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Journal Articles

Development of safety assessment code for decommissioning of nuclear facilities (DecDose)

Shimada, Taro; Oshima, Soichiro*; Sukegawa, Takenori

Journal of Power and Energy Systems (Internet), 4(1), p.40 - 53, 2010/02

https://doi.org/10.1299/jpes.4.40

A safety assessment code, DecDose, for decommissioning of nuclear facilities has been developed, based on the experiences of the decommissioning project of Japan Power Demonstration Reactor (JPDR) at Japan Atomic Energy Research Institute DecDose evaluates the annual exposure dose of the public and workers according to the progress of decommissioning, and also evaluates the public dose at accidental situations including fire and explosion. As for the public, both the internal and the external doses are calculated by considering inhalation, ingestion, direct radiation from radioactive aerosols and radioactive depositions, and skyshine radiation from waste containers. For external dose for workers, the dose rate from contaminated components and structures to be dismantled is calculated. Internal dose for workers is calculated by considering dismantling conditions, e.g. cutting speed, cutting length of the components and exhaust velocity. DecDose was partially verified by comparison with the actual external dose of workers which were acquired during JPDR Decommissioning Project.

Journal Articles

Development of safety assessment code for decommissioning of nuclear facilities (DecDose)

Shimada, Taro; Oshima, Soichiro; Sukegawa, Takenori

Proceedings of 17th International Conference on Nuclear Engineering (ICONE-17) (CD-ROM), 8 Pages, 2009/07

A safety assessment code, DecDose, for decommissioning of nuclear facilities has been developed, based on the experiences of the decommissioning project of Japan Power Demonstration Reactor (JPDR). DecDose evaluates the annual exposure dose of the public and workers according to the progress of decommissioning of the plant, and also evaluates the public dose at accidental situations including fire and explosion. The DecDose is expected to contribute to utilities in formulating rational dismantling plans and to the safety authority in estimating conservativeness in safety assessment of licensing application or risk-based regulatory criteria.

Journal Articles

Observation of high-$$j$$ quasiparticle states in $$^{249}$$Cm by in-beam $$gamma$$-ray spectroscopy using heavy-ion transfer reactions

Ishii, Tetsuro; Makii, Hiroyuki*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shigematsu, Soichiro*; Kaneko, Junichi*; Shizuma, Toshiyuki; et al.

Physical Review C, 78(5), p.054309_1 - 054309_11, 2008/11

https://doi.org/10.1103/PhysRevC.78.054309
 Times Cited Count：14 Percentile：64.91(Physics, Nuclear)

Journal Articles

In-beam $$gamma$$-ray spectroscopy of neutron-rich nuclei in the uranium region through the heavy-ion transfer reaction

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; et al.

Nuclear Physics A, 805(1-4), p.257 - 259, 2008/06

https://doi.org/10.1016/j.nuclphysa.2008.02.090

no abstracts in English

Journal Articles

Z dependence of the $$N = 152$$ deformed shell gap; In-beam $$gamma$$-ray spectroscopy of neutron-rich $$^{245, 246}$$Pu

Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato*; Ichikawa, Shinichi; et al.

Physical Review C, 76(6), p.061301_1 - 061301_5, 2007/12

https://doi.org/10.1103/PhysRevC.76.061301
 Times Cited Count：28 Percentile：83.47(Physics, Nuclear)

We have measured deexcitation $$gamma$$ rays for the first time in the neutron-rich nuclei of $$^{246}$$Pu$$_{152}$$ and $$^{245}$$Pu$$_{151}$$ produced by the ($$^{18}$$O, $$^{16}$$O) and the ($$^{18}$$O, $$^{17}$$O) reactions, respectively. The ground-state band of $$^{246}$$Pu was established up to 12$$^{+}$$ states. The systematics of the moments of inertia of $$_{94}$$Pu isotopes suggests that the $$N = 152$$ deformed subshell closure disappears in these isotopes. The measurements of deexcitation $$gamma$$ rays in $$^{245}$$Pu shows a small energy spacing between neutron orbitals at $$N = 152$$, which explans the disappearance of the subshell closure.

Journal Articles

In-beam $$gamma$$-ray study of the neutron-rich nuclei of $$^{240}$$U, $$^{246}$$Pu, and $$^{250}$$Cm produced by the ($$^{18}$$O, $$^{16}$$O) reaction

Ishii, Tetsuro; Shigematsu, Soichiro*; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.

