| 1. |
- Delsing, Jerker, et al.
(författare)
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A migration approach towards a SOA-based next generation process control and monitoring
- 2012
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Ingår i: IECON 2011. - Piscataway, NJ : IEEE Communications Society. - 9781612849690 ; , s. 4319-4324
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Konferensbidrag (refereegranskat)abstract
- Interest in Service Oriented Architectures (SOA) in the automation domain has seen a rapid increase both from the academia as well as the industry recent years. Since green field plants today are not common, the partial migration of plant automation to SOA design is needed to introduce new functionalities. Thus strategies and approaches for migration from legacy to SOA architectures becomes of vital interest. This paper discusses different views on partial migration of a process monitoring and control system from legacy to SOA. The discussion includes a global top down view, a bottom up view, hardware/software considerations and a hint on training of personnel.
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| 2. |
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| 3. |
- Verma, Vasudha, 1988-, et al.
(författare)
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CALCULATION METHODOLOGY ASSESSMENT TO DETECT LOCALISED PERTURBATION IN SODIUM-COOLED FAST REACTOR WITH EX-CORE INSTRUMENTATION
- 2016
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Ingår i: CALCULATION METHODOLOGY ASSESSMENT TO DETECTLOCALISED PERTURBATION IN SODIUM-COOLED FAST REACTORWITH EX-CORE INSTRUMENTATION.
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Konferensbidrag (refereegranskat)abstract
- Safety and reliability are essential requirements for development and operation of SodiumcooledFast Reactors. Development of a neutron flux monitoring system (NFMS) for the FrenchSFR is one of the key R&D areas identified. Diverse possibilities of detector system installationshould be studied for different locations in the reactor vessel in order to detect any perturbations inthe core. In this paper, we aim to explore two calculation routes available for neutron flux monitoring,assess them for their efficiency to detect fission rate variation at Above-core structure (ACS)location and discuss the associated pros and cons. The two calculational approaches we refer hereare criticality mode and external source mode. We discuss the feasibility of choosing this locationfor detecting in-core perturbations and evaluate the methodology needed to achieve it. The paperfocuses on the difficulties associated with neutron detection when the detectors are located at far-offdistances from the source. We found that for a difficult case such as ours where the detectors arelocated far-away from the source, criticality mode doesn’t work. Variance reduction techniques,employed in the external source mode are indispensable to drive neutrons to areas of interest.
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| 4. |
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| 5. |
- Verma, Vasudha, 1988-, et al.
(författare)
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Feasibility Study of Self Powered Neutron Detectors in Fast Reactors for Detecting Local Change in Neutron Flux Distribution
- 2015
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Ingår i: Feasibility Study of Self Powered Neutron Detectors in Fast Reactors for Detecting Local Change in Neutron Flux Distribution.
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Konferensbidrag (refereegranskat)abstract
- Neutron flux monitoring systems form an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector systems have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local changes in the neutron flux distribution. We show that the gamma contribution from fission products decay and activation of structural materials and sodium is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occuring inside the reactor core.
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| 6. |
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| 7. |
- Verma, Vasudha, 1988-, et al.
(författare)
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Neutron flux monitoring with in-vessel fission chambers to detect an inadvertent control rod withdrawal in a sodium-cooled fast reactor
- 2016
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 94, s. 487-493
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Tidskriftsartikel (refereegranskat)abstract
- The neutron flux monitoring system forms an integral part of the safety design of a Generation IV sodium-cooled fast reactor. During the initial design phase of the neutron flux monitoring system, one needs to explore various detector locations and configurations. Diverse possibilities of the detector system installation should be studied for different locations in the reactor vessel in order to detect any perturbations in the core. In this paper, we investigate the possibility of placing fission chambers beyond the lateral neutron shield, ex-core but in-vessel and study the detectability of an inadvertent control rod withdrawal with these fission chambers. A generic core design of a Generation IV 1500 MWth French sodium-cooled fast reactor is used for the study, and calculations are performed with the Monte Carlo code SERPENT2. We propose certain design changes that are needed to be incorporated, w.r.t. the facilitation of neutron transport to this ex-core location.We are able to show that there is a detectable signature in the fission chambers following an inadvertent control rod withdrawal in the core. The equally-spaced azimuthal detectors are able to follow changes in the neutron flux distribution in the core. This study helps us to analyze multiple detector locations and give the general trends for monitoring indications to detect any perturbations in the core.
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| 8. |
- Verma, Vasudha, 1988-, et al.
(författare)
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Self Powered Neutron Detectors as in-core detectors for Sodium-cooled Fast Reactors
- 2017
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 860, s. 6-12
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Tidskriftsartikel (refereegranskat)abstract
- Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction.In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.
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| 9. |
- Wolniewicz, Peter, 1978-
(författare)
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Development of a Methodology for Detecting Coolant Void in Lead-cooled Fast Reactors by Means of Neutron Measurements
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a lead-cooled fast reactor (LFR), small bubbles (in the order of one mm or less) may enter the coolant from a leaking steam generator. If such a leakage is undetected the small bubbles may eventually coalesce into a larger bubble in local stagnation zones under the active core. If such a bubble or void releases and passes through the core, it could drive the reactor into prompt criticality. It is therefore desirable to be able to detect the initial stages of such void formation.In this thesis, a methodology to detect such leaks is presented together with a study on void-induced reactivity effects in various LFR's. The methodology developed is based on information from two fission chambers positioned radially outside the core. The fissile content of the fission chambers consist either of 235U or 242Pu making them sensitive to different parts of the neutron spectrum. It is shown that the information from the fission chambers can be used to obtain an early indication of the presence of a small leak within typically a month. Furthermore, it is shown that for all but the smallest LFR’s, prompt criticality due to voids passing the core cannot be excluded.One conclusion is that the methodology may form an attractive complement to the general monitoring system of future LFR’s but, as is noted, it has potential for further developments.
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