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TABLE OF CONTENTS Section Page No. 1. BRIEF DESCRIPTION OF NUCLEAR POWER REACTOR SYSTEMS AND PRIMARY COOLANT CHEMISTRY 1-1 1.1 Boiling Water Reactor (BWR) 1-1 1.2 Pressurized Water Reactor (PWR) 1-5 1.3 References 1-7 2. RADIOACTIVITY PRODUCTIONS IN NUCLEAR REACTORS 2-1 2.1 Radioactive Species in Light Water Reactors 2-1 2.2 Nuclear Fission 2-3 2.2.1 Mass Distribution and Fission Product Chains 2-4 2.2.2 Charge Distribution 2-6 2.3 Transuranic Nuclides 2-8 2.4 Activation of Water and Impurities in Reactor Coolant 2-14 2.5 Activation of Corrosion Products 2-17 2.6 References 2-20 2.7 Bibliography 2-20 3. FISSION PRODUCTS 3-1 3.1 Fission Product Release Calculation - A Theoretical Model 3-1 3.1.1 Release of Fission Products into Fuel Gap 3-1 3.1.2 Release of Fission Product from Defective Fuel into Reactor Coolant 3-3 3.1.3 Release of Fission Product from Fuel Containment 3-5 3.2 Characterization of Fission Product Release Patterns in BWR 3-6 3.2.1 Empirical Methods 3-6 3.2.2 Release of Noble Gas Activities 3-8 3.2.3 Release of Iodine Activities 3-12 3.2.4 Calculation of Nonvolatile Soluble Fission Product Release Rate 3-13 3.2.5 Estimation of the Exposure for Defective Fuel Rods 3-14 3.2.6 BWR Radioactivity Source Terms and Fission Product Activities in the Primary Coolant 3-16 3.3 Characteristics of Fission Product Release Patterns in PWR 3-19 3.3.1 Activity Release Rate 3-19 IX
TABLE OF CONTENTS (Continued) Section Page No. 3. FISSION PRODUCTS (Continued) 3.3.2 Fission Product Activities in the Primary Coolant and Characterization of Fuel Failure Pattern 3-20 3.3.3 Estimation of the Number of Failed Fuel Rods 3-22 3.3.4 Steady-State Concentrations of Fission Product Activities in the Primary Coolant 3-23 3.4 Fission Product Transport in the Coolant System 3-24 3.4.1 Fission Products in the Steam/Condensate System inBWR 3-24 3.4.2 Fission Products in the Secondary Coolant System inPWR 3-27 3.5 Fission Product Release During Power Transient 3-28 3.5.1 Release Mechanisms 3-30 3.5.2 Magnitude of 1-131 Spike 3-31 3.5.3 Iodine Release Rate in PWR 3-34 3.5.4 Soluble Fission Products Releases 3-35 3.6 References 3-35 4. ACTIVATED CORROSION PRODUCTS 4-1 4.1 Introduction 4-1 4.2 Activated Corrosion Products in BWRs 4-1 4.2.1 Activation of Corrosion Products on Fuel Surfaces 4-1 4.2.2 Concentrations and Chemical Behavior of Activated Corrosion Products in Reactor Water 4-10 4.2.3 Corrosion Product Spiking in Reactor Coolant During Power Transients 4-14 4.2.4 Corrosion Product Transport and Radiation Field Buildup in the Primary System 4-16 4.2.5 Summary of Major Laboratory Test Results for Co-60 Deposition on Stainless Steel Surfaces 4-23 4.2.6 Radiation Fields and Personnel Exposure Reduction at BWRs 4-29 4.3 Activated Corrosion Products in PWRs 4-29 4.3.1 Deposition of Corrosion Products on Fuel Surfaces 4-29 4.3.2 Radiochemical Composition in PWR Coolants 4-35 4.3.3 Corrosion Product Deposition on Out-of-Core Surfaces 4-38 4.4 References... 4-42
TABLE OF CONTENTS (Continued) Section Page No. 5. WATER AND IMPURITY ACTIVATION PRODUCTS 5-1 5.1 Introduction 5-1 5.2 Tritium in PWRs 5-1 5.3 Na-24 and CL-38 in BWRs 5-4 5.4 N-13 and N-16 in BWRs 5-5 5.5 F-18inBWR 5-11 5.6 References 5-12 6. RADIATION CHEMISTRY IN REACTOR COOLANT 6-1 6.1 Introduction 6-1 6.2 Water Radiolysis in BWR Coolant 6-1 6.3 Radiolytic Gas Production in BWRs 6-6 6.4 Suppression of Water Radiolysis by l\2 Addition 6-6 6.5 The Role of Impurities 6-10 6.6 Hydrogen Water Chemistry in BWR Coolant 6-11 6.7 Chemical Effects of Radiation in BWR Coolant 6-15 6.8 References 6-17 7. ASSAY OF RADIOACTIVE WASTE 7-1 7.1 Introduction 7-1 7.2 Sampling and Sample Preparation 7-4 7.3 Radiochemical Analysis 7-7 7.4 Direct Assay Techniques 7-9 7.5 Radionuclide Correlations and Scaling Factors 7-12 7.6 References 7-16 8. SPECIAL RADIOCHEMICAL STUDD2S 8-1 8.1 Estimation of Noble Gas Transit Time in the BWR Turbine System 8-1 8.2 No-Cleanup Test in a BWR 8-3 8.2.1 Na-24 and Cl-38 Activity Buildup 8-3 8.2.2 Measurement of Iodine Steam Transport 8-8 8.3 Radiochemistry of Iodine 8-10 8.3.1 Chemical Forms of Radioiodine in PWR Coolant 8-10 8.3.2 Chemical Forms of Radioiodine in BWR Coolant 8-10 8.3.3 Chemical Forms of Radioiodine Activities in BWR Condensate andOffgas 8-14 XI
