ASTM_D_2184_-_81_scan.pdf

9009276 0024909 998 Designation:D 2184-81 Vz/-.ri&O/AMERICAN SOCIETY FOR TESTING ANO MATERIALS 1916 Race St.,Philadelphia,Pa.19103 Reprinted from the Annual Book of ASTM Standards,Copyright ASTM If not listed in the current combined index,will appear in the next edition.Standard Method of Testing DEUTERIUM OXIDE This standard is issued under the fixed designation D 2184 the number immediately following the designation indicates the year of original adoption or,in the case of revision.the year of last revision.A number in parenthescsindicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.scope 1.1 This method covers the measurement of the isotopic composition of hydrogen in deu-terium oxide(heavy water)which is nominally 99.75 atom percent deuterium(D),equal to D/(D+H)X 100.The primary use of the heavy water i s as a moderator in production,power,or research reactors in which a fissionable nu-clide is consumed.in such reactors the per-centage of deuterium in the heavy water usually exceeds 95%.2.Applicable Documents 2.1.ASTM Standards:D 1 129 Defrnitions of Terms Relating to Wa-D 1192 Specification for Equipment for D 1193 Specification for Reagent Wate3 D 1217 Test for Density and Specific Grav-E 1 Specification for Thermometers3 E 137 Evaluation of Mass Spectrometers4 t a Complying Water and Steam2 ity*3.Summary of Method 3.1 There are numerous physical properties of heavy water that are different in value from the corresponding value for natural water.These properties form the basis of several in-strumentai methods of analysis of heavy water.The accepted value for the specific gravity of heavy water is S;=1.10775 2 0.00003 which is roughly 1 1%greater than the specific gravity of natural water.Measurement of the specific gravity of heavy water is the most precise and accurate method of determining the isotopic concentration of heavy water.The uncertainty of 30 mg/L in S,:permits determination of atom percent deuterium to no better than k0.03 atom percent deuterium.4.Terminology 4.1 Definitions-Certain terms in this method are defined in accordance with Defi-nitions D 1129,as follows:4.2 Descriptions o f Terms Specific to This Method 4.2.1 normal abundance o f an isotope-the abundance in atom percent of the isotopes of an element as it is found in nature.4.2.2 atom percent o f an isotope-the atom fraction of the isotope expressed in percent.4.2.3 atom fraction o f an isotope-the num-ber of atoms of the isotope divided by the total number of atoms of that element in the sample;this ratio is analogous to moi fraction.For example,using the isotopes of oxygen.the atom fraction of O is 18/(*60+l 7 0 +O).5.Interferences 5.1 One or more of the processes for produc-ing heavy water may increase its oxygen-I8 content.A change in the concentration of either deutenum or oxygen-18 changes the specific gravity of the water in a nearly linear manner.The heavy water that is sold commercially by the Atomic Energy Commission usually con-tains oxygen-18 at about 0.4 atom percent or roughly twice normal abundance.This increase in concentration results from the distillation process because water that contains oxygen-18 has a lower volatility than water that contains oxygen-16.This method is under the jurisdiction of ASTM Com-mittee D-19 on Warer and i i the direct reponsibiliiy o Subcommittee D 1 9.0 4 on Methods of Radiochemical Anal-ysis.Current edition approved Oct.30.1981.Published Janu-ary 1982.Originally published as D 2184-63 T.Lasi pre-vious edition D 21 84-72(1977).Annual Book o f .4STM Siandards.Pan 3 I.Annual Book o f ASTM Siandards.Pans 25 and 44.Annual Book ofASTM Siandards.Pan 23.LOS 2 i pt A-14 NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.0024930 bOT W 5.2 Determine the correction for oxygen-I8 by equilibration with CO2 and a mass spectro-metric analysis of the product COZ.Bubbling large volumes of gas through the sample is not recommended because traces of moisture would dilute the heavy water with normal wa-ter.Therefore,proceed in accordance with 9.5 and 9.6.Calculate the concentration of oxygen-18 and its contribution to the specific gravity of the sample in accordance with 1 1.1.Calcu-late the necessary corrections as outlined in 11.2.5.3 Exercise extreme care in all steps of the analysis to avoid changing the concentration of deuterium.Avoid contact of the sample with moist air or moist reagents to eliminate dilution effects.Distill to dryness to avoid low results because the vapor pressure of hydrogen deute-num oxide(HDO)is slightly greater than that of deutenum oxide(D20).Reduce the risk of dilution by working with quantities of at least 25 mL of the samples.It is not necessary to perform the steps of the analysis in a dry box.6.Apparatus 6.1 Constant-Temperature Bath,maintained at 25&O.0loC,with a device for shakin