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Fuel Cooling in Absence of Forced Flow at Shutdown Condition with PHTS Partially Drained

Abstract

During the plant outage for maintenance on primary side (e.g. for the main Heat Transport System pumps maintenance, the Steam Generators inspection), there are situations which require the primary heat transport system (HTS) drainage to a certain level for opening the circuit. The primary fuel heat sink for this configuration is provided by the shutdown cooling system (SDCS). In case of losing the forced cooling (e.g. due to the loss of SDCS, design basis earthquake-DBE), flow conditions in the reactor core may become stagnant. Inside the fuel channels, natural circulation phenomena known as Intermittent Buoyancy Induced Flow (IBIF) will initiate, providing an alternate heat sink mechanism for the fuel. However, this heat sink is effective only for a limited period of time (recall time). The recall time is defined as the elapsed time until the water temperature in the HTS headers exceeds a certain limit. Until then, compensatory measures need to be taken (e.g. by re-establishing the forced flow or initiate Emergency Core Cooling system injection) to preclude fuel failures. The present paper briefly presents the results of an analysis performed to demonstrate that fuel temperature remains within acceptable limits during IBIF transient. One of the objectives of this analysis  More>>
Authors:
Parasca, L.; Pecheanu, D.L., E-mail: laurentiu.parasca@cne.ro, E-mail: doru.pecheanu@cne.ro [1] 
  1. Cernavoda Nuclear Power Plant, Cernavoda (Romania)
Publication Date:
Sep 15, 2014
Product Type:
Conference
Report Number:
IAEA-TECDOC-CD-1751
Resource Relation:
Conference: Technical Meetings on Pressurized Heavy Water Reactor Fuel: Integrity, Performance and Advanced Concepts, Bucharest (Romania), 24-27 Sep 2012; Other Information: 15 figs.; Related Information: In: Pressurized Heavy Water Reactor Fuel: Integrity, Performance and Advanced Concepts. Proceedings of the Technical Meetings held in Bucharest, 24-27 September 2012, and in Mumbai, 8-11 May 2013| [1 CD-ROM]
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; COOLING; COOLING SYSTEMS; ECCS; FOSSIL FUELS; HEAT SINKS; NUCLEAR FUELS; REACTOR CORES; REACTOR MAINTENANCE; SHUTDOWN; STEAM GENERATORS
OSTI ID:
22309320
Research Organizations:
International Atomic Energy Agency, Nuclear Fuel Cycle and Materials Section, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISBN 978-92-0-158414-4; ISSN 1684-2073; TRN: XA14M6906015493
Availability:
Available from INIS in electronic form. Also available on-line: http://www-pub.iaea.org/MTCD/Publications/PDF/TE_1751_CD/PDF/Tecdoc-1751.pdf 1 CD-ROM from IAEA, Marketing and Sales Unit, Publishing Section, E-mail: sales.publications@iaea.org; Web site: http://www.iaea.org/books
Submitting Site:
INIS
Size:
page(s) 73-85
Announcement Date:
Mar 02, 2015

Citation Formats

Parasca, L., and Pecheanu, D.L., E-mail: laurentiu.parasca@cne.ro, E-mail: doru.pecheanu@cne.ro. Fuel Cooling in Absence of Forced Flow at Shutdown Condition with PHTS Partially Drained. IAEA: N. p., 2014. Web.
Parasca, L., & Pecheanu, D.L., E-mail: laurentiu.parasca@cne.ro, E-mail: doru.pecheanu@cne.ro. Fuel Cooling in Absence of Forced Flow at Shutdown Condition with PHTS Partially Drained. IAEA.
Parasca, L., and Pecheanu, D.L., E-mail: laurentiu.parasca@cne.ro, E-mail: doru.pecheanu@cne.ro. 2014. "Fuel Cooling in Absence of Forced Flow at Shutdown Condition with PHTS Partially Drained." IAEA.
@misc{etde_22309320,
title = {Fuel Cooling in Absence of Forced Flow at Shutdown Condition with PHTS Partially Drained}
author = {Parasca, L., and Pecheanu, D.L., E-mail: laurentiu.parasca@cne.ro, E-mail: doru.pecheanu@cne.ro}
abstractNote = {During the plant outage for maintenance on primary side (e.g. for the main Heat Transport System pumps maintenance, the Steam Generators inspection), there are situations which require the primary heat transport system (HTS) drainage to a certain level for opening the circuit. The primary fuel heat sink for this configuration is provided by the shutdown cooling system (SDCS). In case of losing the forced cooling (e.g. due to the loss of SDCS, design basis earthquake-DBE), flow conditions in the reactor core may become stagnant. Inside the fuel channels, natural circulation phenomena known as Intermittent Buoyancy Induced Flow (IBIF) will initiate, providing an alternate heat sink mechanism for the fuel. However, this heat sink is effective only for a limited period of time (recall time). The recall time is defined as the elapsed time until the water temperature in the HTS headers exceeds a certain limit. Until then, compensatory measures need to be taken (e.g. by re-establishing the forced flow or initiate Emergency Core Cooling system injection) to preclude fuel failures. The present paper briefly presents the results of an analysis performed to demonstrate that fuel temperature remains within acceptable limits during IBIF transient. One of the objectives of this analysis was to determine the earliest moment since the reactor shut down when maintenance activities on the HTS can be started such that IBIF is effective in case of losing the forced circulation. The resulting peak fuel sheath and pressure tube temperatures due to fuel heat up shall be within the acceptable limits to preclude fuel defect or fuel channel defects.Thermalhydraulic circuit conditions were obtained using a CATHENA model for the primary side of HTS (drained to a certain level), an ECC system model and a system model for SDCS. A single channel model was developed in GOTHIC code for the fuel assessment analysis. (author)}
place = {IAEA}
year = {2014}
month = {Sep}
}