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108. . . - APPENDIX F DISPOSAL OF RADIOACTIVE WASTE IN SALT CAVITIES Report prepared for the Committee on Waste Dispo s al in Geologic Structure s by William B. Heroy Marchll, 1957 q . . . ~ ·.~ 3712 Haggar Drive Dallas 9, Texas

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~- 109. CONTENTS Page 1 . Introduction ~ ~ ~ 2. Characteristics of Salt Deposits Il2 3. Distribution of Salt ~ the Unuted States 113 4. Production of Salt In the United States 5. Mining of Rock Sat 6. Production of Radioactive Waste 7. Requirement for Nuclear Energy ., 8. Characteristics of Radioactive Waste 9. Waste Production in Nuclear Power Plants 10. Transportation of Nuclear Waste 121 123 128 129 132 133 134 Il. Accessibility of Salt Space for Waste Disposal 134 12. Utilization of Salt Space for Waste Disposal ~ 3 . Problems of Utilization of M~ed-out Space 135 136 ~ ~ . Recommended Studies ~ 38

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~ - ~~ - #- - ~ - - .-q : - - . - 110. ILLUSTRATIONS FIGURE 1 - Location of Me Principal Deposits of Rock Salt in the United States FIGURE 2 - Area in New York Underiain by Salt FIGURE 3 - Area In Pennsyl~ra:iia Underlain by Salt FIGURE 4 - Area su Ohio UnderInin by Salt FIGURE 5 - Area ~ Michigan Underlain by Salt Page 114 115 116 118 120 FIGURE 6 - Area ~ Texas ~1 New Mexico Underlain by Salt 122 FIGURE 7 - Instated Capacity of Electric Utility Generating Plants - United States - 1920-1954 130 ********$:* TABLE ~ - Salt - Production by States - 1953 Short Tons - TAB LIE II - Rock Salt - Estimated Production by States - 1953-ShortTons 124 127

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111. DISPOSAL OF RADIOACTIVE WASTE IN SALT CAVITIES . . . . 1 . INTRODUC TION . . . . . 1.1 One of the possibilities for the disposal of radioactive waste prod- ucts derived from the operation of nuclear power plants is its under- ground storage in space formed thin deposits of rock salt. This report contains information concerning the characteristics of rock salt, its occurrence ire the United States, and the unclerground space result- ing from mining operations. Consideration is then given to the feasi- bilitY of using such space for waste disposal. 1 . 2 The Division of Earth Sciences, National Research Council, at the request of the Atomic Energy Commission, has undertaken a study of the underground disposal of atomic waste and the preparation of a re- port and recommendations QU the subject. A conference for the discus- sion of the subject was held at Princeton University, September 10-12, 1955, and a Steering Committee was appointed to function in the prepa- ration of a report. During the period subsequent to the conference, as a member of the Steering Committee, the writer of this memorandum had an opportunity to investigate further the possibilit)r of underground disposal particularly In cavities formed by the mining of salt. The ~n- formation obtained has been compiled in this paper as a matter of rec- ord and for such value as it may have ~ further consideration of the disposal problem. The paper is preliminary In character, and is not a complete presentation of this phase of the problem. ~ . 3 Acknowledgment for information supplied concerning salt deposits is gratefully made to Dr. Frank C. Foley, State Geologist of Kansas; Dr. John H. Melvin, Chief, Division of Geological Survey, State of Ohio; Dr. William L. Proust, State Geologist of Michigan,~~Dr. Kenneth K. Landes, Department of Geology, University of Michigan; to Messrs. L. E. Read, Manager, Detroit Mine, ant} C. H. Jacoby, Chief Geolo- ~ist, International Salt Company, Detroit, Michigan; and to Mr. Tom M. Cramer, U. S. Potash Company, Carisbad, New Mexico. The writer has also used freely information contained ~ various publica- tions, references to which are macie at the end of this paper, and wishes to acknowledge the assistance obtained therefrom. ~ am also grateful to Dr. E. G. Stru~ess of Me Oak Ridge National Laboratory, and to Dr. L. P. Hatch of BrooRhaven National Laboratory for courtesies ex- tendeu during visits to these ~nsta~ations. . 6

