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JAEA Reports

Critical mass evaluation of minor actinides in aqueous solution; Data for criticality safety assessment of separation process

Morita, Yasuji; Fukushima, Masahiro; Kashima, Takao*; Tsubata, Yasuhiro

JAEA-Data/Code 2020-013, 38 Pages, 2020/09

JAEA-Data-Code-2020-013.pdf:1.94MB

Critical Masses of Cm, Am and the mixture were calculated in metal-water mixtures with water reflector as a basic data for criticality safety assessment of minor actinide separation process. In the mixture of Cm-244 and Cm-245, higher ratio of Cm-245 gives smaller critical mass, but the amount of Cm-245 in the critical mass can be obtained by concentration of Cm-245 in the Cm mixture without depending on the Cm-245 ratio. Critical mass of Cm isotope mixture with 30% Cm-245 was smaller than that of Pu isotope mixture in the practical reprocessing (71% Pu-239 + 17% Pu-240 + 12% Pu-241). When Cm is separated from other element including Am and the solution is concentrated, measure for the critical accident has to be taken. Critical mass of Am-242m is smaller than that of Cm-245, but the ratio of Am-242m in the Am contained in practical spent fuel is small enough, about several percent, and therefore the critical accident by Am does not have to be considered. That by the mixture of Am and Cm does not either.

Journal Articles

Critical and subcritical mass calculations of curium-243 to -247 based on JENDL-3.2 for revision of ANSI/ANS-8.15

Okuno, Hiroshi; Kawasaki, Hiromitsu*

Journal of Nuclear Science and Technology, 39(10), p.1072 - 1085, 2002/10

https://doi.org/10.3327/jnst.39.1072

Times Cited Count：2 Percentile：17.03(Nuclear Science & Technology)

Critical and subcritical masses were calculated for a sphere of five curium isotopes from 243Cm to 247Cm, in metal and in metal-water mixtures, considering three reflector conditions: bare, with a water reflector or a stainless steel reflector. The calculation were made mainly with a combination of a continuous energy Monte Carlo neutron transport calculation code, MCNP, and the Japanese Evaluated Nuclear Data Library, JENDL-3.2. Other evaluated nuclear data files, ENDF/B-VI and JEF-2.2, were also applied to find differences in calculation results of the neutron multiplication factor originated from different nuclear data files. A large dependence on the evaluated nuclear data files was found in the calculation results.

Journal Articles

Temperature and magnetic field dependence of the critical current density for a mass-produced Nb $_{3}$ Al multifilamentary strand fabricated by a jelly-roll method

Takahashi, Yoshikazu; Koizumi, Norikiyo; Nunoya, Yoshihiko; Takaya, Yoshiyuki*; Tsuji, Hiroshi

IEEE Transactions on Applied Superconductivity, 12(2), p.1799 - 1803, 2002/06

https://doi.org/10.1109/TASC.2002.1020340

Times Cited Count：5 Percentile：35.09(Engineering, Electrical & Electronic)

JAERI has been developing jelly-roll processed multifilamentary Nb $_{3}$ Al/Cu strands for the Toroidal Field (TF) coils of fusion tokamak machines since 1986, in cooperation with industries. One ton of mass-produced strands were successfully manufactured for the 13T-46kA Nb $_{3}$ Al insert which will be tested using the ITER Central Solenoid model coil. The critical current of the Nb3Al strand developed for the ITER project was measured in temperatures from 4.2 K to 15 K and in applied magnetic fields up to 16 T. An empirical equation for the critical current density was devised using these data and the pinning force scaling method. Good agreement between this equation and the measured data is obtained in the operating condition of the ITER machine. The equation is useful in evaluating the performance of the full-size conductor that consists of 1,152 strands and in establishing the optimum design criteria for the conductor in fusion machines.

JAEA Reports