TABLE OF CONTENTS (Continued) Section 8. SPECIAL RADIOCHEMICAL STUDIES (Continued) Page No. 8.4 Transuranic Nuclides in BWR Coolants 8-17 8.5 Application of Na-24 Tracer in Flow Measurements 8-21 8.6 Identification of Defective Fuel 8-24 8.7 References 8-29 Appendix A. NUCLEAR DATA A-1 Table A-1 Summary of Major Nuclides and Radiation Properties A-3 Table A-2 Major Gamma-Ray Energies and Intensities A-5 Table A-3 Cumulative Yields of Major Fission Products in Thermal Neutron Fission of U-235 and Pu-239 A-15 Table A-4 Major Water and Impurity Activation Products in Reactor Coolant A-17 Table A-5 Major Activated Corrosion Products in Light Water Reactors A-18 Table A-6 Recommended Gamma-Ray Standards A-I9 Figure A-1 Chart of the Nuclides (Partial) A-21 Appendix B. SAMPLING PRACTICES AND SAMPLE PREPARATION FOR RADIOCHEMICAL ANALYSES B-1 Appendix C. GAMMA-RAY SPECTROMETRIC ANALYSIS C-1 Appendix D. COUNTING GEOMETRIC CORRECTIONS IN GAMMA-RADIATION MEASUREMENTS D-1 Appendix E. SELECTED RADIOCHEMICAL PROCEDURES E-1 E.I Determination of Radioactive Iodine in Water E-2 E.2 Determination of Strontium-89/90 E-5 E.3 Determination of Iron-55 E-17 E.4 Determination of Nickel-63 E-23 xn
LIST OF FIGURES Figure No. Page No. 1-1 Direct Cycle Boiling Water Reactor System With Forward- Pumped Heater Drains 1-2 1-2 Schematic of a Pressurized Reactor System 1-6 2-1 Yields of Fission Product Chains as a Function of Mass Number for the Thermal-Neutron Fission of U-235 and Pu-239 2-5 2-2 Charge Dispersion for Products with A = 93 from Thermal- Neutron Fission of U-235 2-7 2-3 Actinide Chains in Uranium-Plutonium Fuel 2-11 2-4 Variation of Transuranic Isotope Content with Fuel Exposure in UC<2 Fuel 2-12 2-5 Variation of Fractional Fissions from Fissionable Nuclides in UO2 Fuel (2.5% U-235) with Fuel Exposure 2-13 2-6 Specific Activity of Major Corrosion Products as a Function of Irradiation Time with Neutron Flux 2-19 3-1 Schematic of One Compartment Model 3-4 3-2 Typical Example of Log (Release Rate) vs. Log (Decay Constant) for Noble Gases and Iodine Isotopes 3-7 3-3 Calculated Cs-134 to Cs-13 7 Ratio in the Fuel as a Function of Fuel Burnup 3-15 3-4 Iodine Carryover as a Function of Copper Ion Concentration in Feedwater 3-25 3-5 Iodine-131 Transport Distribution in the Steam, Condensate and Feedwater Systems of a BWR 3-26 3-6 Behavior of Iodine-131 Spiking During Shutdown in a BWR 3-29 3-7 Total 1-131 Release During a Spiking Sequence. 3-32 Xlll
LIST OF FIGURES (Continued) Figure No. Page No. 3-8 Magnitude of 1-131 Spike as a Function of the Ratio of Fission Gas to 1-131 Release Rate During Power Operation in BWRs 3-33 3-9 Behavior of Cs Isotopes Spiking During Shutdown in a PWR 3-36 4-1 Axial Distribution of Iron and Cobalt on Fuel Surface 4-2 4-2 Axial Distribution of Ca-60 and Co-60 Specific Activity on Fuel Surface 4-3 4-3 Fuel Cladding Deposit Sampling Device 4-5 4-4 Bundle Average Specific Activities of Activated Corrosion Products in Fuel Deposits 4-11 4-5 Percent Soluble Co-60 as a Function of Iron Concentration in Reactor Water 4-15 4-6 Variation of Co-60 Concentration in Reactor Water During Shutdown 4-17 4-7 Radiation Fields on BWR Recirculation Lines 4-18 4-8 Block Diagram for Co/Co-60 Transport Model 4-21 4-9 Co-60 Deposition on As-Received (304AR) and Prefilmed (304 PF) 304 SS Samples Under Normal Water Chemistry Conditions 4-24 4-10 Effects of Chemical Additives on Co-60 Deposition on As-Received 304 SS Samples Under Normal Water Chemistry Conditions 4-25 4-11 Comparison of Co-60 Deposition on As-Received 304SS Samples Under Normal Water Chemistry Conditions with Metallic Ions at 15ppb 4-26 4-12 Variation of Co-60 Deposition on 304SS Samples Changing from Normal to Hydrogen Water Chemistry 4-27 4-13 Typical Axial Power and Temperature Distribution in a PWR Core 4-31 xiv
