NUREG/CR-2726 SAND82-1137 R3 Printed August 1983 Light Water Reactor Hydrogen Manual Allen L. Camp, John C. Cummings, Martin P. Sherman, Chester F. Kupiec, Robert J. Healy, Jeffrey S. Caplan, John R. Sandhop, James H. Saunders Prepared by Sandia National Laboratories. W' , 0 Albuquerque, New Mexico 87185 and Livermore, California 94550 ' ,'j, , for the United States Department of Energy under Contract DE-AC04-76DP00789 i , and I, j, General Physics Corporation, 1000 Century Plaza , , Columbia, Maryland 21044 .f. tjI !i I:'• Vtj - I,; -,' Prepared for1 U. S. NUCLEAR REGULATORY COMMISSION NOTICE This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employ- ees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, apparatus product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. Available from GPO Sales Program Division of Technical Information and Document Control U.S. Nuclear Regulatory Commission Washington, D.C. 20555 and National Technical Information Service Springfield, Virginia 22161 NUREG/CR-2726 SAND82-1137 R3 LIGHT WATER REACTOR HYDROGEN MANUAL SANDIA NATIONAL LABORATORIES GENERAL PHYSICS CORPORATION Allen L. Camp Chester F. Kupiec John C. Cummings Robert J. Healy Martin P. Sherman Jeffrey S. Caplan John R. Sandhop James H. Saunders Manuscript Completed: January, 1983 Date Published: June, 1983 Sandia National Laboratories Albuquerque, NM 87185 Operated By Sandia Corporation for the U. S. Department of Energy Prepared for Division of Accident Evaluation Office of Nuclear Regulatory Research U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Under Memorandum of Understanding DOE 40-550-75 NRC FIN No. A 1246 Author's Note While there are no current plans for updating this manual, persons who wish to point out errors or suggest revisions should send comments to the address shown below. If time and funding permits, we will attempt to pass on these comments to other recipients of the manual in an appropriate manner. Reactor Safety Studies Division 9441 Sandia National Laboratories P. 0. Box 5800 Albuquerque, NM 87185 ii ABSTRACT A manual concerning the behavior of hydrogen in light water reactors has been prepared. Both normal operations and accident situations are addressed. Topics considered include hydrogen generation, transport and mixing, detection, and combustion, and mitigation. Basic physical and chemical phenomena are described, and plant-specific examples are provided where appropriate. A wide variety of readers, including operators, designers, and NRC staff, will find parts of this manual useful. Different sections are written at different levels, according to the most likely audience. The manual is not intended to provide specific plant procedures, but rather, to provide general guidance that may assist in the development of such procuedures. iii TABLE OF CONTENTS Pag e Chapter 1 - Introduction and Objectives 1-1 1.1 Statement of the Problem 1-1 1.2 Hydrogen Problems in LWRs 1-1 1.3 Hydrogen Research Efforts 1-2 1.4 Description of Manual 1-4 Chapter 2 - Hydrogen in Light Water Reactors 2-1 2.1 Production of Hydrogen 