[en] This report is prepared from the proceedings of the Workshop on RF Heating in Magnetic Mirror Systems held at DOE Headquarters in Washington, DC, on March 10-12, 1980. The workshop was organized into four consecutive half-day sessions of prepared talks and one half-day discussion. The first session on tandem mirror concepts and program plans served to identify the opportunities for the application of rf power and the specific approaches that are being pursued. A summary of the ideas presented in this session is given. The following sessions of the workshop were devoted to an exposition of current theoretical and experimental knowledge on the interaction of rf power with magnetically confined, dense, high temperature plasmas at frequencies near the electron cyclotron resonance, lower hybrid resonance and ion cyclotron resonance (including magnetosonic) ranges. The conclusions from these proceedings are presented

[en] A common format to present the information on each project has been adopted. Projects are selected for inclusion in this document based on knowledge of their direct relevance or contribution to the magnetic mirror confinement program. The information on each project was first compiled in draft form from published literature and reports available. The draft material was then sent to key individuals associated with each project, with the original source of information identified, to solicit their additions and corrections. The responses were then reviewed and discrepencies with previously published information clarified through further consultations. The information was then incorporated into this document with a revision date to reflect the state of currency of the information

[en] The authors propose an alternative approach to a test facility that eliminates both the need for tritium purchase and allows full testing of the system components as an attractive route for the development of fusion power. The approach is a staged transition in a single engineering test facility from driven deuterium-deuterium (D-D) to full D-T operations. The basic idea is to use the D-D fusion reaction to generate tritium in situ for the D-T reactions to occur at levels comparable to a thermonuclear D-T plasma. The neutrons generated in the process can then be used for material and system testing and for development of effective breeding blankets. The concept differs from fully catalyzed D-D reactors in that it is to be optimized for neutron wall loading rather than power balance. Therefore, the confinement requirements are significantly more relaxes. On the other hand it is possible to attain significant neutron wall loading. There are several advantages associated with this alternative scenario for developing D-T fusion power. First and foremost, it totally eliminates the uncertainty and cost associated with assuring the availability of tritium. Secondly, the approach does not prematurely commit the development of fusion power to a specific confinement configuration. Third, the performance of the device can be continuously upgraded to meet the requirements for more critical testing, thereby compressing the time schedule needed for developing the necessary data

No abstract available

[en] Radiotherapy is a major treatment modality for head and neck cancer. It is often not possible to exclude the salivary glands from the treatment fields. The unique susceptibility of the serous cells of the salivary glands to irradiation often results in xerostomia with ensuing secondary complications and discomfort to the patients. Recent reports have suggested that continuous hyperfractionated accelerated radiotherapy (CHART) can lead to considerably less reduction in salivary flow of the parotid salivary gland than conventional radiotherapy. This study was undertaken to assess histologic changes of salivary glands induced by CHART and conventional radiation fractionation schedules. The parotid and submandibular salivary glands of adult rhesus monkeys were irradiated with cobalt-60 γ radiation at 50 Gy/20 fractions/4 weeks, 55 Gy/25 fractions/5 weeks, or 54 Gy/36 fractions/12 days (CHART). Salivary tissues were harvested at 16 weeks following irradiation and evaluated histopathologically. Microscopically, the glands receiving 50 Gy, 55 Gy, or CHART were virtually indistinguishable. There was severe atrophy and fibrosis of all glands. Quantitative analysis revealed that 50 Gy, 55 Gy, and CHART induced a reduction of serous acini in parotid glands by 86.4%, 84.8%, and 88.8%, respectively. In submandibular glands, serous acini were reduced by 99.4%, 99.0%, and 100%, respectively. The corresponding reduction in mucous acini were 98.4%, 98.4%, and 99.2%, respectively. These histopathologic and quantitative morphologic studies show that the magnitude of serous gland atrophy in the parotid and submandibular salivary glands of rhesus monkeys was similar at 16 weeks after receiving 50 Gy in 20 fractions, 55 Gy in 25 fractions, or CHART

[en] The U.S. program in tandem mirror confinement is being developed on a broad range of experimental facilities. The basic thermal barrier tandem mirror configuration is being developed on TMX-U to demonstrate the basic physics, to be followed at LLNL, with MFTF-B for scaling to close to reactor conditions. Other U.S. facilities include the TARA and Phaedrus tandem mirrors at MIT and the University of Wisconsin, respectively; the Symmetric Tandem Mirror (STM) at TRW; and a number of smaller experiments to study specific aspects of tandem mirror physics. Formation of the thermal barrier end plug potential profile by using sloshing ions and ECRH, was recently demonstrated on TMX-U and axial confinement times of 50-100 msec have been achieved. Several research efforts are now being directed to controlling and improving radial transport

