Classification of Supernovae

The current classification scheme for supernovae is presented. The main observational features of the supernova types are described and the physical implications briefly addressed. Differences between the homogeneous thermonuclear type Ia and similarities among the heterogeneous core collapse type Ib, Ic and II are highlighted. Transforming type IIb, narrow line type IIn, supernovae associated with GRBs and few peculiar objects are also discussed.Comment: 16 Pages, 4 figures, to be published in "Supernovae and Gamma-Ray Bursters," ed. Kurt W. Weile

Review of lifetime analyses for tokamaks

System studies have vividly shown that economic fusion power can only be achieved from the use of long lived components. Lifetime goals of 90 MW-yr/m/sup 2/ for a tokamak based power plant should be established. The stresses generated in a first wall module are a complex function of its geometry, the chosen structural material and the tokamak burn cycle characteristics. A formalism based on the foundaion ASME Code Case 1592 has been established. Methods of incorporating some of the changes expected from irradiation are discussed. The cyclic stress pattern imposed by tokamak operation is expected to cause fatigue related properties to govern the life of the structure. Stress assisted bubble growth is suggested as the possible critical mechanism in establishing the stress-to-rupture life of a fusion first wall component

Thermal stress and creep fatigue limitations in first wall design

The thermal-hydraulic performance of a lithium cooled cylindrical first wall module has been analyzed as a function of the incident neutron wall loading. Three criteria were established for the purpose of defining the maximum wall loading allowable for modules constructed of Type 316 stainless steel and a vanadium alloy. Of the three, the maximum structural temperature criterion of 750/sup 0/C for vanadium resulted in the limiting wall loading value of 7 MW/m/sup 2/. The second criterion limited thermal stress levels to the yield strength of the alloy. This led to the lowest wall loading value for the Type 316 stainless steel wall (1.7 MW/m/sup 2/). The third criterion required that the creep-fatigue characteristics of the module allow a lifetime of 10 MW-yr/m/sup 2/. At wall temperatures of 600/sup 0/C, this lifetime could be achieved in a stainless steel module for wall loadings less than 3.2 MW/m/sup 2/, while the same lifetime could be achieved for much higher wall loadings in a vanadium module

Fusion Power Program quarterly progress report, April--June 1977

Separate abstracts were prepared for four of the included sections. (MOW

Resistive requirements for the vacuum wall of a Tokamak Fusion Reactor

The effect of having a conducting vacuum wall, instead of one with a flux breaker, has been analyzed from a multi-disciplinary standpoint. There is a good indication that a conducting wall will be tolerable. The most serious problems seem to be in designing an acceptable initiation-trimming coil system and in designing a vacuum wall that can withstand the pressure and heat loads following a plasma dump. There appear to be several promising design approaches for the vacuum wall that can achieve a fairly high resistance and may satisfy the latter constraints