Neutron Irradiation Effects on 11B4C and Recovery by Annealing

Donomae, Takako; Tachi, Yoshiaki; Sekine, Manabu; Morohashi, Yuko; Akasaka, N.; Onose, Shoji

doi:10.2109/jcersj2.115.551

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…3d and e), presumably on pre-existing defect. Previous works have shown that lined up or orientated helium bubbles can form during high temperature neutron irradiation or after high temperature annealing [6][7][8]. Helium bubble strings were seen when B 4 C was irradiated by 16 MeV He + at a much higher temperature (1720°C) by Stoto [9].…”

Section: Neutronsmentioning

confidence: 96%

“…As a control rod material, the defect structure in neutron irradiated B 4 C was investigated by Ashbee [3,4], Jostsons [5,6], Hollenberg [7] and Donomae [8] et al He + implantation of B 4 C has been performed by Stoto [9] and Maruyama [10]. Irradiation effects and helium bubble formation in aluminum after high energy proton irradiation were reported by Singh and Victoria [11,12].…”

Section: Neutronsmentioning

confidence: 99%

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Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

et al. 2015

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a b s t r a c tHelium behavior in Al/B 4 C metal matrix composite with two different sets of ion irradiation conditions has been investigated by transmission electron microscopy. Helium bubbles in Al were found to be much larger than those in B 4 C after a helium fluence of 1.5 Â 10 17 ions/cm 2 at the room temperature. Also, bubbles at grain boundaries and their vicinity in aluminum are faceted. With additional proton irradiation, a bubble denuded zone along the aluminum grain boundary appears. The results are discussed in terms of the energetics of the material system.Ó 2015 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.Al/B 4 C metal matrix composite (MMC) is an important neutron absorbing material used in both wet storage pools and dry storage casks of spent nuclear fuel for preventing criticality. Al/B 4 C MMC can effectively absorb fast and thermal neutrons, because of the high neutron absorption cross-section of 10 B through the 10 B(n, a) 7 Li transmutation reaction for a wide energy range of neutrons.The damage produced by elastic collisions between neutrons and other energetic particles generated by transmutation reactions with the target atoms along with the build-up of helium concentration in the MMC may lead to the precipitation of helium bubbles. The gamma and neutron doses received in the MMC depend on a number of factors including fuel burnup, storage time, and the self-shielding of the fuel assemblies. In spent fuel fool storage, the neutron flux can be as high as 2.6 Â 10 5 neutron/cm 2 s and the gamma dose rate is in the range of 0.1-10 kGy/h [1,2], corresponding to several thousand appm of transmuted helium build up and 1-2 dpa (displacement per atom) of damage during the estimated storage period of 60 years in spent fuel pool storage and about 200 years in the dry storage casks.As a control rod material, the defect structure in neutron irradiated B 4 C was investigated by Ashbee [3,4], Jostsons [5,6], Hollenberg [7] and Donomae [8] et al. He + implantation of B 4 C has been performed by Stoto [9] and Maruyama [10]. Irradiation effects and helium bubble formation in aluminum after high energy proton irradiation were reported by Singh and Victoria [11,12]. The precipitation of helium causes not only changes in microstructure but degradation in the physical, chemical and mechanical properties of Al/B 4 C MMC, such as, reduced thermal conductivity, decreased corrosion resistance and volume swelling. The property change in Al/B 4 C MMC affects the long-term performance of the MMC in its working environment. In fact, irradiation induced microcracking in B 4 C that leads to increased boron release was reported by Copeland [13] and Stoto [14].This paper focuses on helium bubble formation upon helium implantation and bubble evolution during additional proton irradiation in the Al/B 4 C MMC. Ion irradiations were conducted to simulate the effects of radiation and helium build-up in Al/B 4 C MMC as neutron absorbers in wet storage pool and dry storage casks. Angular shape B 4 C particles w...

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Section: Neutronsmentioning

confidence: 96%

Section: Neutronsmentioning

confidence: 99%

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

et al. 2015

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“…In the former case, thermal stress relaxation and improvement in the thermal shock resistance are required by improving the thermal and mechanical properties of the pellets. 8), 9) The latter swelling causes internal stress of the pellets, causing not only damage, but also mechanical action to the cladding tube containing the pellets, which also causes cracks in the cladding tube. Pellets of conventional control materials have only a porosity of about 5 to 10%, therefore, those pores are basically closed pores without any directivity and cannot effectively release the helium gas accumulated inside the pellets.…”

Section: Introductionmentioning

confidence: 99%

Preparation of textured B<sub>4</sub>C compact with oriented pore-forming agent by slip casting under strong magnetic field

Azuma

Uchikoshi

Yoshida

et al. 2018

J. Ceram. Soc. Japan

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Control rods are one of the structural components in a nuclear reactor and are required to have a high functionality and reliability to provide a safe nuclear reactor. Random-oriented boron carbide (B 4 C) is normally used as the control rods, but cracks are easily generated during the nuclear reaction because of volume swelling due to the accumulation of helium gas and nonhomogeneous thermal stress distribution during the neutron absorption reaction. In this study, we were able to control the crystalline orientation of the B 4 C and align the tubal pores for controlling the thermal stress distribution and releasing the helium gas by controlling the dispersion of particles in a slurry and the rotation in a magnetic field.

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Fast Spectrum Control Rod Materials

Donomae

Maeda

2012

Comprehensive Nuclear Materials

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Neutron Irradiation Effects on 11B4C and Recovery by Annealing

Cited by 5 publications

References 8 publications

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

Preparation of textured B<sub>4</sub>C compact with oriented pore-forming agent by slip casting under strong magnetic field

Fast Spectrum Control Rod Materials

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