Modelling and Validation of CANDU Shim Operation Using Coupled TRACE/PARCS with Regulating System Response.
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| Title: | Modelling and Validation of CANDU Shim Operation Using Coupled TRACE/PARCS with Regulating System Response. |
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| Authors: | Younan, Simon1 (AUTHOR), Novog, David R.1 (AUTHOR) |
| Source: | Science & Technology of Nuclear Installations. 3/8/2023, p1-21. 21p. |
| Subjects: | CANDU reactors, Model validation, Lead poisoning, Fueling, Nuclear power plants, Fast reactors |
| Abstract: | In CANDU reactors, shim operation is used when the online refuelling capability becomes temporarily unavailable. Adjuster rods, normally in-core to provide flux flattening, are withdrawn in sequence to provide additional reactivity as the fuel is depleted. In a CANDU 900 reactor, up to three of the eight adjuster banks may be withdrawn, with the power derated accordingly. In this study, the shim operation was modelled using a combination of TRACE_Mac1.1, PARCS_Mac1.1, and scripts modelling the reactor regulating system, all running as a single coupled simulation. A driver script simulated the operation as a sequence of steady-state, depletion, and transient models. The results were compared to operational data from a nuclear power plant, evaluating the key figures of merit. The simulation was extended beyond the operational data by reducing the power to 59% FP and withdrawing the remaining adjusters, to observe the behaviour of the simulated reactor for a deeper reactivity-driven transient. Sensitivity cases, including adjuster rod depletion and nuclear data uncertainty, were also evaluated. This study was able to successfully reproduce the general results of the shim operation. Some discrepancies were observed between the simulation and dataset for the duration of the shim, particularly for the one bank out phase of the shim. Several potential causes for the early phase behaviour were identified. When the simulation was extended, the model predicted that a power reduction below 60% FP would lead to xenon poison out when the adjusters were depleted, with the timing sensitive to the adjuster depletion. Nodalisation of the PARCS model also had a significant impact, due to the effect on adjuster nodalisation and its area-of-effect with respect to the actual adjuster locations. Nuclear data uncertainty had a lesser but still noticeable effect. Other parameters, such as the distribution of fuel burnups in the core, only had a small effect on the shim operation. [ABSTRACT FROM AUTHOR] |
| Copyright of Science & Technology of Nuclear Installations is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: egs DbLabel: Engineering Source An: 162327320 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Modelling and Validation of CANDU Shim Operation Using Coupled TRACE/PARCS with Regulating System Response. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Younan%2C+Simon%22">Younan, Simon</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Novog%2C+David+R%2E%22">Novog, David R.</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Science+%26+Technology+of+Nuclear+Installations%22">Science & Technology of Nuclear Installations</searchLink>. 3/8/2023, p1-21. 21p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22CANDU+reactors%22">CANDU reactors</searchLink><br /><searchLink fieldCode="DE" term="%22Model+validation%22">Model validation</searchLink><br /><searchLink fieldCode="DE" term="%22Lead+poisoning%22">Lead poisoning</searchLink><br /><searchLink fieldCode="DE" term="%22Fueling%22">Fueling</searchLink><br /><searchLink fieldCode="DE" term="%22Nuclear+power+plants%22">Nuclear power plants</searchLink><br /><searchLink fieldCode="DE" term="%22Fast+reactors%22">Fast reactors</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: In CANDU reactors, shim operation is used when the online refuelling capability becomes temporarily unavailable. Adjuster rods, normally in-core to provide flux flattening, are withdrawn in sequence to provide additional reactivity as the fuel is depleted. In a CANDU 900 reactor, up to three of the eight adjuster banks may be withdrawn, with the power derated accordingly. In this study, the shim operation was modelled using a combination of TRACE_Mac1.1, PARCS_Mac1.1, and scripts modelling the reactor regulating system, all running as a single coupled simulation. A driver script simulated the operation as a sequence of steady-state, depletion, and transient models. The results were compared to operational data from a nuclear power plant, evaluating the key figures of merit. The simulation was extended beyond the operational data by reducing the power to 59% FP and withdrawing the remaining adjusters, to observe the behaviour of the simulated reactor for a deeper reactivity-driven transient. Sensitivity cases, including adjuster rod depletion and nuclear data uncertainty, were also evaluated. This study was able to successfully reproduce the general results of the shim operation. Some discrepancies were observed between the simulation and dataset for the duration of the shim, particularly for the one bank out phase of the shim. Several potential causes for the early phase behaviour were identified. When the simulation was extended, the model predicted that a power reduction below 60% FP would lead to xenon poison out when the adjusters were depleted, with the timing sensitive to the adjuster depletion. Nodalisation of the PARCS model also had a significant impact, due to the effect on adjuster nodalisation and its area-of-effect with respect to the actual adjuster locations. Nuclear data uncertainty had a lesser but still noticeable effect. Other parameters, such as the distribution of fuel burnups in the core, only had a small effect on the shim operation. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Science & Technology of Nuclear Installations is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1155/2023/6163974 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 21 StartPage: 1 Subjects: – SubjectFull: CANDU reactors Type: general – SubjectFull: Model validation Type: general – SubjectFull: Lead poisoning Type: general – SubjectFull: Fueling Type: general – SubjectFull: Nuclear power plants Type: general – SubjectFull: Fast reactors Type: general Titles: – TitleFull: Modelling and Validation of CANDU Shim Operation Using Coupled TRACE/PARCS with Regulating System Response. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Younan, Simon – PersonEntity: Name: NameFull: Novog, David R. IsPartOfRelationships: – BibEntity: Dates: – D: 08 M: 03 Text: 3/8/2023 Type: published Y: 2023 Identifiers: – Type: issn-print Value: 16876075 Titles: – TitleFull: Science & Technology of Nuclear Installations Type: main |
| ResultId | 1 |
