Evaluation of Guidelines for Exposures to Technologically Enhanced Naturally Occurring Radioactive Materials (1999) / Chapter Skim
Currently Skimming:
9 Other Guidances for TENORM
9 Other Guidances for TENORM
Pages 183-203
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 183... ...
This chapter discusses guidances that are directly applicable, or potentially relevant, to TENORM other than indoor radon that have been developed by the National Council on Radiation Protection and Measurements, the International Commission on Radiological Protection, the Health Physics Society, the Nuclear Regulatory Commission, the Department of Energy, various state governments and the Conference of Radiation Control Program Directors, the International Atomic Energy Agency, and the Commission of the European Communities and other nations. The roles of these organizations in radiation protection of the public and the regulation of TENORM are discussed in chapter 6.
|
From page 184... ...
is recommended. This action level is recognized as 10 times the national average for indoor radon and appears to be justified partly on the basis of feasibility, rather than attainment of an a priori numerical risk limit.5 NCRP states that "a remedial action level must, therefore, be chosen for which the greatest risks are avoided but the societal impacts are not excessive" and NCRP goes on to state that "Therefore, NCRP has proposed a remedial action level which is based on excess lifetime risk being no more than ten times the excess lifetime risk associated with the average annual background level found in homes that is 7.0 x 10-3 Jhlm3/y." sAlthough it seems clear in NCRP Report No.
|
From page 185... ...
annually." As in the case of radon, the 5-mSv action level appears to be justified, at least partly, on the basis of feasibility rather than attainment of an a priori numerical risk; lathe committee has assumed that this remedial action level is applicable only to pre-existing situations for which remedial action is the only remedy, and not to future practices. It is important to note that the 5-mSv remedial action level is a total dose (except of radon)
|
From page 186... ...
For the case of radioactive residues from previous events, ICRP states that "the need for and extent of remedial action has to be judged by comparing the benefit of the reductions in dose with the detriment of the remedial work, including that due to doses incurred in the remedial work." HEALTH PHYSICS SOCIETY The Health Physics Society (HPS) , a US professional organization of radiation-protection specialists, has issued policy statements on radiation dose limits for the general public (HPS 1992)
|
From page 187... ...
· For decisions on decommissioning strategies, the ALARA principle should be applied to the total radiation dose to society, including workers at the site as well as the general public. · For unrestricted use of a restored site, HPS endorses the limit of 1 mSv for the total effective dose equivalents (TEDE)
|
From page 188... ...
· HPS recommends that standards for site cleanup and restoration be based on probabilistic risk assessments designed to provide the best estimates of the distributions and uncertainties of doses that are likely to be received after restoration through the use of state-of-the-art, peer-reviewed, thoroughly documented mathematical models and computer codes. NUCLEAR REGULATORY COMMISSION The Nuclear Regulatory Commission is not authorized to regulate TENORM as defined in this study, because such materials exclude source, special nuclear, and byproduct materials as defined in the Atomic Energy Act and the Nuclear Regulatory Commission's licensing authority is derived entirely from the act (see chapter 6~.
|
From page 189... ...
If the dose constraint of 0.25 mSv per year for unrestricted use is not reasonably achievable or if compliance with the dose constraint would result in net harm, sites will be considered acceptable for license termination under restricted conditions if provisions for legally enforceable institutional controls would provide reasonable assurance that the annual effective dose equivalent will not exceed 0.25 mSv (25 mrem) or the annual effective dose equivalent is ALARA and would not exceed 1 mSv (100 mrem)
|
From page 190... ...
The concentration limits were derived from the assumed dose constraints on the basis of an analysis of inhalation and ingestion pathways for an assumed exposure scenario (Nuclear Regulatory Commission 1981~. As discussed later in this chapter, an exemption level or cleanup standard for 226Ra of 1.1 Bq/g (30 pCi/g)
|
From page 191... ...
for individual members of the public from all DOE sources combined (DOE 1990) , acceptable disposals of low-level waste at DOE sites are defined by the following performance objectives for the disposal facility (DOE 1988~: · A limit on annual effective dose equivalent for individual members of the public of 0.25 mSv (25 mrem)
|
From page 192... ...