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112. I.4 This report was first circulates] unties date of July 20, 1956. It has since been renewed by Dr. Floyd L. CuDer, Oak Ridge National L.aboratory, Oak Ridge, Tennessee, Dr. M. King Hubbert, Shell Oil Company, Inc., Houston, Texas, end Dr. C. V. Theis, U. S. Geolog_ ical Survey, Albuquerque, New Mexico. ~ am greatly indebted to these associates on the Princeton Committee for their critical comments on the paper, which have generally~ocen~ncorporated~ the present re- vision of the report. Any responsibility for errors or other is~adequa- cies and for opinions expressed ~ the report are, however, my own. 2. CHARACTERISTICS OF SALT DEPOSITS . . 2. ~ Rock salt an its crystalline form is the mine rat halite (NaCI; sodium 39.4, chlorine 60.6f~o). Halite is isometric ~d occurs In crys- tals with cubical cleavage, which are transparent or translucent. Hardness is 2 . 5. Specific gravity of pure crystal salt is about 2. 17 (136 Ibs. per cu. ft.~. Index of refraction Is t.5442. It is highly non- conductive of electricity. The melton point of salt is 801° C. any He boiling point, 1413° C. Solubility in water ~ grams per 100 ml. is 35~7 at 0° C, and 39.12 at 100° C.~2) (3) 2.2 In its usual occurrence, rock salt contains impurities. As mined for commercial purposes, it is gener;~1ty not less than 97~e pure, with grades used in the chemical industry over 99'o pure. As mined, the specific gra~ri~,r ranges from 2 . ~ to 2. 6, depending upon the degree of purity. It has a coarse granular to compact structure. Its toughness makes it resistant to mining with power machines and explosives are used ~ its production In solid form. Its volubility In water permits its solution and extraction as brine. 2.3 From the geological st~dpo~t, ';alt is plastic ~d flows under pressure. In that respect it is similar to ice, but the pressure and time required to produce observable plastic Dow ~ Basic are very much greater. The pressure required for He rapid deformation of rock salt is very great but, over long periods of time, much lower pressure may be expected to result ~ nowage. Pla';tic movement of rock salt has apparently not been observed ~ the pillars left In salt mines ~ the United States, with the amount of overburden as much as 2 , 000 feet. mining potash ~ New Mexico, where He depth of the deposit is about 900 feet, the sylv~nite ore (a mixture of halite, NaCI, ~d sylvite, KCI) shows positive evidence of plastic flow. Horizontal drip holes in the sylvinite ore show vertical compression of about 25~o ~ about ten years. Sulfite, the principal potash-bearing tnineral in the ore, is apparently more plastic than halite. (4)

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is 113. 2. 4 Salt deposits are of sedimentary origin and cornrn only occur ~- terbedded with other rocks, such as limestone, dolorn~te, skywrite and shale. Under conditions of temperature en c! pressure present at great depths and during geologic time, bedded salt has flowed along lines of weakness and risen into overlying beds ~ the form of plugs and domes. 3. DISTRIBUTION OF SALT IN THI: UNITED STATES . 3. ~ The most commercially important deposits of bedded salt are found ~ New York, Michigan, Ohio and Kansas. They underlie many thousand square miles extending from the outcrop downward to depths of more than 5, 000 feet. Figure ~ shows the location of the principal deposits of rock salt ~ the Utter! States. 3.2 In New York, the salt occurs ~ the Salina formation of Silurian age. (5) It crops out along a band extending from the Mohawk Valley on the east to the Niagara River OTT Me West. The salt is not present at the outcrop because it has beer dissolved. The Salina beds dip south- ward at a low angle. The dip is variable, averaging from 50 to 100 feet per mile, depending on the local structural conditions. At its maximum, the Salina is about 1,000 feet ~ thickness. The salt may be present ~ several beds. Its total Sickness is more than 300 feet · ~ ~ ~ - ~ ~ ~ ~ ~ _ In central New York, south of Syracuse. ~ the western part of the state, the salt becomes thirster and may be absent On the Buffalo area. It continues southward under the increasing thickness of younger beds into southern New York and northern Pennsylvania, where the thickness of salt is over 600 feet in some deep weds. The total area ~ New York underlain by salt is roughly ~ O. 000 square mile a, as shows` on Figure 2 . 3 . 3 The entire northwestern Dart of PennsvIvanza is underman bar the Salina formation Ad salt has been found in many wells droned for oil and gas. (6) - Throughout most of the area the aggregate thickness of Me salt becis.--is at icast ~0 feet. In half Me area the aggregate thick- ness is over 100 feet and the aggregate thickness reaches a maximum of over 500 feet. The salt basis are found at depths of from 1500 feet In northwestern Pennsylvania to more than 8000 feet ~ Me cieenest _ _ _ , ~ ,Ē part ot the Emcee. Allure ~ chows the area ~ ~e~sylv~a under- I~ by salt and the depth below sea level of the top of Me salt. 3 . 4 The saline beds continue westward suto eastern Ohio and underlie about one-third of the state . {7) (63) The salt occurs ~ beds of Silurian age, which probably represent the westward! extension of the Saliva for- mation of New York and PennsyIvn?~ia. This horizon is below Me surface

