Group 1 Best Group

Kim Sea Jun Kim Byoung Koo Kim Ki Jun Bu Hyung Sik Lee Dong Woo Yang Won Chel

Malfunction List B-12. Leakages of Reactor Coolant Into Containment or Into The Secondary System D-28,  Reactor Coolant Pump Shaft Break D-26,  Reactor Coolant Pump Trip

Case #1 B-12 Leakages of reactor coolant into containment Leakages of reactor coolant into the secondary system Break node : 1 Leak size : 3000cm2

Steam generator

Working condition S/G Operating temp 330ºc Operating pressure 150 atm Material Inconel

Rupture initial condition Parameter Assumed Value Core Power Level, MWt 2871 Core Inlet Coolant Temp ºC 298.89 Reactor Coolant System Pre(kg/cm2A) 163.45 Core Mass Flow Rate (kg/hr) 61.6 One Pin Integrated Radial Peaking Factor 1.515 Steam Generator Pressure (kg/cm2) 1144 Moderator Coefficient Multiplier 0.0 Doppler Coefficient Multiplier 1.0 CEA Worth at Trip, % -9.0 Steam Generator Water Level % 95

Diagnosis of the SGTR Radiation monitor alarm RCS pressure level  decrease Pressurizer level  decrease Affected steam generator level  increase

Sequence of events for the steam generator tube rupture 0.0 Tube Rupture Occurs 0.45 High Steam Generator Level 0.55 Trip Breaker Open Turbine Trip; Stop Valves Closed MSIS Generated on High Steam Generator Level, 5.0 Main Steam Safety Valves Open, Psia (kg/cm2A) 5.5 Main Steam and Main Feedwater Isolation Valves Close Completely 10.0 Maximum Steam Generator Pressure ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 920.0 Safety Injection Flow Initiated Pressurizer begins to refill 1800 Operator isolates the Dammaged Steam Generator and Initiates Plant Cooldown at 55.6ºC/hr for the 1.5-hour time period 28800 Shutdown Cooling Entry Conditions are Assumed to be reached, RCS

Radiological Consequences of The SGTR Location Offsite Doses GIS PIS Exclusion Area Boundary 0-2 hr Thyroid 1.58 4.71 Whole Body 1.85 2.25 Low Population Zone outer Boundary 0-8 hr 0.1 2.62 1.06 1.26

Every Thing is all right. Conclusion Radiological releases at SGTR event are well in the 10 CFR 100 Guidelines . RCS and main steam system keep the integrity firmly. No violation of the fuel thermal limit occurs. Every Thing is all right.

Loss of External Power Same as w/o Loss of External Power before Reactor Trip Reactor Trip  Turbine-Generator Trip Unstable Electricity Grid (Frequency Decrease) Trying to Correct Frequency Separate from Grid  Loss of External Power

Sequence of events for the steam generator tube rupture with Loss of External Power 0.0 Tube Rupture Occurs 0.45 High Steam Generator Level 0.55 Trip Breaker Open Turbine Trip; Stop Valves Closed MSIS Generated on High Steam Generator Level, 3.55 Loss of External Power 4.4 Main Steam Safety Valves Open, Psia (kg/cm2A) 5.5 Main Steam and Main Feedwater Isolation Valves Close Completely 12.95 Maximum Steam Generator Pressure 946.95 Safety Injection Flow Initiated 1422.0 Pressurizer is exhausted 1800 Operator isolates the Dammaged Steam Generator and Initiates Plant Cooldown at 55.6ºC/hr for the 1.5-hour time period 28800 Shutdown Cooling Entry Conditions are Assumed to be reached, RCS

Difference in comparison with Case w/o Loss of External Power After Reactor Trip, RCS Pressure decrease suddenly RCP decelerate Coolant level decrease  Boiling occurs in Reactor Head area RCS pressure decreasing velocity decelerate because of Air Bubble Air bubble disappeared after Safety Injection

Radiological Consequences of The SGTR with Loss of External Power Location Offsite Doses GIS PIS Exclusion Area Boundary 0-2 hr Thyroid 1.72 5.03 Whole Body 1.63 1.84 Low Population Zone outer Boundary 0-8 hr 1.14 0.28 9.44 1.03

Conclusion Radiological releases at SGTR with Loss of External Power event are well in the 10 CFR 100 Guidelines . RCS and main steam system keep the integrity firmly. RCP stop dose not cause Accident. No violation of the fuel thermal limit occurs.