2-1 2.1.1 Summary 2-1 2.1.2 Steam:Zirconium Reaction 2-1 2.1.3 Steam:Steel Reaction 2-3 2.1.4 Radiolysis of Water 2-7 2.1.5 Core:Concrete Interactions 2-10 2.1.6 Other Sources 2-13 2.1.7 Time Sequence of Hydrogen Production 2-16 2.2 Hydrogen Solubility, Transport, and Mixing 2-19 2.2.1 Introduction 2-19 2.2.2 Solubility of Hydrogen in Water 2-19 2.2.3 Transport and Mixing Within Containment 2-24 2.2.4 Air:Steam:Hydrogen Concentration Within Containment 2-26 2.3 Combustion of Hydrogen 2-28 2.3.1 Introduction 2-28 2.3.2 Example Calculation 2-28 2.3.3 Conditions Necessary for Combustion 2-36 2.3.4 Deflagrations 2-42 2.3.5 Combustion of a Steam:Hydrogen Jet 2-47 2.3.6 Detonation of Hydrogen 2-49 2.3.6.1 Detonation Limits 2-49 2.3.6.2 Transition to Detonation 2-54 2.3.6.3 Detonation Pressures and Temperatures 2-54 2.3.6.4 Local Detonations 2-55 2.3.6.5 Missile Generation 2-59 2.4 Mitigation Schemes 2-60 2.4.1 Deliberate Ignition 2-60 2.4.2 Water Sprays, Fogs and Foams 2-61 2.4.3 Pre-Accident Inerting 2-61 2.4.4 Post-Accident Inerting 2-65 2.4.5 Partial Pre-Inerting 2-65 2.4.6 High-Point-Vent Flaring 2-66 2.4.7 Other Methods 2-66 iv Page Chapter 3 - Hydrogen Behavior and Control--Normal Operation 3-1 3.1 Introduction 3-1 3.2 Hydrogen Considerations Common to PWRs and BWRs 3-1 3.2.1 Radiolysis 3-1 3.2.2 Radiation Synthesis 3-2 3.2.3 Control of Hydrogen from Radiolysis and Radiation Synthesis 3-3 3.2.4 Corrosion 3-4 3.2.5 Electrical Generators 3-8 3.2.6 Hydrogen Bulk Storage Facility 3-11 3.2.7 Gas Chromatography 3-12 3.2.8 Battery Room 3-12 3.2.9 Resin Beds 3-13 3.3 Hydrogen Considerations Specific to PWRs 3-13 3.3.1 Reactor Coolant System 3-14 3.3.1.1 Pressurizer 3-14 3.3.1.2 Control Rod Drive Mechanisms 3-16 3.3.1.3 RCS Leakage 3-18 3.3.2 Chemical and Volume Control System 3-18 3.3.3 Containment Entry 3-19 3.3.4 Gaseous Waste Disposal 3-19 3.4 Hydrogen Considerations'Specific to BWRs 3-22 3.4.1 Reactor Coolant System 3-22 3.4.2 Off-Gas System 3-22 3.4.3 Chemistry 3-27 3.4.4 Containment Entry 3-27 Chapter 4 - Hydrogen Behavior and Controi--Accident Conditions 4-1 4.1 Introduction 4-1 4.2 Containment Structure and Integrity 4-1 4.2.1 LWR Containment Comparison 4-1 4.2.2 PWR Containments 4-4 4.2.3 BWR Continments 4-7 4.3 Indications of a Loss-of-Coolant Accident 4-10 4.3.1 Introduction 4-10 4.3.2 PWR Indications Internal to the Reactor Coolant System 4-13 4.3.2.1 Temperature 4-13 4.3.2.2 Flow 4-13 4.3.2.3 Pressure 4-15 4.3.2.4 Pressurizer Level 4-15 4.3.2.5 Reactor Vessel Water Level 4-17 4.3.2.6 Nuclear Instrumentation 4-17 4.3.3 PWR Indications External to the Reactor Coolant System 4-22 V Page 4.3.3.1 Containment Pressure 4-23 4.3.3.2 Containment Temperature 4-23 4.3.3.3 Containment Humidity 4-23 4.3.3.4 Containment Activity 4-23 4.3.3.5 Containment Sump Level 4-23 4.3.4 BWR Indications Internal to the Reactor Coolant System 4-23 4.3.4.1 Temperature 4-23 4.3.4.2 Flow 4-23 4.3.4.3 Pressure 4-24 4.3.4.4 Reactor Vessel Level 4-24 4.3.4.5 Nuclear Instrumentation 4-28 4.3.5 BWR Indications External to the Reactor Coolant System 4-28 4.3.5.1 Drywell/Containment