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.

Trial manufacturing of titanium-carbon steel composite overpack

*; *; Tanai, Kenji

JNC TN8400 99-048, 85 Pages, 1999/11

JNC-TN8400-99-048.pdf:4.31MB

This paper reports the results of design analysis and trial manufacturing of full-scale titanium-carbon steel composite overpacks. The overpack is one of the key components of the engineered barrier system, hence, it is necessary to confirm the applicability of current technique in their manufacture. The required thickness was calculated according to mechanical resistance analysis, based on models used in current nuclear facilities. The Adequacy of the calculated dimensions was confirmed by finite-element methods. To investigate the necessity of a radiation shielding function of the overpack, the irradiation from vitrified waste has been calculated. As a result, it was shown that shielding on handling and transport equipment is a more reasonable and practical approach than to increase thickness of overpack to attain a self-shielding capability. After the above investigation, trial manufacturing of full-scale model of titanium-carbon steel composite overpack has been carried out. For corrosion-resistant material, ASTM Grade-2 titanium was selected. The titanium layer was bonded individually to a cylindrical shell and flat cover plates (top and bottom) made of carbon steel. For the cylindrical shell portion, a cylindrically formed titanium layer was fitted to the inner carbon steel vessel by shrinkage. For the flat cover plates (top and bottom), titanium plate material was coated by explosive bonding. Electron beam welding and gas metal arc welding were combined to weld of the cover plates to the body. No significant failure was evident from inspections of the fabrication process, and the applicability of current technology for manufacturing titanium-carbon steel composite overpack was confirmed. Future research and development items regarding titanium-carbon steel composite overpacks are also discussed.

Compatibility test of blanket structural materials with beryllium sphere in helium gas environment

Kurasawa, Toshimasa; Takatsu, Hideyuki; Seki, Masahiro; *; *

JAERI-Tech 95-011, 24 Pages, 1995/03

JAERI-Tech-95-011.pdf:2.09MB

no abstracts in English

None

PNC TJ1150 92-003, 136 Pages, 1992/02

PNC-TJ1150-92-003.pdf:2.57MB

None

None

*

PNC TN8410 90-067, 112 Pages, 1990/05

PNC-TN8410-90-067.pdf:0.09MB

None

Influence of interstitial elements on micromechanical properties in titanium alloys monitored by in-situ neutron diffraction

Morooka, Satoshi; Tsuchiyama, Toshihiro*; Kawasaki, Takuro; Harjo, S.

no journal, , 

Titanium-based high entropy alloys; Fabrication challenge

Wakai, Eiichi; Noto, Hiroyuki*; Makimura, Shunsuke*; Ishida, Taku*; Furuya, Kazuyuki*; Shibayama, Tamaki*

no journal, , 

Recently, high-entropy alloys have been vigorously researched and developed by research institutes around the world because of their higher strength and ductility than conventional materials due to their atomic mixing ratio and composition. In this study, titanium-based high-entropy alloys (HEAs), TiVCrZrTa, TiVZrTaAl, and TiVCrZrW, were melted by the cold crucible surface melting method and subjected to homogenization heat treatment at 1200C for 5 hours. Mechanical property tests and properties of these HEAs were investigated, and it was found that the TiVCrZrTa HEAs have relatively better hot-rollability and hot-forgeability than other titanium-based HEAs. The Vickers hardness of these titanium-based HEAs was also found to be considerably higher than that of normal titanium alloys.