Quantitative determination of the amount of3H and14C in reactor graphite

Bushuev, A. V.; Verzilov, Yu. M.; Zubarev, V. N.; Kachanovskii, A. E.; Matveev, O. V.; Proshin, I. M.; Bidulya, L. V.; Ivanov, A. A.; Kalugin, A. K.

doi:10.1007/bf00761431

Cited by 17 publications

(9 citation statements)

References 1 publication

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“…The main problematic radionuclides present in the irradiated graphite are tritium ( 3 H), carbon‐14 ( 14 C), and chlorine‐36 ( 36 Cl). These problematic radionuclides are released over time due to diffusion from the graphite structure in gaseous form ( 3 H 2 , 14 CO 2 , 14 CH 4 , and 36 Cl 2 ) with the main activity being produced by the tritium and carbon‐14, which will make it difficult to store irradiated graphite waste in confined spaces, like proposed underground storage repositories. Of these radionuclides, tritium gas will most likely permeate faster than the other radioactive gases due to its small molecular size.…”

Section: Introductionmentioning

confidence: 99%

Improving the helium gas barrier properties of epoxy coatings through the incorporation of graphene nanoplatelets and the influence of preparation techniques

Rooyen

Karger‐Kocsis

Kock

2015

J of Applied Polymer Sci

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Graphene/epoxy nanocomposite coatings were formulated by applying different dispersion and preparation methods to determine whether the coatings might be a potential gas barrier material for irradiated graphite waste which is known to release radioactive gases like tritium ( 3 H2). Helium was used as a substitute gas for tritium and the gas permeability was measured with the use of a helium leak detector. The dispersion and fabrication techniques influenced the abillity of the coatings to reduce the helium gas permeability. Characterisation of the graphene nanoplatelets and the composite morphology showed that the dispersion techniques influenced the graphene nanoplatelet geometry which reduced the aspect ratio of the platelets. The results showed that by incorporating 2 wt% graphene into the epoxy matrix, combined with a multilayer fabrication method, reduced the helium gas permeability by 83% when compared to the reference epoxy samples. Modelling the gas permeability 2 according to the tortuous path theory confirmed the aspect ratios which were estimated by the microscopic methods and particle size analysis.

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Section: Introductionmentioning

confidence: 99%

Improving the helium gas barrier properties of epoxy coatings through the incorporation of graphene nanoplatelets and the influence of preparation techniques

Rooyen

Karger‐Kocsis

Kock

2015

J of Applied Polymer Sci

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“…A detection limit of 30 mBq was reported for the analysis of nuclear waste and environmental sample such as graphite, concrete, soil, and milk powder, using low -level Quantulus TM 1200 LSC [120]. This is sensitive enough for the waste samples and the present environmental samples [120,[126][127][128][129][130]. The traditional sample preparation method for the analysis of solid sample using combustion [126][127][128][129][130] is very time consuming , this makes the analytical capacity of LSC very low (< 3 sample per day per person).…”

Section: Carbon-14mentioning

confidence: 99%

“…This is sensitive enough for the waste samples and the present environmental samples [120,[126][127][128][129][130]. The traditional sample preparation method for the analysis of solid sample using combustion [126][127][128][129][130] is very time consuming , this makes the analytical capacity of LSC very low (< 3 sample per day per person). Hou [120] developed a rapid method for separation of C-14 from solid samples by using a sample Oxidizer, using this method the sample preparation time was reduced to only 2-3 minutes per sample.…”

Section: Carbon-14mentioning

confidence: 99%

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

Hou

Roos

2008

Analytica Chimica Acta

342

253

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“…4 Of these, tritium is considered to be one of the critical radionuclides. [5][6][7] Previous studies of tritium in concrete, 4,[8][9][10][11] have mainly focused on structural concretes exposed to tritiated water (HTO) and have not specifically considered bioshield concrete. Neutron activation of trace Li impurities in bioshield concrete provides an alternative mechanism for 3 H production, and such 3 H produced in situ may be expected to be present in a different, potentially less-available, form since it may be locked/trapped inside mineral lattices.…”

Section: B(n 2rmentioning

confidence: 99%

Tritium Speciation in Nuclear Reactor Bioshield Concrete and its Impact on Accurate Analysis

2008

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Tritium ((3)H) is produced in nuclear reactors via several neutron-induced reactions [(2)H(n, gamma)(3)H, (6)Li(n, alpha)(3)H, (10)B(n, 2alpha)(3)H, (14)N(n, (3)H)(12)C, and ternary fission (fission yield <0.01%)]. Typically, (3)H is present as tritiated water (HTO) and can become adsorbed into structural concrete from the surface inward where it will be held in a weakly bound form. However, a systematic analysis of a sequence of subsamples taken from a reactor bioshield using combustion and liquid scintillation analysis has identified two forms of (3)H, one weakly bound and one strongly bound. The strongly bound tritium, which originates from neutron capture on trace lithium ((6)Li) within mineral phases, requires temperatures in excess of 350 degrees C to achieve quantitative recovery. The weakly bound form of tritium can be liberated at significantly lower temperatures (100 degrees C) as HTO and is associated with dehydration of hydrous mineral components. Without an appreciation that two forms of tritium can exist in reactor bioshields, the (3)H content of samples may be severely underestimated using conventional analytical approaches. These findings exemplify the need to develop robust radioactive waste characterization procedures in support of nuclear decommissioning programs.

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Quantitative determination of the amount of3H and14C in reactor graphite

Cited by 17 publications

References 1 publication

Improving the helium gas barrier properties of epoxy coatings through the incorporation of graphene nanoplatelets and the influence of preparation techniques

Improving the helium gas barrier properties of epoxy coatings through the incorporation of graphene nanoplatelets and the influence of preparation techniques

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

Tritium Speciation in Nuclear Reactor Bioshield Concrete and its Impact on Accurate Analysis

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