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117 throughout Ohio and its character is known only from weds, of which more than 3, 500 have been Brined through it. The salt thins westward and disappears beyond a line extending from Lora~n, on Cake Erie, to Marietta, near the Ohio River. Over most of this area the salt beds have an aggregate thickness of more than 100 feet. The maximum is reached near Carton, Stark County, where well logs indicate the pres- ence of several beds with an aggregate thickne s s e stimated at more than 200 feet. Along Lake Erie, recent borings for the purpose of prospecting the salt beds Delicate that their thickne s se ~ total 60 to 7 0 feet In Cuyahoga, Lake and Ashtabula counties. Near the Pennsylvania Are, in Ashtabula County, the salt occurs at a depth of about 2, 300 feet below the water petrel of Lake Erie . The depth decreases westward to a depth of about I, 300 feet near Lorain. From Lake Erie the befit dip gently southward. At Barberton, about 40 miles south of Cleveland, the uppermost salt is at a depth of 2750 feet. ~ Harrison County, 50 miles farther southeast, the salt was reached at over 4700 feet. The tote area ~ Ohio uncleria~n by salt de- posits is over 15,000 square miles. Figure 4 shows the area ~ Ohio underlain by rock Art and the depth below sea level of the top of the salt. 3 . 5 Michigan has the largest reserves of salt of any state . Rock salt underlies most of the state, ~nthir~ the Michigan bash. It is found In the Saliva formation, which is deposited In a ~;aucer-lilce form, taper- ing toward the margin of the basin, where it is overlapped by younger formations anc! does not appear at the surface. Brine is found ~ sev- eral other formations . (9) In the southeastern part of the state, along the Detroit River, the aggregate thickness of rock salt is from 200 to 500 feet. The thick- '.. ness increases northwestward into the basin. In Bay County, about 90 miles northeast of Detroit, a maxim urn thickness of IB00 feet of salt was peaetrated.- Around the periphery of the basin, the salt thickness generally increases clown dip from 0 at the edge of the Salina wedge to a thickne s s of ~ 000 feet in about 50 miles . In Wayne County, near Detroit, the depth to the first salt bed ranges from 800 feet at Ecorse to IlS0 feet at Oakwood {Detroit} and over 1600 feet at Port Huron. On the west side of the basin, near Lur~ington and Manistee, the salt has been reached at depths of about i!000-2300 feet. The total area of the southern peninsula of Michigan that is probably underlain by salt-bearing formations is 35,000 square miles. The

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~- 118 ~ __ -~L r I;=:' FIG.4— AREA IN OHIO UNDERLAIN BY ROCK SAM a; WESTERN LIMIT OF SAW DEPOSITS ~ CONTOURS stowage DEPTH OF UPPERS - T SALT BED BELOW SEA LEVEL

