[en] The effect of pair correlation, one of the most important residual interactions associated with the super-deformed rotation band, is discussed in terms of the characteristics of the rotation band (its effect on the moment of inertia in particular), and the tunneling into an normal deformed state in relation to its effect on the angular momentum dependence of the potential energy plane as a function of the deformation. The characteristics of the rotation band is discussed in terms of the kinematic and dynamic momenta of inertia. It is shown that the pair correlation in a super-deformed rotation band acts to decrease the former and increase the latter momentum mainly due to dynamic pair correlation. A theoretical approach that takes this effect into account can provide results that are consistent with measured momenta, although large differences can occur in some cases. Major conflicts include a large measured kinetic momentum of inertia compared to the theoretical value, and the absence of the abnormality (shape increase) generally seen in low-spin experiments. The former seems likely to be associated with the method of measuring the angular momentum. (N.K.)

[en] The improvement of the dose evaluation method for criticality accidents is important to rationalize design of the nuclear fuel cycle facilities. The source spectrums of neutron and gamma ray of a criticality accident depend on the condition of the source, its materials, moderation, density and so on. The comparison of the dose evaluation methods for a criticality accident is made. Some methods, which are combination of criticality calculation and shielding calculation, are proposed. Prompt neutron and gamma ray doses from nuclear criticality of some uranium systems have been evaluated as the Nuclear Criticality Slide Rule. The uranium metal source (unmoderated system) and the uranyl nitrate solution source (moderated system) in the rule are evaluated by some calculation methods, which are combinations of code and cross section library, as follows: (a) SAS1X (ENDF/B-IV), (b) MCNP4C (ENDF/B-VI)-ANISN (DLC23E or JSD120), (c) MCNP4C-MCNP4C (ENDF/B-VI). They have consisted of criticality calculation and shielding calculation. These calculation methods are compared about the tissue absorbed dose and the spectrums at 2 m from the source. (author)

[en] Criticality Accident Alarm Systems (CASs) are important for the rapid evacuation and the reduction of the operators' exposure. Though some methods shown in ANSI/ANS-8.3 etc., the relation between fissions and dose were evaluated for some source materials and shields under criticality accident. The connection of the criticality calculation for the decision of the source spectrum and the shielding calculation for the evaluation of the dose at the detectors were executed. MCNP4C and ENDF/B-VI cross-section library were used to criticality calculation and ANISN and DLC-23E cross-section library were used for shielding calculation. As the sources of the criticality accident, the uranyl nitrate solution, plutonium nitrate solution, and PuO₂ powder were considered. The concrete and iron were considered for the shielding material of the facilities. The distance from the accident points to the detectors of CAS was constant for simplification. The possibility of the detection of the CAS and area monitors was studied numerically. The effectiveness of area monitors for the detection of the slow excursion was also evaluated numerically. (author)

[en] If the fire accident was occurred in the Glove Box (GB) in the nuclear fuel cycle facilities, it is important to clear the fluctuation of the negative pressure in GB and the influence of the ventilation system. In Japan Nuclear Cycle Development Institute, the fire and extinguishment experiments about the GB ventilation system were executed. The simulations with a calculation code of these experiments were also performed. In this report, FIRAC was improved and these experiments were evaluated with FIRAC. FIRAC, which was developed in Los Alamos National Laboratory in U.S., is a computer code to simulate fire accidents in nuclear facilities. The original FIRAC can not simulate the GB ventilation system adequately. The original FIRAC can not simulate the inflow of the suffocative gas for the extinguishment experiments. The control damper model, the correction of storage of heat, the heat conduction of the construction materials, the model of the hot layer and cold layer, the model of inflow of the suffocative gas, etc., were improved, and the FIRAC is performed to simulate these experiments fitly. (author)

[en] Fifty-one patients with gynecologic malignancies were tested for paraaortic lymphnode metastasis by ultrasound and computed tomography (CT). Eleven patients were found to have paraaortic lymphnode metastasis by ultrasound, and CT also showed the same metastatic image in the same patients. The site and size of the positive image found by both means were identical. The other forty patients diagnosed by ultrasound as free of metastasis were also proved to have no metastasis by CT. Ultrasound is as useful as CT in the evaluation of paraaortic nodes. However, ultrasound is more convenient and easier to use than CT. (author)

