[en] In the past, the after-heat output was determined by various methods of calculation. The differences in the results this produced frequently led to unnecessary difficulties in the licensing procedure. It was for this reason that the Nuclear Technology Standards Committee (Normenausschuss Kerntechnik, NKe) of the German Standards Institution, DIN, decided to have a German standard elaborated in order to provide a method of calculation which would be free from unnecessary conservatism and could be cited in the body of nuclear rules and regulations. Experience accumulated with a corresponding US standard had already demonstrated the advantages of having a standardized procedure for calculating the after-heat output. That standard therefore was to be made the basis of the German method of calculation. However, in order to achieve a more precise determination of the after-heat output over long periods of time, new methods were developed to take into account the neutron capture in fission products and the actinide buildup for a typical light water reactor. (orig./HP)

[en] During the decommissioning of nuclear facilities, the radioactivity of the various systems and components calls for particular attention and special methods in order to prevent harmful effects on the environment. Such methods and strategies are being developed and tested for years now. They refer to radiation protection, the handling and dismantling of large-size radioactive components, the decontamination of component parts and systems, and to the safe transport and storage of radioactive materials. National efforts in this field have been accompanied for the last five years by activities sponsored by a research programme of the EC Commission, the results hitherto achieved being discussed at the conference under review. (orig.)

[en] The German Reactor Safety Research Program was started 1972 and has been continued to this day, concentrating on a number of varying topics. Initially, it was launched to advance engineered safeguards against the occurrence of accidents and to limit the consequences of accidents, were they to occur nevertheless. The program by and large has reached these goals. Reactor safety research has considerably increased our knowledge about the causes and sequences of accidents in nuclear power plants. Promoting reactor safety research will continue to be a duty of the government also on a longer term basis though on a clearly reduced financial level after completion of the large scale experiments currently being conducted. (orig.)

[en] The wish of some countries to exercise 'prior-consent rights' in the use and transfer of nuclear fuels supplied by them implies burdens upon the recipient countries. These burdens do not lie in the restrictions imposed upon a recipient state as to the way in which it may use for peaceful purposes the nuclear fuel it has accepted, for in most cases the peaceful utilization is guaranteed and also monitored internationally anyway. They rather consist in the expense required of the recipient country and its industry, respectively, to be able to prove at any time the whereabouts of the amount of fuel accepted as distinguished from many other quantities from other states. For, only this allows the 'right' prior-consent country to be asked for approval if a quantity is to be transferred to a third country. An aggravating factor is the complete absence of harmonization among the systems prescribed by various supplier countries in handling and accounting for quantities of fuel. What is lacking is a standardized rule under which primarily the fissile material (e.g., uranium-235) and only in the second instance the carrier material (e.g., uranium-238) is the object of 'prior-consent rights'. An arrangement of this kind would allow the system of managing prior-consent rights as proposed here to be set up on the basis of the fissile material. This article is an attempt to describe how this system would work. (orig.)

[en] The listing of data on nuclear power plants in Germany to be started up in the years 1982-1989 is based on information from the Society of Power Industry (VIK). We must take into consideration, however, that not all projects are likely to be started up at the dates given by the operators. As for the other start-ups, which are planned for the time after 1990, the listing refers, at least as far as the hard coal power plants in this list are concerned, to site determinations. (orig.)

[en] For nearly ten years, realistic release experiments have been conducted at the Karlsruhe Nuclear Research Center, which have furnished a rather precise idea of the possible sequence of events in a core meltdown accident, also in terms of time. First of all, the phase of concrete melting must be studied. A factor of major importance in this regard is the retention capability of the containment. The effects of core meltdown accidents have so far been overestimated by several orders of magnitude. (orig.)

[en] There has been a great deal of discussion recently about the advanced pressurized water reactor as a successor to the present life of pressurized water reactors prior to the introduction of the fast breeder line. The basic underlying idea is the rise in the conversion ratio to 0.9-0.95 by means of spectrum hardening achieved as a result of a reduced moderator fraction. Aside from all technical problems it is assumed that an advanced pressurized water reactor is technically feasible and will be licensed. For a utility company the first question arising is that of the reduction of costs of a kilowatthour of electricity generated in the advanced reactor as against a classic pressurized water reactor. More specifically, the point of interest is the uranium price level from which an advanced pressurized water reactor with its higher conversion ratio is able to reduce the electricity generating costs compared to a present pressurized water reactor. (orig.)

[en] Reprocessing several hundred thousand tons of spent fuel from military reactors has demonstrated the excellent suitability of the liquid-liquid extraction technique also for the separation of radioactive substances. The transferability of that experience with low-burnup fuel to the extraction behavior of high-burnup fuel is influenced greatly by the cooling time of the fuel. Low-burnup fuel from military reactors is reprocessed after only a short cooling time, while high-burnup fuel from light water reactors is not reprocessed before a few year's cooling time. The activity concentration, heat output and dose rate data determined with the help of a computer program for low-burnup fuel and fuel from modern light water reactors show that extraction behavior is comparable for the cooling times to be considered. As a consequence, the positive experience accumulated in reprocessing low-burnup fuel by the PUREX process can in practice be transferred to the reprocessing of high-burnup LWR fuel. (orig.)

[en] In accordance with the decision by the heads of the Federal and State Governments of September 28, 1979 about the back end of fuel cycle, the direct final storage of spent fuel is investigated in addition to the waste management approach including reprocessing. The German Federal Ministry for Research and Technology (BMFT) in 1979 commissioned the Karlsruhe Nuclear Research Center to carry out a preparatory study of the worldwide state of the art in the field of direct final storage. That study constituted the basis of the follow-up activities carried out since early 1981 on behalf of BMFT within the framework of the ''Other Waste Management Techniques'' main activity. A technical concept of the direct final storage of spent fuel from light water reactors is to be elaborated by late 1984, on the basis of which the comparison of the safety aspects of the waste management concepts with and without reprocessing is to be made as requested by the political agencies. (orig.)

[en] The construction and operation of nuclear power plants is forbidden by law in Austria. This rule is based on the Nuclear Ban Act of December 30, 1978, not the referendum of November 5, 1978, as is frequently assumed. As the Act has never been the subject of a referendum, it could be repealed by parliament in a simple majority vote. This course is prevented merely by political opinions. One major cause of the misconceptions about the legal situation is the lack of clarity in the original Act rejected in the referendum which, on the one hand, was to render the commissioning of nuclear power plants more difficult by introducing another approval step but, on the other hand, at the same time expressed a permit for the finished plant of Zwentendorf. The politicians interpreted the rejection of the Act by a slight margin not as a rejection of the additional aggravation, which would have left the legal situation unchanged, but as a rejection merely of the new permit for Zwentendorf (which thus had never been decided upon). (orig.)