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132. 8. CHARACTERISTICS OF RADIOACTIVE WASTE 8. ~ If natural or enriched uranium is used ~ metallic form in a heter- ogeneous reactor, the fissioning process proceeds to some pout limited by economics, corrosion or mechanical stability. It is probable that large quantities of fissionable and fertile material wiU reman ~ the irradiated fuel. Thus spent fuel elements are s~ very valuable Mace they contain part of the initial charge of fissionable and fertile material along with my new fissionable material produced. They are trans- ported, usually ~ solid form, to a chemical processing plant for re- covery and separation of fissionable ~d fertile material from fission products In dilueut. This is accomplished by dissolving tibe elements an acid such as nitric acid, followed by selective solvent extraction of valuable components from diluents arid fission products. This leaves the Ossion products in the bark of the depleted processing stream or radiate. This raff~ate stream is the high level waste and poses the principal disposal problem. . . . . .. 8. 2 After irradiation ~ a. reactor, the medic elements ~ which un- consumed fuel and waste are mixed are highly radioactive and they are accordingly stored before processing for a period clef time, during which further decay of fi;88ioU products occurs. Cooling periods vary. How- ever, the rate of decay of fission products is approximately the same; e . g ., after 135 days the activity of the fission products is reduced by a factor 10-4 from their activity level at Me time of discharge from the reactor. At the time of discharge from reactor, the gross fission prod- uct actor r is 5.7 per cent of the rated power of the reactor. ~- ~ . 3 If ~e fuel is fed to a reactor of homogeneous type ir~ liquz~ form, tlie spent fuel must also be processed in liquid form. Because it is, uncle r pr e ~ eat condition, mo re difficult to to aD.8pO rt the waste ~ ~ qui d than ~ solid form, the chemical processing for Me remove, of the waste from the fuel win presumably be accomplished at each reactor. Future developments may make it feasible to transport such liquid waste economically and safely. (3.4 In either case, the waste products of the reactor, except for those disposed of to the atmosphere ~ gaseous form, wig be presented for disposal as liquids. The characteristics of Me liquid waste are deter- mined by the particular method of chemical processing used. Wastes resulting from the operation of nuclear reactors are classified as high- level wastes. 5 . , . ,, it,. .

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133. 8. 5 These high-le~rel wastes, as produced by process plants, have concentrations varying from 0. 5 gals . to TO gals. per grain of U235 burned. (29) One figure used for calculations of waste volumes result- ing from solvent extraction is 820 gals. per metric ton of fuel charged to the reactor, which is equivalent, at 4000 mwd/ton, to 2 gals. of waste per mwd of heat produced by a nuclear reactor. (30) 8. 6 The principal problems ~ connection with the transportation and storage of radioactive waste arise from its chemical character, the energy given off as heat, and radioactivity. The waste is produced as ~ acid solution, and, unless neutralized by au alkali, such as sodium hydroxide, is corrosive to processing equipment. The corrosion is Screamed with high temperature and it may, therefore, be desirable that the temperature of waste ~ metallic storage be moderate; below 120-150° F. is desirable. B. 7 Depending upon the concentration of fiBBioU product,; ~ the waste, Me power produced per emit of fuel charged to We reactor, ~d the de- cay cooling time, fission product'; ~ Me waste will produce heat at the rate of about 1 to 3 Btu / gal /hr . ( 3 1 ) Thi s rate of he at p ro auction would be sufficient to raise high-level waste above the boiling pout in a few days. In storage of waste i~ndergroun`1~ liquid formic it would therefore be necessary to profile means for cooling the waste and re- mo~ving the heat, miens the waste were greatly diluted. ~3 . ~ The radic~acti~nty of liquid waste from nature uranium is from 20 to 400 curies per gallon depending upon its chemical character. (32) Adequate protection of personnel from ~i8 amount of energy requires heavy shielding. The weight of the shielding adds greatly to Me cost of transportation. 9. WASTE PRODUCTION IN NUCl FAR POWER PLANTS . 9.1 IN a preceding paragraph it was assumed that the thermal capacitor of nuclear power plants would reach 700, 000 mw by the year 2000, re- qu~ring a feed of about 63,500 tons of natural uranium, or equivalent, per year. Using a figure of 820 gallons of high-acti~rity waste per metric Icon of fuel charged gives a total annual volume of waste of about !;2 mil- lion gallons, equivalent to 7,000,000 cu. ft. or about 160 acre-feet. If jib power were produced ~ 350 power plants, Me amount of underground space required annually for each power plant would tee about 0.fi acre- foot.

