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; Hayashi, Hideyuki; ; ;
PNC TN9410 94-222, 355 Pages, 1994/07
A design study on a large scale fast reactor was performed with focusing on enhancement of passive safety and capital cost reduction. The passive safety feature in the plant design of next generation fast reactors is one of the important subjects to be sought. In FY 1993, studies on 1300MWe class lage fast reactor were performed aiming at passive shutdown in a typical ATWS such as the unprotected loss of flow accident (ULOF). This report describes the core design, systems design, equipments design and the technical assessment in terms of the passive safety feature. It also includes the evaluation of the seismic as well as thermal capacity of reactor building of the large fast reactor.
Shimoyama, Kazuhito; Hamada, Hirotsugu; Tanabe, Hiromi; Usami, Masayuki
PNC TN9410 93-212, 134 Pages, 1993/09
A one-through unit type steam generator (SG) having the Mod.9Cr-1MO Steel for its heat transfer tube is considered to be promising for the development of large FBR SGs. Wastage data of the tube material was already obtained for the micro-/small leak region as formerly reported. Therefore, intermediate leak wastage tests were conducted in the range from 10 g/s to around 200 g/s by using the SWAT-1 test facility and the test results are summarized as follows: (1)The wastage resistivity of the Mod.9Cr-1Mo steel is between that of 2.25Cr-1Mo steel and austenitic stainless steel; namely, the Mod.9Cr-1Mo steel has about half the of wastage rate of the 2.25Cr-1Mo steel. An experimental wastage formula in the intermediate leak region was derived from the test data. (2)Almost all of the wastage profile of target tubes was toroidal type and it became about half the cross section area of the 2.25Cr-1Mo steel. An experimental formula on initial leak diameters versus equivalent secondary failure diameters was derived in the intermediate leak region. These test results would be applied to failure propagation analysis code LBAP which is to be used for the design of a one-through unit type SG.
M.E.Kab*; Hayafune, Hiroki
PNC TN9410 92-018, 58 Pages, 1992/01
This report describes the result of the analysis of unprotected Loss of Flow (LOF) ansient experiment conducted at the PLANt Dynamics Test Loop (PLANDTL) experimentalfility by Super System Code (SSC) and SubAssembly Boiling EvolutioN Analysis (SABENA)ode. This report also describes the effect of the modification we made in SSC with t recent void fraction and two-phase friction multiplier models during the analysis othe experiment. After the analysis, it was found that the two-fluid two-phase flow mel of SABENA 1-D is better than the homogeneous model of SSC in predictiong the therhydraulic behavior within the simulated fuel bundle test section of thePLANDTL facily in case of high quality sodium boiling experiment. Moreover, it wasalso revealed tt the two-fluid one dimensional model is not accurate enough in predicting the onsetf boiling and axial evolution of boiling region inside the heatedchannel.
*; *; Aoi, Sadanori*
PNC TN941 82-74VOL1, 151 Pages, 1982/03
PNC-TN941-82-74VOL1.pdf:7.53MB
A study of hypothetical core disruptive accidents (HCDAs) in the prototype fast breeder reactor Monju (714 MWt) has been conducted by using the SAS3D
accident analysis code. A loss-of-flow (LOF) due to the loss of off-site power and a transient overpower (TOP) due to control assembly withdrawal, both at rated power, are considered as the HCDA initiators with a postulated total failure of the reactor shutdown system. The accident scenarios of each postulated anticipated transient without scram are studied for the three burnup stages of Monju: the beginning-of-initial cycle (BOIC) ; a beginning-of-equilibrium cycle (BOEC); and an end-of-equilibrium cycle (EOEC). The neutronics data used in this study has been obtained by a 3-dimensional HEX-Z diffusion code and the first order perturbation calculations. The reactivity coefficients used in this study are the design nominal values without taking into account their uncertainties. The nominal design value of the maximum positive sodium void worth in Monju is a relatively small value of 2.5$ in the EOEC core. In the 2 cents/sec TOP, the reactor power shows a sudden increase following the onset of FCIs (Molten-Fuel/Coolant Interactions) in high-powered fuel assemblies but the maximum power level reached is less than 5 times the rated power and due to the fuel sweepout negative reactivity in the FCI fuel assemblies, the reactor is shutdown within 0.1 sec at the latest after the first FCI onset. The extent of damaged fuel assemblies is largest in the clean (FP-gas free) BOIC core in which the radial power peaking is smaller than in BOEC and EOEC cores, and about 17% of the fuel assemblies are damaged in the central region of the core. In the equilibrium cycle cores the damage extents are limited to about 5% core-center assemblies and this is smaller than in the BOIC core because of the larger radial power peaking and the rapid fuel sweepout reactivity insertion accelerated by the FP-gas pressure in the ...
Tobita, Yoshiharu; Suzuki, Toru; Tagami, Hirotaka
no journal, ,
The event progression in the transition phase of ULOF (Unprotected Loss of Flow), which is the representative event in ATWS (Anticipated Transient without Scram) of fast breeding reactor. The existing experimental knowledges on the important phenomena, which dominates the event progression, were adopted in the nominal case. The reactivity lowered with accordance to the fuel discharge through control rod guide tube and the event terminated without prompt criticality. If the uncertainty was considered in the analysis, the reactivity slightly exceeded the prompt criticality, but no mechanical energy was produced.
Sogabe, Joji; Wada, Yusaku*; Suzuki, Toru*; Tobita, Yoshiharu
no journal, ,
no abstracts in English
Hamase, Erina; Ohgama, Kazuya; Kawamura, Takumi*; Doda, Norihiro; Yamano, Hidemasa; Tanaka, Masaaki
no journal, ,
Validation of an analysis model for a plant dynamic analysis code named Super-COPD including neutronics calculation of a one-point reactor kinetics model necessitates the further work on the beyond design basis accident. Therefore, JAEA participated in IAEA benchmark for Loss of Flow without Scram (LOFWOS) test No.13 performed at the Fast Flux Test Facility (FFTF), and the transient analysis at the first blind phase considering with major reactivity feedback mechanisms was carried out. It was observed that the whole plant dynamics analysis could follow the measured data. As a future work, the gap conductance model for transient, the upper plenum of reactor vessel with dividing several regions or multi-dimensional modeling, and the core model that can evaluate the radial heat transfer rate more accurately will be refined.