Activation Neutronics for a Swiss Pressurized Water Reactor

Pantelias, Manuel; Volmert, Benjamin

doi:10.13182/nt15-13

Cited by 13 publications

(3 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the activities of both components could be measured and compared to the calculations. With regard to the publication of M. Pantelias and B. Volmert [5], where the validation of the neutron transport calculations with an in situ full-cycle foil activation for a PWR under exact-known boundary conditions is presented, about the same C/M-factors resulted as shown in Table 1. The activities of H-3 are overestimated by the calculation which can be explained by the following characteristic of H-3: After H-3 is formed it partially escapes from the components due to its high mobility.…”

Section: General Results Of the Calculation Proceduresmentioning

confidence: 96%

Activation calculation for the dismantling and decommissioning of a light water reactor using MCNP™ with ADVANTG and ORIGEN-S

Schlömer¹,

Phlippen²,

Lukas

2017

EPJ Web Conf.

View full text Add to dashboard Cite

Abstract. The decommissioning of a light water reactor (LWR), which is licensed under § 7 of the German Atomic Energy Act, following the post-operational phase requires a comprehensive licensing procedure including in particular radiation protection aspects and possible impacts to the environment. Decommissioning includes essential changes in requirements for the systems and components and will mainly lead to the direct dismantling. In this context, neutron induced activation calculations for the structural components have to be carried out to predict activities in structures and to estimate future costs for conditioning and packaging. To avoid an overestimation of the radioactive inventory and to calculate the expenses for decommissioning as accurate as possible, modern state-of-theart Monte-Carlo-Techniques (MCNP™) are applied and coupled with present-day activation and decay codes (ORIGEN-S). In this context ADVANTG is used as weight window generator for MCNP™ i. e. as variance reduction tool to speed up the calculation in deep penetration problems. In this paper the calculation procedure is described and the obtained results are presented with a validation along with measured activities and photon dose rates measured in the post-operational phase. The validation shows that the applied calculation procedure is suitable for the determination of the radioactive inventory of a nuclear power plant. Even the measured gamma dose rates in the postoperational phase at different positions in the reactor building agree within a factor of 2 to 3 with the calculation results. The obtained results are accurate and suitable to support effectively the decommissioning planning process.

show abstract

Section: General Results Of the Calculation Proceduresmentioning

confidence: 96%

Activation calculation for the dismantling and decommissioning of a light water reactor using MCNP™ with ADVANTG and ORIGEN-S

Schlömer¹,

Phlippen²,

Lukas

2017

EPJ Web Conf.

View full text Add to dashboard Cite

show abstract

“…Neutrons are emitted from SNF discharged from the reactor core through spontaneous fissions, (α, n) reactions, etc., and radioactive activation products are to be produced by interactions of neutrons with surrounding structures or components through neutron activation reactions such as (n, γ) and (n, p). Accordingly, a few studies have been reported on the activation of not only reactor pressure vessels (RPVs) housing the reactor core and internals, but also out-of-core structures, systems, and components (SSCs) including components in the SFP [4][5][6]. A study on neutron activation of metallic storage racks of an SFP in which SF has been stored for 40 years reported that the SFP racks are to be activated to form radionuclides 51 Cr, 54 Mn, 55 Fe, 58 Co, and 60 Co showing activity concentrations of 4.64, 0.64, 3.20, 1.31, and 3.19 Bq/g, respectively, which implies that during the decommissioning of NPPs, the SFP racks could be generated as a radioactive waste subject to land disposal [6].…”

Section: Of 25mentioning

confidence: 99%

Neutron Activation of Structural Materials of a Dry Storage System for Spent Nuclear Fuel and Implications for Radioactive Waste Management

Lee

Cheong

2020

Energies

View full text Add to dashboard Cite

In order to estimate the radiological characteristics of disused dry storage systems for spent nuclear fuel, a stepwise framework to calculate neutron sources (ORIGEN-ARP), incident neutron flux and reaction rate (MCNPX), effective cross-section (hand calculation), and residual activity (ORIGEN-2) was established. Applicability of the framework was demonstrated by comparing the residual activity of a commercialized storage system, HI-STORM 100, listed in the safety analysis report and calculated in this study. For a reference case assuming an impurity-free storage system, the modified effective cross-sections were theoretically interpreted and the need for managing disused components as a radioactive waste for at least four years was demonstrated. Sensitivity analyses showed that the higher burnup induces the higher residual radioactivity, and the impurity 59Co may extend the minimum decay-in-storage period up to 51 years within the reported range of 59Co content in stainless steel. The extended long-term storage over 100 years, however, caused no significant increase in residual radioactivity. Impurity control together with appropriate decay-in-storage was proposed as an effective approach to minimize the secondary radioactive waste arising from disused dry storage systems. The results of this study could be used to optimize the decommissioning and waste management plan regarding interim storage of spent fuel.

show abstract

“…Most of them lose their radioactivity during the initial cool-down period in the NPP decommissioning process. The remaining radioactive elements that are of major concern are 60 Co and 152 Eu or 154 Eu [9][10][11][12], and these elements are reported to reside in the hydrated cement paste rather than the aggregate [11][12][13]. This means, if the cement paste portion of concrete can be successfully removed from the surface of the aggregate, most of the aggregate can be processed as "Exempt Waste" [14,15] to reduce the total amount of radioactive concrete waste generated from the decommissioning of NPP.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Changes in the Separation Process for the Performance of Recycled Cement Powder: A Comparison with a Previous Study for Radioactive Waste Immobilization

et al. 2022

View full text Add to dashboard Cite

Separation of hydrated cement paste from aggregate is a key technology to reduce the amount of radioactive concrete waste during the decommissioning process. If separated cement-paste portions can be recycled as a solidifying agent for other radioactive waste, the amount of radioactive concrete waste could be close to “zero”. A study was conducted to achieve circular economy in the area of concrete decommissioning and found it to be successfully used as a solidifying agent for immobilization of liquid radioactive waste. However, previous work used a process that requires large amounts of energy (heat treatment was applied to most of the concrete fraction) because the objective was to completely remove hydrated cement powder from the aggregate. In this work, the separation system was modified to increase energy efficiency (heat treatment was applied to separated powder only), but such a change decreased the surface area of the recycled cement powder due to a higher inclusion of aggregate powder. A relatively lower solution to binder ratio could have been achieved for the preparation of wasteform specimens, and as a result, a 28 day compressive strength of wasteform could have become higher, but the final leachability indices were lower than the results observed from previous work. The results from 28 day compressive strength, thermal cycling and 90 day leaching experiments met the acceptance criteria for wasteform, indicating that this modified system can also be used for immobilization of liquid radioactive waste to meet the “zero” production of concrete waste during the decommissioning of a nuclear power plant. It should be noted that accurate monitoring of aggregate content in recycled cement powder during production is important to maintain proper reactivity of recycled cement powder.

show abstract

Activation Neutronics for a Swiss Pressurized Water Reactor

Cited by 13 publications

References 2 publications

Activation calculation for the dismantling and decommissioning of a light water reactor using MCNP™ with ADVANTG and ORIGEN-S

Activation calculation for the dismantling and decommissioning of a light water reactor using MCNP™ with ADVANTG and ORIGEN-S

Neutron Activation of Structural Materials of a Dry Storage System for Spent Nuclear Fuel and Implications for Radioactive Waste Management

The Effect of Changes in the Separation Process for the Performance of Recycled Cement Powder: A Comparison with a Previous Study for Radioactive Waste Immobilization

Contact Info

Product

Resources

About