Physics of Atomic Nuclei, 70(8), p.1457 - 1461, 2007/08

https://doi.org/10.1134/S1063778807080224
 Times Cited Count：9 Percentile：56.38(Physics, Nuclear)

We have measured deexcitation $$gamma$$ rays in the neutron-rich nuclei of $$^{240}$$U, $$^{246}$$Pu and $$^{250}$$Cm. These nuclei were produced by the ($$^{18}$$O, $$^{16}$$O) two-neutron transfer reactions with a 200, 162 and 162 MeV $$^{18}$$O beams and a $$^{238}$$U, $$^{244}$$Pu and $$^{248}$$Cm targets, respectively, using the tandem accelerator at Tokai, Japan. The $$gamma$$ rays in residual nuclei were measured by taking coincidence with scattering particles using Si $$Delta E$$-$$E$$ detectors. We have identified $$gamma$$ rays in $$^{240}$$U, $$^{246}$$Pu and $$^{250}$$Cm by selecting the kinetic energies of $$^{16}$$O particles which correspond to the excitation energies in these nuclei below their neutron separation energies. The ground-state bands of $$^{240}$$U, $$^{246}$$Pu and $$^{250}$$Cm were established up to 12$$^{+}$$ states and the $$K^{pi}=0^{-}$$ octupole band of $$^{240}$$U was established up to 9$$^{-}$$ state. Because the deformations of these nuclei are well developed, the moments of inertia reflect the pairing gap, which is expected to be smaller, resulting in a larger moment of inertia, at the deformed shell closure. We have found that the moment of inertia of the ground-state band of $$^{248}$$Cm$$_{152}$$ is considerably larger than that of $$^{250}$$Cm$$_{154}$$. This fact supports the existence of the deformed subshell closure at $$N=152$$ in Cm isotopes. On the other hand, the moment of inertia of $$^{246}$$Pu$$_{152}$$ was found to be smaller than that of $$^{244}$$Pu$$_{150}$$, which suggests that the deformed subshell closure at $$N=152$$ weakens or disappears in Pu isotopes. These results are consistent with the prediction by a cranking model calculation.

Journal Articles

Ground-state bands of neutron-rich $$^{236}$$Th and $$^{242}$$U nuclei and implication of spherical shell closure at $$N=164$$

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; et al.

Physical Review C, 76(1), p.011303_1 - 011303_5, 2007/07

https://doi.org/10.1103/PhysRevC.76.011303
 Times Cited Count：14 Percentile：67.84(Physics, Nuclear)

The ground-state bands of the neutron-rich $$^{236}$$Th and $$^{242}$$U nuclei were established up to spin 10 and 8, respectively, by in-beam $$gamma$$-ray spectroscopy using the ($$^{18}$$O, $$^{20}$$Ne) two-proton pickup reaction with a $$^{238}$$U and a $$^{244}$$Pu target. Deexcitation $$gamma$$ rays in $$^{236}$$Th and $$^{242}$$U were identified by selecting the kinetic energies of $$^{20}$$Ne using Si $$Delta E$$-$$E$$ detectors. The excitation energies of the first 2$$^{+}$$ states in U and Pu isotopes have local minima at $$N simeq 146$$, suggesting the possibility that nuclei with $$Z simeq 92$$ have a spherical shell closure of $$N=164$$. Calculation using the Koura-Yamada single-particle potential gives an energy gap of 1.8 MeV at $$N=164$$ for $$^{256}$$U.

Journal Articles

Ground-state band of the neutron-rich transuranium nucleus $$^{250}$$Cm$$_{154}$$

Ishii, Tetsuro; Shigematsu, Soichiro; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.

Journal of the Physical Society of Japan, 75(4), p.043201_1 - 043201_4, 2006/04

https://doi.org/10.1143/JPSJ.75.043201
 Times Cited Count：19 Percentile：68.4(Physics, Multidisciplinary)

The ground-state band of the neutron-rich transuranium nucleus $$^{250}$$Cm was established up to spin 12 by in-beam $$gamma$$-ray spectroscopy using the two-neutron-transfer reaction with a $$^{248}$$Cm target and a 162 MeV $$^{18}$$O beam. Deexcitation $$gamma$$ rays in $$^{250}$$Cm were identified by selecting the kinetic energies of $$^{16}$$O particles with Si $$Delta E$$-$$E$$ detectors. The moment of inertia of $$^{250}$$Cm$$_{154}$$ is considerably smaller than that of $$^{248}$$Cm$$_{152}$$, which supports the existence of the deformed subshell closure at $$N=152$$ in Cm isotopes.

