Removal of cover gas boundary components on the rotating plug of the experimental fast reactor Joyo

Okuda, Eiji; Suzuki, Toshiaki; Fujinaka, Hideaki

JAEA-Technology 2013-038, 42 Pages, 2014/01

JAEA-Technology-2013-038.pdf:82.62MB

With the incident as an opportunity, repair techniques were developed in Joyo. The cover gas boundary components on rotating plug were removed as a preparation work for Joyo restoration work. The removed components are the door valve for fuel handling hole, hold-down shaft driving mechanism and door valve for inspection hole (A). Because these components were designed as the maintenance free. These components haven't been overhauled for more than 30 years since the construction of Joyo. Since the cover gas radioactivity was quite low due to the long time reactor shutdown, the new method was applied in this removal work. In order to prevent the contaminant of impurities in cover gas, the boundary was secured by temporary green house with slight negative pressure. Achievement of this work and accumulated experience will be able to provide valuable insights for further improving and verifying repair techniques in sodium cooled fast reactors.

Periodic Safety Review of the Experimental Fast Reactor JOYO; Review of Aging Management

Isozaki, Kazunori; Ogawa, Toru; Nishino, Kazunari; Kaito, Yasuaki; Ichige, Satoshi; Sumino, Kozo; Suto, Masayoshi; Kawahara, Hirotaka; Suzuki, Toshiaki; Takamatsu, Misao; et al.

JNC TN9440 2005-003, 708 Pages, 2005/05

JNC-TN9440-2005-003.pdf:31.46MB

Periodic safety review (Review of the aging management) which consisted of Technical review on aging for the safety related structures, systems and components and Establish a long term maintenance program was carried out up to April 2005.1. Technical review on aging for the safety related structures, systems and components It was technically confirmed to prevent the loss of function of the safety related structures, systems and components due to aging phenomena, which (1) irradiation damage, (2) corrosion, (3) abrasion and erosion, (4) thermal aging, (5) creep and fatigue, (6) Stress Corrosion Cracking, (7) insulation deterioration and (8) general deterioration, under the periodic monitoring or renewal of them 2. Establish a long term maintenance program The long term maintenance program during JPY2005 to 2014 were established based on the technical review on aging for the safety related structures, systems and components. It was evaluated that the inspection or renewal based on the long term maintenance program, in addition to the spontaneous inspection long-term schedule of the long term voluntary inspection plan, could prevent the loss of function of the safety related structures, systems and components in future.

Experimental Fast Reactor "JOYO" MK-3 Function Test; Interlock test of the primary and secondary cooling system and function test of the remote automatic fuel handling control system

Michino, Masanobu; Suzuki, Toshiaki; Aita, Tsuyoshi; Suto, Masayoshi; Saito, Takakazu; Kawahara, Hirotaka; Isozaki, Kazunori; Ito, Hideaki; Inoue, Setsunari; Aoki, Hiroshi; et al.

JNC TN9430 2004-001, 103 Pages, 2004/03

JNC-TN9430-2004-001.pdf:4.06MB

This report describes the results of the primary and secondary cooling system interlock test and the fuel handling system function test, which were done as a part of JOYO MK-3 function test. The items of the test are: (1) Primary and secondary cooling system interlock test (SKS-106,210) (2) Loss of electric power supply test (SKS-116) (3) In-vessel and ex-vessel automatic fuel transportation test (SKS-501,502) As the interlock of the primary and secondary cooling system was changed, the interlock test by the reactor scram and the loss of electric power supply was carried out. The function of the remote automatic fuel handling system was confirmed before the handling of the fuel for MK-3 core configuration. The results of the test satisfied the required performance, and it was confirmed that operation of the primary and secondary cooling system interlock and operation of the fuel handling system in JOYO MK-3 were normal.

non

Aoyama, Takafumi; Suzuki, Toshiaki; Takatsuto, Hiroshi; Oowada, Toshio; Oyama, Nobumi; Emori, Shuichi

PNC TN9418 97-006, 93 Pages, 1997/12

PNC-TN9418-97-006.pdf:52.66MB

non

Summary of countermeasures for reduction of radiation exposure from radioactive corrosion products(CPs) deposited on fuel cleaning system of "JOYO"

; Ito, Hideaki; Okubo, Toshiyuki;

PNC TN9410 95-105, 85 Pages, 1995/05

PNC-TN9410-95-105.pdf:3.86MB

Many subassemblies have been washed by water in the fuel cleaning system of JOYO, and a large amount of radioactive corrosion products(CPs) was removed from the surface of the subassemblies. These CPs deposited on the wall of piping and components in the system cause radiation exposure of personnel at operation and maintenance of the system. Following countermeasures for the reduction of radiation exposure have been conducted from 1991 to 1994. (1)ldentification of radiation source points by a Radiation image Display(RID). (2)Shielding of components in the system. (3)Rearrangment of water drain lines. (4)Replacement of water circulation piping. (5)lnstallation of a mist trap to the argon gas circulation line. (6)Installatlon of drain piping to valves of the argon gas circulation line. The dose rate in the fuel cleaning equipment room(A-212) was reduced to about one third after conducting the countermeasures. This report discribes the result of the countermeasures for the reduction of radiation exposure of personnel at operation and maintenance of the fuel cleaning system in "JOYO".

Inspection and repair techniques in reactor vessel of sodium cooled fast reactor, 2; Visual inspection technique in reactor vessel of the experimental fast reactor Joyo

Saito, Takakazu; Suzuki, Toshiaki; Kawahara, Hirotaka; Isozaki, Kazunori; Nagai, Akinori

no journal, , 

no abstracts in English

Inspection and repair techniques in reactor vessel of sodium cooled fast reactor, 4-2; Replacement of the upper core structure, 2

Sekine, Takashi; Takamatsu, Misao; Naito, Hiroyuki; Maeda, Shigetaka; Suzuki, Toshiaki; Isozaki, Kazunori

no journal, , 

Restoration work for restart of the experimental fast reactor Joyo need to replace the damaged upper core structure (UCS). The in-vessel dose rate was measured to evaluate the activation of the UCS which is reflected to optimize the shielding design of a UCS replacement cask and a MARICO-2 handling tool. In-vessel visual observation using radiation resistant fiberscopes was conducted to investigate the sodium deposition on the surface of the UCS and small rotating-plug.

Regular evaluation of "Joyo" (2nd) about long-term maintenance plan and its implementation situation (I)

Kikuchi, Yuki; Tobita, Shigeharu; Suzuki, Toshiaki; Kawahara, Hirotaka

no journal, , 

no abstracts in English

Maintenance management of fuel handling and storage system in the experimental fast reactor "JOYO"

Kawakami, Shodai; Suzuki, Toshiaki; Takahashi, Tsuyoshi*; Fujinaka, Hideaki; Miura, Yoshiyuki

no journal, , 

no abstracts in English