Consideration on the earthquake-resistant margin of equipment base-bolts receiving the shearing load during seismic movements

Sakaguchi, Shinobu; Tachibana, Ikuya; Koshino, Katsuhiko; Shirozu, Hidetomo; Shirai, Nobutoshi; Imamoto, Nobuo; Tomita, Tsuneo; Tobita, Hiroo; Yamanaka, Atsushi; Kobayashi, Daisuke; et al.

JAEA-Technology 2011-006, 24 Pages, 2011/03

JAEA-Technology-2011-006.pdf:3.07MB

In the Niigataken Chuetsu-oki Earthquake on 2007, observed earthquake motion exceeded design base at the Kashiwazaki Kariwa nuclear plant. However, there was no earthquake damage in safety important equipments to stop reactor, to cool reactor, and to contain radioactive materials. One of this reason is said that many safety margin are included in the design and the permissible value. To know more accurate safety margin, shearing force examinations for the base bolts were conducted. In examinations, delegate test-bolts were made; the test bolts were selected from heavier equipment in Tokai Reprocessing Plant. In this report, the shearing strength obtained from the examinations shows more accurate safety margin.

Design and Manufacture of JOYO MK-III Heat Transport System; Main Intermediate Heat Exchanger

Kondo, Hitoshi; Isozaki, Kazunori; Kawahara, Hirotaka; Tomita, Naoki

JNC TN9410 2003-004, 137 Pages, 2003/06

JNC-TN9410-2003-004.pdf:10.25MB

The MK-III project to improve the irradiation capability of the experimental fast reactor JOYO have been in underway.The MK-III project has three major purposes such as increasing high neutron flux, improvement of plant availability factor and upgrading in irradiation techniques. The increase of fast neutron flux and the enlargement of that field increase the reactor thermal rate from 100MWt to 140MWt. The main components in the cooling system such as intermediate heat exchangers (IHXs) and dump heat exchangers (DHXs) were replaced in MK-III modification in order to increase heat removal capability. These components replacement has been safely carried out from October 30, 2000 to September 21, 2001.The new IHX that has 70MWt rated heat exchange rate was installed to the location where old one was installed, so the mew IHX was designed with almost same geometry as old one. The design was carefully reviewed on structural integrity, shielding performance, thermal hydraulics, pressure loss, flow induced vibration and component design criterion and earthquake-proof class. A newly developed stainless steel named 316FR was adopted as a major structure material of the new IHX. The 316FR was developed for usage of sodium cooled fast reactor and has improved creep rupture and creep fatigue strength. In the design the following problems to be solved were cleared, These problems arise from defect of old IHX, increase of temperature difference between outlet and inlet and increase of sodium flow rate.(1)Reduction of ineffective flow to increase the heat transfer efficiency.(2)Suppression of CP(Corrosion Products) adhesion.(3)To prevent falling down of sodium free surface accompanied by increase of sodium flow.(4)Mitigation of thermal transient.This report describes the specific characteristic in the design and manufacturing, design data and principle of the design for the new IHX. The design was proved on above mentioned problem (3) by measurement of sodium free surface lev

Compensation of higher order dispersion on idler pulse compression scheme, 2; Idler dispersion compensation with pump phase modulation

Akahane, Yutaka; Tomita, Hitoshi*; Ogawa, Kanade; Nishioka, Hajime*; Yamakawa, Koichi

no journal, , 

For generation of intense few-cycle laser pulse with our idler pulse compression scheme, we have now been studying residual high-order dispersion compensation of idler pulses with pump phase modulation. The pump pulse has a narrow bandwidth with respect to signal or idler pulses, which you can easily control the pump phase by spatial light modulator or other conventional devices. And once a proper phase modulation is fixed, you can apply the modulation by some robust device such as such fiber Bragg grating or volume Bragg grating in practical use. From the first phase measurement of OPA interacting pulses, we have found that the sign of the 3rd order dispersion of the idler pulse have been inverted from the signal one and the sign of 4th order have not been inverted, which had not been expected from theory without considering the effect from pump phase modulation.