ML19284A885
| ML19284A885 | |
| Person / Time | |
|---|---|
| Issue date: | 02/29/1980 |
| From: | Rochefarmer L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| References | |
| NUREG-0656, NUREG-656, NUDOCS 8003140133 | |
| Download: ML19284A885 (34) | |
Text
NUREG-0656 Study of Alternative Methods for the Management of Liquid Scintillation Counting Wastes L. Roch6-Farmer u ea Material Safety and Safeguards Com ssion l-
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Available from GP0 Sales Program Division of Technical Information and Document Control U.S. Nuclear Regulatory Conmission Washington, D.C.
20555 and National Technical Information Service Springfield, Virginia 22161
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Study of Alternative Methods for the Management of Liquid Scintillation Counting Wastes
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Manuscript Completed: January 1980 Date Published: February 1980 L. Roche-Farmer Division of Fuel Cycle and Material Safety Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington, D.C. 20555 y %,,,
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TABLE OF CONTENTS PAGE Foreword III
===1.
Background===
1 A.
Liquid Scintillation Counting 1
B.
Problems Associated with Liquid Scintillation 3
Counting Waste (LSCW)
C.
Disposal Methods Available Provided Under 10 CFR 20 4
1.
General (Section 20.301, 10 CFR Part 20) 4 2.
Releases of Air and Liquid Effluents 4
(Section 20.106, 10 CFR Part 20) 3.
Sewer Disposals (Section 20.303, 10 CFR Part 20) 5 4.
Burials (Section 20.304, 10 CFR Part 20) 5 5.
Incineration (Section 20.305, 10 CFR Part 20) 6 7.
Other Methods (Section 20.302, 10 CFR Part 20) 6 II.
Purpose of the Report 7
III. Waste Management Alternatives for LSCW 7
A.
Evaporation 7
B.
Distillation 9
C.
Solidification 12 1.
Microencapsulation 12 2.
Polymerization 13 D.
Conversion to a Less Hazardous Chemical Form 15 E.
Combustion 17 1.
Incineration 17 2.
Addition to Fuel 19 IV.
Sunmary 20 i
7.
References 23 List of Tables I.
Relative Scintillation Yields of Some Commonly Used Solvents 25 II.
Toxicity of Toluene, Xylenes and 1,2,4-trimethylbenzene 26 III.
Physical Properties of Solvents Used in Most Common 29 LSC Cocktails IV. Toxicity of Benzoic Acid and Phthalic Acid 31 V.
Research Octane Ratings of Hydrocarbons 32 APPENDICES Appendix 1.
Guideline for Incineration of Liquid 33 Scintillation Waste Appendix 2.
Radiation Dose Assessment 35 ii
FOREWORD The Nuclear Engineering Waste Disposal Site in Richland, Washington, is the only radioactive waste disposal facility thct will accept liquid scintillation counting wastes (LSCW) for disposal.
That site is scheduled to discontinue receiving LSCW by the end of 1982. We do not anticipate that any other waste burial facilities will accept radioactive organic liquids in the future.
It should be also noted that waste collectors will probably not be able to accept your LSCW in the future since they in turn will have no method for its disposal. Alternative methods for management of LSCW must be found.
This document explores alternatives presently available for management of LSCW.
Some of the alternatives outlined require further development before they can be made operational.
You are encouraged to assess your alternatives and begin to develop a method for management of your LSCW other than sending it to the Richland burial ground.
You will note that one of the most viable alternatives for LSCW management appears to be incineration.
Information relevant to obtaining a license amendment to incinerate this material is included with the paper.
iii
STUDY Of ALTERNATIVE METHODS FOR THE MANAGEMENT OF LIQUID SCINTILLATION COUNTING WASTES Lidia Rochs-Farmer Technology Assessment Branch Division of Fuel Cycle and Material Safety I.
Background
A.
Liquid Scintillation Counting Liquid Scintillation Counting (LSC) is used in biomedical research and mostly owes its popularity to the ability of measuring tritium easily; it also facil-itates C assay.
In the past C was counted as a solid or gas with trany problems associated with its quantitative analysis.
There are other radio-nuclides assayed by this technique, e.g.,
l, p, 355, but these are b
2 3
not used as widely as H and C.
The scientific breakthroughs achieved with LSC have been a powerful stimulus to the increased use of the technique by the scientific community.
The objective of all procedures to prepare samples for LSC is to use a method that yields clear homogeneous preparations.
The liquid scintillation prepara-tion has three components, the solvent, the solute and the sample itself.
The
" solvent" and " solute" constitute what is known as the LSC cocktail.
The samples may be non-aqueous, e.g.,
steroids, lipids, and non polar organics.
However, aqueous samples are by far the most common type encountered in the research laboratory.
These aqueous samples are incorporated into emulsifiable
2 LSC cocktails.
Altnough an emulsified sample is not truly homogeneous, it benaves as such in the counting environment.
Scintillation counting involves the following basic processes:
(a) nuclear radiation produces a number of excited molecules in the cocktail organic solution, (b) these excited molecules will either emit photons or efficiently transfer the energy to an acceptor (fluor) which in turn will emit the photons.
The release of energy in the form of photons is referred to as fluorescence, which can be measured by a photomultiplier tube and converted to electrical pulses. The solvent dissolves the sample and scintillator (fluor) and acts as a medium for absorbing the energy of the nuclear radiation.
A good solvent for LSC must be a compound with molecules that produce excited states easily, i.e., aromatic-type molecules (toluene, p-xylene, 1,2,4-trimethylbenzene), dioxane and otners.
The solute acts as a source of photons af ter accepting energy from the excited solvent molecules.
Efficient energy transfer is accomplished by a homogeneous or emulsified sample preparation.
There is also a variation among the aromatic solvents in scintillation effic-iency (see Table 1).
This efficiency is improved by using high-grade (purity) solvents. The availability of toluene in high purity at moderate prices has led, in the past, to its use over p-xylene and 1,2,4-trimethylbenzene even though these latter solvents have higher scintillation efficiencies.
At onc time, dioxane, owing to its complete miscibility with water, was the preferred sclvent for aqueous samples, but it has some objectionable features.
First, it is a power-ful carcinogen, thus it presents potential health hazards to laboratory personnel.
Secondly, dioxane is unstable, decomposing spontaneously to form products, such as peroxides, which act as energy quenchers.
These objectionable
3 features of dioxane led to tne development of the emulsifiable cocktails using water immiscible solvents, i.e., toluene, xylene and 1,2,4-trimethylbenzene currently used.
Dioxane is used in very limited amounts, but apparently is not completely off the market.3,7,ll B.
Problems Associated with Liquid Scintillation Counting Waste (LSCW) 6 Research laboratories throughout the country are using approximately 84 x 10 LSC vials / year.
This generates an average of 840,000 liters / year of LSCW.
3 I4 Raujoactivity content is estimated at 3 Ci/ year of primarily H and C which are low energy beta emitters.
Although this amount of radioacitivity is rel-atively small, LSC must be treated as radioactive waste under existing regulations.
Disposal problems are compounde-. and some options limited because of the chemical nature of the organic solvents, e.g., their flammability and chemical toxicity (see Table II).
