Uncertainty analyses of spent nuclear fuel decay heat calculations using SCALE modules

Shama, Ahmed; Rochman, D.; Pudollek, Susanne; Caruso, S.; Pautz, Andreas

doi:10.1016/j.net.2021.03.013

Cited by 16 publications

(18 citation statements)

References 20 publications

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“…In green/turquoise, FP's such as 95Zr, 106Ru, 134Cs, 137Cs and 90Sr dominate over 80% of the total decay heat for initial cooling times of 1-10 years, followed by 90Sr and 137Cs making up the bulk of FP heat up to 100 years. This FP list supports other literature, suggesting that FP's dominate the decay heat process during the interim storage and transportation period [3,12,13]. In particular, a similar investigation for light-water reactor (LWR) designs was proposed by [13], identifying all FP's highlighted in Fig.…”

Section: Percentage Decay Heat Contributorssupporting

confidence: 84%

“…This FP list supports other literature, suggesting that FP's dominate the decay heat process during the interim storage and transportation period [3,12,13]. In particular, a similar investigation for light-water reactor (LWR) designs was proposed by [13], identifying all FP's highlighted in Fig. 2, also identifying 90Y, 144Pr, 137mBa (which in this work have been included within the decay energy of their longer-lived parents).…”

Section: Percentage Decay Heat Contributorssupporting

confidence: 83%

“…This was also seen in [12] for PWR SNF at burnup 50 MWd/tHM, where the decay chains of 239Pu, 240Pu and 241Am reach their maximum decay heat for these cooling times. Actinides 241Pu, 242Am and 244Cm were also identified in [13] for total decay heat contributions of ≥ 99% for a cooling period between 2 and 100 years. These additional nuclides which prior literature suggest are important have also been included within this analysis.…”

Section: Percentage Decay Heat Contributorsmentioning

confidence: 99%

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Nuclear data evaluation for decay heat analysis of spent nuclear fuel over 1–100 k year timescale

et al. 2022

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Accurate nuclear data are essential in the evaluation of decay heat from spent nuclear fuel (SNF). The accuracy of such data was assessed using an approach that compares values reported in different evaluated libraries and determines whether discrepancies reflect inaccuracies in primary data. A short list of 43 isotopes which are most significant to SNF decay heat calculations over 1–100 k years was produced by combining generic reactor inventory code with decay heat analysis for undifferentiated SNF. Decay properties (half-lives and decay energies) and neutron interactions (cross section and fission yields) were compared from 6 evaluated libraries. Fission product (FP) discrepancies identified are 90Sr half-life, where inclusion of a single measurement significantly reduces the evaluated value; 95mNb beta energy, where DDEP evaluation omits the decay to the 95Mo ground state; 99Tc beta energy, where evaluations differ by approximately 10% with a variety of shape factors used; 126Sb/126mSb beta (JEF2.2/3.1.1/3.3) and electron energies (JEFF3.1.1), where intensity differences are reported; and 137Cs beta energy, where ENDF/B-VIII.0 and JEF3.3 evaluations use incorrect shape factors. For actinides, the major discrepancies identified were 237Np alpha energy (JEF2.2/3.1.1) and 225Ac electron energies (ENDF/B-VIII.0) but overall show less discrepancies during long-term disposal (0.1–100 ky) compared to FP’s during interim storage (1–100 years). Further assessments of the 90Sr half-life and the best shape factor for the 99Tc beta decay are needed to improve future decay heat analyses, which are important for designing future stores and evaluating schemes for possible heat recovery.

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Section: Percentage Decay Heat Contributorssupporting

confidence: 84%

Section: Percentage Decay Heat Contributorssupporting

confidence: 83%

Section: Percentage Decay Heat Contributorsmentioning

confidence: 99%

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Nuclear data evaluation for decay heat analysis of spent nuclear fuel over 1–100 k year timescale

et al. 2022

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“…For the decay power, the considered values correspond to ±10% of the decay power employed in the base case (30 kW): this choice is supported by [47], where a total uncertainty of 5.6% has been calculated in relation to the decay power of a spent fuel assembly (SFA) of around 50 GWd/tU. As for air, temperatures ranging from 273.15 K to 323.15 K have been taken into account to address the climate in different places in the world.…”

Section: Sensitivity Casesmentioning

confidence: 97%

Uncertainty and Sensitivity Analysis of a Dry Cask for Spent Nuclear Fuel

et al. 2022

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Nuclear safety relies to a good extent on thoroughly validated codes. However, code predictions are affected by uncertainties that need to be quantified for a more accurate evaluation of safety margins. In this regard, the present paper proposes a preliminary uncertainty and sensitivity analysis of the thermal behavior of a concrete-based dry cask for spent nuclear fuel storage, employing the MELCOR code and a series of MATLAB scripts. As thermal behavior is of utmost importance for the fulfillment of United States Nuclear Regulatory Commission (USNRC) safety requirements, the Peak Cladding Temperature (PCT) has been addressed as the key Figure of Merit (FOM). Variables related to the main heat transfer mechanisms have been selected as input parameters for the uncertainty quantification, whereas heat source and heat sink, namely decay power and external air temperature, have been dealt with in a separate sensitivity analysis. The results show that the selected parameters have a weak influence on the PCT, whereas it is strongly related to the decay power and external air temperature values. In any case, PCT stays below the regulatory threshold even under the considered off-normal conditions.

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“…Several studies have been concerned with the analysis and study of the radioactive isotopes that most affect the nuclear safety of spent fuel as a result of the decay/buildup of fission products [4]- [12].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Fission Fragments Contributors on Total Decay Heat of Thermal Neutron-Induced Fission of U-235

Alramady¹

2022

JAMP

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Calculation of the decay heat from the decay/buildup of radionuclides generated after nuclear fission is one of the highest priorities in the nuclear industry. These calculations become more important if they are made together with the analysis of the most important isotopes affecting the decay heat. They are useful in designing the necessary nuclear safety for spent fuels, and their importance cannot be overlooked in the designs of transporting fuel storage containers as well as in the management of the radioactive waste generated. In this paper, by using MATLAB, the decay heat after the thermal fission of a U-235 nucleus was numerically calculated by solving linear differential equations for all the buildups/decays of the fission products. Also, the most contribution of radioactive isotopes to the decay heat was analyzed by using Microsoft Excel. The most influential isotopes were deduced in two ways; either by calculating the most influential isotopes at specific times, or by determining the largest influences in a cumulative manner. All required nuclear data such as decay constants their branching ratios, independent fission yield, and average α-, β-, and γ-energies released per disintegration of any nuclide, have

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Uncertainty analyses of spent nuclear fuel decay heat calculations using SCALE modules

Cited by 16 publications

References 20 publications

Nuclear data evaluation for decay heat analysis of spent nuclear fuel over 1–100 k year timescale

Nuclear data evaluation for decay heat analysis of spent nuclear fuel over 1–100 k year timescale

Uncertainty and Sensitivity Analysis of a Dry Cask for Spent Nuclear Fuel

Analysis of Fission Fragments Contributors on Total Decay Heat of Thermal Neutron-Induced Fission of U-235

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