APR1400 DESIGN CONTROL DOCUMENT TIER 2 CHAPTER 4 REACTOR APR1400-K-X-FS-14002-NP REVISION 0 DECEMBER 2014 2014 KOREA ELECTRIC POWER CORPORATION & KOREA HYDRO & NUCLEAR POWER CO., LTD All Rights Reserved This document was prepared for the design certification application to the U.S. Nuclear Regulatory Commission and contains technological information that constitutes intellectual property. Copying, using, or distributing the information in this document in whole or in part is permitted only by the U.S. Nuclear Regulatory Commission and its contractors for the purpose of reviewing design certification application materials. Other uses are strictly prohibited without the written permission of Korea Electric Power Corporation and Korea Hydro & Nuclear Power Co., Ltd. Rev. 0 APR1400 DCD TIER 2 CHAPTER 4 – REACTOR TABLE OF CONTENTS NUMBER TITLE PAGE CHAPTER 4 – REACTOR ............................................................................................ 4.1-1 4.1 Summary Description ......................................................................................... 4.1-1 4.1.1 Initial Core Design Description and Permissible Changes ..................... 4.1-2 4.1.2 Analytical Techniques ............................................................................ 4.1-2 4.1.3 Combined License Information .............................................................. 4.1-2 4.2 Fuel System Design ............................................................................................. 4.2-1 4.2.1 Design Bases .......................................................................................... 4.2-1 4.2.1.1 Cladding ................................................................................. 4.2-2 4.2.1.2 Fuel Material .......................................................................... 4.2-3 4.2.1.3 Fuel Rod Performance ........................................................... 4.2-5 4.2.1.4 Grid ........................................................................................ 4.2-6 4.2.1.5 Fuel Assembly........................................................................ 4.2-7 4.2.1.6 In-Core Control Components ................................................. 4.2-9 4.2.1.7 Surveillance Program ........................................................... 4.2-15 4.2.2 Description and Design Drawings ........................................................ 4.2-15 4.2.2.1 Fuel Rod ............................................................................... 4.2-15 4.2.2.2 Burnable Absorber Rod ....................................................... 4.2-16 4.2.2.3 Fuel Assembly...................................................................... 4.2-16 4.2.2.4 In-Core Control Components ............................................... 4.2-19 4.2.3 Design Evaluation ................................................................................ 4.2-21 4.2.3.1 Cladding ............................................................................... 4.2-21 4.2.3.2 Fuel....................................................................................... 4.2-29 4.2.3.3 Fuel Rod Performance ......................................................... 4.2-30 4.2.3.4 Grid ...................................................................................... 4.2-34 4.2.3.5 Fuel Assembly...................................................................... 4.2-35 4.2.3.6 In-Core Control Components ............................................... 4.2-37 4.2.4 Testing and Inspection Plan .................................................................. 4.2-40 i Rev. 0 APR1400 DCD TIER 2 4.2.4.1 Fuel Assembly...................................................................... 4.2-40 4.2.4.2 Fuel Rod ............................................................................... 4.2-42 4.2.4.3 Burnable Absorber Rod ....................................................... 4.2-45 4.2.4.4 Control Element Assembly .................................................. 4.2-45 4.2.4.5 Onsite Inspection.................................................................. 4.2-46 4.2.4.6 Fuel Rod Failure Monitoring ............................................... 4.2-46 4.2.4.7 Inservice Surveillance .......................................................... 4.2-47 4.2.5 Combined License Information ............................................................ 4.2-47 4.2.6 References ............................................................................................ 4.2-48 4.3 Nuclear Design .................................................................................................... 4.3-1 4.3.1 Design Bases .......................................................................................... 4.3-1 4.3.1.1 Excess Reactivity and Fuel Burnup ....................................... 4.3-3 4.3.1.2 Negative Reactivity Feedback ............................................... 4.3-3 4.3.1.3 Core Design Lifetime and Fuel Replacement Program ......... 4.3-3 4.3.1.4 Reactivity Coefficients ........................................................... 4.3-3 4.3.1.5 Burnable Absorber Requirements .......................................... 4.3-3 4.3.1.6 Stability Criteria ..................................................................... 4.3-4 4.3.1.7 Maximum Controlled Reactivity Insertion Rate .................... 4.3-4 4.3.1.8 Control of Power Distribution................................................ 4.3-4 4.3.1.9 Excess Control Element Assembly Worth with Stuck Rod Criteria ............................................................................ 4.3-5 4.3.1.10 Chemical Reactivity Control .................................................. 4.3-5 4.3.1.11 Maximum Control Element Assembly Speeds ...................... 4.3-5 4.3.2 Description ............................................................................................. 4.3-5 4.3.2.1 Nuclear Design Description ................................................... 4.3-5 4.3.2.2 Power Distribution ................................................................. 4.3-6 4.3.2.3 Reactivity Coefficients ......................................................... 4.3-11 4.3.2.4 Control Requirements .......................................................... 4.3-16 4.3.2.5 Control Element Assembly Patterns and Reactivity Worths .................................................................................. 4.3-20 4.3.2.6 Criticality of Reactor During Refueling ............................... 4.3-22 4.3.2.7 Stability ................................................................................ 4.3-22 ii Rev. 0 APR1400 DCD TIER 2 4.3.2.8 Vessel Irradiation ................................................................. 4.3-26 4.3.3 Analytical Methods .............................................................................. 4.3-26 4.3.3.1 Reactivity and Power Distribution ....................................... 4.3-26 4.3.3.2 Spatial Stability .................................................................... 4.3-40 4.3.3.3 Reactor Vessel Fluence Calculation Model ......................... 4.3-42 4.3.4 Changes ................................................................................................ 4.3-42 4.3.5 Combined License Information ............................................................ 4.3-43 4.3.6 References ............................................................................................ 4.3-43 4.4 Thermal-Hydraulic Design ................................................................................ 4.4-1 4.4.1 Design Bases .......................................................................................... 4.4-1 4.4.1.1 Departure from Nucleate Boiling ........................................... 4.4-1 4.4.1.2 Fuel Temperature ................................................................... 4.4-2 4.4.1.3 Coolant Flow, Velocity, and Void Fraction ........................... 4.4-3 4.4.1.4 Hydraulic Instability .............................................................. 4.4-4 4.4.1.5 Fuel Cladding and Fuel Assembly Integrity .......................... 4.4-5 4.4.2 Description of Thermal-Hydraulic Design of the Reactor Core............. 4.4-5 4.4.2.1 Summary Comparison............................................................ 4.4-5 4.4.2.2 Critical Heat Flux Ratios........................................................ 4.4-5 4.4.2.3 Linear Heat Rate .................................................................... 4.4-8 4.4.2.4 Void Fraction Distribution ..................................................... 4.4-8 4.4.2.5 Core Coolant Flow Distribution ............................................. 4.4-8 4.4.2.6 Core Pressure Drops and Hydraulic Loads ............................ 4.4-8 4.4.2.7 Correlations and Physical Data ............................................ 4.4-10 4.4.2.8 Thermal Effects of Operational Transients .......................... 4.4-12 4.4.2.9 Uncertainties in Estimates .................................................... 4.4-12 4.4.2.10 Flux Tilt Considerations....................................................... 4.4-15 4.4.3 Description of Thermal-Hydraulic Design of the Reactor Coolant System ..................................................................................... 4.4-15 4.4.3.1 Plant Configuration Data ..................................................... 4.4-16 4.4.3.2 Operating Restrictions on Pumps ......................................... 4.4-16 4.4.3.3