ICRP recommendations

In 1959 the International Commission on Radiological Protection (ICRP) recommended a "maximum permissible concentration of plutonium in water (MPCW) for unlimited public use" of 5x10 5 Ci/m3 ( xlO6 Bq/m3) (64). In 1979 ICRP introduced the concept of ALI ("annual limits of intake"). For 239Pu the value was set at 2xl06 Bq (or 0.9 mg) per year (35). Because man consumes about 0.5 m3 water/year, this ALI value corresponds to 4x106 Bq/m3 potable water. 

ICRP, Recommendations of the International Commission on Radiological Protection, ICRP Publication 26, International Commission on Radiological Protection, Stockholm, 1977. 

TM 3 225(1958) 10)S.Kinsman et al, "Radiological Health Handbook , US Dept of Health, Education and Welfare, Cincinnati, Ohio(1959) 11)ICRP, "Recommendations of the International Commission on Radiological Protection , Pergamon Press, NY(1959) 12)Glossary of Ord(1959), 38(Biological Warfare or "Biowar ) 69(Chemical Warfare), and 233(Radiological Warfare) 13)Anon, "Research in CBR , Dept of the Army Pamphlet, No 3 2(1960) 14)US Congress,... 

For routine exposures of the public, ICRP recommends a total detriment per unit equivalent dose from uniform whole-body irradiation of 7.3 X 10 2 Sv 1, as shown in Table 3.2. Of this, the recommended probability coefficient for fatal cancers is 5.0 X 10 2 Sv-1, or about two-thirds of the total detriment, and the contributions from severe hereditary responses and weighted nonfatal cancers are 1.3 X 10 2 Sv-1 and 1.0 X 10 2 Sv, respectively. These probability coefficients are summarized in Table 3.3, and their use in radiation protection is discussed in the following section. As noted previously, the probability coefficient for weighted nonfatal cancers is not the same as the probability coefficient for incidence of nonfatal cancers. The probability coefficient for fatal cancers also gives the probability of a fatal cancer per unit effective dose. The effective dose was developed to describe nonuniform irradiations of the body and is discussed below. 

The biological effectiveness of dose depends on the type of radiation and also on the mass and sensitivity of the irradiated tissue. For alpha irradiation, a quality factor of 20 is assumed (ICRP, 1981), and the dose in Sieverts is 20 times the dose in Grays. In addition, ICRP recommends a weighting factor of 0.12 for irradiation of the whole lung and 0.06 for irradiation of bronchial epithelium only. Thus the effective dose equivalent , symbol HE, is defined as the dose to the whole body which carries the same risk as the given dose to the organ or tissue. This, for irradiation of bronchial tissue is 20 x 0.06 = 1.2 times the dose to the organ in Gy. 

The ICRP Task Group (1988) has recommended a conversion factor of 1.0 x 10-5 mSv per Bqh m-3 of equilibrium equivalent decay product concentration, with a possible 30% uncertainty either way depending on the value of fp. Since 1 Bq m 3 equilibrium equivalent gives 5.54 nj m-3 (Appendix 1.1) the ICRP recommendation is equivalent to 1.8 Sv per Jh m-3 or 6.3 mSv per WLM. 

In 1958, the International Commission on Radiological Protection (ICRP) recommended that the genetic dose to the general population, excluding natural background radiation, not exceed 5 rems plus the lowest practicable contribution from medical exposure in a 30-yr period, or 170 mrems/yr. 

In the field of radiation safety of the environment - regulated, in particular, by the Federal Law On the Environmental Protection - the legislation does not address the issues of standardization of radiation quality of objects of environment. Moreover, a number of the law provisions contradicts the existing legislation and real practice of radiation protection of the environment which use the sanitary-hygienic approach where if man is protected, the environment is protected too , as per the ICRP Recommendations in force (Publication 60). 

Recent reports of the ICRP (ICRP 1991) and the NCRP (NCRP 1993) contain recommendations for lower worker dose limits. The ICRP recommends a limit on total effective dose of 2 rem/year averaged over 5 years, with the additional provision that the dose not exceed 5 rem in any single year. The NCRP s recommendations are that a worker s total accumulated dose should not exceed his or her age in years time 1 rem, and that the dose should not exceed 5 rem in any single year. These recommendations have not yet been incorporated into U.S. regulations. 

The control of the uses of radioactivity, should ensure that the levels in water are below limits derived from the International Commission on Radiological Protection (ICRP) recommendations (ICRP, 1977). Where appropriate, the radioactive content of water is measured by the operator who is authorised to discharge radioactivity, and the results are checked by the appropriate authorising government Departments in addition, tracer experiments to follow water movement are usually carried out by specialist groups with the appropriate measuring equipment. The measurement of the radioactive content of water is carried out by some Water Authorities as a check on trends and natural levels to be expected in the environment (see for example Greenberg et al., 1981). 

ICRP Recommended dose limits3 Effective dose 1 mSv per year ICRP 1994b... 

Radioactive waste is any waste material—gas, liquid, or solid—whose radioactivity exceeds certain limits. These limits have been established by governments or by local authorities, guided by the recommendations of the International Commission on Radiation Protection (ICRP). The ICRP recommendations define the maximum permissible concentration (MPC) for each individual radionuclide and for mixtures of radionuclides in water or air. The U.S. regulation defines such limiting concentration as the radioactivity concentration limit (C), which is the terminology used in this text, Values of C for selected actinides and long-lived fission products in water or air are given in App. D. 

