ORP/EERF 73-2 CONSTRUCTION AND OPERATION OF AN ION EXCHANGE CARTRIDGE FOR MONITORING RADIONUCLIDES IN THE ENVIRONMENT U.S. ENVIRONMENTAL PROTECTION AGENCY Office of Radiation Programs ------- OFFICE OF RADIATION PROGRAMS EASTERN ENVIRONMENTAL RADIATION FACILITY TECHNICAL REPORTS Technical reports of the Eastern Environmental Radiation Facility are available from the National Technical Information Service, Springfield, Virginia 22151, when a PB number is indicated after the title. Microfiche copies are $0.95; prices for paper copies are indicated after the PB number. Bulk order prices are available from NTIS. The PB number should be cited when ordering. Title Radiological Survey of Major California Nuclear Ports (April 1967) (PB 178 728 $6.00) BRH/SERHL 70-1 RO/EERL 71-1 EERL 71-2 ORP/EERF 73-1 ORP/EERF 73-2 ORP/EERF 73-3 Radiological Survey of Hampton Roads, Virginia (January 1968) (AD 683 208 $6.00) Laboratory Examination of a Ruptured 50-mg Radium Source (May 1970) (PB 191 810 $3.00) Development of Ion Exchange Processes for the Removal of Radionuclides from Milk (January 1971) (PB 198 052 $0.50) Investigation of Tritiated Luminous Compounds (June 1971) Suitability of Glass-Encapsulated CaF2:Mn Thermoluminescent Dosimeters for Environ- mental Radiation Surveillance (June 1973) Construction and Operation of an Ion Exchange Cartridge for Monitoring Radio- nuclides in the Environment (June 1973) Portable Annealer for Thermoluminescent Dosimeters (June 1973) ------- ORP/EERF 73-2 CONSTRUCTION AND OPERATION OF AN ION EXCHANGE CARTRIDGE FOR MONITORING RADIONUCLIDES IN THE ENVIRONMENT J. K. Hasuike S. T. Windham Eastern Environmental Radiation Facility P. 0. Box 61 Montgomery, Alabama 36101 June 1973 I \ ENVIRONMENTAL PROTECTION AGENCY Office of Radiation Programs Waterside Mall East 401 M Street, S.W. Washington, D.C. 20460 ------- The mention of commercial products, their source, or their use in connection with material reported herein is not to be construed as either an actual or implied endorse- ment of such products by the U. S. Environmental Protection Agency- 11 ------- FOREWORD The Eastern Environmental Radiation Facility participates in the identification of solutions to problem areas as defined by the Office of Radiation Programs. The Facility provides laboratory capability for evaluation and assess- ment of radiation sources through environmental studies and surveillance and analysis. The EERF provides technical assistance to the State and local health departments in their radiological health programs and provides special laboratory support for EPA Regional Offices and other federal government agencies as JE:equested. ^ /\ /> iarles R. Porter Acting Director Eastern Environmental Radiation Facility 111 ------- CONTENTS Page Foreword ii List of Tables and Figures iv Introduction 1 Ion Exchange Method of Sampling 2 Description of Equipment 6 Laboratory Results 8 Conclusion 8 References 10 v ------- TABLES Page 1. Laboratory tests of cartridges 9 FIGURES 1. Assembled and disassembled column ... .4 2. Details of column with settling chamber. .5 3. Construction details of ion exchange column 7 Vi ------- EERF TECHNICAL REPORT ORP/EERF-73-2 CONSTRUCTION AND OPERATION OF AN ION EXCHANGE CARTRIDGE FOR MONITORING RADIONUCLIDES IN THE ENVIRONMENT J. K. Hasuike and S. T. Windham SUMMARY The increased emphasis on measuring environmental levels of radioactivity requires a maximum of sensitivity in the collection and analysis of samples. Described below is an ion exchange sampler developed by this Facility that has proved very useful in monitoring for low-level radioactive effluents in the environment. The sampler consists of a compartmentalized ion exchange column containing a particulate prefilter and cation and anion resins. After use the prefilter and resin are gamma analyzed directly and/or processed via chemical analysis. The column is easy to construct and use, is inexpensive, and is reusable. INTRODUCTION The Atomic Energy Commission (AEC) has the responsi- bility of regulating radioactive discharges from nuclear power plants. It is the reactor operators, State health departments, private contractors, and other groups who are actually charged with monitoring the environs of nuclear facilities to ascertain the actual radioactive contents discharged. In 1970 the AEC published in the Federal Register amendments which specified that operators of light-water cooled reactors keep levels of radioactive effluents released to unrestricted areas as low as practicable. The AEC's quantitative definition of "as low as practicable" recommends that for population groups in uncontrolled areas their maximum exposures resulting from these effluents be less than approximately one percent of natural background. ------- Thus there is an increased need to identify and quantify low levels of environmental radioactivity with a minimum commitment of equipment, time and expense. The Environmental Studies Branch of the Eastern Environ- mental Radiation Facility designed and