JAEA Reports

Study of decommissioning cost evaluation technique for nuclear reactor dismantlement; Calculation of decommissioning cost by COSMARD

Oshima, Soichiro; Shiraishi, Kunio; Shimada, Taro; Sukegawa, Takenori; Yanagihara, Satoshi

JAERI-Tech 2005-046, 46 Pages, 2005/09

JAERI-Tech-2005-046.pdf:3.43MB

A model for estimating decommissioning costs consisting of labor cost, device cost and expense, was developed for items which OECD/NEA had standardized, and was installed into the computer system for planning and management of reactor decommissioning (COSMARD). Input data files and databases for the decommissioning of JPDR were prepared, and the decommissioning cost was calculated with COSMARD. In addition, the decommissioning cost for a large scale BWR power plant was also calculated on the assumption of the advantage of scale. The calculations have shown that it is useful and efficient for studying the decommissioning costs for nuclear reactors to apply the COSMARD with database for cost estimation to the decommissioning cost calculation.

Journal Articles

Development of public dose assessment code for decommissioning of nuclear reactors (DecDose)

Shimada, Taro; Oshima, Soichiro; Ishigami, Tsutomu; Yanagihara, Satoshi

Proceedings of 10th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '05) (CD-ROM), 8 Pages, 2005/09

In order to review an operator's "Decommissioning Plan" applied to the regulatory body for approval accurately and quickly, Public Dose Assessment Code for Decommissioning of Nuclear Reactors (DecDose) was developed. It evaluates public exposure doses for each year during dismantling activities in accordance with the "Decommissioning Plan". DecDose takes account of various exposure pathways such as cloudshine, surface ground deposition, ingestion of seafood, and direct and skyshine radiation based on the quantity of radionuclides discharged to the environment, and containers stored in the facility in consideration of cutting and storage of components and structures. Example evaluations with DecDose have shown that it is a useful tool for assessing public dose during decommissioning of nuclear reactors.

JAEA Reports

Characterization of the nuclear power plants in decommissioning program and influence evaluation on decommissioning costs

Mizukoshi, Seiji; Oshima, Soichiro; Shimada, Taro

JAERI-Tech 2005-011, 122 Pages, 2005/03

JAERI-Tech-2005-011.pdf:13.25MB

The radiological and physical characteristic on decommissioning, such as component and structure weights and radioactivity of the 1.1 MWe class reference nuclear power plants summarized in the NUREG reports of the US NRC were classified,arranged and compared with the domestic commercial nuclear power plants and JPDR from a view point of dismantling plan and waste management for decommissioning. As the results, it was found that the radioactive component and structure weights was about 28,000ton、and non-radioactive structure weights was about 124,000ton less than the domestic commercial BWR. And it was found that this differences has mainly influenced dismantling costs for decommissioning. Farther, it was found that the concrete element composition rates of B, Ni, Nb and so were differerence of one or more figures btween the reference nuclear power plants and the domestic commercial PWR or JPDR.Also,it was found that the this difference became about two or three times by radioactivity concentration and has mainly influenced transport and disposal costs for decommissioning.

JAEA Reports

Development of computer systems for planning and management of reactor decommissioning; A Study on influence of work difficulty factors on project management data and simplification of work breakdown structures (Contract research)

Oshima, Soichiro; Sukegawa, Takenori; Shiraishi, Kunio; Yanagihara, Satoshi

JAERI-Tech 2001-086, 83 Pages, 2001/12

JAERI-Tech-2001-086.pdf:5.23MB

Project management data on dismantling the Japan Power Demonstration Reactor (JPDR) was calculated using the Code System for Planning and Management of Reactor Decommissioning (COSMARD), and then its validity was studied by comparing the calculation results with actual data. In addition, work breakdown structure models and database were modified to meet an evaluation with changing work difficulty of preparation and cleanup activities, and calculations were further conducted to analyze feasibility by changing various conditions on cutting and conditioning activities. As the results, COSMARD was verified to be useful by confirming calculation capability on reflection of actual work conditions and relatively good agreement between actual data and calculations. Moreover, it was cleared that main parameters such as work difficulty of preparation and cleanup activities and the cutting speed in demolition work could affect to manpower within 30% in each calculations.