Fires have occurred during transportation of then wastes and, at the burial sites, the organic solvents have spilled ouc of the 5-gallon drums in which they were buried.
The spillage is probably due to the packagirg procedures.
The drums are normally lined with polyethylene bags.
Generally, vermiculite has been used as an " absorbent" for packing the LSCW vials in the lined-drums.
However, vermiculite does not absorb the LSCW.
It also settles down at the bottom of the drum leaving the LSCW as free-standing liquid. The screw caps of the LSC vials (and some of the vials) are also made of polyethylene which is permeable ta toluene and other LSC solvents.
Even high-density polyethylene is not adequate for the long-term storage of these organic solvents.
Although the LSCil does not pose a radioactive hazard itself, the organic solvents can compromise the integrity of the burial ground.
The solvents may act as a vehicle for transport of other radioactive wastes through
4 the geologic structure.
Furthermore, the solvents spilled in the burial trenches are also a fire (perhaps explosion) hazard.
Approximately 84 percent of the country's low-level radioactive waste was being buried at Barnwell, South Carolina.
But since June 21, 1979, radioactive organic liquids were banned from this site.
Two other facilities were available in Beatty, Nevada and Richland, Washington.
The future use of these sites for burial of radioactive organic liquids is very questionable.
C.
Disposal Methods Available Provided Under 10 CFR 20 Considering only the radioactivity aspect, the methods presently available to licensees are:
1.
General (Section 20.301, 10 CFR Part 20) a.
By transfer of wastes to authorized recipients as autherized by 10 CFR Parts 30, 40, or 70 (e.g., commercial waste disposal ground).
b.
As authorized by Section 20.106, 20.302, or 20.304, 10 CFR Part 20 (see 2, 3, and 4 in the following).
2.
Releases of Air and Liquid Effluents (Section 20.106, 10 CFR Part 20) a.
Air and liquids may be released to unrestricted areas provided the concentration of licensed material in the air or liquids do not exceed the concentrations specified in Appendix B, Table II, 10 CFR Part 20, when averaged over a period not exceeding one year, e.g.,
3
-7 for H, 2 x 10 Ci/ml.
5 b.
Higher limits may be approved provided the licensee provides information described in 20.106(b).
Approvals are granted on an individual basis (approvals require amendments to licenses).
3.
Sewer Disposals (Section 20.303, 10 CFR Part 20) a.
Must not exceed daily concentration lilits specified in Appendix 13, Table I, Column 2 of 10 CFR Part 20, 0.E b.
Quantities must not exceed 10 times the amounts shown in Appendix C of 10 CFR Part 20, a_J1d c.
The average concentration of releases in any one month must not exceed the limits specified in Appendix 13, Table I, Column 2 of 10 CFR Part 20, a_ny d.
The gross quantity of licensed material must not exceed 1 Curie per year.
4.
Burials (Section 20.304, 10 CFR Part 20)*
a.
Total quantity buried at any one location and time mi not exceed 1000 times the amounts specified in Appendix C of Il Part 20.
b.
Burials must be at a minimum depth of four feet.
c.
Burials must be separated by at least six feet and no more than 12 burials may be made per year,
^This rule is expected to be deleted in the near future.
It will be substituted by a rule which requires specific approval by license amendment for burial.
6 S.
Incineration (Section 20.305, 10 CFR Part 20]
The incineration of liquid scintillation wastes may, in some instances, be a viable means for disposal of such wastes.
As required by Section 20.305, 10 CFR Part 20, specific approval must be obtained for such incineration.
The attached guideline, INCINERATION OF LIQUID SCINTILLATION WASTL, specifies the type of information which should be included in an application for authorization to incinerate liquid scintillation waste.
(See Appendix 1) 6.
Other Methods (Section 20.302, 10 CFR Part 20)
Includes other methods not covered specif~cally in 10 CFR Part 20 (e.g.,
by license amendment authorizing licensee to dispose of krypton 85 gas by release to atmosphere although the concentrations exceed limits in 10 CFR Part 20).
Commercial radioactive waste disposal requirements are covered by this Section in 10 CFR Part 20.
In regard to the 10 CFR 2C provisicns, it should be noted that:
a.
The sewer and burial disposals of the LSC organic solvents are generally not permissible because of state and local restrictions on disposal of organic solvents.
b.
The Sewer Disposal, 10 CFR-20.303 says:
"No licensees shall discharge material into a sanitary sewerage system unless:
(a) It is readily soluble or dispersible in water."
The most widely used solvents in the L'3C cocktails, i.e., toluene, xylene and 1,2,4-trimethylbenzene, are not soluble or dispersible in water.
Dioxane is soluble in water but it is a carcinogen and must be disposed of according to the regulations for such materials.
c.
The Burial Disposal, 10 CFR-20.304, is not desirable without treatment or immobilization of LSCW because the organic solvents are a fire hazard
7 and may compromise the integrity of the burial ground by acting as vehicle for transport of other potentially hazardous materials.
II.
Purpose of the Report:
To evaluate alternative methods for the management of LSCW.
The techniques that have been evaluated as alternative methods for the management of LSCW are:
A.
Evaporation 8.
Distillation C.
Solidification 1.
Microencapsulation 2.
Polynerization D.
Conversion to a less hazardous chemical form E.
Coubustion 1.
Incineration 2.
Addition to fuel III. Waste Management Alternatives for LSCW A.
Evaporation The volatility of the aromatic solvents used in the LSC cocktails makes the use af evaporation techniques relatively easy although the process is slow.
It can be made faster by blowing air on the liquid surface, large surface area contain-ers and warm temperatures, but overall it does not demand particularly special equipment nor expenditure of energy.
8 The simplicity of this technique is portrayed by tne following examples.
2 Information obtained in a visit to Todd Research and Technical Division, Galveston, Texas, indicates that some laboratories in Texas put the LSCW in shallow pans that are placed on top of ventilation hoods and allowed to evaporate. Blotting-paper at the bottom of the pan catches any particulate wnich might remain af ter the liquid evaporates, and finally discarded as regular trash. However, when extensive usage of the LSC technique generated larger volumes, the wastes were sent to Todd Research and Technical Division for disposal.
Initially, Todd Research also evaporated the wastes when they were handling a volume of 1500 gallons per month, but the process has become inadequate for the 20,000 gallons / month which are being handled now from mul ciple sources.
(They used to dispose of, among others, the LSCW generated at NIH, but have not done so since November 1978.) The waste is shipped to Todd Research in 65-gallon drums which are stored in an open field for about six months before processing.
During this storage most radioisotopes used 3
I4 in LSC have decayed with the exception of H and C.
The drums are manually opened and the vials thrown into a crusher where the vials and liquid are separated. The solid wastes (crushed vials) are surveyed for radioactivity.
(Todd did not specify how these surveys were conducted.) The contaminated vials are sent to the low-level burial sites and the other vials (presumably non-contaminated) are released in the regular trash. The liquid waste goes into tanks where it evaporates by the hot Texas climate, at a faster rate in the summer than in the winter. Once the liquid is in the tank, the evaporation is accelerated by blowing air across the surface. After four or five years of this operation the sludge at the bottom of the tanks registered 10-4 uCi/cc (the volume of the sludge was not specified). Todd is planning to
9 incinerate the LSCW in the near future.