[en] The high temperature gas-cooled test reactor HTR-10 achieved the first criticality in last December in Institute of Nuclear Energy Technology of Tsinghua University in Beijing. Fuji Electric and Nissho Iwai have a cooperative information exchange agreement on the commercialization of the HTGRs with INET, and held an information exchange meeting in last March in INET. INET has started a study on the modification of the HTR-10 to couple with gas turbine system and a pre-feasibility study on the commercial HTGR under the cooperation with China State Power Company. The experiences and abilities of INET in the field of the HTGR and the aggressive plan for commercialization of the HTGR in China are summarized and discussed. (author)

[en] As a part of the safety confirmation work of Tokai Reprocessing Plant, the appropriateness was checked on the basic data used in criticality safety and shielding design of early-designed facilities in the plant on the basis of recent knowledge and safety evaluation methods. In the criticality safety design, it was confirmed that critical and subcritical values concerning mass and concentration of U and Pu and equipment dimension were appropriate. In the shielding design, it was found that the relation between shielding thickness and permissible radioactivity might give underestimated results of shielding thickness necessary to limit dose rate to the designated one on some condition. In this cases, however, it was confirmed that necessary shielding thickness has been secured because of the conservative calculation conditions for the real conditions except the operation test laboratory (OTL). However, the amount of radioactivity handled at OTL needs to be limited. From a viewpoint of criticality safety, operational control for U and Pu transfer was also investigated. As a result of it, at the transfer route where erroneous batch-wise transfer of process solution might lead to a criticality accident, the reliability of U and Pu concentration measurement needs to be improved by multiple measurements. At other transfer routes, it was confirmed that single failure of equipment or operation error would not lead to a criticality problem. (author)

[en] In plant designs and safety evaluations of nuclear fuel cycle facilities, it is important to evaluate the direct radiation and the skyshine (air-scattered photon radiation) from facilities reasonably. The Neutron and Photon Shielding Calculation System for Workstation (NPSS-W) was developed. The NPSS-W can carry out the shielding calculations of the photon and the neutron easily and rapidly. The NPSS-W can easily calculate the radiation source intensity by ORIGEN-S and the dose equivalent rate by SN transport calculational codes, which are ANISN and DOT3.5. The NPSS-W consists of five modules, which named CAL1, CAL2, CAL3, CAL4, CAL5). Some kinds of shielding calculational systems are calculated. The user's manual of NPSS-W, the examples of calculations for each module and the output data are appended. (author)

[en] At the Plutonium Conversion Development Facility (PCDF) in the Nuclear Fuel Cycle Engineering Laboratories, the co-conversion technologies to purify the mixed plutonium and uranium nitrate solution discharged from a reprocessing plant have been developed. The probability of a criticality accident in PCDF is extremely low. However, the criticality accident alarm system (CAAS) has been in place since 1982 to reduce the radiation dose to workers in case of such a rare criticality accident. The CAAS contains criticality accident detector units (CADs), one unit consisting of three plastic scintillation detectors, and using the 2 out of 3 voting system for the purpose of high reliability. Currently, eight CADs are installed in PCDF evaluating the dose using a simple equation allowing for a safety margin. The purpose of this study is to show the determination procedures for the adequate relocation of the CADs which adequately ensures safety in PCDF. (author)

[en] The prognosis was examined in 41 patients who underwent total hysterectomy for localized recurrence following radiotherapy for cervica cancer. The clinical stage of the cancer prior to radiotherapy, its histological type, the time elapsed from the initial radiotherapy to recurrence, the extent of tumor removal upon hysterectomy, the maximum diameter of the tumor in the excised uterus, and the presence or absence of endometrial invasion were assessed as possible factors affecting prognosis. The following conclusions were reached : 1) The three-year and five-year survival rates of the 41 patients were 62.2 percent and 51.7 percent, respectively. 2) The clinical stage and histological type of the cancer prior to radiotherapy did not significantly affect the prognosis after total hysterectomy. 3) The time elapsed from the initial radiotherapy to the localized recurrence was not correlated with the prognosis. 4) The three-year survival rate for the patients in whom the tumor could be removed completely was 73.3 percent, while it was 14.3 percent among those in whom only subtotal removal was possible; the prognosis was clearly better (p < 0.01) after total tumor resection. 5) The prognosis was better (p < 0.01) when the maximum diameter of the tumor in the excised uterus was less than 2 cm than when the maximum diameter was 2 cm or more. 6) The prognosis was clearly better (p < 0.01) when endometrial infiltration was found in tissue samples of the excised uterus than when there was no endometrial involvement. (author)