In 1973 the ICRU recommended dropping the F from QF, a suggestion that has now become practice. In 1977 the ICRP recommended that the dose equivalent (//) at a point in tissue be written as... 

The ICRP recommended exposure limit to man-made sources of ionizing radiation (Reference 2) is 20 mSv/yr averaged over 5 years, with the dose in any one year not to exceed 50 mSv. 

Figure 18.10 shows a number of hypothetical dose-effect relations The "unmeasurable range" is indicated widiin the circle. The dashed-dotted line outside the circle indicates the uncertainty in the "measurable range". Line a is based on the ICRP recommendations and the message is clear the risk is zero only at zero radiation dose. Curve b indicates a threshold around SO mSv, below which their is no increase in cancer (or other radiation induced diseases) many radiologists support this hypothesis. Curve d assumes that there is a constant risk at the lowest doses. Curve c illustrates the "quadratic-linear" model, which presently seems to be favored by several radiation protection agencies (incl. ICRP), who assume that the slope near zero is one half of the slope at higher doses and dose rates. As this slope is unknown, it could as well be less. 

FromS. F. Mobbsetal. Dose-risk conversion factor = 1.65 x 10 Sv recommended by ICRPin 1977 [ICRP, 1977]. However, ICRP recommended a higher value, 5.0xl0 Sv , in 1990 [ICRP 60,1990]. 

Once the retention parameters were determined for each individual, the thyroid activity was estimated at time 24 h from the linear regression of the activity as a function of time. The uptake is thyroid burden at time 24 h divided by the decay corrected amount administered by the hospital. The average fractional uptake (0.16 0.01) of the thyroid has declined from the ICRP recommended value of 0.3. A one-sided r-test comparing the average fractional uptake with the ICRP value (assuming that it has a similar uncertainty to the uptake value determined in this work) gives a... 

The biological half-life of radioiodine in this subset of a North American population is 20% lower than the ICRP recommended 80 days. 

Particle mass density (p) is assumed to be triangularly distributed ranging from 1 to 10g-cm with a mode of 3g-cm (ICRP, 1994). The ICRP recommends a reference value of 3g-cm, because it is a typical value for many natural materials. The assumed range includes particles such as polystyrene, Teflon, iron oxide and uranium oxide (ICRP, 1994). 

The ICRP-recommended dose constraint is a few mil-lisievert per episode. The ICRP-94 claims that restrictions following the release of patients should focus on the sensitive subgroup (i.e., infants and children). 

Different concentrations of various metals are observed between open and nearly closed bayg232 effective half-hfe of nOmAg (equation 55) in squids after Chernobyl is 7 (i/2)eff = 130 days, in oysters after the Chernobyl accident r(i/2)eff = 140 days and in oysters after the 26th Chinese test r(i/2)eff = 160 days. The r(i/2)eff value is shorter than the physical half-hfe, Tphys = 249.76 days. Taking T a = 150 days for D9 Ag in oysters, we find that T = 375 days. This number probably reflects the half-residence time of ii° Ag in the sea water rather than the biological half-hfe in the oysters. The 7 (i/2)eff values of ii° Ag for oysters and squids are similar. The specific radioactivity of l° Ag for oysters was found to be 0.026 0.008 Bq/mg silver at the open Japanese coast which compares with value of 0.021 0.005 Bq/mg silver for squid in the Pacific Ocean. This coincidence suggests the similar behaviour of i0 Ag in Pacific Ocean oysters and squids and also a uniform distribuhon of i° Ag in the Pacific Ocean water. Thus the present levels of ii° Ag or lo m g found in the above environmental studies do not ensue a health hazard. The ICRP recommended the value of 2 x 10 Bq for llOmAg us an annual hmit of intake. 

The International Commission on Radiological Protection (ICRP) recommends specific limits of dose, applicable to stated time intervals (a quarter, a year, and so forth) as guidance for protection of radiation workers these are called maximum permissible doses and are applicable to individuals exposed continuously or intermittently from time to time as their work requires (40). To assist the planning of nuclear designs and operations so as to minimize, appropriately, the low level exposure of members of the public which may ordinarily result from normal operations, dose limits for individual members of the public are recommended by ICRP which are one-tenth or less of the maximum permissible doses for radiation workers. Though these maximum permissible doses and dose limits have little to do directly with the control of major radiation emergencies (i.e., reactor accidents) they are quoted in brief in Table VII. 

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 Commission is an advisory body that offers its recommendations to regulatory and advisory agencies, mainly by providing development of the ICRP recommendations including weight factors. 

The ICRP Recommendation is to be applied to all sources and to individuals exposed to radiation but distinguishes three different types of exposure situations. 

The last two groups are exposed to natural sources in metal mining mainly to radon, the aircrew to cosmic rays. With the exception of mining, the average annual doses fi om most types of occupational exposure due to artificial sources, including the nuclear industry, are below 2 mSv. Doses have been reduced in recent decades primarily because of the widespread introduction of the ICRP recommendations and control by appropriate authorities. 

Any system of protection should include an overall assessment of its effectiveness in practice. The international standards (IBSS 1996) established on the bases of the ICRP recommendations specify the basic requirements for protection of people against exposure to ionizing radiation and for the safety of radiation sources. In addition to the viewpoints of protection and safety in radiation, the technical developments, economics, and social situations are to be included in the general requirements of the system. Therefore ... 

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