They expect to install an incinerator, the design of which is being planned, and have it ready for operation by January 19d0.
Critique of the Evaporation Technique 1.
It is a very slow process.
2.
It releases the radioactive material and the chemically toxic solvents into the environment.
3.
It poses fire hazards.
4.
If not performed at the site where the waste is generated, the potential accidents incurred during transportation must be added to the above comments.
It is simple and inexpensive, aside from transportation costs.
o.
8.
Distillation Several distillation processes have been reviewed.
These processes (3,4,5) involved standard distillation procedures, e.g., simple distillations, reduced-pressure distillation and fractional distillation.
The major objectives given for using this technique are:
(1) to reduce the volume of LSCW, and (2) recovery of distillates for potential reuse, e.g., toluene.
Overall, two major types of distillation may be considered:
(1) simple distillation, and (2) fractional distillation.
Each type may be performed either under atmospheric or at reduced pressures.
Simple distillation is generally used to separate any two components of a mixture which boil at least d0 apart.
For materials whose boiling points differ by
10 30" to 8d, separation may still be ef fected by repeated simple distillations, but fractional distillation is a much more convenient technique for efficient separation of such mixtures or for mixtures of liquids which boil a few degrees apart.
(See Table III for physical properties of solvents used in most common LSC cocktails.)
However, as mentioned in the t.
kground section, LSC preparations are mostly emulsions. Emulsions are not directly separable into their components by dis-tillation techniques.
Even fractional distillation techniques will fail since tnere will be formation of azeotropes.
An azeotrope is a constant-boiling mixture (at a specific pressure) in which the pure component is never obtained.
In general, the practical methods for separation of azeotropes are: chromo-tography, extraction, or some chemical transformation of the components followed by distillation.
There are several successful techniques used in the laboratory to break down emulsions, e.g., sal ting out, addition of a strong acid (H 50 ), and addition of a solvent which would increase the density dif-2 4 ference between the components of the emulsion.
If the liquid organic layer in the anulsion is slightly lighter than the aqueous layer, as in the LSC cocktails, addition of a low density organic solvent will separate the layers.
However, addition of organic solvents will only compound the LSCW problems.
The salting out effect is the addition of ionic salts to the emulsion and will also lead to pnase separation.
The processes which were reviewed basically used the phase separation methods described above.
But one of these processes demands special equipment capable of freezing the samples to separate the aqueous and organic phases.
11 Although distillation is routinely used in industry, it does not seem practical nor economically feasible for the small-scale LSC user.5 It is not as slow as evaporation, but it is generally a slow and tedious process.
It is also hazardous because even though no open flame is involved (heating mantles, heat lamp, steam bath, oil bath, etc., are used for heating), the temperature must be raised and we are dealing with flammable materials. The process must be monitored at all times by well trained personnel. Thus, in distillation many potential problems can arise particularly when one deals with multicomponent systems, which is tne case with LSCW.
Critique of the Distillation Technique 1.
It requires trained personnel to monitor all fractions of the process.
2.
It is time consuming, particularly for multicomponent systems.
3.
Large industries use the process successfully on a routine basis, but it might not be practical nor economically feasible for the smaller laboratory.
4.
Residue fractions must be disposed of, e.g.,
by incineration or by burial, according to regulations.
The following comments pertain to the recovery of " reusable material"-
6.
It is doubtful that to " recycle" the cocktail for further usage will be reliable because:
(a) each batch will have different residual radioactivity.
This will introduce appreciable source of error in future counting unless the left-over radioactivity is accurately determined, which is time consuming; (b) the " recycled" formulation will not be as the original. Thus it may require trial and error mixing ratios with the samples to obtain a homogeneous
12 preparation if this is ever possible.
The surfactants and other compounds,
whicn are used in the cocktails to solubilize the aqueous samples, will be depleted in the process, leaving compounds which are not able to solubilize tne samples.
6.
Considering the potential volume reduction of LSCW generated at the source, it might be advantageous to recover toluene, xylene, etc.,
for technical grade solvent use at the source.
It might be particularly wortnwhile to recover these solvents if they become unavailable or highly priced.10 However, for the process to be successful and economically feasible, it should be done by the appropriate industrial organization or large-scale LSC user.
C.
Solidification The fire nazards of the LSC cocktails could be diminished by solidification of wastes because this would reduce the vapor pressure of the aromatic solvents and consequently their flammability.
The alternatives considered for the final disposal of tne solidified waste are incineration and internment at a low-level burial site. The solidification methods that have been evaluated are:
(a) microencapsulation and (b) polynerization.
1.
Microencapsulation Microencapsulation is the entrapment of the LSCW in a polymer matrix. The microencapsulation methods that have been evaluated so far do not off er absolute 6
assurance of solidifying the waste without liquid residues. Thus, the methcds must be further developed to ensure total solidification of the waste.
13 The microencapsulation technique does not render a thermodynamically stable s ta te. The organic solvents will eventuallj be released and evaporated from the solid matrix.
For any microencapsulation technique to be useful, it should give a product that maintains its integrity for a sufficient period of time af ter solidification to permit transportation and final disposal.
Provided that the product integrity is maintained for an adequate time, microencapsulation would be a safer waste form for transportation because the vapor pressure of the solvent is reduced. Under the assumption that the waste interred at a burial site will remain there permanently, the organic solvents will be released into the trenches over a relatively short period of time.
Microencapsulation is not an adequate method to treat the LSCW if this release into the burial grounds is undesirable (see Background Section).
Critique for tne Micreencaosulation/ Incineration / Burial Alternatives 1.
The technique must be developed further.
2.
The integrity of the product must be tested for the period of time elapsed from solidification until incineration.
3.
It is a safer form for transportation than the methods presently used.
4.
If final disposal is long term aurial, it is not adequate because the organic solvents will be relcased.
2.
Polymerization Polymerization is "the chemical union of many small molecules to make very large molecules." The basic molecules that constitute a polymer are called monomers. Polymers, i.e., plastics, synthetic rubber, etc., are widely used in our modern world in multiple forms.
But the process of polymerization is
14 not simple.
It is achieved through the action of light, heat, pressure, or a chemical catalyst.
It requires skilled personnel and special equipment.
Polymerization of the organic solvents of LSCW (after separation from the aqueous phase) has been considered as an alternative solidification method.
The process is being considered by some manufacturers of labelled compounds, e.g., New England Nuclear.7 To date, no polymerization procedure has been proposed or used specifically for the LSCW.
However, polymerization is a true solidification of the organic solvents since it involves direct chemical bonding of the compounds of concern, unlike the previously discussed microencapsulation techniques. As for the encapsulation method, the final disposal for the polymerized-waste under consideration are incineration, and intement at a low-level burial site.
There is no need for polymerization if the final disposal is incineration at the site where the waste is generated. Assuming that: (1) a successful polymerization process for the LSCW can be developed, and (2) the polymerized-waste form is trans-ported to an incinerator or burial ground, the following comments must be considered.
_Criticue for the Polymerization / Incineration / Burial Alternatives 1.
The polymerized-waste fom would be safer for transport than the methods presently used.
2.
It is stable; there will not be release of the volatile compounds.
15 3.
The polymerization process requires specialized personnel, technology and equipment.