Pressure 4-28 4.3.5.2 Drywell/Containment Temperature 4-29 4.3.5.3 Drywell/Containment Activity 4-29 4.3.5.4 Suppression Pool Water Level 4-29 4.4 Indications of Hydrogen Production 4-29 4.4.1 Indications of Hydrogen Production Internal to the Reactor Coolant System of a PWR 4-30 4.4.1.1 Temperature 4-30 4.4.1.2 Flow 4-30 4.4.1.3 Pressure 4-32 4.4.1.4 Pressurizer Level 4-34 4.4.1.5 Reactor Vessel Water Level 4-34 4.4.1.6 Reactor Coolant Sampling 4-34 4.4.1.7 Reactor Coolant Activity 4-34 4.4.2 Indications of Hydrogen Production External to the Reactor Coolant System of a PWR 4-38 4.4.2.1 Containment Pressure 4-38 4.4.2.2 Containment Temperature 4-38 4.4.2.3 Containment Humidity 4-38 4.4.2.4 Containment Sampling 4-39 4.4.2.5 Steam Line Radiation 4-40 4.4.2.6 Gross Radiation Level Detection 4-40 4.4.3 Indications of Hydrogen Production Internal to the Reactor Coolant System of a BWR 4-41 4.4.3.1 Temperature 4-41 4.4.3.2 Flow 4-41 4.4.3.3 Pressure 4-42 4.4.3.4 Reactor Vessel Water Level 4-42 4.4.3.5 Reactor Coolant Activity 4-44 4.4.4 Indications of Hydrogen Production External to the Reactor Coolant System of a BWR 4-44 4.4.4.1 Drywell/Containment Pressure 4-44 4.4.4.2 Drywell/Containment Temperature 4-46 4.4.4.3 Drywell/Containment Humidity 4-46 4.4.4.4 Drywell/Containment Sampling 4-46 4.4.4.'5 Steam Line Radiation Monitoring 4-47 4.4.4.6 Gross Radiation Level 4-47 4.4.4.7 Sump Leak Detection 4-47 4.4.4.8 Suppression Pool Temperature 4-48 vi Page 4.5 Hydrogen Detection 4-48 4.5.1 Combustion Detector 4-49 4.5.2 Solid-State Detector 4-50 4.5.3 Electromechanical Detector 4-50 4.5.4 Thermal Conductivity Detector 4-50 4.5.5 Absorption Detector 4-50 4.5.6 Detector Availability 4-51 4.6 Transport and Mixing of Hydrogen 4-51 4.6.1 Introduction 4-51 4.6.2 Hydrogen Transport Pathways in a PWR 4-53 4.6.2.1 Hydrogen Transport Through the Reactor Vessel Head Vent 4-53 4.6.2.2 Hydrogen Transport Through the Hot Leg and Cold Leg Piping 4-57 4.6.2.3 Hydrogen Transport Into the Pressurizer and Pressurizer Relief Tank 4-58 4.6.2.4 Hydrogen Transport From Containment to Other Buildings 4-60 4.6.2.5 Considerations to Minimize Hydrogen Transport to Other Buildings 4-62 4.6.3 General Hydrogen Transport Pathways in a BWR 4-63 4.6.3.1 Hydrogen Transport Through a Reactor Coolant System Break 4-63 4.6.3.2 Hydrogen Transport Through a Stuck Open Safety/Relief Valve to the Suppression Pool 4-66 4.6.3.3 Primary Containment Leakage to the Secondary Containment (Mark I and II BWR Designs) 4-66 4.6.3.4 Hydrogen Transport via the Drywell Purge System and Vacuum Breaker 4-68 4.6.3.5 Hydrogen Transport Through the Bypass Leakage Paths From the Drywell 4-70 4.6.3.6 Considerations to Minimize Hydrogen Release to Other Buildings 4-72 4.6.4 Air Handling Fans 4-74 4.7 Hydrogen Combustion 4-74 4.7.1 introduction 4-74 4.7.2 Potential Sources of Accidental Hydrogen Ignition 4-75 4.7.3 Evidence of Hydrogen Combustion in PWRs 4-76 4.7.3.1 Containment Pressure Effects 4-77 4.7.3.2 Pressurizer Pressure Effects 4-77 4.7.3.3 Steam Generator Pressure Effects 4-77 4.7.3.4 Containment