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JAEA Reports

The 4th technological meeting of Tokai Reprocessing Plant

; Maki, Akira; ; ; ; ; Fukuda, Kazuhito

JNC TN8410 2001-023, 188 Pages, 2001/11

JNC-TN8410-2001-023.pdf:30.98MB

"The 4th technological meeting of Tokai Reprocessing Plant (TRP)" was held in JNFL Rokkasyo site on octorber 11 $^{th}$ , 2001. The report contains the proceedings, transparancies and questionnaires of themeetin. This time, we reported about "Maintenance and repair results of Tokai Reprocessing Plant" based on technology and knowledge accumulated in Tokai Reprocessing Plant.

JAEA Reports

Manufacture of ultrasonic thickness measurement apparatus

Oba, Toshihiro; Yanagihara, Takao; Kato, Chiaki; Hamada, Shozo

JAERI-Tech 2001-059, 36 Pages, 2001/09

JAERI-Tech-2001-059.pdf:7.8MB

The demonstration test for evaluating reliability of the acid recovery evaporator at Rokkasho Reprocessing Plant has been carried out at JAERI. For the nondestructive mesurement of the thickness of heat transfer tubes in the acid recovery evaporator and short tubes used in corrosion test, we have developed ultra sonic thickness measuring apparatus using immersion method with high resolution. This apparatus can measure and record tube thickness automatically with a personal computer. The results obtained by this apparatus are coincident with the results obtained by a destructive method using an optical microscope.

JAEA Reports

Long-term durability test of acid recovery evaporators made of Ti-5% Ta aIloy and zirconium

; Fujisaku, Kazuhiko*; *; ; Koyama, Tomozo

JNC TN8410 2001-013, 255 Pages, 2001/05

JNC-TN8410-2001-013.pdf:24.24MB

Mock-ups of acid recovery evaporators which are made of Ti-5% Ta alloy and Zr were tested under inactive condition for forty thousands hours to improve a corrosion resistance of acid recovery evaporator in Tokai reprocessing plant (TRP). The mock-up unit was designed and produced referring to the specification of acid recovery evaporator in TRP and the evaporation performance of the mock-up was 1/27 of TRP. A long-term durability of both evaporators was demonstrated by results of operation data, evaporation performance and corrosion resistance. The mock-up unit did not suffer from any trouble during the running test and the operation data such as temperature, flow, concentrations of nitric acid and metal ions were fairly stable within standard condition. As for the corrosion resistance, cracks and local corrosion such as intergranular attack were not observed on both evaporators after the running test, and a corrosion of weld was not selective. The average corrosion rates at measuring points were less than 0.1mm/yr, respectively, however, thickness of the Ti-5% Ta alloy evaporator was slightly reduced at all points of vapor phase region. In addition, from the result by test coupon, it is found that both materials have low susceptibility to stress corrosion cracking in this environment. The destructive inspection showed that the mechanical properties of both materials were not degraded during the running test. Finally, the total running time of the mock-up unit is much more than a maximum running time of acid recovery evaporator made of stainless steel in TRP (nearly 15,000 hours). On the basis of the test results, an excellent durability of Ti-5% Ta alloy and Zr evaporators under was successfully demonstrated throughout the mock-up test from an engineering perspective.

JAEA Reports

The 3rd technological meeting of Tokai reprocessing plant

Maki, Akira; ; Taguchi, Katsuya; ; Shimizu, Ryo; Shoji, Kenji;

JNC TN8410 2001-012, 185 Pages, 2001/04

JNC-TN8410-2001-012.pdf:9.61MB

"The third technological meeting of Tokai Reprocessing plant (TRP)" was held in JNFL Rokkasyo site on March 14 $^{th}$ , 2001. The technical meetings have been held in the past two times. The first one was about the present status and future plan of the TRP and second one was about safety evaluation work on the TRP. At this time, the meeting focussed on the corrosion experrience, in-service inspection technology and future maintenance plan. The report contains the proceedings, transparancies and questionnaires of the meeting are contained.

JAEA Reports