4.
It is rather expensive.
Additionally, for the burial alternative:
5.
Burial of the waste implies long-term interment at a shallow site.
Materials are not inert forever with respect to their surroundings. With time, water and air, e.g.,
from rain, will react with the waste, breaking down the polymeric macromolecules into smeller fractions.
As long as the polymer maintains its integrity it is not likely that any migration will occur.
However, the smaller fractions will migrate.
Compared with the microencapsula-tion, the polymerized-waste will maintain its integrity for longer period of time. Accelerated tests on the integrity of possible polymeric-waste forms should be performed to determine their impact on the environment.
D.
Conversion to a Less Hazardous Chemical Form The problems associated with the aromatic solvents used in LSC cocktails are their flammability and chemical toxicity (see Table II).
It is possible to lessen the hazards associated with them by conversion of the organic phase solvents to other chemical forms which might be disposed of more easily.
The first step involved is the separation of the organic and aqt.eous phases.
This may be accomplished by the salting-out technique.
The aqueous phase might be disposed of by release as a liquid effluent or release to the sewer under 10 CFR 20 provisions. The cocktails use different solvents which can be identified by the manufacturers.
Some of the solvents, e.g., toluene, may be oxidized, under mild conditions, to give benzoic acid.
The properties of
16 benzoic acid are given in Table IV.
Comparison of these properties of benzoic acid with those for toluene in Table II, shows the decrease in potential hazards for the latter compound. This alternative should be explored and tested in the laboratory.
The technique offers potential application for LSC cocktails using toluene and xylene. The xylene may be oxidized to phthalic acid (see Table IV).
For dioxane and 1,2,4-trimethylbenzene some method other than oxidation should be used for conversion to less hazardous chemical forms.
The 1,2,4-trimethylbenzene would not likely oxidize under mild conditions. Unlike all the above aromatic solvents, dioxane is an ether and soluble in water.
As all ethers, it absorbs oxygen from the air to form unstable peroxides which on heating may be an explosive hazard. Thus, oxidation is not recommended for dioxane based cocktails.
Critique of Conversion to a Less Hazardous Chemical Form 1.
It may be done on site, where waste is generated.
2.
It may be simpler and less costly than present methods of processing waste for disposal.
3.
It offers potential application for LSC cocktails using toluene and xylene.
4.
It may be applicable for use by small research laboratories.
5.
Disposal of aqueous phase under 10 CFR 20 provisions and of the less hazardous chemical form of the organic phase to a suitable burial s.ite.
17 E.
Combustion Combustion of the LSCW is a promising alternative since it would ideally convert noxious materials to CO nd H 0.
The combustion process may be 2
2 carried out without utilizing the energy content of the waste, i.e.,
as in incineration, or it may utilize the LSCW energy content, e.g.,
by addition to heating fuel.
But before these alternatives are discussed, it is necessary to consider the relative environmental impacts of burning radioactive materials.
3 l4 The radionuclides used in LSC are all short-lived except H and C As stated earlier, the radioactivity contained in LSCW is estimated to be eight Ci per year, primarily from tritium and carbon-14.
lhe ratio of tritium to carbon-14 is estimated to be about 100 to 1.
Appendix 2 contains calculated doses for the maximally exposed individual downwind from inciner: Mon of LSCW.
The maximum doses are from the ingestion pathway and are 0.5 mrem per year per Ci of tritium burned in a single incinerator and 3.1 mrem per year per 10 millicuries of carbon-14.
1.
Incineration As was mentioned previously in this report, Todd Research is considering the installation of an incinerator to burn the LSCW, but it is only in the planning stage.
18 The Mound Facility in Miamisburg, Ohio, has a cyclone incinerator, which has been used to dispose of their solid operational waste, e.g., disposable labora-tory gowns, towels, shoe covers, etc.8 The incinerator has been in operation for a total of 432 hours0.005 days <br />0.12 hours <br />7.142857e-4 weeks <br />1.64376e-4 months <br /> over a 2-1/2 year span, and 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of maximum operatian at a time.
The waste is placed in stainless steel or carbon steel drums, which last 70-100 and 10 incineration cycies, respectively.
To our knowledge, the Mound Facility is the only laboratory which has actually tested the incineration technique for LSCW.
This waste, i.e., the LSC vials with their cont....
are fed to the incinerator at a controlled rate.
A drum full of waste cannot oe incinerated because there is enough vapor pressure build-up in the process to make it dangerous.O The Cyclone Incinerators, built by a company in Massachusetts, range in cost from $148,000 to $500,000, depending on the degree of automation of the equip-ment.
Besides this equipment cost, a special building and support equipment for the incinerator would be needed.
Total combustion of the LSCW is apparently an effective method to break down the solvent molecules into, ideally innocuous species, i.e.,
CO
- H 0.
But 2
2 off gas analyses to determine effluents have not been carried out.8 The vials are either glass or polyethylene.
Aside from the problems that molten glass might cause, the polyethylene should, with total combustion, burn to CO2 nd H 0.
Thus, incineration seems a promising alternative to dispose of the LSCW.
2
19 Critique of the Incineration Alternative 1.
It has already been tested and proved feasible and relatively efficient.
2.
It breaks down the toxic solvents to CO nd H 0.
2 2
3.
It is a costly process which requires a special facility to run its operation.
4.
If the waste must be shipped to a central incinerator site, costs and hazards of transportation are involved.
5.
Incineration results in the release of radioactive materials to the environment.
Environmental impacts must be carefully evaluated on a case by case basis.
2.
Addition to Fuel The five methods discussed previously for the disposal of LSC organic solvents completely ignore the energetic value of some of these solvents.
The University 0
of Illinois has incorporated the LSCW (without phase separations) into their heating oil.
The combustion of toluene and xylene can produce a considerable amount of thermal energy.
Burning such solvents as a heat source is a better use of our resources than incinerating, burying or disposal as trash.
- However, it is perhaps not the best utilization of their contained energy, because it is like burning gasoline as a source of heat.
Toluene and xylene are prime con-stituents of gascline.
They have high octane numbers, thus they are very desirable for engine combustion because of this antiknock quality (see Table V).
The toluene and xylene wastes could, after separation from the
^Some of the information was obtained by telephone conversation between L. Roche-Farmer and technical staff of Arco Chemical Division of Atlantic Richfield Petroleum Corporation.
20 aqueous phase, be added to gasoline and thus disposed of in a useful manner.
The aqueous phase could be disposed of in the sewer under 10 CFR 20 provisions.
The organic solvents would have some residual aqueous (tritiated) material after phase separation, but it would be a very small fraction of what already had very small radiation content.
A rough estimate of the dilution factor involved was calculated.
Normal hexane was taken as a model for engine combustion.
Approxi-mately 1 liter of fuel would produce 8,000 liters of gases at the exhaust, or a dilutioi, factor of 1:8000.
Critique of Addition of Organic Solvents to fuel 1.
Produces energy.
2.
Result is the release of some radioactivity to the environment which must be evaluated.
3.
10 CFR Part 20 would probably allow addition af organic solvents to heating oil under the incineration provisions for a specific licensee.
4.
Addition to gasoline would require an amendment to the regulations.
5.