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134. 9~2 Thief; amount of total space is approximately lO$o of the arnotmt of space berg produced a~uaDy Me the niining of rock salt at the present time . By the year 2000 it is to be expected that the volume of. salt production win Decrease several times, production having doubled in the last IS years. 10. TRANSPORTATION OF NUC:T.F^AR WASTE 10. ~ The three methods Ed use for transportation of high-level nuclear waste, trucks on highways, barges and fillips onwaterways, and cars by railway, are all costly because of the necessity for shielding and over requirements for safety ~ trans~t.~33~. Truck'; are used for tr~s- portation of waste for relatively short distances ~d generally in areas where safety is care~y controlled. The transportation of waste from processing plants to pouts of disposal za principally by rail or water. Estimates of cost indicate that rail transportation costs several times as much as water transportation for equivalent distances. The hazards of transportation of highly radio active materials by rail through popu- lated areas are also greater ~ is generally the case Bong water routes. For these reasons it maybe advamtageaus to locate plats for the prc~cesa~g of apent fuel at pouts where the spent fuel cam be tra"~- po rat d by wate r f rom the r e acto r . 11. ACC~SS~ILITY OF SALT SPACE FOR WASTE DISPOSAL Il . ~ The principal Areas ~ which salt deposits occur are tickle In the north central states and ~ ~e southern states along the Gulf Coast.. It.2 The salt deposits of the north central states, New York, PennsyI- vania, Ohio and Michigan, are adjacent to the Great-Takes ancl lie In part beneath Were bodies of water. It is possible ~ this region to use water transportation for Me movement of spent fuel to a processing plant from points as far separated as New York City on the east to Chicago or Duluth on the west. ~ ~ . 3 In southeastern Michigan or in northern Ohio a processing plant could be located on Die shore of Lalce Erie d;iree~y above salt deposits occurring at a Kept of about 2,000 feet. Suitable facilities for ~oad- ~g barges conic] be provided at the plant. Shafts couicI be driven to the underlying salt ~d the salt produced and marketed. The m~ec3-c'~t space could be so planed as to provide adequate roof support and safe routes for the transportation of waste to pouts of storage. The mining

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135. operations could be performed by an industrial contractor so that the net cost of the niine d-out storage space might tee very small. De- tailed consideration should also be given to the Datability and availa- bility of space ~ existing or abandoner] salt mines ~ this area. Il.4 The area along We Gulf Coast ~ which salt domes occur is ac- cessible to water transportation through the Mississippi Ri~rer and its distributaries and the ~ntercoastal canal. Numerous salt domes are present ~ the area but ~ many of Hem Be salt is at uneconomic depth. Some oftbe salt domes are berg m~ed end worked-gut space now exists. The feasibility of utilizing such '~pace for Me storage of radioactive waste ~d at the same tisne contra sing the operation of the salt mines would require detailed investigation. A few salt domes exist ~ We area In which ~ nes hare not been opened add which are favorable as to depth of Cut ~d convenience of transportation. 12. UTILIZATION OF SALT SPACE FOR WASTE DEPOSAL , 12. ~ The storage of radioactive waste ~ properly located apace ob- t~ed by We miming out of rock a sit has may advantages as compared with other methods of djaposal. Some of these are the following: a. The salt itself ha'; consiciera~ble strength so Mat pillars left — mining may provide sufficient strength to support the roof. 1u bedded salt deposi~ce the overlying strata such as limestone and dolomite pro- ~nde truss-like support to Me overburden. The poasibilit-~r of roof coDapee causing the release of radioactive materials stored under these conditions appears very amaH but merits verification. . .` be The Balt is impervious to Me passage of water because of its plasticity and crystalline structure, 80 that the mine d-out space is very dry. This dryness Acreages Me life of metals by reducing rust and corrosion. c. The salt deposits are quite level so that suitable vehicles can be usec! ~ transportation underground. d. The No principal areas where deposits of rock salt occur ~ the United States have very low seismicity and the possibility of space me-out area'' berg collapsed by earn movements is extremely amaD. Geological extenuation of mine d-out areas indicates that fault'' are not present, confirming a geological history of stability.

