Analysis of the impact of different scenarios on the simulation results of unauthorized dilution of boric acid in the coolant of the primary circuit of the NPP-2006
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B. E. Shumskiy
Abstract
Unauthorized dilution of boric acid in the reactor coolant due to improper operation of the chemical and volume control system (KBA) is a project mode with the violation of normal operation. The operator is obliged to identify unauthorized dilution within half an hour and stop feeding with pure condensate. The power unit has automation, which stops feeding on EP (emergency protection) and ATWS (Anticipated transient without scram) signals. The situation without the intervention of the operator and the failure of automation to stop dilution can be considered as a beyond design basis accident. The article presents an analysis of unauthorized boric acid dilution process in the primary circuit coolant of the NPP-2006 power unit up to the controlled state, either considering the operator's intervention after a 30-minute period of process, i. e. with a forced cessation of dilution, or without the operator's intervention until the tanks with pure condensate are completely emptied.
Kurzfassung
Die unzulässige Verdünnung von Borsäure im Reaktorkühlmittel durch unsachgemäßen Betrieb des Chemikalien- und Mengenregelsystems (KBA) ist ein Projektmodus mit Verstoß gegen den Normalbetrieb. Der Betreiber ist verpflichtet, unzulässige Verdünnungen innerhalb einer halben Stunde zu erkennen und die Beschickung mit reinem Kondensat einzustellen. Das Netzteil verfügt über eine Automatisierung, die die Einspeisung von EP- (Notfallschutz) und ATWS-Signalen (Anticipated Transient without Scram) stoppt. Die Situation ohne das Eingreifen des Bedieners und das Versagen der Automatisierung, die Verdünnung zu stoppen, kann als Störfall angesehen werden. Der Artikel stellt eine Analyse des unzulässigen Borsäureverdünnungsprozesses im Primärkreislauf des NPP-2006 Aggregates bis zum Erreichen des kontrollierten Zustands dar, entweder unter Berücksichtigung des Eingriffs des Betreibers nach 30 Minuten, d. h. bei erzwungener Beendigung der Verdünnung, oder ohne Eingriff des Betreibers, bis die Tanks mit reinem Kondensat vollständig entleert sind.
References
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© 2018, Carl Hanser Verlag, München
Articles in the same Issue
- Contents/Inhalt
- Contents
- Technical Contributions/Fachbeiträge
- Reactor safety research within the Helmholtz Association
- Analysis of the impact of different scenarios on the simulation results of unauthorized dilution of boric acid in the coolant of the primary circuit of the NPP-2006
- Assessment of void fraction predictability of system codes in subchannels
- Review on using nanofluids for heat transfer enhancement in nuclear power plants
- Analysis of operating characteristics of IPWR under natural circulation
- Impact of spacer on inter sub-channel mixing of coolant in nuclear fuel bundle: a survey and future patterns of research and advances
Articles in the same Issue
- Contents/Inhalt
- Contents
- Technical Contributions/Fachbeiträge
- Reactor safety research within the Helmholtz Association
- Analysis of the impact of different scenarios on the simulation results of unauthorized dilution of boric acid in the coolant of the primary circuit of the NPP-2006
- Assessment of void fraction predictability of system codes in subchannels
- Review on using nanofluids for heat transfer enhancement in nuclear power plants
- Analysis of operating characteristics of IPWR under natural circulation
- Impact of spacer on inter sub-channel mixing of coolant in nuclear fuel bundle: a survey and future patterns of research and advances