If added to gasoline, an aqueous phase separation would likely be needed.
6.
These are probably the simplest methods for disposal of LSCW.
IV.
Summary Evaporation is not a safe or efficient method to dispose of the LSCW.
Distillation does not seem to be practical nor economically feasible for the small laboratory.
However, industry has used the process successfully on a routine basis.
If the supply of toluene and xylene becomes scarce due t.o competition from gasoline and other chemical usert, it might be worthwhile to recover these solvents by distillation processes.
21 Solidification methods need further development.
They also require expense and effort of specialized personnel.
If successful nethods are found, it should provide c cafer LSCW form for transportation and disposal by burial in the ground.
However, solids would be expected to break down in the ground over the long term.
Conversion of toluene and xylene to less hazardous chemical forms by a simple oxidation procedure seems to have some potential.
Chemical conversion must be tested in the laboratory but it is relatively simple and inexpensive which might make it suitable for a small research laboratory.
In general, it would probably be more acceptable to the environmentalists than the combustion techniques (incineration and addition to gasoline or heating oil).
Incineration is a technique which has already been tested for LSCW at the Mound and H 0, Facility.
Ideally it should break down the toxic solvents to CO2 2
but it is obvious that some of the LSCW generators cannot afford the cost of this technique.
For those who cannot, who are the majority, it would mean having to transport the waste to the incineration facility.
Thus, transportation hazards and cost are the primary major disadvantages of this alternative.
Combustion of toluene and xylene, which are the solvents mostly used in the cocktails as a source of energy, seems the simplest and most useful disposal alternatives.
Addition of the organic solvents to the heating oil would probably be allowed under the regulations on a case by case basis.
But addition to gasoline would require an amendment to the regulations.
22 Reduction of the volume of waste generated at the source would likely simplify its disposal.
Segregation of the waste by radioactivity concentration and by solvent has been found helpful in managing the waste by manufacturers of radio-active chemicals.
The staff of the commercial burial grounds has surveyed shipments of radioactive-labelled waste which proved to Se non.adioactive.
Thus, better control of the LSCW at the source by encouraging reduction of volume and radioactivity segregation might be helpful procedures in the management of the waste.
23 References 1.
Donald L. Harrocks, " Applications of Liquid Scintillation Counting,"
Academic Press, 1974.
2.
Information obtained by staff visit to Todd Research and Technical Division, Galveston, Texas, on September 19, 1979.
3.
Proprietary Method for Volume Reduction of LSCW, submitted to NRC by Robert Nakamura and George E. Harwood, School of Medicine, University of Southern California, Los Angeles, California, July 30, 1979.
4.
Proprietary Method for Volume Reduction of LSCW, submitted to NRC by Finley C. Watts, Robert L. Dixon, and Kenneth E. Edstrand, Radiation Physics Consultants, Inc., Winston-Salem, North Carolina, July 13, 1979.
5.
H. Gregg Claycamp, Herman Cember and Eli A. Port, " Volume Recuction of Liquid Scintillation Counting Wastes," Northwestern University, The Technological Institute, published in Health Physics Vol. 34 (June), pp. 716-718, Pergamon Press Ltd., 1978.
6.
Proprietary Method for Solidifaction of LSCW, by Phillip M.
- Lorio, Columbia-Presbyterian Medical Center, and James F. Pritchard and William T. Randolph, II, Industrial Services International (ISI), Inc.,
Chattanooga, Tennessee.
Staff also visited the ISI facilities on September 19, 1979.
24 7.
Information obtained by staff visit to New England Nuclear, Boston, Massachusetts, in August 9 and 10, 1979.
8.
Information obtained by staff visit to the Mound Facility, Monsanto Research Corporation, Miamisburg, Ohio, in September 20, 1979.
9.
Chemical and Engineering News, Issue of Deceraer 11, 1978, page 12,
" Gasoline, Chemicals Producers Vie for Toluene," and page 13, " Pressures on 0-Xylene Use Raise Price Tag."
10.
Information obtained from NRC Material Licensing Files, University of Illinois, Urbana, Illinois, June 4, 1976.
25 Table I Relative Scintillation Yields of Some Conmonly Used Solvents Reiauve scinu!!auon Solvent Structure yieid' CH:
1.2.4-Tn:nethylbenzene 112 p-Xylene H,C
-CH,
llo Toluene HC 100 3
Benzene 83 CHa-CH Dioune O
O 65 CHs-CHs Cycloheune S
30
- Measured by relauve troluene = 100) pulse height of the Comptot edge for the 662 kev y rays of ""Ba.
Donald L. Horrocks, " Applications of Liquid Scintillation Counting,"
Table III-1, page 38, Academic Press (1974). Permission to use this copyrighted material was granted by Academic Press.
26 Table II Toxicity of Toluene, Xylenes and 1,2,4-trimethylbenzene (Pseudocumene)
TOLtJENE
- General laf armados Synonyms: methylbenzene: phenylmethane; toluol.
Colorless liquid: benzon.hke odor.
Formula: C.H.CH, Mot wt: 92.13. rnp: -95'C to -94.5'C bp: llo.4*C.
84sh p.: 40*F (C.C.), ule: 15-40 lel y 1.27% uei 7.0"a. d: 0.g66 at 20*/4*C. autosgn. temp.:
Exposure to concentradons up to 200 ppm pro-947'F. vap. press.: 36.7 mm at 30*C vip. d.: 3.14-duces few symptoms. At 200 to 500 ppm.' headache.
Hazard Analysis nausea. loss of appeute, a bad taste, lassitude, im-Touc Hazard Rating:
pairment of coordinanon and reaction time are re-
.' cute Local: Irntant 1.
ported, but are not usually accomparued by any
. Acue Systenue: Ingesdon 2: Inhalanon 2; Skin Ab-laboratory or physical 6mdings of signadcance. With sorpoon 1.
higher concentrauons, the above complatats are in.
Chronte Local: Irntant 1.
creased and m addition, anemia. leucopenia and Chrocue Systemic: Ingesdon 2: Inhaladon 2: Sim Ab-enlarged liver may be found in rare cases.
sorpuan 2.
A common att contaminant.
Toxicology: Toluene is derived from coal tar, and com-Fire Hazard: Dangerous. when exposed to heat or flame.
mercal grades usually contain small ammunts of Spontaneous Heaung: No, wazece as an impunty. Acute poisoning, resultma Explosaon Hazard: Moderate, when exposed to Pama from exposures to high concentranons of the Disaster Hazard: Moderately dangerous: when bested.
vapors, are rare with toluena. Inhalation of 200 it enuts touc fumes; can reset vigorously with oxi.
ppm of toluene for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> may cause impairment dinn materials, of coordinauon and reacdon time; with higher ca
,,,s,,,,,,
concentrauons (up to 300 rpm) these efects are Venuladon Control: Section 2.
increased ard are observed to a shorter ume, in To Fight Fire: Foam. carbon dioxide, dry chemical or the few cases of acute toluene poisontes reported-carbon tetrachlonde (Seenon 7).
the edect has been that of a narcotic, the workman Penonnel Protection: Section 2.
passing through a stage of intoxicauon into one Storsse and Handling: Secuon 7.
of coma. Recovery following removal from ex-Shipping Regulations: Secuon 11.
posure has been the rule. An occasional report of Regulated by !ATA.
chronic poisoning desenbes an anemia and leuco-perus, with biopsy showtog a bone marrow hypo-plasia. These edects, bowever, are less comrnon in people working with toluene, and they are not as severa.