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136. e. The comparatively high thermal con~ucti~ty of salt and its sul- ficiently high melting point would permit the storage of wastes at moderate temperature Without exact on the walls of the cawty, pro- videdthe plasticity of saltis not increased bylong-continued exposure to execrated temperatures. 12.2 These advantages would not east to the same extent if the salt cavities were produced by pumping water into the salt formations ~d the removal of the salt as brie. The large extent of cavities formed by this method, the absence of roof support, and Me lack of control over Me uDdergrouncI distribution of radioactive waste introduced into such ca~ntie'; are di';advantages which make it inadvisable to consider the use of such space for disposal. The possibilities of collapse of such cavities are considerable and in`;t~ces of surface subsistence from such collapse are know to the salt Poultry. 13. PROBI~fS OF UTILIZATION OF MINED-OUT SPACE . . . 13.1 The storage of high-level radioactive waste ~ underground salt space presents selrerai problems of ~ engineering character. These problems differ ~ some respects depending upon tide physical form and characteristic.~-of Me waste as it word be produced by reactors or processing plants. 13 . 2 High - level waste now berg produced from these sources is ~ liquid form. The :liquz~ as produced is chemically acute, radioactive, and produces heat through radioactive decay. It is therefore desirable that the waste be treated before storage to ~sii3iimize these hazardous characteristics. It is also, ~ some cases, diluted in the course of the chemical separation process so that the volume is materially increased. .. . - 13 e 3 The activity of Me waste is now chemically neutralized by treat- ment with able solutions before it is placed In surface storage tanks for aging. This process results ~ an increase of about four times in the volume of the waste but this can be reduced by evaporation to a ~ point where the slurry contains about 35% solids . (34) Waste so neutra- lized would apparently not have any cheniical effect on the walls of a salt cay: th which it mores into direct contact but further study should be glared to his problem. 13.4 The storage of the waste In surface tankage for a period of six monks or more permits the decay of some of the fission products that Ģ Am,, ,,, _, ,, it, .

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137. have a short half-life, so that radioactivity and heat are both largely reduceci. However, other Hasion proclucts, such as Ca-137, with a half-life of 33 years and Sr-90, with a half-life of 25 years, are stiO pre sent in the waste in important quantities after months of storage . (3 5 ) 13. 5 The transportation of such wastes to cooling Saz~ce and its storage In such tanks, whether earth or metal, requires the exercise of much precaution.- The piping ~d other ~ressele used In transportation must be chemically resistant to corrosion and the stripers steels and other metals required are costly. The building of metal Woks or the exca~ra- tion of earth reservoirs for storage lung the cooling period is also a serious economic burden. These co`;t,; must be balanced again'`" costs of shielding and handling required to transport the waste to sites of disposal. It, therefore, becomes a problem In economics as to how long it is feasible to hold such wastes ~ temporary storage to reduce their activity before ultimate disposal. The engineering problems re- lated to the transportation and storage during the cooling period hare been soldered but at high mat cost. 13 . 6 Perhaps Me most diHic~t engineering problem connected Any the m~dergrou$~d storage of high-level waste is that calf heating. The energy released from such waste as heat is, depending upon~oncentra- tion, expected to be from ~ to 3 Btu per hour per gaHon. An acre-fc~ot of such waste would, at the higher figure, produce about I,000~000 Btu's per hour, equivalent to the combustion of about 700 Ibs. of Come From the standpoint of usable power, his is low-level heat and below the level of economic utilization. But, from the Newport of disposal, ff,is amount of heat creates a problem that would be - cont~mug for a period of 20-30 years. 13.7 It is feasible to excavate In underground salt deposits reservoirs . that are adequate to contain the volumes of liqu~d-waste that are con- -templated ~ a program of development of nuclear power. However, the waste stored ~ such reservoirs would soon, from its own energy, rise ~ temperature to the boiling point, creating an additional hazard of production of raclioacti~re vapor. The holding of We ternperat~re ~ such undergro~md reservoirs below the boiling point would require the re- moval of the heat by a cooling system instated ~ the reservoirs. The m~te~ce and operation of such a system presents problems of eng~- neer~g desigm which, In themselves, appear to be manageable but only with s~st~ti~ ~sta~ation, maintenance and operating costs. An al- ternative method would be to let the temperature of We tanks exceed the boiling point and remove the heated air and vapor by a circulating sys- tem, filtering, and discharging the gases to the atmosphere. The