Journal Articles

Development of computer systems for planing and management of reactor decommissioning; Estimation of project management data on Dismantling Tokai Power Station

Yanagihara, Satoshi; Oshima, Soichiro; Sukegawa, Takenori; Tanabe, Norio*; Takaya, Junichi*; Kiuchi, Yoshio*; Yokota, Shuichi*

Nihon Genshiryoku Gakkai-Shi, 43(5), p.493 - 502, 2001/05

https://doi.org/10.3327/jaesj.43.493
 Times Cited Count：1 Percentile：12.01(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Development of project management data calculation models relating to dismantling of nuclear facilities (Contract research)

Sukegawa, Takenori; Oshima, Soichiro; ; Yanagihara, Satoshi

JAERI-Data/Code 99-005, 65 Pages, 1999/02

JAERI-Data-Code-99-005.pdf:3.5MB

no abstracts in English

Oral presentation

Development of computer programs for evaluation of public exposure dose in decommissioning of nuclear reactor facilities, 4

Shimada, Taro; Oshima, Soichiro; Ishigami, Tsutomu

no journal, , 

no abstracts in English

Oral presentation

In-beam $$gamma$$-ray measurement of the neutron-rich nucleus $$^{250}_{96}$$Cm$$_{154}$$

Ishii, Tetsuro; Shigematsu, Soichiro; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.

no journal, , 

no abstracts in English

Oral presentation

In beam $$gamma$$-ray measurement of the neutron-rich nucleus $$^{246}$$Pu

Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato; Ichikawa, Shinichi; et al.

no journal, , 

no abstracts in English

Oral presentation

In-beam $$gamma$$-ray spectroscopy of the neutron-rich $$^{236}$$Th and $$^{242}$$U nuclei produced by the ($$^{18}$$O,$$^{20}$$Ne) reaction

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato; et al.

no journal, , 

no abstracts in English

Oral presentation

In-beam $$gamma$$-ray spectroscopy of neutron-rich $$^{245,246}$$Pu and properties of $$N = 152$$ deformed shell closure

Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato; Ichikawa, Shinichi; et al.

no journal, , 

We have measured in-beam $$gamma$$ rays in the neutron-rich $$^{246}$$Pu$$_{152}$$ and $$^{245}$$Pu$$_{151}$$ nuclei by means of $$^{244}$$Pu($$^{18}$$O, $$^{16}$$O)$$^{246}$$Pu and $$^{244}$$Pu($$^{18}$$O, $$^{17}$$O)$$^{245}$$Pu neutron transfer reactions, respectively. The ground-state band of $$^{246}$$Pu was established up to the $$12^+$$ state. The systematics of the 2$$^+$$ energies for the ground-state bands of Pu isotopes suggests that the $$N = 152$$ deformed shell closure disappears in Pu. The measurement of deexcitation $$gamma$$ rays in $$^{245}$$Pu shows a small energy spacing between the neutron orbitals at $$N = 152$$, which explains the disappearance of the shell closure.

Oral presentation

In-beam $$gamma$$-ray spectroscopy of more neutron-rich nuclei than the $$beta$$-stability line in the U region; $$^{236}$$Th, $$^{240,242}$$U, $$^{246}$$Pu, $$^{250}$$Cm

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; et al.

no journal, , 

The ground-state bands of $$^{236}$$Th,$$^{240,242}$$U, $$^{246}$$Pu and $$^{250}$$Cm were established by measuring deexcitation $$gamma$$ rays. These nuclei were produced by the ($$^{18}$$O, $$^{16}$$O) and ($$^{18}$$O, $$^{20}$$Ne) two-nucleon transfer reactions with $$^{238}$$U, $$^{244}$$Pu and $$^{248}$$Cm targets. The $$gamma$$ rays in residual nuclei were identified by taking coincidence with scattering particles using high-resolution Si $$Delta E$$-$$E$$ detectors. By extending the systematics of the 2$$_{1}^{+}$$ energies into neutron-rich nuclei, we have found that the $$N=152$$ deformed shell gap disappears at $$_{94}$$Pu isotopes and that U and Pu isotopes have the possibility of the spherical shell closure at $$N=164$$.

27 (Records 1-20 displayed on this page)