- This matertal has been asaasned a Thmhoto Linut Value by ACGill See complete reyrun of TLV's ta Secdos 1.
From DANGEROUS PROPERTIES OF INDUSTRIAL MATERIALS, 5th edition by N. Irving Sax (c) 1975 by Litton Educational Pubing.
Reprinted by permission of Van Nostrand Reinhold Company.
27 Table II (cont'd) xnzxz =
General taiermados Synonym: o-xylol Colorlesa liqmd.
Formula: C.H.(CH.)
- m. XYLEM "
Mot wt: 106.2 bp: 144.4*C fp: -25.3*C ule: 4M S.
Gwral lafor"W tel = 1.0%. ucl = 6.0%. f. ash p.: !!3*F (T.O.Ch Synoorm: m.sylot d: 0.880 at 20*/4*C vap. presa.: 10 mm at 32.1*C, Coloriesa liamd-vap. d.: 3.66, autoign. temp.: 867'F.
Formula: C.H.(C1kb Hazard Analysts Mot =t: 106.2. mp: -47.9'C bp: 139'C lel = 1.1%.
Toxicity: See m-xylene.
uel = 7.0%. Sash p.: 84*F. d: 0.864 at 20*/4*C Note: A common air coatsmmant.
vap. press.: 10 mm at 28.3*C, vap.1: 3.66 autoign.
Fire Hazard: Moderate. =bco exposed to beat.or Sams; temp.: 982*F.
can react with oxidazing matenals.
Hazard Analysis.
Explomon Hazard: Slight, in the form of vapor eben Toau: Hazard Raung:
exposed to beat or flame.
Acute Locah Irntant 1.
Coastermeasures Acute Systerrue: Inhalation 2; Skin Absorption 2-Venulanon Control: Secuon 2.
Chrotue Locat Irntant I.
To Fight Fire: Foam. carbon dioxide, dry chemical or Chrozuc Systemic: Inhalation 2; Skin Absorpdon 2-carboo tetrachionde (Section 7).
Note: A common air contaminant. Oral MLD (rats) =
Storate and Handling: Secdoo 7.
48/kE.
Shipping Regulauona: Section 11.
Fire Hazard: Dangerous. when exposed to heat or Regulated by CG, DOT. IATA.
Same; can react with oxidizmg materia.la.
Explomon Hazard Moderate, in the form of vapor P NT *
- when exposed to heat or flame.
General Infoematon Disaster Hazard: Dangerous. Kaep aver from open Synonym: p-xylol Same.
Cear liqund.
Conniermeasures Formula: C.H.(CH.h Venulauon Control: Section 2.
Mot =t: 106.2. bp: 138.3* C tel = 1.1%. ue! 7.0*6 fp:
To Fight Fire: Foam, carbon dioxide, dry chemical or 13.2*C Sash p.: 103*F (T.O.C) d: 0.8611 at carbon tetrachlande (Sectico 7).
20*/4*C vap. presa.: 10 mm at 27.3*C van d.:
Personnel Frotecdon: Secuon 2.
3.66.
Storiss and Handling: Secuan 7.
Hazard Analysis Shippmg Regulanona: Seenom 11.
Tomaaty: See m. xylene.
Repalated ECG DQTSTA.
Note: A cx>mmon air corirammanr Fire Hazard: Moderate. = ben exposed to beat or Same; can reset with oxidiz:ng matenals.
Explosion Hazard: Moderate in the form of vapor when exposed to beat or f!ams.
Cosatermeasures Ventilanon Control: Section 2.
To Fisht Fire: Foam. carbon dioxide, dry chmient as carbon tetrachionde (Section 7)
Storage and Handling: Section 7.
Shipping Regulaoons: Secuan 11.
Regulated by CO DOT, IATA.
28 Table II (Cont'd) 1.4. DIOXANE
- General lafoceandoe Synonyms: edioaase; diethylene oxide: diethylene di-orade.
Colorless liquid. pleasant odor.
Formula: OCH,CH OCH,CH, Mot wt: 83.10, rnp: 12*C bp: 101.1*C, lei = 2.0'5, nel
= 22.2*r. f. ash p.: 54*F (C.C), d: 1.0353 at e
20*/4*C autoign. temp.: 356*F vap. press.: 40 mm at 25.2*C, vap d.: 3.03.
Hazard Analysis Toxic Hazard Raung:
Acute 14 cal: Irntant 2.
Acuta Systenue: Ingestion 3: Inhalation 3; Skin Ab.
PSEUDOCUMENE sorption 2.
Gend talowta=
Chronic Local: U.
Synonyms: 1.2,4-trunethylbenzene; pseudocumol Chronic Systenue: Ingestion 3; Inhalation 3; sun Ab.
Liquid: insol. in water; sol in alcohol. beawae, and sorpuon 2.
ether.
T1us matenalis an experimental carcinosen (Section 8).
Formula: (C.H (CH.)
Mol wt: 1:D.19, d: 0.88 8 (4*/4*C), fp: -61*C, bp:
Toascology: Exposure of animals to concentration of 0.1 to 3% of diomane vapor causes irntataan of the 164.89'C flash p.: 130*F.
eyes and nose, followed by narcosis and/or pul.
Hazard Analysts monary edema and death. The irntauve efecu Tozac Hazard Rating:
probably provide sudicient warning, in acute ex.
Acu:e Local: Irntant !.
posures, to enable the workman to leave exposure Acute Systecuc: Inhalation 2: Ingestion 2; Skin Ab.
before he is senously affected. On the other hand, sorpuon 2.
repeated exposure to low concentrations has re-Chroate Local:U.
sulted in human fatalities, the organs chiefly afected Chic::ic Systemic: Inhalauon 2: Skin Absorption 2.
being the liver and kidneys. Death resulted from Toxicology: Can cause CNS depression. anemia, bron.
acute hemorrhagic nephntas. The bepanc lesion chitis. Lp. LD trats) = 2 g/kg.
consists of an acute central necrosts of the lobules Fire Hazard: Moderata, where a===d to beat or Pama Cm 7 - _
The brain and lungs may show acute edema.
In acute exposures, the signs and symptoms con.
Storage and Handlins Section 7.
srst of irntauon of the eyes and naso-pharynx.
To Fight Fire Foam, alcohol foam, mist (Secuon 7).
which may later subside. to be fodowed by head-sche, drowsiness, daznness and occasionally nausea and vomiting In chronze exposures, there may be loss of appeute, nausea and womating pam and tenderness in the abdomen and lumbar res:on.
malaise, and enlargement of the liver without jaun-dice. There may be changes in the blood picture.
Furtber exposure may result in suppressaon of unne, followed by urenua and death.
Fire Hazard: Dangerous, when exposed to beat or f.ame; Can react Y1gorously with oa2dizing mate.
nait Explosion Hazard: Moderatc, when exposed to flame or by chemical reaction with casdizers.
Countermenswes Ventdataan Control: Section 2.