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138. underground storage of the liquid} waste ~ barrels or other containers would present similar problems of heat remora and would probably, comparison, be more costly than underground storage ~ bulk. 13.8 The fixation of the liquid waste ~ some solid form after cooling and prior to undergrour~ct disposal would be advantageous as regards both transportation and storage. Various methods of conversion of waste to Solid form have been suggested and some of Were have been carried through the stage of pilot plot operations. Meg ~th cement In the proportion of about 15 Ibs. per gallon would result in a solid mixture of about 7 cubic feet. weighing about 80 Ibs. ner cubic foot. {36) ~ O — — _ ~ _ _ _ . . . .. . . . . . . . on a large scale, at a processing plant, MOB mete real COU1u be cast In molds into a form suitable for handing by automatic conveyors and shielded fork-lift trucks wit rery low hazard from irracliation. Other methods of solidification, such as Corporation ~ slag or ceramic products, have considerable merit.~37) 13 . 9 On the assumption Cat a disposal plant could be located ~ the immediate ~ricisuty of underground storage In m~ed-out-salt space, the designing of a system of transportation from Me plant tootle pout of disposal would seem to present no serious problems, using belt conveyors for movement and shielcled fork-lift trucks for stacking or piling In Me underground rooms. The sotidiBed mete ria1 would produce heat ~ storage but the problem of boiling Pronto be eHm~ated and the airs temperature could become high without eHect on the surrounding salt. The cement blocks could be cant ~ such form that fir s:ould pass .. . .. ~ to remove the heat from "rouge teem. A system of air circulation to remove me heat from storage rooms would be more feasible the the cooling of liqu~ci waste In underground reservoirs. . 14. RECOMMENDED STUDE:S In the light of present knowledge, no insurmo~mtable obstacles to the storage of radioactive waste In solid form ~ undergro~ci cannier In salt appear to exist. Detailed studies should be carried out on the fol- low~ng engineering and economic phases of the problems related to salt: a. The availability ~d cost of Citable space ~ ~dergrour~c! Cut ileposits; b. The most effective and economical melody of proceas~g liquid waste in large quantities into solid form; .... ... .

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139. c. The development of suitable conveyors and other devices for the underground transportation ~d clisposal of waste in bond form; d. The design of suitable ventilation facilities for the removal of excessive heat from underground storage chambers. William B. Heroy tIMarchI957 . . . -

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140. REFERENCES , Hess, Harry H., Chairman, Report of the Committee on Waste Disposal, Division of Earth Sciences, National Academy of Sciences - National Research Council, ~956. Whalen, W. C., Salt resources of the United States: U. S. Geol. Surv. Bull. 609, p e 234, 19 19 . 3. Whalen, W. C., Salt: Chapter 37, Industrial minerals ~d rocks, Am. Inst. My. Eng., p. 643-670, 1947. SchaHer, Waldemar T., ~d Ec~warc3 P. Henderson, Mineralogy of driD cores from the potash field of New Mexico and Texas: U. S. Geol. Swrv. B~. 833, p. 74, 1932. 5. Alli~g, H. L`., The geoic~gy and origin of the Silurian salt of Near York State: New York State Mus. BuU. 27S, p. 139, 1928. 6. Fence, Chas. R., Occurrence of rock salt ~ ~e~syl~rar~ia: Pen". Geol. Surv. Progress Rept. 145, ~ sheet, 1955. 7. Stout, Wilber, R. E. Lomborn and Downs Schaaf, Brines of Ohio: Obio Geol. Surer. Bull. 37, 4th ser., p. 123, 193~. B. Pepper, James F., Aze=1 extent and Sickness of the salt deposits of Ohio: Ohio Geol. Surv. Rept. ~vest. no. 3, Ohio Jour. Sci., trot. 47, no. 6, p. 225-239, 1947. 9. Cook, (:;haries W., The brim anti salt deports of Michigan: Mich. Geol. and Biol. Surer. Publ. 15, Geol. Series 12,~ p. IS8, 1914. 10. Taft, Robert, Kansas and t~e~ti~--~t: K;33BĒS -Cam. Sci. Tram., vol. 49, no. 3, p. 223-272, Dec. 1946. Il. Barton, D. C., Mechanics calf formation of salt domes why special reference to Gulf Coast ant domes of Texas and Lomaiana: Am. Assoc. Petr. Geol. By., vol. 17, no. 9, p. 1025-1083, 1933. 12. Nettleton, L. L., History of concepts of Gulf Coast salt-dome for- mations: Am. Asso<:. Petr. Geol. Bull., vat. 39, no. 12, p. 2373- 2383, 1955.

