Research Program for the Evaluation of Fission Product and Actinide Release Behaviour, Focusing on their Chemical Forms

Miwa, Shuhei; Yamashita, Shinichiro; Ishimi, Akihiro; Osaka, Masahiko; Amaya, Masaki; Tanaka, Kosuke; Nagase, Fumihisa

doi:10.1016/j.egypro.2014.11.867

Cited by 21 publications

(6 citation statements)

References 35 publications

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“…Thus, the main datasets and models are for the chemical system of Cs and I. Since the BWR control and FP materials, boron (B) and molybdenum (Mo) respectively, have high chemical affinities and thus affects the chemistry of Cs and I, they are also included (Miwa, 2015;Miwa, 2016). In addition, as Cs can form compounds with iron (Fe) and silicon (Si) in the chemical reaction of Cs with stainless steel (SS) (hereafter, Cs chemisorption onto SS) (Di Lemma, 2016;Di Lemma, 2017), they are also considered.…”

Section: Chemical Systemmentioning

confidence: 99%

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Development of fission product chemistry database ECUME for the LWR severe accident

Miwa

Nakajima

Miyahara

et al. 2020

Mechanical Engineering Journal

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The SA analysis codes can estimate the release of fission products (FPs) into environment and distribution of FPs in a reactor based on the models of thermal-hydraulics and FP behaviors at each region in a reactor, from reactor pressure vessel (RPV) to containment vessel (CV) and reactor building (RB) through reactor cooling system (RCS). Thus, the improvement of FP models is one of the key issues for the improved source term (IAEA, 2008). The FP models have been improved based on results of the researches on various FP behaviors (Soffer, 1995; Clément, 2007; Allelein, 2009). The main issues for the improvement are FP chemistry (Haste, 2009; Miwa 2015) and treatment of fine space resolution in a reactor. As for the latter issue of fine space resolution, it is especially important for the decommissioning of 1F since a detailed and fine FP distribution is required (Nuclear Damage Compensation and Decommissioning Facilitation

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Section: Chemical Systemmentioning

confidence: 99%

“…Regarding the FP chemistry issue, it has been recognized as the most effective and promising way for the overall improvement of source term (Haste, 2009;Miwa 2015). This is because the FP chemistry significantly affects all the FP release and transport behaviors.…”

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confidence: 99%

Development of fission product chemistry database ECUME for the LWR severe accident

Miwa

Nakajima

Miyahara

et al. 2020

Mechanical Engineering Journal

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“…Aerosol as the main component of fission products behaves strong diffusion and migration properties, thus, it is important to prevent aerosol leak into the environment. According to its solubility, aerosol can be divided into soluble aerosol (such as CsI, CsOH, etc) and insoluble aerosol (such as 90 Sr, SnO 2 , etc) (Jokiniemi, 2007;Tamotsu et al, 2007;Miwa et al, 2015). Soluble aerosol has hygroscopic properties.…”

Section: Introductionmentioning

confidence: 99%

Study on Calculation Method of Soluble Aerosol Removal Efficiency Under High Humidity Condition

Sun

et al. 2019

Front. Energy Res.

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Pool scrubbing is a potential method to remove aerosol particles under accident conditions of nuclear power plants. The relative humidity of aerosol laden gas will increase significantly when passing through the water pool, which will most likely induce hygroscopic growth of soluble aerosol. The hygroscopic growth of soluble aerosol can lead to the deviation of the size distribution of aerosol at the outlet of the water pool, resulting in a large evaluation error of the removal efficiency. In order to solve this problem, the size distributions of sodium chloride at the upstream and downstream of bubble column were measured at a gas flow rate of 4 lpm and a liquid height of 80 cm, respectively. Two methods of calculating aerosol actual size-dependency removal efficiency were proposed and compared. One method is directly calculating the removal efficiency by adding a diffusion drying tube installed at the upstream of Scanning Mobility Particle Sizer (SMPS) to reduce the relative humidity of sample gas below the efflorescence point. Another method is modifying the aerosol size distribution and concentration curve by using the hygroscopic growth theory of soluble aerosols. The experiment results obtained by the two methods are in good agreement.

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“…Several published studies dealt with the calculation of core inventory and source term for nuclear reactor accidents using different methodologies and assumptions or through the measurements of the environmental samples around the reactor site. Knowing the inventory of the radionuclides of the burnt fuel is crucial to assess the estimation of the environmental consequences of radionuclide releases following a severe nuclear accident [11,[13][14][15][23][24][25][26][27][28][29].…”

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confidence: 99%

Isotopic Inventory and Activity Calculations of Fukushima Daiichi Unit-1 Accident

Mahmoud

Abdu

Shaat³

2021

Arab Journal of Nuclear Sciences and Applications

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Nuclear characterization of the spent nuclear fuel in a reactor core is essential, especially in case of severe accidents. The radionuclide inventory and its activity can assist in the management of spent fuel handling, transport or reprocessing.In this paper, the core of Fukushima Daiichi Unit-1(FD-U1) accident was modeled using the Monte Carlo code (MCNPX 2.7) linked to the depletion calculation code CINDER'90 and ENDF/B-VII.0 cross section data library. The isotopic inventory and the activity of the radionuclides for the burned fuel were calculated. The input to the code depends on the previous evolution of the reactor core configurations, dimensions and material of the fuel assemblies, initial uranium enrichment, fuel burn-up and reactor core operational history.The calculations were validated with experimental measurements which were carried out by the Japan Nuclear Energy Safety Organization (JNES) and verified with published results using ORIGEN2-code by Japan Atomic Energy Agency (JAEA). The validation and verification results were in good agreement.The masses, activities, specific activities, half-lives and decay schemes for the actinides and fission products were calculated at the time of the accident and after 50 years cooling time. The calculations showed that, total activity of the burned fuel in the core at the time of the accident was 9.86E+19Bq and after 50 years was 1.89E+17Bq and the higher inventory concentration in the fuel was dominated by the trans-uranic elements. Also, the specific activity in the core at the time of the accident and after 50 years cooling time was found to be 1.84E+15Bq/g and 5.86E+12Bq/g, respectively. These calculations are required for nuclear characterization of the corium and in the estimation of the radiological consequences of the source term in the environment. Also, the results can support the recovery program for Fukushima Daiichi-Unit-1.

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Research Program for the Evaluation of Fission Product and Actinide Release Behaviour, Focusing on their Chemical Forms

Cited by 21 publications

References 35 publications

Development of fission product chemistry database ECUME for the LWR severe accident

Development of fission product chemistry database ECUME for the LWR severe accident

Study on Calculation Method of Soluble Aerosol Removal Efficiency Under High Humidity Condition

Isotopic Inventory and Activity Calculations of Fukushima Daiichi Unit-1 Accident

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