[en] In the present scenario for the development of magnetic confinement fusion, the availability of tritium needed to fuel a D-T burning plasma in order to generate 14 MeV neutrons for material and system component testing is not being fully addressed. An alternate approach based on the in situ generation of tritium in a driven D-D reacting plasma is proposed. The feasibility of this approach to attain 14 MeV neutron flux levels comparable with D-T fueled burning plasma from a modest beta, first generation fusion power reactor can be established from known results. A staged scenario, is described in which tritium bred from developmental blankets is used to fuel the system to incrementally raise the neutron wall loading to simulate more advanced fusion reactors

[en] The effect of fludarabine (9-β-d-arabinosyl-2-fluoroadenine-5'-monophosphate), an adenine nucleoside analogue, on the tolerance of the spinal cord to fractionated irradiation was studied in a rat model. Anesthesized female Fisher 344 rats received irradiation to 2 cm of the cervical spine with a telecobalt unit (dose rate 1.14 Gy/min). Radiation was administered in two, four or eight fractions spread over a 48-h period with or without fludarabine. Animals assigned to combined therapy received two daily intraperitoneal injections of fludarabine (150 mg/kg) given 3 h prior to the first daily radiation fraction. It was found that fludarabine reduced the iso-effect dose required to induce leg paresis at 9 months after irradiation for all fractionation schedules. Dose modification factors of 1.23, 1.29 and greater than 1.27 were obtained for two, four and eight fractions, respectively. Fitting the data with the direct analysis method of Thames et al. with an incomplete repair model [18] showed that the potentiating effect of fludarabine may be mediated through reduction in the number of 'tissue-rescuing units' (lnK). Alpha and β values were slightly but not significantly decreased, whereas the (α(β)) ratio was unchanged. These features suggest that fludarabine did not significantly inhibit cellular repair processes but rather reduced the spinal cord tolerance by a fixed additive toxic effect on the same target cells. In rodent models, the combination of fludarabine and fractionated radiation has previously been found to yield a therapeutic gain, i.e., the drug enhanced tumor response to a greater extent than it reduced normal tissue tolerance. However, given our results, caution should be exercised in extrapolating these findings to the clinic. Normal tissue reactions will have to be monitored rigorously in phase I clinical studies

[en] The principal purpose of this study was to make an assessment of potential risks to the public from earthquake-caused accidents at the Diablo Canyon Nuclear Power Plant. Since large earthquakes are relatively rare events at any given location and nuclear power plants are required to be designed to high standards of strength, such studies deal inevitably with small probabilities determined from combinations of rare events. Some of the methods used in the study were based on those used in the Reactor Safety Study, a recent comprehensive study conducted by the Nuclear Regulatory Commission for nuclear plants of the Diablo Canyon type. In this study, which was specifically devoted to risks from earthquakes, all the data and conditions used were based on those applicable to the Diablo Canyon Plant and site characteristics. Among other results, it was found that even when considering the impact on the plant of accelerations well in excess of the maximum which the NRC has asked the company to consider, the risk to the health and safety of the public caused by possible earthquake damage to the plant was found to be extremely remote. As an illustration, the probability of an individual in the closest community to the site being exposed to as much as 25 Rem of radiation to the whole body is only about one in seven million per year

[en] An experiment was conducted to test for the existence of a volume effect in radiation myelopathy using Rhesus monkeys treated with clinically relevant field sizes and fractionation schedules. Five groups of Rhesus monkeys were irradiated using 2.2 Gy per fraction to their spinal cords. Three groups were irradiated with 8 cm fields to total doses of 70.4, 77, and 83.6 Gy. Two additional groups were irradiated to 70.4 Gy using 4 and 16 cm fields. The incidence of paresis expressed within 2 years following the completion of treatment was determined for each group. Maximum likelihood estimation was used to determine parameters of a logistic dose response function. The volume effect was modeled using the probability model in which the probability of producing a lesion in an irradiated volume is governed by the probability of the occurrence of independent events. This is a two parameter model requiring only the estimates of the parameters of the dose-response function for the reference volume, but not needing any additional parameters for describing the volume effect. The probability model using a logistic dose-response function fits the data well with the D₅₀ = 75.8 Gy for the 8-cm field. No evidence was seen for a difference in sensitivities for different anatomical levels of the spinal cord. Most lesions were type 3, combined white matter parenchymal and vascular lesions. Latent periods did not differ significantly from those of type 3 lesions in humans. The spinal cord exhibits a volume effect that is well described by the probability model. Because the dose response function for radiation myelopathy is steep, the volume effect is modest. The Rhesus monkey remains the animal model most similar to humans in dose response, histopathology, and latency for radiation myelopathy. 22 refs., 3 figs., 1 tab