LIST OF FIGURES (Continued) Figure No. Page No. 4-14 Relative Specific Crud Activity of Fuel Deposits 4-32 4-15 Iron Solubility for Magnetite as a Function of Hydroxide Concentration at 250°C and 300°C, at Hydrogen Partial Pressure of 1 atm 4-34 4-16 Concentrations of Co-58 and Co-60 Activities in a PWR Primary Coolant During Shutdown Operation 4-37 4-17 Comparison of Unit Surface Activities at Three Different Locations and Materials of Construction 4-39 4-18 CORA Model Nodel Diagram 4-40 4-19 Measured Steam Generator Channel Head Dose Rates and Range of CORA Results 4-41 5-1 Tritium Level in a PWR Primary Coolant 5-3 5-2 Variation of Radiation Fields and N-16 Concentrations in Steam as a Function of H2 Concentration in Feedwater 5-7 5-3 Gamma-Ray Spectrum Observed at a High Pressure Turbine with a Shielded Collimator 5-8 5-4 Variation of N-13 Species in Reactor Water with H2 Concentration 5-9 5-5 Variation of N-13 Species in Steam Condensate with \\2 Concentration in Reactor Water 5-9 6-1 Radiolytic Products in Water Radiolysis with 1 Gy/s Dose Rate 6-4 6-2 Radiolytic Gas Production Rates in BWRs 6-7 6-3 Depletion of ©2 in Water by Irradiation in the Presence of Surplus H2 6-10 XV
LIST OF FIGURES (Continued) Figure No. Page No. 6-4 Hydrogen and Oxygen Concentrations in Steam as a Function of Hydrogen Concentration in Reactor Water 6-12 6-5 Recirculation Water Oxygen Concentration as a Function of Recirculation Water Hydrogen Concentration 6-14 7-1 Flow Diagram of Sample Preparation 7-8 7-2 Schematic of the Sample Chemical Analysis Program 7-10 8-1 Apparent Transit Time for Gaseous Activities from RPV to SJAE 8-2 8-2 Variation of Conductivity and pH Value in Reactor Water During a No-Cleanup Test 8-4 8-3 Variation of Reactor Water Conductivity with RWCU Returning to Service 8-5 8-4 Variation of Na-24 and Cl-38 Concentrations in Reactor Water During a No-Cleanup Test 8-7 8-5 Variation of Iodine Activity Concentrations in Reactor Water During a No-Cleanup Test 8-9 8-6 Separation of Iodine Chemical Forms by Exchange/Extraction Processes 8-12 8-7 Variation of Cm-242 to Zr-95 Activity Ratio in Coolant as a Function of Average Core Burnup 8-20 8-8 Schematic Diagram of a Vacuum-Sipper System 8-28 xvi
LIST OF TABLES Table No. Page No. 1-1 BWR Water Quality Specifications 1-4 1-2 Vendor Reactor Coolant Chemistry Specifications for Power Operation 1-8 1-3 Current Westinghouse Specifications for the Reactor Coolant System 1-9 2-1 Beta Decay Chain for Mass Number 93 2-7 2-2 Cumulative Yields of Major Fission Products in Thermal Neutron Fission of U-235 and Pu-239 2-9 2-3 Major Water and Impurity Activation Products in Reactor Coolant 2-15 2-4 Major Activated Corrosion Products in Light Water Reactors 2-18 3-1 Standard Plant Design Basis Noble Gas and Halogen Leakage Rates 3-17 3-2 Selected ANS Standard Radionuclide Concentrations in Reactor Coolants - Fission Products 3-18 4-1 Empirical Release Constants and Equilibrium Specific Activities for Activation Products in BWR Fuel Deposits 4-10 4-2 Selected ANS Standard Radionuclide Concentrations in Reactor Coolants - Activation Products 4-12 4-3 Typical Concentrations of Major Activated Corrosion Products in Reactor Water 4-13 4-4 Average Radioisotope Concentrations on BWR Recirculation Lines 4-19 4-5 Calculated Dose Rate Conversion Factors for 20-28 in. O.D. Pipe 4-20 4-6 Summary of Cobalt Deposition Mechanisms 4-28 xvn
