Annual dose limit

Conduct work in designated controlled areas (e.g. in UK these are areas in which instantaneous dose rates >7.5 pSv/hour occur, or where employees may exceed 6 mSv annual dose limit, or where air concentration or surface contamination exceeds specified levels). 

The development of many standards that specify dose constraints for specific practices or sources at levels well below the annual dose limit of 1 mSv for all controlled sources combined (Kocher, 1988 Mills et al., 1988) is an important means of ensuring that the lifetime cancer risk from exposure to controlled sources normally will not... 

Establishing an acceptable risk or dose. There also are a number of precedents for establishing an acceptable (barely tolerable) risk or dose of substances that cause stochastic responses for the purpose of classifying waste as low-hazard or high-hazard. For radionuclides, the annual dose limit for the public of 1 mSv currently recommended by ICRP (1991) and NCRP (1993a) and contained in current radiation protection standards (DOE, 1990 NRC, 1991) could be applied to hypothetical inadvertent intruders at licensed near-surface disposal facilities for low-hazard waste. This dose corresponds to an estimated lifetime fatal cancer risk of about 4 X 10 3. Alternatively, the limits on concentrations of radionuclides in radioactive waste that is generally acceptable for near-surface disposal,... 

Some general annual dose limits for exposure to radiation are as follows ... 

In March 1979 one of the nuclear reactor plants at the Three Mile Island (TMI) site (in Pennsylvania) had an equipment failure that led to a loss of cooling water from the reactor core. Operator errors compounded this mechanical malfunction, resulting in the destruction of most of the reactor core and melting some of the fuel. In spite of the extensive damage, the nuclear reaction was stopped and very little radiation was released to the environment. In fact, no person off site received more than a few millirem (equivalent to a few days background exposure) and no person on site exceeded their annual dose limit of 5 rem. This was not known at first, however, and the governor of Pennsylvania ordered the evacuation of many people from the area. 

For x-ray diffraction systems, the diffracted beam is also small and focused with an intensity of up to 80 R/h ( 22 mR/s). Prolonged or repeated exposures to a beam of this intensity could result in an individual exceeding the annual dose limit for the particular tissue irradiated. 

Personnel monitoring is required when an occupational worker is likely to receive an excess of 10% of the annual dose limit from radiation sources and for individuals entering high or very high radiation areas. Monitoring is accomplished by using film badges or thermoluminiscent dosimeters (TLD). 

Occupational dose limits for minors 10% of the annual dose limits specified for adult workers in 10CFR20.1201 NRC 20010 10CFR20.1207... 

Cumulative annual dose limit for general population from nuclear power plant operations... 

Besides, increased requirements of safety are imposed on a repository, as it is a subject of danger for the present and future generations of mankind. So, the International Commission on Radiologic Protection (ICRP) recommends a possible dose commitment from a repository within the limits of 1-3 % from the regulated annual dose limit of 1 mSv, corresponding to a risk 10" year" (the number of fatal diseases of cancer per one year). 

The maximum permissible concentrations (MFC) were those that correspond to an organ burden that would cause the annual dose limits to be attained. Control measures, therefore, were designed to maintain the concentrations below the MFCs. 

Five times the annual dose limits during the individual s lifetime. 

A licensee or license applicant may apply for prior NRC authorization to operate up to an annual dose limit for an individual member of the public of 0.5 rem (5 mSv). The licensee or license applicant shall include the following information in this application (l) demonstra-tion of the need for and the expected duration of operations in excess of the limit in paragraph (a) of this section (2) the licensee s program to assess and control dose within the 0.5 rem (5 mSv) annual limit and (3) the procedures to be followed to maintain the dose as low as is reasonably achievable. The licensee must make surveys, measurements, and/or calculations to prove that the limits would not be exceeded for an individual likely to receive the highest dose from the licensed operations. 

The environmental conditions obtainable at the site determine the quantum of annual dose limit apportionment to each of the air, water and land environments. The apportionment for the air route is then translated into a set of derived working limits taking into account the following ... 

The above derived working limits are, further apportioned for daily routine releases, and occasional short term high releases, in such a manner that the annual dose limit is not exceeded. 

To facilitate the control of doses to persons, the Regulations specify criteria for designating areas as controlled or supervised areas. The underlying basis of designation is to define areas where doses may exceed 3/10 or 1/10, respectively, of the annual dose limit for employees. Areas are designated on the basis of dose rate, total activity being handled, air activity concentration and surface contamination levels. 

Annual dose limit 500 mSv/person ( dose received during inserting the screws into... 

Controlled areas should be divided into zones on the basis of the anticipated radiation levels and radioactive contamination levels (i.e. dose rates and activity concentrations for surface or airborne radionuclides see Annex V). The greater the radiation or contamination related risks of a zone, the greater is the need to control access to that zone for the purpose of ensuring compliance with individual annual dose limits and taking account of dose constraints. 

The design of a research reactor should be such as to ensure that authorized annual dose limits for site personnel and the public will not be exceeded in operational states (normal operation and anticipated operational... 

Table 3 indicates how actinide compounds should be assigned to each default absorption type. The parameter is the fraction of actinide absorbed by the gut following clearance from the respiratory tract. The dose per unit intake (DPUI) is for a 5g actinide aerosol inhalation, in gSv Bq. The armual limit on intake (ALI), on inhalation, is the activity (Bq) corresponding to the annual dose limit (20 mSv). For uranium the DPUI increased by a factor of ten between Type F and S materials, but for plutonimn the DPUI... 

---