Preparation of low O/M MOX pellets for fast reactors using carbothermic reduction

Murakami, Tatsutoshi; Kato, Masato; Suzuki, Kiichi; Uno, Hiroki*

Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.1859 - 1865, 2010/06

The sintering behavior of the de-waxed pellets containing about 3000 ppm of carbon was analyzed during the sintering process using thermal gravimetry and dilatometer measurements as a parameter of the ratio of hydrogen partial pressure-to-moisture partial pressure (H/HO) in the sintering atmosphere. The attained O/M ratio and the shrinkage rate increased with decreasing H/HO ratio in the sintering atmosphere. As a result, it is considered that a carbothermic reduction caused the significant decrease of the O/M ratio in the case of the sintering in the atmosphere of high H/HO ratio. In contrast, decrement of O/M ratio could be inhibited by keeping the oxygen potential of the atmosphere high in the case of the sintering in the atmosphere of lower H/HO ratio.

Application of integrated safety assessment methodology (ISAM) to Japanese sodium-cooled fast reactor (JSFR)

Kurisaka, Kenichi; Shimakawa, Yoshio*

Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.1220 - 1227, 2010/06

JAEA participates in activities of the Generation IV International Forum's Risk and Safety Working Group (GIF/RSWG). The GIF/RSWG has developed the Integrated Safety Assessment Methodology (ISAM), which consists of five distinct analytical tools; i.e., Qualitative Safety Features Review, Phenomena Identification and Ranking Table (PIRT), Objective Provision Tree (OPT), Deterministic and Phenomenological Analyses (DPA) and Probabilistic Safety Analysis (PSA). Among them, PIRT, OPT, DPA and PSA were applied preliminarily to the Japanese Sodium-cooled Fast Reactor (JSFR) system. The JSFR system includes major innovative safety features such as Self-Actuated Shutdown System (SASS), passive decay heat removal system. PIRT was applied to examination of the reactor safe shutdown by means of SASS during a loss-of-flow accident with a failure of conventional reactor shutdown system. OPTs were developed to assess the structure of safety architecture of the JSFR in an adequate manner based on the defence-in-depth philosophy. Some provisions explicitly shown in the OPT are characterized with the safety design requirements of decay heat removal function. Sufficiency to those requirements was confirmed by DPA. PSA was conducted with analytical models, which were based on those OPT and DPA results. The PSA served to quantification of the level of safety and to the system design improvement in the JSFR.

Comparative study on advanced fuel handling systems for JSFR

Chikazawa, Yoshitaka; Uzawa, Masayuki*; Usui, Shinichi*; Tozawa, Katsuhiro*; Kotake, Shoji

Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.10142_1 - 10142_9, 2010/06

Development of the JSFR fuel handling system and mockup experiments of fuel handling machine in abnormal conditions

Kato, Atsushi; Hirata, Shingo; Chikazawa, Yoshitaka; Uto, Nariaki; Obata, Hiroyuki*; Kotake, Shoji*; Uzawa, Masayuki*

Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.692 - 699, 2010/06

In the JSFR design, a single rotating plug and an upper inner structure (UIS) with a vertically penetrating slit are proposed, so that the fuel handling machine (FHM) can access any subassembly by horizontal movement of the FHM arm in the slit space. As a result of a full-scale mockup test, excellent performance in normal operation has been shown. In this study, from the viewpoint of achieving reliability of the pantograph type FHM, behavior of the FHM mockup have been investigated under abnormal conditions.

U-RANS simulation of unsteady eddy motion in pipe elbow at high Reynolds number conditions

Tanaka, Masaaki; Ohshima, Hiroyuki; Yamano, Hidemasa; Aizawa, Kosuke; Fujisaki, Tatsuya*

Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.1699 - 1708, 2010/06

Numerical simulations with the Unsteady Reynolds Averaged Navier Stokes equation (U-RANS) approach are examined at high Reynolds number conditions in the 1/3 scale water experiment which is a scale model of the hot-leg piping of JSFR. Applicability of the U-RANS approach to the unsteady flow through the short-elbow is confirmed and the pressure fluctuation generation mechanism in relation to the unsteady large scale eddy motion is clarified. Moreover, preliminary numerical simulation of a full-scale model of the hot-leg piping of JSFR is examined and applicability of the URANS approach to the hot-leg piping of JSFR is confirmed.

An Indirect effect of green technology by Japanese LWRs

Yanagisawa, Kazuaki; Nagano, Koji*

Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.2140 - 2149, 2010/06

(1) The cost of electricity generated by 54 Japanese light water reactors in 2005 is 16,466 million dollars at the supply end and is 42,682 million dollars at the demand end. (2) The nuclear market is expensive for the construction cost (2.0 cent per kWh) but cheap for the fuel cost (1.4 cent per kWh). The introduction of LWR can reduce gross amounts of fuels and then increase the gross domestic products (GDP). (3) During a nuclear cycle the emitted carbons from LWR (22g per kWh) is from one 23rd to one 44th of those from fossil power plants. The gross electricity produced in Japan in 2004 is about 8,651 TWh. Emitted carbons assuming that coal and petroleum are main carbon contributors are 7.43E08 ton. The no fossil fuels can suppress the amounts by 3.79E08 ton, where the contributing ratio of nuclear energy is 57%. An indirect effect of green technology by Japanese LWRs is estimated to be from 3,993 to 5,989 million dollars.