[en] A proposal is made to permit compliance with a limit by radioactivity measurements, taking into account the statistical nature ofradioactivy. The proposal has also some influence to the quality of the measurement under given conditions. (author)

[en] This second part is relative to radiation protection, it includes: developments and problems of radiation protection law: a permanent challenge, the caution principle, the new commune directive on base standards in the field of radiation protection, the dose limits, the case law of the European court of Justice in the Nuclear field from 1971 to the present Day. (N.C.)

[en] Biological dosimetry allows us to assess absorbed dose in cases of accidental overexposure to ionizing radiations. It is recommended in many particular cases of suspected irradiation and also as complementary to existing physical data. In this article, a review of its applications is made, some common practical situations are presented and different techniques for routinary use and others in

[en] The four-wheel steering (4WS) is an efficient method to improve the manoeuvrability of electric vehicle with the tendency of understeer, by providing the sufficient steering angles. Because of the various kinds of driving environments, the inner coupling between the active front and rear wheels of the 4WS vehicle is a challenging problem, which usually results in unstable yaw stability of the vehicle. In order to solve this coupling problem, this paper presents a double-layer dynamic decoupling control system (DDDCS), which consists of an upper part-dynamic decoupling unit (DDU) and a lower part-steering control unit (SCU). The DDU is presented to solve the dynamic coupling problem between the active front and rear wheels, and separately establishes two decoupled models by the diagonal decoupling method. The SCU is designed to obtain the decoupled control signals by the model predictive controller, then, the yaw stability of 4WS vehicle can be guaranteed. The results of the simulation show that the proposed DDDCS has good decoupling performance and stable yaw performance for 4WS vehicle.

[en] Ultra fast, sub-nanosecond (picosecond to femtosecond) duration, laser pulses present unique challenges when performing laser safety analysis involving mode-locked lasers, which operate at pulse repetition frequencies above the critical frequency in the near infrared wavelength bands. Two specific cases are presented, one such case that agrees and one that disagrees with the general rule on critical frequency. The results show that in all cases the appropriate maximum permissible exposure is always the smallest of the values calculated from ANSI rule 1, 2 and 3

[en] The International Commission on Radiological Protection (ICRP) issued a new and revised standard (ICRP 60) with recommendations for limits of radiation doses. The impacts for the exploitation and personnel of related industrial and medical sectors are outlined

[en] The US Nuclear Regulatory Commission (NRC), with the participation of the US Environmental Protection Agency (EPA), plans to complete a series of seven regional workshops by June 1993. The workshops will solicit concerns and viewpoints from a wide variety of interests on issues related to generic radiological criteria for decommissioning lands and structures for release. The NRC and EPA have adopted a neutral, unbiased position for solicitation of the input of all issues, including the fundamental approach to regulation - risk- or dose-based goals or limits; best effort or return to natural background. The pros and cons of all concerns and viewpoints will be considered in the staff recommendations to the commission. A status report on those considerations will be provided. Establishment of criteria for radiological contamination levels for residual radioactivity and criteria for the release of materials is a crucial requirement for decommissioning of nuclear installations. Several federal agencies, including the US Department of Energy (DOE), Environmental Protection Agency (EPA), and Nuclear Regulatory Commission (NRC), are developing criteria. Establishing such criteria requires considerations of the technology and cost of cleanup as well as health risk. A primary consideration is that the criteria be expressed in a format that can be readily translated into measurable quantities. Newly proposed DOE criteria for protection of the public and the environment (10CFR834) require that sites be surveyed to determine both mass and surface contamination, that doses to members of the public not exceed primary or secondary guidelines, and that these exposures are as low as is reasonably achievable (ALARA). In this evaluation, doses from actual or likely use scenarios should be shown to be only a small fraction of the applicable dose limits, and doses from the worst plausible use must be below the dose limit for members of the public (1mSv/yr, 100mrem/yr)

[en] The distinction between practices and interventions in the System of Radiation Protection has created a lot of confusion in the population and amongst decision-makers, especially with regards to the concepts of dose limits and intervention levels. The experience gained after the Chernobyl accident indicated that many actions taken led to an unnecessarily large expenditure of national resources, and many instances occurred of contradictory national responses. A major reason was the mixture of dose limits for the population, which apply only to exposures from practices, and intervention levels, which apply only to protective measures in de-facto exposure situations. The existing System of Radiation Protection is revisited and it is suggested that the System can be revised with no dose limits for the public without causing a lower degree of protection of the population. With the widespread use of source-related dose constraints and practical restrictions on the sources of public exposure from practices, generally applicable dose limits are rarely limiting in any practical situation, even if dose constraints might, at least in principle, fail to take adequate account of the exposures from other practices. Constraints can be expressed as operational protection quantities, e.g. nuclide-specific release rates, dose rate at the fence of a facility or nuclide-specific surface contamination density in the environment. A revised System of Radiation Protection without public dose limits would not cause any reduced protection of the public compared to the existing System, and it has a potential for removing much of the confusion with regards to application of intervention/action levels. It would also have the potential for improving public perception of radiation protection and radiation risks as well as for saving vast resources in intervention situations for better application in general health care of the public. (au)

[en] In this paper dose limits in connection with optimization of protection are discussed. The amount of money that would be appropriate to pay to eliminate a unit collective dose is taken into account. Thereby dose limits and source-related dose constraints play an important role. Finally ethical problems due to most exposed individuals and the overall risk are taken into account from a practical point of view. (Suda)

[en] Unlike other fields of toxicology, radiation protection has a dual system of quantities, one set for assessment and the derivation of authorised limits and another set for monitoring radiation performance and compliance. Neutrons are an important or dominant constituent of the radiation field around high energy accelerators and the evolution of the radiation protection quantities used to measure neutrons is described. In 1990 ICRP introduced a new quantity, the effective dose, E, with which to express its protection limits. E represented a radical departure from previous advice of the Commission, particularly in the manner by which it weighted the absorbed dose deposited by high LET radiations. This advice had profound consequences for neutron dosimetry. Over the past decade analyses have revealed logical flaws and inconsistencies in the definition of effective dose. These are briefly discussed with most emphasis being placed on inconsistencies in radiation weighting. Suggestions are made with a view to resolving these inconsistencies. (author)