[en] This paper concerns five figures or charts presented during the workshop: nuclear power generation in Japan, nuclear waste in Japan, development of japanese HLW disposal, framework of implementation, stepwise approach for siting. (A.L.B.)

[en] Since the commencement of Japan's civil nuclear programme in 1966, the importance of nuclear power as an energy source has been growing. This paper discusses Japan's current and future nuclear policy and the issues that will have to be resolved to achieve the twin goals of sufficient energy generation and meeting the requirements of the Kyoto protocol. (author)

[en] Extensive in-pile fuel experiments, simulating both transient and long-term irradiation conditions, have been carried out by the Japanese Atomic Energy Research Institute (JAERI) in the NSR, JMT and HBW reactors. The test results are reflected in the verification and development of analytical codes to predict fuel behaviour. The NSRR is a test programme to investigate fuel failure thresholds and post-failure phenomena under reactivity accident conditions. In these tests, fuel samples in a capsule or a loop are exposed to a rapid pulse power with up to 1.12ms reactor period to experience failure. More than fifty experiments have been performed in NSRR on fresh fuel rods. Test results show that fuel failure occurs by the cladding melting at a fuel enthalpy around 265cal/g UO₂ and that serious failure with mechanical energy release is caused by the melting of UO₂ pellets only at very high fuel enthalpy over 340cal/g UO₂. Water-logged fuels suffer failure by internal pressure at approximately 110cal/g UO₂. A total of approximately 400 experiments using 800 fuel rods will be carried out until 1980 as the first phase of the NSRR programme. Regarding long-term irradiation, five fuel rods were irradiated in JMTR and are undergoing post-irradiation examination. Densification phenomena due to change in density, grain size and pore distribution in pellets are being investigated. Furthermore, a total of 23 fuel assemblies have been irradiated in HBWR to investigate hydriding effect, moisture failure, pellet densification and pellet-clad interaction. A computer code, FREG-3, has been developed to predict the change in fuel characteristics with irradiation history such as swelling, relocation, densification and change in gap conductance. (author)

[en] Extensive inpile fuel experiments, simulating both transient and long term irradiation conditions, have been carried out by JAERI. Those are the experiments in NSRR, JMTR and HBWR. The test results have been reflected in verification and development of analytical codes to predict fuel behavior. The NSRR is a test program to investigate fuel failure thresholds and post failure phenomena under reactivity accident conditions. In these tests, fuel samples in a capsule or a loop are exposed to a rapid pulse power with up to 1.12 msec of reactor period to suffer failure. More than fifty experiments, have been performed in NSRR on fresh fuel rods. Test reults show that fuel failure occurs by melting of cladding at heat deposition around 265 cal/gr.UO₂ and that serious failure with mechanical energy release is caused by melting of UO₂ pellets only at very high heat deposition over 340 cal/gr.UO₂. Water-logged fuels suffer failure by internal pressure at approximately 110 cal/gr.UO₂. A total of approximately 400 experiments using 800 fuel rods will be carried out until 1980, as the first phase of the NSRR program. As for long term irradiation, five fuel rods were irradiated in JMTR and they are undergoing post irradiation examination. Densification phenomena due to the change in density, grain size and pore distribution in pellets are being investigated. Furthermore, a total of 23 fuel assemblies have been irradiated in HBWR to investigate hydriding effect, moisture failure, pellet densification and PCMI. A computer code FREG-3 has been developed to predict the change in fuel characteristics with irradiation history such as swelling, relocation, densification and change in gap conductance. FREG-3 calculation on IFA-224 experiment shows excellent agreement in center temperature between measurements and analysis in the test range of irradiation up to 10,000 MWD/T.UO₂ under heat rate of up to 600 W/cm

[en] Sequelae of the treatment of children with acute lymphocytic leukemia (ALL) include multiple effects on the endocrine system, especially as it relates to growth and puberty. Thyroid dysfunction, and in particular, the occurrence of thyroid neoplasia, has been only rarely described. We report the development of benign thyroid neoplasms in two patients 9 years following the diagnosis and treatment of ALL. Both patients were clinically and biochemically euthyroid with noncystic cold nodules found on thyroid scan. In light of these observations, and along with previous reports of malignant thyroid neoplasia in children with ALL, long-term careful observation of children successfully treated for ALL is indicated. 17 references