioactive material (such as delay tanks), and for monitoring instrumentation for radiation and airborne radioactive material inside and outside the controlled area. 

The coatings of fuel storage ponds and fuel handling ponds, as well as the equipment used in these areas, will become contaminated. When the water level in such ponds is lowered, surfaces may dry out, and this may cause a hazard due to airborne radioactive material. Systems should be provided for decontaminating such surfaces before they dry out. Systems should also be provided for decontaminating, before they dry out, fuel transport flasks and components that may have to be removed from the ponds for repair. 

Area monitoring includes the measurement of radiation dose rates and amounts of airborne radioactive material. 

To limit the discharge or release of radioactive waste and airborne radioactive materials to below prescribed limits in all operational states ... 

Analysis of the particle size and solubility of samples of airborne radioactive material can assist in the development of biokinetic models for dose assessment (Section 6). Direct comparison of air samples with values of derived air concentrations (Section 2) can be used as an input to the evaluation of workplace conditions and to the estimation of doses. 

This section should provide a description of all on-site radiation sources, with account taken of both contained and immobile sources and potential sources of airborne radioactive material. It should also cover the possible pathways of exposures. 

This section should provide a description of the design features of the equipment and the facility that ensure radiation protection. It should provide information on the shielding for each of the radiation sources identified, describe the features for occupational radiation protection, describe the instrumentation for fixed area monitoring of radiation and continuous monitoring of airborne radioactive material, and the criteria for their selection and placement, and address design provisions for any decontamination of equipment, if necessary. 

Monitors shall be provided for measuring the activity of radioactive substances in the atmosphere in those areas routinely occupied by personnel and where the levels of activity of airborne radioactive materials may on occasion be expected to be such as to necessitate protective measures. These systems shall give an indication in the control room, or other appropriate locations, when a high concentration of radionuclides is detected. 

In addition to appropriate controls on sources, physical controls should be put in place, such as the provision of shielding and ventilation, and separation in distance and time. Shielding is used to reduce the dose rates everywhere outside the shield, ventilation is used to control airborne radioactive material, distance is used to reduce the dose rate at occupied locations, and time limits are used to reduce the total dose for a given dose rate. The ways in which these factors apply in the operation of research reactors are considered in the following section. 

A. 1240. This section shall demonstrate that the estimated radiation exposure of personnel due to inhalation in areas with airborne radioactive material is acceptable. If data are available, a summary of the annual doses to facility staff shall be provided. 

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