Committed effective dose

Food item Transfer factors 241 Am concentration4 Committed effective dose ( lSv) from241 Amb ... 

Occupational - the committed effective dose equivalent (Internal) and annual effective dose equivalent (external) combined... 

The Annual Limit of Intake (ALI) for any radionuclide is obtained by dividing the annual average effective dose limit (20 mSv) by the committed effective dose (E) resulting from the intake of 1 Bq of that radionuclide. ALI data for Individual radionuclides are given in ICRP (1991b). 

Kendall, G.M., Kennedy, B.W., Greenhalgh, J.R., Adams, N. Fell, T.P. (1987) Committed doses to selected organs and committed effective doses from intake of radionuclides. Report GS7. National Radiological Protection Board. Chilton, Oxon. 

The ALI is the activity of a radionuclide that can be taken into the body in a year, by inhalation or ingestion, without exceeding a committed effective dose equivalent (CEDE) of 5 rem/year or a committed dose equivalent to any organ of 50 rem/year, whichever is more limiting. The total effective dose equivalent TEDE is the sum of the CEDE and any penetrating external dose (10 CFR 20). If any external dose is present the ALI must be reduced by a proportional amount to ensure that the dose limits are not exceeded. For example, if a worker received an external dose of 1 rem/year, the ALI would have to be reduced by 20% to ensure that the TEDE did not exceed 5 rem/year. 

The SITP is a quantity derived from the Annual Limit on Intake (ALI), an internationally accepted concept that has been acknowledged by the Government s Radioactive Waste Management Committee (RWMAC) as a valid method of establishing equivalent hazards of different waste types. The ALI is a derived limit for the permissible amount of radioactive material taken into the body of an adult radiation worker by inhalation or ingestion in a year. The ALI is the smaller value of intake of a given radionuclide in a year by the reference man that would result in either a committed effective dose equivalent of 0.05 Sv or 0.5 Sv to any individual organ or tissue. 

F. Radiation Dose (committed dose equivalent, committed effective dose)... 

After an elapsed time T following an intake of radioactive substances, the committed effective dose is defined as ... 

Absorbed dose, organ dose, equivalent dose, effective dose, committed equivalent dose, or committed effective dose, depending on the context. The modifying terms are often omitted when they are not necessary for defining the quantity of interest. 

For the purpose of demonstrating compliance with dose limits, the sum of the personal dose equivalent from external exposure to penetrating radiation in the specified period and the committed equivalent dose or committed effective dose, as appropriate, from intakes of radioactive substances in the same period shall be taken into account. 

The committed effective dose per unit intake following ingestion of Zr is 9.5 X 10 Sv Bq for adults > 17 years of age (IAEA, 1996). However, due to its relatively short physical half-life, the major environmental impact of Zr is likely to be short-term external irradiation. 

Handl et al. (2000) reported measured transfer factors for silver in pasture grass ranging from 0.009 to 0.065. This range is slightly higher than the rather limited collection of soil-plant transfer factors quoted by lUR (1989) of 0.00027 for lettuce, 0.0008 for tomato, and 0.0013 for radish. Ng et al. (1982) quoted a transfer factor value of 0.15 for Ag in unspecified plant material. The committed effective dose per unit intake following ingestion of " "Ag is 2.8 x 10- Sv Bq for adults older than 17 years of age (IAEA, 1996). 

Total effective dose equivalent (TEDE) is the sum of the deep-dose equivalent (for external exposure) and the committed effective dose equivalent (for internal exposure). 

The Food and Drug Administration (FDA) develops standards for radioactive material concentrations in food (FDA 1998), and medical devices used in radiation therapy (FDA 1997). The FDA recently updated its guidance document that presents recommended action levels for radionuclides in foods, both domestic and imported (FDA 1998). These derived intervention levels (DILs) are estimated levels in food that could lead to individuals receiving a radiation equivalent dose equal to the FDA protection action guide (PAG) that is set as the more limiting of either 0.5 rem (5 mSv) for committed effective dose or 5 rem (50 mSv) committed dose equivalent to any individual tissue or organ. Table 8-2 presents the most restrictive DILs for strontium. 

Derived intervention levels (DIL) are concentrations of radioactivity in food whose consumption would deliver a committed effective dose equivalent equal to the most limiting of the protection action guides (PAGs) developed by FDA (1998). 

Tab. 26.1-1 Typical annual intake and committed effective dose (E), for individuals exposed to naturally occurring actinides and selected decay products (UNSCEAR 2000)...

Actinide Annuai intake [Bq] Committed effective dose [EUflSv a- ] ... 

Committed effective dose equivalent the sum, over all relevant tissues... 

By considering all possible transfer routes, one can estimate what amount of a radionuclide released to the environment may end up in plants, animals, or man. When these figures are combined with the dose conversion factors ("committed effective dose equivalent per unit intake", according to ICRP) in Table 18.12, it is possible to calculate the dose received by man from intake of a radionuclide in the environment. The dose conversion factors dep d on the mode of intake (usually only inhalation or ingestion). Thus... 

One remaining barrier to significant injury, electric shock (>50 volts AC), radiation exposure (one event >1000 mr uptake, intake or Committed Effective Dose Equivalent [CEDE]) or Industrial Hygience Exposure (>3 times OSHA limits), exceed criticality limit or double contingency is not maintained... 

Dose limits means the permissible upper bounds of radiation doses. These are usually set for a calendar year. They apply to the dose equivalent received during the set interval, the committed effective dose equivalent resulting from the intake of radioactive material during the interval or the effective dose equivalent received in 1 year The external dose and the internal dose must be combined so as not to exceed the permissible limits. The following equation can be used to compute the relative amounts of each, for the annual intake Ij of nuclide J ... 

The 95 Quantile X/Q at 3000 m for a ground release with wake as calculated by the MACCS2 code is 5.16E-05 sec/m at 3000 m and 1.16E-03 secern at a distance of 300 m, yielding a X/Q ratio of. 044. Thus, the calculated bounding dose at 3000 meters is. 044 (1 rem) or 44 mrem. The DOE calculated dose and this dose that is derived from it include dose contributions from committed effective dose for 50 years (CEDE) and immersion in the radioactive plume (cloud shine). This potential dose consequence represents a conservative upper bound on the public dose since the maximum radiological inventory corresponding to HC2 levels was used in the analysis, and no mitigation of the release was taken into account. 

For reprocessed uranium, Aj values may be calculated by using the equation for mixtures in para. 404 and taking account of the physical and chanical characteristics likely to arise in both normal and accident conditions. It may also be possible to demonstrate that the value is unlimited by showing that 10 mg of the uranium will have less activity than that giving rise to a committed effective dose of 50 mSv for that mixture. In addition, for calculating Aj values in the case of reprocessed uranium, the advice given in Ref. [8] may provide useful information. 

The SI unit of committed effective dose is Sv, the same as for effective dose. Similarly, one can derive a committed equivalent dose. The quantity of dose commitment differs from the committed dose only by the upper integration limit. It is defined as the infinite time integral (t = oo) of the per caput dose rate Hi or E) ofthe population due to a specified event. The unit of the dose commitment is the same as for committed dose. Both individual dose commitment and collective dose commitment can be defined. 

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