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141. 13. Shoemaker, E. M., Structural features of southeastern Utah and adjacent parts of Colorado, New Mexico and Arizona: Utah Geol. Society, Gu~clebook to the geology of Utah, no. 9, p. 48-69, 1954. 14. Hoots, H. W., Geology of a part of western Texas ~d south- easters~ New Mexico, web special reference to salt and potash: U. S. Geol. Surv. BuO. 780, p. 33-126, 1926. 15. U. S. Bureau of M~es, Salt ~ 1953: Mineral Market Report no. . 2374, p. 7, March 29, 1955. 16. L`a Vigne, E. F., Mining and preparation of rock salt at the Retsof Mae: Am. mat. My. Eng. Tech. Pub., no. 661, p. 21, 1936. 17. Jacoby, C. H., personal communication. 18. Foley, Frank C., personal communication. Weigel, W. M., The mat industry of Louisiana and Texas: Am. Inst. Mm. Eng. Tech. Pub., no. 620, p. 19, 1935. 20. Culled, F. L`., fir., Notes on fission product wastes from pro- posed power reactors: ~ Report of meeting on ocean disposal of . reactor wastes held at Woods Hole, Mass., Aug. 5-6, 1954; Atomic Energy Comm., NYO, Waste Disposal, p. 79 (mimeo), MayI5, 1955. 21. Glasetone, Samuel, Prmciples of nuclear reactor engineering: New York, D. VanNostraD6 Co., p. Al, 1955. 22. Cutlers, F. L`., Jr., He. c ., p. 15. Z3. Joseph, Arnold B., and Hassles M. Morgan, Jr., Radioactive ~~ th-e~-~n~c-energy industry; Me problem of disposing of high petrel waste, Appendix 2, p. 24: The Johns Hopkins Uns~rer- sity, p . 32 (mimed); under ARC Contract No . AT(3~)- ~ ~ - ~ 477, March 3l, 1955. 24. Ayres, Eugene, and Charles A. Scariott, Energy sources - Me wealth of the world, p. 102: New York, McGraw-HiD Book Co., p. 344, 1952. 25. U. S. Federal Power Commission, Electric Power Statistics, Report No. 55-12C, p. 15, December 1955.

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142 . 26. CaDe, J. A., Nuclear power requirements for large-scale in- dustrial power: Nucleon~cs, p. 65, October 1954. 27. Zeitlin, H. R., E. D. Arnold and J. W. filly, Processing requirements, b~iild-up of fission product activity, and liquid radiochemical waste volumes in a predicted nuclear power econ- omy: Oak Ridge National L`aboratory, JaD.uary 30, 1956, File 56-l -162. 28. Culler, F. L`., Jr., personal communication. 29. Culler, F. L., fir., Notes on Vision product wastes from pro- posed power reactors, Table 5, p. 22. 30. Zeitlin, H. R., op. cit., Figure 4, p. Il. 31. Joseph, A. B., op._., Table 1, p. 3. 32. Culler, F. L., Jr., op. cit., Table 7, p. 26. 33. Harr~gton, A. C., R. G. Shaver, andC. W. Sorenson, Perma- nent melody of radioactive waste disposal - an economic evalua- tion: U. S . Atomic Energy Comm., Report K-1005 ~ Waste Disposal, p. 50, March Il. 1953. 34. Clark, Joseph R., Radioactive wastes at the Savannah River plant, p. 40: ~ Report of meeting on ocean disposal of reactor wastes held at Woods Hole, Mass., Aug. 5-6, 1954; Atomic Energy Comm NYO, Waste Disposal, p. 79 (mimer), May 15, 1955. Caller, F. 1~., AT., - ._., Figures 2, 3, pp. 5, 6. i 36. Vitro Corporation of America, Disposal of radioactive wastes in cement: U ~ S ~ Atomic Energy Comets,; Report KXL-13?? ~ p. 15 June 18, 1952. . 37. Hatch, L. P., Ultimate disposal of radioactive wastes: American Scientist, trot. 4l, no. 3, p. 410-421. July 1953. 6