To Fignt Fire: Alcohol foam. carbon dioxide, dry chem.
ical or carbon tetrachlande (Section 7).
Personnel Protecten: Secuan 2.
Storage and Handling: Section 7.
Shipping Regulauens: Section 11.
Regulated by LATA.
Table III Physical Properties of Solvents used in Most Conmon LSC Cocktails
- FlashPo{nt Boiling Point Vapor Pressure Product Base Solvent (T.C.C.)
of Pure Solvent (at 25'C)4 Manufacturer TLV5 Organic Counting Thon-Aqueous 4a20 Xylene 80*F o - 291.2*F 2 9
ndig Research Products 100 ppm m - 282.2*F International p - 280.4*F Betafluor Aromatic (151)'F 2
mdig National Diagnostics Econofluor Xylene 72*F 9
milg New England Nuclear 100 ppm Liquifluor Toluene 40*F 231.l*F 27.5 nmHg New England Nuclear 100 ppm LSC Toluene 41*F 27.5 ndig Yorktown 100 ppm OCS Xylene 79'F 9
udig Amersham 100 ppm Aqueous Counting ACS Xylene 58'F 9
ndig Amersham 100 ppm S
Aquasol Xylene 5/*F 9
ndig New England Nuclear 100 ppm Aquassure Pseudocumene (121*)F 337.l*F 2
odig New England Nuclear 25 ppm Biofluor Pseudocumene 122*F 2
ndig New England Nuclear 25 ppm Filtron - X Dioxane 54*F 213.8'F3 40 nndig National Diagnostics 50 ppm GP Toluene (47' F 27.5 udig Beckman IC0 ppm IIP Toluene (44* F 27.5 mdig Beckman 100 ppm llydrofluor Aromatic (148' F 2
ndig National Diagnostics llydromix Xylene 68*F 9
nodig Yorktown 100 ppm Insta-Gel Xylene 84*F 9
ndig Packard 100 ppm Monofluor Aromatic (149*)F 2
ndig National Diugr.astics Riafluor Pseudocumene 126*F 2
ndig New England Nuclear 25 ppm Ul trafluor Aromatic (149*)F 2
mJig National Diagnostics
Table III (cont'd)
Table III was obtained from tilli Safety Office and may not represent a complete list of all the products on the market. Flash point determinations were made by the fiH1 Quality Assurance Branch.
I Flash point is the minimum temperature of a liquid at which sufficient vapor is given off to form an ignitable mixture with the air near the surface of the liquid.
A liquid having a flash point of 50*F is much more flammable than a liquid having a flash point of 140*F.
2 There are three xylene isomers, i.e., ortho, meta and para.
3 There are two isomers for dioxane, i.e.
1,3 and 1,4 dioxane.
The boiling point given in the table is for 1,4 dioxane.
g 4
Vapor pressure is the pressure characteristic at any given temperature of a vapor in equilibrium with its liquid or solid form. Both vapor pressure and TLV data should be examined when determining overall toxicity since a low vapor pressure would indicate less chance for exposure.
5 Threshold Limit Value is the average concentration for a normal 8-hour workday to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.
31 Table IV Toxicity of Benzo:c Acid and Phthalic Acid BENZOIC ACID Ceneral Informatine Synonym: phenylfornue sod.
%te powder.
ictmula: C.H COOIL PHTHALIC ACID Mol *t: 1 2.12, mp: 121.7*C b: 249'C, Eash p:
General talorisatbo S Y"*" T"'
' # I',' '
250"F (CC). d: 1.316. aatoigrL temp. : 1065'F.
vap. presa.: 1 mrn at 9WC (sublimes), van d.:
fo a: C.H,0, Harard I@
Mol wt: 166!. mp: 206-208*C, d: 1.59.
Toaac Hazard Rating:
Itazard Analyds Acute Local: Imtant I; Ingesdon 1; Inhalation 1.
Toxic Hamd Rating:
Acute Systemic: Ingestion 1.
Acute Local: Allergen 1; Imtant 2.
. Chronic (M: 0.
Acute Systemuc: U.
Chronic Systemic: Ingestion 1.
Chronic Local: Allergen 1.
A chemscal preserv.ithtfmi.additirel$ection 101 Chreruc Systemic: U.
Fire Hazard: Sugrit. = hen expc. sed to' heat or f.ame; Oral LD,. (rats) = 8 g/kg.
~
can react with otsdinns materials.
Fire Hazard: Susht, when heated (Section 7).
Spontaneous Headng: Na Countermeasures Coonfermeasures Personal Hygiene: Section 2.
To Fight Fire: Water. carbon dioxide, water spray or Storage and Handling: Section 7.
mat, dry chemical or carbon tetrachloride (Section 7).
Ventilation Control: Seedon 2.
Personal Hygiene: Secdon 2.
Storage and Handlins: Section 7.
From DANGEROUS PROPERTIES OF INDUSTRIAL MATERIALS, 5th edition by N. Irving Sax (c) 1975 by Litton Educational Pubing.
Reprinted by pernission of Van Nostrand Reinhold Company.
32 Table V Research Octane Ratings of Hydrocarbons Name Formula Octane number ALKANES C. n-Butane CH CH CH CH 94 3
2 2
101 3
3 C n-Pentane CH (CH )3CH 62 3
3 2
92 2-Methylbutane 3
2 3
2 2-Methylpentane CH (CH )2CHiCH ):
73 3
2 3
3-Methylpentane CH CH CH(CH )OI CH 75 3
2 3
3 CH Oi CCH)3 92 2.2 Dimethylbutane 3
3 (neohexane) 102 CH 01(CH3)CH(CH )C93 2.3-Dimethylbutane 3
3 0
C, n-Heptane 01 (Gi:1 CH3 3
3 C. 3-Methytheptane CH (CH )3Of(CH )CH CH 27 3
2 3
2 3
34 CH (Gi:1 CH(C H )CH CH3 3-Ethythexane 3
2 2 3 2
01 (Ola)3C(CH ):
73 2 2-Dimethylhexane 3
3 2-Methyl 3-ethylpen'tane Gi CH CH(C H )CH(01 ):
87 3
2 3 3
2.2.4-Trimethylpentane (CH )3CCH:CH(01 ):
100 3
3 (isooctane)
ALKENES Butene 1 CH CH CH=CH 97 3
2 Butene 2 CH CH=CHCH 100 3
91 3
OI COi )=CHOI, 97 2 Methylbutene-2 3
3 Gi (3fa)2CH=CHCH 93 Hexene 2 3
3 N APHTHEN ES Methyleydopentane C H.CH 91 3
3 67 C H,Gi CH3 Ethylcyclopentane 3
Cyclohexane C.H m 83 i
75 Methyleyclohexane C.HnCH3 AROMATICS C.H Oi, 107 Toluene 3
104 C.H CH:CH3 Ethylbenzene 3
105 C.H CH:CH3 n-Propylbenzene 3
" Environmental Chemistry," Edited by J. 0'm. Bockris, page 275, Plenum Press, 1977.
Permission to use this copyrighted material was granted by Plenum Press.
APPENDIX 1 GUIDELINE FOR INCINERATION OF LIQUID SCINTILLATION WASTE 1.
Specify the nuclides which will be contained in the liquid scintillation waste.
