Developement of CHF Correlation "MG-NV" for Low Pressure and Low Velocity Conditions Applied to PWR Safety Analysis
NURETH-14 - 2011 September 25-30

Presented at:
2011 September 25-30
Toronto, Canada
Session Title:
B3-3 Core Thermalhydraulics and Subchannel Analysis

Takanori Yumura (Mitsubishi Heavy Industries, LTD.)
Tadakatsu Yodo (Mitsubishi Heavy Industries, LTD.)
Yasushi Makino (Mitsubishi Heavy Industries, LTD.)
Takayuki Suemura (Mitsubishi Heavy Industries, LTD.)


The Critical Heat Flux (CHF) is one of the important parameters in the safety analysis of Pressurized Water Reactor (PWR). If the CHF is reached, an abrupt drop occurs in the heat transfer between the fuel rod cladding and the reactor coolant, which may induce a large temperature excursion of fuel cladding and a subsequent fuel failure. Therefore, accurate prediction of CHF is required in order to assure a sufficient safety margin in the PWR core.

Mitsubishi Heavy Industries, ltd (MHI) is developing a new series of CHF correlations which covers various fuel designs and wide range of fluid conditions with sufficient reliability. In this paper, a new CHF correlation, MG-NV (Mitsubishi Generalized correlation for Non-Vane grid spacers) is presented. This correlation is one of the basic components of the new correlation series and was developed to cover low pressure and low velocity conditions where the rod bundle CHF data are limited. The CHF correlation was developed based on open CHF database and provides conservative but more reliable rod bundle CHF predictions compared with the conventional CHF correlations used in safety analyses at low pressure condition, such as Main Steam Line Break event.

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