04.02.2013 Views

Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course in Korea

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

<strong>Regional</strong> <strong>Basic</strong> <strong>Professional</strong> <strong>Tra<strong>in</strong><strong>in</strong>g</strong> <strong>Course</strong> (BPTC) on Nuclear Safety<br />

the upper plenum pool and the level of the tow‐phase mixture can reach the hot leg.<br />

Liquid carried over by vapor through hot legs may reach steam generators where it will<br />

evaporate caus<strong>in</strong>g an <strong>in</strong>crease of pressure <strong>in</strong> SG and upper plenum. This reduces the<br />

reflood rate giv<strong>in</strong>g rise to the steam b<strong>in</strong>d<strong>in</strong>g effect. Vapor mass flow rates decrease with<br />

decreas<strong>in</strong>g quench velocity. This reduces the amount of liquid entra<strong>in</strong>ed and carried over<br />

to decreases caus<strong>in</strong>g an <strong>in</strong>crease <strong>in</strong> flood<strong>in</strong>g rates. This process may cont<strong>in</strong>ue with<br />

decreas<strong>in</strong>g effects until the entire core is reflooded. For some conditions, manometer<br />

oscillation between liquid <strong>in</strong> downcomer and core can also lead to oscillatory reflood<br />

rates.<br />

Figure 8.7‐4 Flow regimes associated with reflood<br />

❙ 520 ❙

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!