[en] There is an introductory review on the present status of covariance for evaluated nuclear data. The following articles are briefly discussed: Necessity of covariance for evaluated data, basic assumption of covariance production, dependency of produced covariance on methods, consistency of evaluated value and covariance, confirming of produced covariance and methods of comparing covariance matrices. (author)

[en] Covariances for evaluated nuclear data can be usefully estimated by combining experimental and theoretical information. In this report, the covariances generated on various assumptions are compared to search their significance by using neutron-induced reactions of ⁵⁶Fe and ⁵⁴Fe as examples. The theoretical information used to calculate their cross sections is the Hauser-Feshbach formulae and the parameters required in it. Only level density parameters are considered as the sources of the theoretical uncertainty and the other parameters used in the cross section calculation such as optical model parameters are fixed. The reference correlation (a covariance matrix is factored to a correlation matrix and a standard deviation vector) is defined as the resultant one calculated with prior level density parameters which originate in Gilbert-Cameron. The prior level density parameters are adjusted to make the calculated cross sections fitting to the experimental encounters as possible, and then the new covariance estimated with the adjusted level density parameters is obtained, called the posterior covariance. Comparing the posterior with the prior, the effect of the experimental information to the resultant covariance can be estimated. This makes it clear that the posterior correlation is finely changed as that correlation at the further distance is smaller than the prior (the reference). It is reasonably understood that short range correlation is strengthen through the experimental data. In addition, the effects of the correlation between level density parameters and between experimental points in the identical set are studied. They are small. On the basis of these works, the useful method of the covariances estimation from combined experimental and theoretical data can be developed

[en] The six activation cross sections, ²⁷Al(n,p), ²⁷Al(n,α), ⁵⁴Fe(n,p), ⁵⁶Fe(n,p), ⁵⁹Co(n,α), and ⁵⁸Ni(n,p) and their covariances have been simultaneously evaluated from differential experiments in which samples are activated with monoenergetic neutron sources and the integral experiments with ²³⁵U(n,f) and ²⁵²Cf(spontaneous) fission neutron spectra. The evaluated cross sections are smaller than those only with the differential data. It depends on a temperature in the Maxwellian formula of the fission neutron spectrum

[en] Position-dependent optimization calculations have been carried out on a D-D fusion reactor blanket/shield to maximize the energy gain in the blanket and to minimize the atomic displacement rate of the copper stabilizer in the superconducting magnet. The results obtained by using the optimization code SWAN indicate the advantage of D₂O coolant over H₂O coolant with respect to increasing the energy gain, and the difference in the optimal shield distributions between D-T and D-D neutron sources. The possibility of improving both the energy gain and radiation shielding characteristics is also discussed

[en] Covariances for evaluated cross sections are generated with the methods based on the uncertainties of experimental data or estimated by combining experimental and theoretical information. The former methods are in principle preferred but are limited in application because of lack of experimental information. The latter methods are available in many cases. However, they have been generated with the procedures which are adopted by individual evaluators as to adapt to their understanding for covariances. The values of the estimated covariances which decisively depend on the adopted procedures are too different at every evaluation to be agree by other evaluators and be accepted by users of them. In order to arrive at an agreement about the definitive understanding of the covariance generation we must discuss on this problem. It is another problem to solve the one mentioned above that the method to visualize the covariance must be developed to quantitatively compare it with the other. (author)

[en] A nuclear analysis was carried out for a heavy ion-beam fusion reactor, HIBLIC. The analysis includes the target and chamber neutronics, time-dependent radiation damage in the first wall, and radiation streaming through beam ports. It is found that the reactor chamber is characterized by its high tritium breeding ratio, low radiation damage in the second wall, and low induced activity. To reduce the radiation damage in the superconducting, focusing magnets, tapering the beam ports along the direct line-of-sight component of thesource neutron is necessary in the magnet regions and also in the collimator region

[en] Neutronic calculations were performed to optimize the SENRI blanket in terms of energy multiplication as well as tritium breeding ratio. The blanket employs a thick ( about 64-cm) Li layer as breeder/coolant. Three approaches were taken here to achieve the goal: reduction of ⁶Li in the lithium, replacement of the Li layer by a molten-salt (flibe) layer, and shipment of excess tritium to a nonbreeding blanket. It was found that the excess tritium produced in the SENRI blanket could be used effectively to obtain additional power by fueling a nonbreeding D-T reactor

[en] A new method to detect the quench of a superconducting magnet is presented. This method detects a change of the acoustic transfer function of a magnet caused by the local temperature rise, wire movement, etc. This time, we have tried to improve the detection sensitivity to a temperature rise of 2-3 K. Some experiments have been carried out using a small epoxy impregnated superconducting magnet and a plain GFRP rod. Experimental results show that although the gain characteristics of the transfer function do not change clearly, the phase characteristics show a clear change through the local temperature rise. We have also considered the optimal frequency of the acoustic wave for the detection of the local temperature rise. (orig.)

[en] Characteristics and estimated methods of the uncertainty of evaluated cross sections are discussed restricting to the evaluation of cross sections from differential experiments. The reason on the adoption of the differential data is described from the definition of the cross section. The evaluation is based on the assumption that the experimental data distribute in Gaussian distribution and the theory of error is applicable. The errors in a few typical experiments are shown to understand partial errors. The uncertainties associated with evaluation to are discussed. (author)

[en] Secondary ion mass spectrometry (SIMS) provides very sensitive chemical and elemental information. Nanoscale SIMS analysis is, however, very difficult to carry out by conventional methods, mainly because of the primary beam diameter and vibrations. In our work, we used the latest technology for focused ion beam (FIB) formation, which realizes nanoscale beam diameter. Our detection system (Mattauch-Herzog type mass-analyzer and 120-channel parallel detector) realizes highly sensitive parallel-mass-detection with parallel counting units. In order to minimize the influence of vibrations, the sample was mounted on the end cap of FIB column directly. Under this condition, the ion induced secondary electron image of a vacuum-evaporated Au film on a carbon plate was obtained without the influence of vibrations. The beam profile and a secondary ion image of the IC pattern was obtained using same geometry. The lateral resolution was estimated to be 30 nm at worst. As a result, simultaneous multi-elemental measurements on nanoscale dimension became possible