2.
Specify the approximate concentration of each nuclide and total quantity of radioactivity in material which will be incinerated in a single burn.
Estimate the quantity of radioactivity in material to be incinerated per year.
3.
Provide information concerning the characteristics of the incinerator including temperature, air flow, and stack height.
4.
Provide information concerning the location of the incinerator with respect to occupied buildings and areas in the vicinity.
A sketch showing distances to occupied areas and buildings, prevailing wind direction, and designation of north should be provided.
5.
Provide information concerning anticipated concentrations of nuclides at the exit of the incinerator stack.
If concentrations will not exceed 10%
of those specified in Appendix B, Table II, Column 1,10 CFR Part 20, no further information concerning concentrations is necessary.
If higher concentrations are anticipated, provide calculations which demonstrate
34 that individuals in the unrestricted area are not likely to be exposed to concentrations of radioactivity in excess of 10% of those specified in Appendix 8, Table II, Column 1, of 10 CFR Part 20.
6.
If nuclides contained in the liquid scintillation waste will not be volatalized, provide procedures for collection, handling, and disposal of residues in the incinerator including radiation safety precautions for performing these operations.
7.
Provide evidence of compliance with all State and local regulations concerning incinerations of radioactive material.
35 APPENDIX 2 RADIATION DOSE ASSESSMENT The followin,g calculations have been performed to assess the dose to a maximally exposed individual from incinerator effluents produced in the disposal of liquid scintillation counting waste by combustion. As shown below, the assumptiens for the calculations are extremely conservative yielding results higher than would be expected from an actual facility. The effluent concentrations and subsequent dose commitments are normalized to one Ci per year for tritium and 0.01 Ci per I4 year for C.
Once exiting the incinerator, the activity is diluted by an atmospheric dilution factor of 10-3 sec/m,
The facility is assumed to be in 3*
operation for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> per year. The concentration of radioactive effluents at the location of interest is calculated as follows:
1 Ci x 10-3 sec hour
= 1.39 10-10 Ci 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> yx 3600 sec A teenager is assumed to receive the potential maximum dose from inhaling tritium I4 and a child from inhaling C.
Regulatory Guide 1.109 is used as the basis for breathing rate calculations as well as for both inhalation dose conversion factors used in this analysis.
3 3
3 8000 x
x 000
= 1.83 x 10
, teenager / adult 87 hr y
r 3
3 2m 3 700 *- x 8[hr x 2000
= 8.44 x 10 --, child
- For cose calculational purposes in an unknown environment, we have assumed that a dilution ' factor (X/Q) of 10~3 sec/m3 is an appropriate upper bound at short (10-40 m) distances.
3G Using the dose conversion factor of 1.59 x 10-7
- from the Regulatory Guide we calculate:
3
-2 * '"
Pfx1.83x10
- x 1. 59 x 10-7 m
- 4.04 x 10 139.0 m
I4 For C, the maximum affected organ from inhalation is tne bone.
Substituting tne dose conversion factor from the Regulatory Guide and assuming a release of 10 millicuries, the bone dose to a child can be calculated.
3 i
2m
-6 n
-2 mr 1.39
-- x d.44 x 10 - x 9. 70 x 10
= i.14 x 10 Ingestion Pathway:
For eacn calculation, the dose calculational methods and associated conversion factors are those developed by Oak Ridge National Laboratories and presented in ORNL-4992, A Methodology for Calculating Radiation Doses from Radioactivity _
Released to the Environment.
Assuming food and drinking water to be in equilibrium with the specific activity of H in the atmosphere, the corresponding dose rate factors for H are 3.65 x 109 **"/
and 3.37 x 10 r/
, respectively.
9 '"#
- When the source and amount of drinking water is not defined, it is assumed that 3
2 the atmospheric H is diluted by a factor of 10 producing a dose factor of 7 mr 3
3.37 x 10
/
for that pathwdy. The dose rate then, for g
.ed in m
both food and drinking water is conservatively 3.68 x 10
'"/.
9*
m
37 Froin before, 9 mrem n
-10
-I
- 3.68 x 10 1.39 x 10
- = 5.12 x 10 m
I4 To calculate the dose from ingestion of C, it is assumed that the specific activity in human tissue is equal to the average steady state value in the 12 m atmosphere.
Based on tnis assumption, a dose factor of 2.22 x 10 m/
was used. As stated before, this dose factor was taken from ORf4L-4992 with the red marrow as critical organ.
Using this dose factor as well as the concentration calculated before, we get 12 rarem m
-12 2.22 x 10 x 1.39 x 10
= 3.09
- Appendix 1 and Appendix 2 prepared by staff of the Division of Fuel Cycle and Material Safety, Office of fluclear Material Safety and Safeguards.
U.S. NUCLE AR REGULATORY CCrdMISSION BIBLIOGRAPHIC DATA SHEET NUREG-0656
- 4. TITLE AND SUBTITLE (Add Vo4,me No., #f appropneret 2 ILeere cemi*t Study of Alternative Methods for the Management of Liquid 3
33 Scintillation Counting Wastes
- 7. AUTHoRIS)
- 5. D ATE REPORT COYPLETED Lidia Roche-Farmer, Ph.D.
January 1980
- 9. PE RFoRMING ORGANIZATroN N AME AND MAILING ADDRESS (lactude I,p Cooel DATE REPORT ISSUED U.S. Nuclear, Regulatory Commission
-outs jveaa Februarv 1980 Division of fuel Cycle and Material Safety Office of Nuclear Material Safety and Safeguards 6 (Lee e orneal Washington, D.C.
20555 8 (Leeve blankt
- 12. SPONSORING ORGANIZATION N AME AND MAILING ADDRESd (lactuar 2,0 Codel U.S. Nuclear Regulatory Commission Division of fuel Cycle and Material Safety ii. cONTR ACT No Office of Nuclear Material Safety and Safeguards Washington, D.C.
20555
- 13. TYPE OF RE PORT Pt R400 COV E AE D Ilac/us+e datesl Technical Report
- 15. SUPPLEVEN TARY NOTES 14 (Leave o/ noel
- 16. ABSTR ACT 000 words or lessl The Nuclear Engineering Waste Disposal Site in Richland, Washington, is the only radioactive waste disposal facility that will actapt liquid scintillation counting wastes (LSCW) for disposal. That site is scheduled to discontinue receiving LSCW by December of 1982.
The objective of this document is to study alternative methods for the management of LSCW which constitutes 40% in volume of the institutional waste generated in the U.S.
The LSCW total radioactivity centent is estimated at 8 Ci/ year. Although this amount of radioactivity is relatively emall, LSCW must be treated as radioactive waste under existing regulations.
Disposal problems are compounded and some options limited because of the chemical nature of the organic solvents, e.g., their flarmability and chemical toxicity. The techniques that have been evaluated as alternative methods for the management of LSCW are: (1) evaporation, (2) distillation, (3) solidification, (4) conversion to a less hazardous chemical form, and (5) combustion (which includes incineration and addition to fuel). Presently, incineration appears to be the most viable ~ alternative although some of the other methods seem promising but require further development. Also, the waste disposal is likely to be simplified by reduction of the volume generated at tt.e source and segregation of th'e waste by radioactivity concentration.
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