LIST OF TABLES (Continued) Table No. Page No. 4-7 Average Radiochemical Composition of Deposits on the Fuel Surface in a PWR After One Cycle 4-33 4-8 Average Activities of Selected Nuclides in Reactor Coolants from the Beaver Valley and Trojan Plants 4-36 5-1 Tritium Inventories in Plant Components in a PWR. 5-2 5-2 Equilibrium Concentrations and Source Input Rates of Na+ (Na-24) and CP (Cl-38) During Normal Operation in a BWR 5-5 5-3 Summary of N-13 Chemical Forms Measured During HWC Testa 5-10 5-4 N-16 Steam Concentration at Various Locations in Three Classes of BWRs 5-11 6-1 G-Values of Primary Radiolytic Species in Water 6-5 6-2 Reaction and Rate Constants Used in Water Radiolysis Simulation 6-9 6-3 Examples of Impurity Reaction Rate Constants 6-11 7-1 10 CFR 61 Waste Classification Activity Limits 7-2 7-2 Nuclear Data for Difficult-to-Measure Radionuclides 7-3 7-3 Typical BWRNuclide Concentration by Waste Stream 7-5 7-4 Typical PWRNuclide Concentrations by Waste Stream 7-6 8-1 Chemical Forms of Radioiodine in BWR Primary Coolant (%) 8-11 8-2 Chemical Forms of Radioiodine in Condensate (%) 8-15 8-3 Chemical Forms of Iodine Activities in BWR Offgas (%) 8-15 8-4 Comparison of Iodine Isotopic Ratios in Reactor Water Condensate and Offgas 8-15 xvin
LIST OF TABLES (Continued) Table No. Page No. 8-5 Transuranic Isotopes in Reactor Water 8-19 8-6 Ratios of Total Alpha Activity to Insoluble Fission Products in Reactor Water 8-19 8-7 Comparison of Fuel-Sipping Methods 8-25 XIX
1. BRIEF DESCRIPTION OF NUCLEAR POWER REACTOR SYSTEMS AND PRIMARY COOLANT CHEMISTRY 1.1 BOILING WATER REACTOR (BWR) The direct cycle boiling water reactor nuclear system (Figure 1-1) is a steam generating system consisting of a nuclear core and an internal structure assembled within a pressure vessel, auxiliary systems to accommodate the operational and safeguard requirements of the nuclear reactor, and necessary controls and instrumentation. High-purity water is circulated through the reactor core, serving as moderator and coolant. Saturated steam is produced in the reactor core, separated from recirculation water, dried in the top of the vessel, and directed to the steam turbine generator. The turbine employs a conventional regenerative cycle with condenser deaeration and condensate demineralization. The reactor core, the source of nuclear heat, consists of fuel assemblies and control rods contained within the reactor vessel and cooled by the recirculating water system. A typical 1220 MWe BWR/6 core consists of 748 fuel assemblies and 177 control rods, forming a core array about 5 meters in diameter and 4.3 meters high. The power level is maintained or adjusted by positioning control rods up and down within the core. The BWR core power level is further adjusted by changing the recirculation flow rate without changing the control rods positions. The boiling water reactor requires substantially lower primary coolant flow through the core than pressurized water reactors. The core flow of a BWR is the sum of the feedwater flow and the recirculation flow. The function of the reactor water recirculation system is to circulate the required coolant through the reactor core. The system consists of two or more loops external to the reactor vessel, each loop containing a pump with a directly coupled water-cooled (air- water) motor, a flow control valve, and two shutoff valves. High-performance jet pumps located within the reactor vessel are used in the BWR recirculation system. The jet pumps, which have no moving parts, provide a continuous internal circulation path for the total core coolant flow. 1-1