developed a sectional ion exchange sampler which when used with the technique described by Krieger1, is very effective in monitoring for low-level radioactive liquid effluents in the environment. The sampler has been used extensively in a study of the long-term buildup of radionuclides in an impounded lake supplying cooling water to a nuclear power plant1". Preliminary data to be published later verifies that the columns are operating successfully. The ion exchange field method has been employed by others1, but it is felt that the columns described here far surpass any others for simplicity, reliability, and efficiency. ION EXCHANGE METHOD OF SAMPLING Ion exchange techniques have received rather wide- spread acceptance as a method of selectively removing radionuclides from solutions; e.g., separation of iodine from milk2'3 and_the radioactive decontamination of water supplies. "* 7 Samuelson has described ion exchange separation techniques8, and Krieger1 has developed a technique for selectively collecting and analyzing environmental levels of radioactive effluents. The equipment discussed here implements Krieger's technique. Routine environmental sample analysis involves the collection and return to the laboratory of large sample volumes to obtain adequately low detection capabilities. By using the field ion exchange method, it is possible ^Study of the Long-Term Buildup of Radioactivity in an Impounded Cooling Lake. Being conducted by Nuclear Facilities Research Branch, Eastern Environmental Radiation Facility. Results not yet published. ------- to achieve improved detection sensitivity while at the same time reducing the size of the sample to be trans- ported to the laboratory. As a routine field ion exchange procedure used at the EERF radionuclides are quantitatively removed from 200 liters (438 pounds) of water on site and returned to the laboratory on a resin column weighing 2.3 kg (5 pounds). This reduction in weight and volume plus increased sensitivity makes it possible to collect samples at more locations and to provide data with greater statistical significance. These ion exchange columns were developed through laboratory studies and field testing. The column was designed to satisfy the following criteria: 1. Easy and inexpensive to construct using ordinary shop tools; 2. Easy to set up and use in the field; 3. Easy to process in the laboratory; 4. Provide an efficient means of collecting radionuclides from water. The column shown in figure 1 consists of several separate compartments. The number and size of the compartments are determined by the requirements of the particular situation. The one shown has three compartments for resin plus a glass wool prefliter. The prefliter removes coarse suspended materials which would clog the resin. The top resin compartment contains 300 ml of Dowex 50W-X8 cation resin; the center resin compartment contains 300 ml of Dowex 2-X8 anion resin; and the bottom compartment contains 300 ml of Dowex 50W-X8 cation resin. The bottom compartment of cation resin is a backup or safety section and would collect the radionuclides should they not be quantitatively removed by the upper cation resin. The compartmentalized design makes the column very versatile to fit varied field requirements. For example, in waters containing large amounts of suspended materials, it is essential that these materials be removed prior to entering the resin beds. A settling chamber was incorporated on top of the column which solved this problem, (figure 2) ------- Column assembled for use Components of disassembled column Figure 1. Assembled and disassembled column ------- Column with settling chamber attached mater (low r plate - -{/, vent holes (4) •(i holes(6) -6 PVC pipe -3 O.D. plexiglass baffle yss^^^i R^:^S^^ * 11=4! f I PVC pipe I FPT resin *\fc XSrXG* S plenglass ^ to dia. holes (4) 3 O.D. "0"ring.'/i thick Construction diagram of settling chamber Figure 2. Details of column with settling chamber. ------- DESCRIPTION OF EQUIPMENT The column, as shown in figure 3, is constructed of materials which are commercially available. Plexiglas tubing with a 3-inch outside diameter and 2 3/4-inch inside diameter is used. Pieces of 1/2-inch Plexiglas are used as the flanges to join the sections of the column. Figure 3 shows the "0" ring seal and the resin- retaining screen. The columns flow by syphon action and it is necessary to insure that each compartment is leakproof to prevent air pockets in the resin. The "0" ring seal is very effective in assuring a leak-free system. The resin-retaining screen is 80 mesh stainless steel screen which is glued in place between rings in the lower end of each compartment. These screens pre- vent the resin from mixing, but permit the water to flow through unimpeded. All Plexiglas to Plexiglas joints in the columns are made using ethylene dichloride as the adhesive. The only tools required for construction are a band saw, a disc sander, and a 1/2-inch drill press with circle cutting and regular bits. PREPARATION