Kazuaki Yanagisawa

Transient fuel behavior of preirradiated PWR fuels under reactivity initiated accident conditions

Abstract Since 1975, extensive studies on transient fuel behavior under reactivity initiated accident (RIA) conditions have been continued in the Nuclear Safety Research Reactor (NSRR) of Japan Atomic Energy Research Institute. A new experimental program with preirradiated LWR fuel rods as test samples has recently been started. In this program, transient behavior and failure initiation have been studied with 14 × 14 type PWR fuel rods preirradiated to a burnup of 20 to 42 MWd/kgU. The test fuel rods contained in a capsule filled with the coolant water were subjected to a pulse irradiation in the NSRR to simulate a prompt power surge in an RIA. The effects of preirradiation on the transient fission gas release, pellet-cladding mechanical interaction and fuel failure were clearly observed through the transient in-core measurements and postirradiation examination.

Economic Scale of Utilization of Radiation (III) : Medicine : Comparison between Japan and the U. S. A.

Our previous study revealed that the use of radiological technology in medicine was spreading in Japan. For example, in 1991, the economic scale was about 10b

Dimensional Stability of Uranium Silicide Plate-Type Reactors at Transient Condition

(billion dollars, 1

Out-of-pile tests of simulated rock-like oxide (ROX) fuels

=121¥) corresponding to 4% of the national health expenditures (240b

A study on the behavior of pressurized hollow UO2 fuel under reactivity initiated accident conditions

) or 0.24% of the nominal GDP (gross domestic products, 4,231b

Fuel microstructural analysis of incubation burn-up for fission gas release

). This time, the economic scale was compared between Japan and the U.S.A. within limited parameters. (1) For the TDHE (total domestic health expenditures) base, it was 981b

Fuel densification and swelling: Relationship between burn-up induced axial and radial fuel dimensional changes

in the U.S.A. and 219b

Density, Porosity and Grain Size, (I) Unirradiated ROX Fuels

in Japan, implying that the American people spent rather much money for their health. (2) For the economic scale estimated by studying parameters (ESP), approximately 49b

Behaviour of small-sized BWR fuel under reactivity initiated accident conditions in comparison with standard BWR fuel

for the U.S.A. and 12b

Density, Porosity and Grain Size, (II) Irradiated ROX Fuels to Burn-up of 28%FIMA

for Japan. ESP in the former is large in magnitude by a factor of 4, implying that U.S.A. people do not hesitate to use radiological technologies for curing their diseases. This tendency was clearly observed by the expenditures on prostate cancer and the FDG-PET and so on. (3) The ratio between ESP and GDP within the scope of this study was 0.6% for the U.S.A. and 0.3% for Japan. The use of medical radiology may be enlarged in the future due to its high quality of life (QOL).