[en] In 1983, Pacific Northwest Laboratory published a series of reports that describe the Allowable Residual Contamination Level (ARCL) method for decommissioning US Department of Energy (DOE) nuclear facilities and sites. The purpose of the method was to provide engineers with a useful tool for conducting safety and cost comparisons for decommissioning alternatives. The ARCL results are based on a scenario/exposure-pathway analysis and compliance with an annual radiation dose limit. Recently, revisions were made to the method that are designed to make it more useful for site- or facility-specific model applications. These revisions include analysis of additional exposure scenarios and pathways, the addition of area/volume correction factors to account for small areas or volumes of residual contamination, and an evaluation of barrier and waste-form credit factors to be applied in the analysis. This paper contains a description of the area/volume correction factors that are intended to permit the model to account for small areas or volumes of residual contamination

[en] This report contains the results of a study sponsored by UNC Nuclear Industries to determine Allowable Residual Contamination Levels (ARCL) for five generic categories of facilities in the 100 Areas of the Hanford Site. The purpose of this study is to provide ARCL data useful to UNC engineers in conducting safety and cost comparisons for decommissioning alternatives. The ARCL results are based on a scenario/exposure-pathway analysis and compliance with an annual dose limit for three specific modes of future use of the land and facilities. These modes of use are restricted, controlled, and unrestricted. The information on ARCL values for restricted and controlled use provided by this report is intended to permit a full consideration of decommissioning alternatives. ARCL results are presented both for surface contamination remaining in facilities (in dpm/100 cm₂), and for unconfined surface and confined subsurface soil conditions (in pCi/g). Two confined soil conditions are considered: contamination at depths between 1 and 4 m, and contamination at depths greater than or equal to 5 m. A set of worksheets are presented in an appendix for modifying the ARCL values to accommodate changes in the radionuclide mixture or concentrations, to consider the impacts of radioactive decay, and to predict instrument responses. Finally, a comparison is made between the unrestricted release ARCL values for the 100 Area facilities and existing decommissioning and land disposal regulations. For surface contamination, the comparison shows good agreement. For soil contamination, the comparison shows good agreement if reasonable modification factors are applied to account for the differences in modeling soil contamination and licensed low-level waste

[en] A re-assessment of derived limits (DLs) for surface contamination was published in NRPB-DL2 in 1979. The re-assessment was based on the dose equivalent limits given in ICRP Publication 26 and the information on derived air concentrations (DACs) and annual limits of intake (ALIs) available at that time. Since then, ICRP has published data for the DACs and ALIs of all the radionuclides considered in the re-assessment. Some changes to the values and the classification of radionuclides given in NRPB-DL2 are required as a result, and these are given in this supplement to the original report. (author)

[en] Dismantled reactor components from nuclear facilities represent a considerable value; from an economic point of view, the utilization of such materials is considered imperative, as stipulated by section 9 of the Atomic Energy Act and sect. 5 of the Federal Nuisance Control law (BImSchG). The dismantled reactor components are not to be disposed of as radioactive waste, but to be utilized in an unharmful way. The unharmful utilization is 'handling of radiactive materials' according to section 1 of the Radiation Protection Ordinance, Successful decontamination in an indispensable precondition for handling of such materials without the need for approval and/or notification (Sect. 4, Radiation Protection Ordinance). In the past, considerable problems emerged as to the reproducibility of dose rate and contamination measurements. Most of these irregularities occurred because of different measuring methods and the use of improper and/or different measuring equipment. To minimize these problems, a standardization of measurement is suggested. For this purpose, a measurement regulation was elaborated. The lecturer enters into the problem of giving proof of the dose limits for surface contamination prescribed by law for approval measurements. The work carried out so far is reviewed. Measurement problems occurred in the past are illustrated by individual examples. The difficulties and proposals for possible solutions are put up for discussion. (orig.)

No abstract available

[en] Derived limits (DLs) for surface contamination were first established for use in the nuclear energy industry where a wide variety of radionuclides is encountered. They were later used in factories, hospitals, and universities, where the radionuclides used are normally fewer in number, either known or readily identifiable, and often of low toxicity. In these situations the current limits are frequently over-restrictive. This report describes a reassessment of the values in the light of more recent information on the possible pathways of exposure and the dose equivalent limits given in ICRP Publication 26. The reassessment is prompted also by the introduction of SI units. The results of the reassessment are used to produce a classification of DLs for all radionuclides for active and inactive area surfaces and for skin. (author)

[en] In this paper there is description of methods calculating surface concentrations of solid particles. There is preliminary design-theoretical mathematical model helping foresee the behavior of different size solid particles in the near ground layer of atmosphere during volley discharges. Basing on the model there were obtained preliminary forecasting data on clarification of the calculation model were determined. (author)

[en] Characteristic limits such as decision threshold, detection limit and confidence limits give an answer to the following questions: (1) Is the measurement procedure used suitable for the intended measurement purpose? (2) Is the number of event collected be attributed to the radioactive element? (3) Which range of true values may be reasonably attributed to the measure and given the measured results? ISO provided the theoretical framework and rules for the calculation of characteristics limits for ionizing radiation. This paper gives an example of applications of ISO for a contamination surface ratemeter

[en] The manufacture of illicit amphetamine-type stimulant (ATS) drugs in clandestine drug laboratories is undertaken in a range of locations that include residential homes/apartments, hotels/motels, backyard sheds, commercial/industrial premises and cars. Unlike controlled manufacturing of chemicals/drugs, the manufacture of illegal ATSs results in uncontrolled storage and use of precursor chemicals, uncontrolled release of by-products including gases/aerosols, disposition of drug residues on all surfaces in the premises and uncontrolled dumping of waste materials. This can result in significant exposure and risk issues within the premises during and after the drugs have been “cooked”. These hazards and risks are typically known and managed by law enforcement (and forensic scientists), however they are not known by the general public who may subsequently live or work in the premises. This paper aims to present the results of research into the characterisation of contamination inside residential homes in Australia, and the importance of identifying and remediating these premises prior to occupancy. (author)

[en] A brief article describes standards in preparation for the methods of assessment of the activity on contaminated surfaces. Three categories of sources recommended to meet the requirements for primary standards, the determination of instrument performance characteristics and routine calibration are described. These standards will help to ensure consistency between the calibration of instruments and the interpretation of measurements. (U.K.)