AND USE OF THE COLUMN To allow for maximum convenience in the field, each cartridge is completely prepared and sealed in the laboratory. The cation resin is converted to the H+ form, and the anion resin is converted to the OH~ form as recommended by the manufacturer.9 The resin is then measured and loaded into the compartments, the compart- ments are assembled, and each column is backwashed gently with distilled water and sealed with hose clamps. At the field sampling site it is only necessary to set the column on a ring stand or other convenient support and connect the inlet tube to the water source to be sampled. Approximately 30 centimeters (12 inches) of syphon head is required to deliver a suitable flow rate through the column. The flow rate is set between 300 to 400 ml/minute, and at this flow rate approximately 10 to 11 hours is required to process 200 liters. Once started, the column is allowed to run overnight with the outlet hose from the column secured at a position above the top resin level. This allows for continuous flow, at the same time preventing the resin from drying out. After processing the entire sample, the column is sealed at the inlet and outlet using hose clamps and returned to the laboratory for analysis. ------- 2 3/4" 0-RINGS 1/8" THICK RINGS CUT FROM 2 3/4" PLEXIGLASS HOLES FOR 1/4" BOLTS USE WING NUTS 3" O.D. PLEXIGLASS RESIN RETAINING SCREEN Figure S. Construction details of ion exchange colwm. ------- The multi-compartment design of the column expedites laboratory processing. After the water is drained from the column it is physically disassembled and the resin from each compartment is transferred to separate counting containers. These are directly gamma counted for activity- If desired, the resin may then be eluted or stripped using appropriate techniques to permit chemical separations and analyses for specific isotopes. LABORATORY RESULTS Since the ion exchange concept for removing radio- nuclides from water is a proven method, little emphasis has been placed on extensive laboratory testing. Instead, this report deals with equipment development and not ion exchange procedure. Tests were run with flow rates of 500 ml/minute to determine if any radioisotope break- through would occur in the top section of the column. Table 1 shows results of 3 runs made using water spiked with strontium-85 and cesium-137. No breakthrough was observed. CONCLUSION The ion exchange sampler described is simple, reliable, efficient, and inexpensive. It can be easily constructed and used by most groups conducting environ- mental radiological surveillance programs. In addition to sampling for radioactivity, applications of these columns could be made in marine research, water pollution studies, and pesticide studies. ------- Total original activity in 200 liters1 Glass Wool Top Cation Resin: Anion Resin3 Bottom Cation3 Run 1 500 ml/min "Sr cpm 41,215 168 35,228 0 30 TABLE I LABORATORY TESTS OF CARTRIDGES Run 2 ml/min Run 3 85 500 ml/min s 22 22 r cpm ,435 NA ,977 0 31 iJ/Cs cpm 13,518 NA 13,725 0 6 Sr cpm 14,950 NA 15,750 0 0 -L-j'Cs cpm 13,518 NA 13,725 0 0 NA - not available 1 Samples were counted in 300 ml solution before addition to 200 L of tap water 2Counted in cottage cheese containers, amount not available transferred all 300 ml of resin into a container for counting ------- REFERENCES (1) H. L. Krieger, G. W. Frishkorn, Evaluation of Ion Exchange Surveillance Sampler for Analyzing Radioactive Liquid Effluents. Health Phys: 21: No. 4, 591-5 (Oct 1971). (2) D. G. Easterly, I. B. Brooks, J. K. Hasuike, Development of Ion Exchange Processes for the Removal of Radionuclides from Milk. Eastern Environmental Radiation Laboratory Report RD/EERL 71-1 (Jan 1971). (3) G. K. Murthy, J. E. Gilchrist, J. E. Campbell; Method for Removing Iodine-131 from Milk. J. Dairy Sci., 45:1066-74 (Sept 1962). (4) D. C. Lindsten, J. K. Hasuike, A. G. Friend; Removal of Radioactive Contaminants from a Seminatural Water Source with U. S. Army Water Purification Equip- ment. Health Phys., Vol. 11, pp 723-729 (Aug 1965). (5) D. C. Lindsten et al., Removal of Radioactive Contaminants from Water with the Corps of Engineers Mobile Water Purification Unit, Office of Technical Services; Department of Commerce, Report PB 135996 (1955). (6) D. C. Lindsten et al., Removal of Nuclear Bomb Debris, Strontium-90-Yttrium-90 and Cesium-137-Barium- 137 from Water with Corps of Engineers Mobile Water Treating Equipment, Office of Technical Services, Department of Commerce, Report PBAD 265585 (1961). (7) D. C. Lindsten,and R. P. Schmitt, Removal of Chemical, Biological, and Radiological Contaminants from Water with Corps of Engineers Field Water Supply Equipment, Office of Technical Services, Department of Commerce, Report PBAD 274300 (1961). (8) 0. Samuelson, Ion Exchanges^ in Analytical Chemistry John Wiley, New York (1953). (9) Dowex; Ion Exchange, The Dow Chemical Company, Midland, Michigan. U.S. Government Printing Office: 1973 — 743 - 905/7766 Region No. 4 ------- |