Thus, these materials are intended for disposal at specially designated DOE sites or at mill tailings disposal sites established under the Uranium Mill Tailings Radiation Control Act. The requirements for control of residual radioactive materials at DOE sites that apply to TENORM managed as mill tailings are contained in Order 5400.5 (DOE 1990~.
|
From page 193... ...
from all DOE sources combined: · Limits on residual concentrations of radium and thorium in soil, airborne radon decay products in occupied or habitable structures on private property, and external gamma radiation level inside buildings or habitable structures on a site as given in Subpart B of EPA's mill tailings standards in 40 CFR Part 192. · Limits on residual concentrations of other radionuclides in soil shall be derived from the annual dose limit of 1 mSv (100 mrem)
|
From page 194... ...
for individual members of the public from all routine DOE activities combined, including exposure to TENORM and other residual radioactive material, as specified in Order 5400.5 (DOE 1990~. · Compliance with provisions for residual radioactive material based primarily on EPA's standards for uranium and thorium mill tailings in 40 CFR Part 192.
|
From page 195... ...
: · Operations, uses, or transfers of TENORM are to be conducted in a manner such that no member of the public will receive an annual total effective dose equivalent (excluding radon and its decay products) of 1 mSv (100 mrem)
|
From page 196... ...
. · The disposal methods used with uranium mill tailings regulated under 40 CFR 192 are generally acceptable for TENORM.
|
From page 197... ...
This radon flux rate is the post-remedial action level specified for the disposal of uranium mill tailings in 40 CFR 192.02. Low radon factor is a radon emanation rate less than 0.7 Bq (20 psi)
|
From page 198... ...
First, paragraph 2.5 of the "Requirements for Practices" specifies that "exposure to natural sources shall normally be considered as a chronic exposure situation and, if necessary, shall be subject to the requirements for intervention, except that ... public exposure delivered by effluent discharges or the disposal of radioactive waste arising from a practice involving natural sources shall be subject to the requirements for practices ..., unless the exposure is excluded or the practice or the source is exempted." In that statement, practice and intervention have the same meanings as in ICRP recommendations discussed earlier in this chapter, requirements for practices include a limit on annual effective dose of 1 mSv (100 mrem)
|
From page 199... ...
Especially for uranium, thorium, and radium, the recommended exemption levels given above are substantially higher than EPA's standards for cleanup of residual radioactive material at mill tailings sites, as given in Subpart B of 40 CFR Part 192 (see chapter 7~. However, as noted previously, the recommended exemption levels for naturally occurring radionuclides do not apply to residual radioactive materials that contain TENORM.
|
From page 200... ...
Title VII of the standards addresses substantial increases in exposure due to natural radiation sources. In particular, the standards call attention, first, to operations with and storage of materials not usually regarded as radioactive but that contain naturally occurring radionuclides and cause a substantial increase in exposures of the public, and second, to activities that lead to the production of residues not usually regarded as radioactive but that contain naturally occurring radionuclides and cause a substantial increase in exposures of the public.
|
From page 201... ...
. UMTRCA governs remedial actions for uranium mill tailings disposal sites and discontinued uranium-milling facilities.
|
From page 202... ...
The scientific validity of applying the soil-radium cleanup standard to TENORM wastes outside the nuclear fuel cycle, including industrial materials that are not classified as wastes, depends on the degree of similarity that such materials exhibit to the UMTRCA materials for which the standard was derived. Yet many non-fuel-cycle TENORM have initial mineralogies and processing histories different from uranium mill tailings.
|
From page 203... ...
annual dose constraint deemed protective by EPA (Luftig and Weinstock 1997) and focusing only on external exposure, we note that this dose is equivalent to an incremental increase in the 226Ra concentration in soil of about 0.04 Bq/g (1 pCi/g)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.