Nuclear-data uncertainty propagations in burnup calculation for the PWR assembly

2017 ◽  
Vol 100 ◽  
pp. 20-31 ◽  
Author(s):  
Chenghui Wan ◽  
Liangzhi Cao ◽  
Hongchun Wu ◽  
Wei Shen
2021 ◽  
Vol 11 (14) ◽  
pp. 6499
Author(s):  
Matthias Frankl ◽  
Mathieu Hursin ◽  
Dimitri Rochman ◽  
Alexander Vasiliev ◽  
Hakim Ferroukhi

Presently, a criticality safety evaluation methodology for the final geological disposal of Swiss spent nuclear fuel is under development at the Paul Scherrer Institute in collaboration with the Swiss National Technical Competence Centre in the field of deep geological disposal of radioactive waste. This method in essence pursues a best estimate plus uncertainty approach and includes burnup credit. Burnup credit is applied by means of a computational scheme called BUCSS-R (Burnup Credit System for the Swiss Reactors–Repository case) which is complemented by the quantification of uncertainties from various sources. BUCSS-R consists in depletion, decay and criticality calculations with CASMO5, SERPENT2 and MCNP6, respectively, determining the keff eigenvalues of the disposal canister loaded with the Swiss spent nuclear fuel assemblies. However, the depletion calculation in the first and the criticality calculation in the third step, in particular, are subject to uncertainties in the nuclear data input. In previous studies, the effects of these nuclear data-related uncertainties on obtained keff values, stemming from each of the two steps, have been quantified independently. Both contributions to the overall uncertainty in the calculated keff values have, therefore, been considered as fully correlated leading to an overly conservative estimation of total uncertainties. This study presents a consistent approach eliminating the need to assume and take into account unrealistically strong correlations in the keff results. The nuclear data uncertainty quantification for both depletion and criticality calculation is now performed at once using one and the same set of perturbation factors for uncertainty propagation through the corresponding calculation steps of the evaluation method. The present results reveal the overestimation of nuclear data-related uncertainties by the previous approach, in particular for spent nuclear fuel with a high burn-up, and underline the importance of consistent nuclear data uncertainty quantification methods. However, only canister loadings with UO2 fuel assemblies are considered, not offering insights into potentially different trends in nuclear data-related uncertainties for mixed oxide fuel assemblies.


Author(s):  
Branislav Vrban ◽  
Stefan Cerba ◽  
Jakub Luley ◽  
Filip Osuský ◽  
Vladimir Necas

Abstract The properties of nuclear fuel depend on the actual isotopic composition which develops during a reactor operation. In practice, the prediction accuracy of burnup calculations serves as the basis for the future precise estimation of a core lifetime and other safety-based core characteristics. The present study quantifies nuclear data induced uncertainties of nuclide concentrations and multiplication factors in VVER-440 fuel depletion analysis. The well-known SCALE system and the TRITON sequence are used with the NEWT deterministic solver in the SAMPLER module that implements stochastic techniques to assess the uncertainty in computed results. The propagation of uncertainties in neutron cross section and fission yields is studied through the depletion calculation of 2D heterogeneous VVER-440 fuel assembly with an average enrichment of 4.87 wt % of 235U and six gadolinium rods with 3.35 % of Gd2O3. In the paper, fixed nominal depletion conditions are based on the real operational data of the Slovak NPP Bohunice unit 4 during cycle 30. In total 250 cases with uncertain parameters are computed and the results are evaluated by an auxiliary tool.


Author(s):  
Chenghui Wan ◽  
Liangzhi Cao ◽  
Hongchun Wu ◽  
Tiejun Zu ◽  
Wei Shen

2011 ◽  
Vol 59 (2(3)) ◽  
pp. 1191-1194 ◽  
Author(s):  
D. Rochman ◽  
A. J. Koning ◽  
D. F. Dacruz ◽  
S. C. van der Marck

Author(s):  
Shiho Asai ◽  
Keisuke Okumura ◽  
Yukiko Hanzawa ◽  
Hideya Suzuki ◽  
Masaaki Toshimitsu ◽  
...  

Correlations between Nd isotopes and difficult-to-measure (DTM) nuclides, such as Se-79, Tc-99, Sn-126, and Cs-135, predicted using a calculation code have been validated by postirradiation examination (PIE). The calculation was performed with a burnup calculation code, MVP-BURN, using the updated nuclear data library JENDL-4.0. An irradiated PWR fuel with a burnup of 44.9 GWd/t and a cooling time of 7458 days was used as a standard sample. The concentrations of Nd isotopes in the sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS) after purification by two consecutive anion-exchange separations. The ratios of Se-79 and Cs-135 to Nd isotopes (Nd-145, Nd-146, and Nd-145+Nd-146) calculated using MVP-BURN were in good agreement with PIE values within the deviations of 8% and 6%, respectively. This indicates that these calculated ratios are applicable to the scaling factors of Se-79 and Cs-135. For Tc-99 and Sn-126, the calculated values were respectively about 50% and 20% higher than the PIE values. These overestimations were mainly caused by the lack of the contribution of an insoluble residue to the measured concentrations.


2016 ◽  
Vol 307 ◽  
pp. 328-338 ◽  
Author(s):  
Qiang Zhao ◽  
Chunyan Zhang ◽  
Chen Hao ◽  
Fu Li ◽  
Dongyong Wang ◽  
...  

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