FINAL ATMOSPHERIC SOURCE TERMS FOR THE IDAHO CHEMICAL PROCESSING PLANT, 1957–1959 Contract No. 200-2002-00367 Task Order No. 1, Subtask 1 A final report to the Centers for Disease Control and Prevention Atlanta, Georgia 30335 SC&A, Inc. 6858 Old Dominion Drive, Suite 301 McLean, Virginia 22101 SENES Oak Ridge, Inc. 102 Donner Drive Oak Ridge, Tennessee 37830 Authors: Robert P. Wichner, SENES Oak Ridge, Inc. John-Paul Renier, SENES Oak Ridge, Inc. A. Iulian Apostoaei, SENES Oak Ridge, Inc. July 2005 ICPP Source Terms July 2005 TABLE OF CONTENTS EXECUTIVE SUMMARY .......................................................................................................ES-1 1.0 SCOPE AND APPROACH ............................................................................................. 1-1 1.1 Scope .................................................................................................................. 1-1 1.2 Approach.............................................................................................................. 1-1 1.2.1 Operational RaLa Releases ...................................................................... 1-1 1.2.2 Idaho Chemical Processing Plant Criticality Approach........................... 1-2 2.0 THE RADIOACTIVE LANTHANUM (RaLa) PROCESS ............................................ 2-1 2.1 Background .......................................................................................................... 2-1 2.1.1 Requirement ............................................................................................. 2-1 2.1.2 Work at Oak Ridge National Laboratory................................................. 2-1 2.1.3 Early Process Decisions ........................................................................... 2-2 2.1.4 The RaLa Development Program at the Idaho Chemical Processing Plant ......................................................................................................... 2-2 2.2 Idaho RaLa Process Reporting............................................................................. 2-4 2.2.1 Primary Sources of Information............................................................... 2-4 2.2.2 Secondary Sources ................................................................................... 2-4 2.3 Chemical Flow Sheet ........................................................................................... 2-4 2.4 Process Equipment............................................................................................... 2-9 2.5 Iodine and Other Fission Product Distribution Tests......................................... 2-17 2.6 Operational History and Process Modifications ................................................ 2-20 2.7 Off-Gas Flow System ........................................................................................ 2-23 2.7.1 The Idaho Chemical Processing Plant Ventilation and Off-Gas System...................................................................................... 2-23 2.7.2 Description of the Dissolver .................................................................. 2-25 2.7.3 Description of the Scrubber ................................................................... 2-28 2.7.4 Operation of the Charcoal Beds ............................................................. 2-28 2.8 Summary and Conclusions ................................................................................ 2-28 3.0 IODINE BEHAVIOR IN THE RALA SYSTEM ........................................................... 3-1 3.1 Radioactive Properties of Iodine Radionuclides.................................................. 3-1 3.1.1 Birth and Decay Diagram ........................................................................ 3-1 3.1.2 Iodine and Tellurium Inventory in the Feed ............................................ 3-3 3.1.3 Radioiodine Gamma Ray Emissions ....................................................... 3-3 3.2 Iodine Behavior in the Caustic Dissolver ............................................................ 3-6 3.3 Iodine Behavior in the Centrifuge and Acidified Waste Tank ............................ 3-7 3.4 Iodine Behavior in the Scrubber—Effect of Sodium Thiosulfate ....................... 3-7 3.5 Mercury Complexing in Acid Solutions .............................................................. 3-8 i ICPP Source Terms July 2005 TABLE OF CONTENTS (continued) 3.6 Behavior of Iodine in the Stack Monitor Sampler ............................................... 3-9 3.7 Tellurium Chemistry in the Alkaline and Acid Dissolvers.................................. 3-9 3.8 Production of Organic Iodide............................................................................. 3-10 3.9 Summary and Conclusions ............................................................................... 3-11 4.0 RADIOIODINE PRODUCTION IN THE MATERIALS TESTING REACTOR, 1957–1959........................................................................................................................ 4-1 4.1 Introduction.......................................................................................................... 4-1 4.2 Materials Testing Reactor Description ................................................................ 4-2 4.3 Estimation of Barium-140 and Radioiodine Production in the Materials Testing Reactor .................................................................................................... 4-5 4.3.1 1957 Method ............................................................................................ 4-5 4.3.2 Isotope Buildup Using ORIGEN2 ........................................................... 4-8 4.4 RaLa Fuel Element Irradiation Histories ............................................................. 4-9 4.4.1 Documented RaLa Fuel Elements and Irradiation Histories ................... 4-9 4.4.2 Surmised RaLa Fuel Elements and Irradiation Histories......................... 4-9 4.4.3 Recreated Rala Fuel Elements and Irradiation Histories ....................... 4-12 4.5 ORIGEN2 Results.............................................................................................. 4-19 4.5.1 Radioiodine Production ......................................................................... 4-19 4.6 Reported Iodine-131 Production in the Materials Testing Reactor ................... 4-20 5.0 THE STACK MONITOR ............................................................................................... 5-1 5.1 Introduction.......................................................................................................... 5-1 5.2 General Features of the Stack Monitor System ................................................... 5-1 5.2.1 Flow Diagram .......................................................................................... 5-1 5.2.2 System Operation and the Iodine Sampler............................................... 5-3 5.2.3 Early Stack Monitor Experience .............................................................. 5-5 5.2.4 Relation of Stack Sampler Activity to Release........................................ 5-5 5.3 The Stack Monitor Datasheets ............................................................................. 5-7 5.3.1 General Features ...................................................................................... 5-7 5.3.2 Sample Datasheets ................................................................................... 5-8 5.4 Stack Monitor System Evaluation ..................................................................... 5-13 5.4.1 Evaluation of Sampler Efficiency.......................................................... 5-13 5.4.2 Iodine Deposition Error ......................................................................... 5-18 5.4.3 Effect of Variable Iodine Release .......................................................... 5-20 5.4.4 Possible Radiation Detection Errors ...................................................... 5-21 5.5 Summary and Conclusions Regarding the Stack Monitor Datasheets............... 5-23 5.5.1 Summary of Stack Sampler Error Evaluation........................................ 5-23 5.5.2 Conclusions............................................................................................ 5-24 ii ICPP Source Terms July 2005 TABLE OF CONTENTS (continued) 6.0 IODINE RELEASES FROM THE RALA PROCESS, FEBRUARY 1957 TO DECEMBER 1959........................................................................................................... 6-1 6.1 Early Iodine Releases........................................................................................... 6-1 6.2 Existing Reports of Iodine Releases from the RaLa Process............................... 6-1 6.2.1 The Hayden Notegrams ........................................................................... 6-1 6.2.2 The Health and Safety Division Annuals................................................. 6-2 6.2.3 The Historical Dose Evaluation Study..................................................... 6-2 6.3 Iodine, Tellurium, and Xenon Nuclides Fed to the Dissolver ............................. 6-4 6.4 Recommended Daily Releases of Iodine-131...................................................... 6-5 6.5 Evaluation of Iodine-132 Release Data ............................................................... 6-5 6.5.1 Cases of High Iodine-132 Release Readings ........................................... 6-5 6.5.2 Possible Contributing Factors to the Observed High Iodine-132 Releases ................................................................................