ML20195E406
| ML20195E406 | |
| Person / Time | |
|---|---|
| Issue date: | 06/10/1988 |
| From: | Tokar M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Boyle R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-3 NUDOCS 8806240038 | |
| Download: ML20195E406 (6) | |
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20YLE/ DAW /88/06/09 MEMORANDUM FOR: Regis Boyle, Section Leader Regulatory Branch Division of Low-Level Weste Management and Decomissioning, NMSS FROM: Michael Tokar, Section Leader Technical Branch Division of Low-Level Waste Management and Decomissioning, liMSS
SUBJECT:
REVIEW 0F ANALYTICAL BIOCHEMISTRY LAECRATORIES, INC.
DISPOSAL OF RADI0 ACTIVE MATERIALS We have reviewed the n.aterials submitted to Michael Kearney from Vandy Miller via memorandum dated March 21, 1988 requesting comments and recomendations on the long-term acceptability of Analytical Biochemistry Laboratories, Inc.'
disposal of contaminated waste water. Our evaluation and coments are enclosed.
Derek Widmayer of my staff serformed this review. He can be reached at x20505 if you have any questions a)out his review, origind Signed W Michael Tokar, Section Leader Technical Branch Division of Low. Level Waste Management and Decomissioning, HMSS
Enclosure:
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EVALUATION OF DISPOSAL METHOD OF ANALYTICAL BIOCHEMISTRY LABORATORIES, INC.
Evaluation Performed by : Derek A. Widmayer, Civil Engineer Technical Branch Division of Low-Lev 31 Waste Management and Deconnissioning, NMSS Date: June 9, 1988
_B_ACKGROUND:
Analytical Biochemistry Laboratories, Inc. of Columbia, M0 proposes to dispose of water slightly contaminated with C-14 using an existing lagoon system known as "land application." The system is described in enclosure 1. Region III staff have determined that there appears to be no immediate threat to health and safety because quantities released to the lagoon system meet the concentration levels of Appendix B, Table 1 of 10 CFR 20.303. There is, however, concern over the long-term use in view of possible concentration of C-14 in the soil. .
EVALUATION:
To evaluate the long-term use of this method of disposal, the MAXII computer program for evalution of Intruder Dose Pathway Analysis for Onsite Disposals of Radioactive Materials was utilized, and two scenarios were examined. In scenario 1, it was assured that soil contaminated with C-14 fro'm the long-term use of this disposal method was left in place and external exposure to potential onsite intruders was evaluated. In scenario 2, it was assumed that the source of drinkirl and irrigation water was contaminated by the disposal method, and the pathways considered for this scenario were; external exposure to surface contamination, inhalation of resuspended materials, ingestion of agricultural products irrigated by the contaminated water, and drinking water ingestion. For both scenarios, conservative values were assumed for source terms. For scenario 1, the soil was assumed to be contaminated to a concentration of 14 pCi/gm, which is the value reported as the measured value of soil / sediments from a similar older lagoon system used by Analytical Biochemistry Laboratories for a period of 6 years. For scenario 2, it was assumed that water contaminated to the concentration of Appendix B, Table 1 of 10 CFR 20.303 was released to the drinking and irrigation water. For both scenarios,theAnnualEffectiveDoseEquivalent(AEDE)(ICRP30)was calculated.
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4 RESULTS:
For scenario 1, the AEDE calculated due to external exposure is 4.7 x 10-14 mrem. For scenario 2, the AEDE calculated due to exposure from the four pathways described is 1.6 x 10"7 mrem.
COMMENTS AND REC 0FMENDATIONS:
- 1. The results of the cvaluation using the MAXII computer program indicate that the expected doses from long-term disposal using the described method are low. However, the usual application of the MAXII computer 3rogram is to model individual dispciais of discrete packages of waste rather tian to model the application of slightly contaminated water over a large area. Because of this difference, the dose calculations conducted for these scenarios cannot be relied upon with the same level of confidence than for a study modeling discrete burials. Since the licensee has comitted to remove and dispose of any soils contaminated with C-14 in the restricted area (page 2 of their letter dated August 10,1987), we recomend that the licensee carry out this action.
- 2. The licensee states (page 1 of their August 10, 1987 letter) that there is negligible potential for C-14 entry into the ground water. In the lagoon system description, the licensee describes the soil profile as 4" to 7" of well drained, moderately sloping, eroded soils, overlying significant amounts of plastic, sandy clay. It is stated that the ares below the application site is deep, poorly drained, medium textured silty loam. It is also stated that the high ground-water levels at the site indicated in the one monitoring well is 4 feet below the surface.
This description of the soil and highest level of ground whter would seem to agree with the licensee's claim that there is negligible potential for C-14 entry into the ground water. However, Region III may want to require the licensee to supply a more detailed soil arofile with better characterizations of soil thicknesses and permeabilities t1at will substantiate their claim.
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Enclosure 1 SEVAGE SYSTEM DESCRIPTION The following description is of the present lagoon systen used by The sewage systes used by ABC is knowns as Land Application. Bis systes returns water to the soil. The lagoon has a continuous discharge utilizing a gated pipe distribution systaa.
The application system and rate depend greatly on the slope of the and the soil type to which the water will be applied. The slope of the land at the lagoon site ranges from 5 to 7 percent. The soil is a Lindley loas (La) and a clay loaa. The soil has a permeability of 1.2 inches per hour. This soil is additionally charac te riaed as deep, moderately well drained, moderately sloping, eroded soils of the up-lands. The soil layer of 4" to 7" overlays significant amounts of plastic, saudy clay that was used for construction of the lagoon.
The area below the application site is Westerville silt loas (Vf).
This soil is deep, poorly drained, and medium textured.
As sentioned before the land application systes used is a continua ous discharge gated pipe distribution system.
Because of the natural slope of the land at the site, a gravity-gated pipe systca works well on the grassed slopes. With an annual flow of 2.7 MG. this facility meets the criteria of the Department of Natural
, Resources Management Guide VP83-3I entitled "Gated Pipe Irrigation Systema for Small Operations". nis guide details several possible alternatives and tyr! cal design options. The guide generally provides for a typical pumpec. spray system providing wastewater for the enhance-ment of crop production. Howaver. it also notes the'use of this type of system for filtering and treatment where nutrient use is not the primary objective.
By protecting the discharge piping from freezing, a system can discharge the whole year. This was accomplished by installing the pipe in the lagoon beru so that the waste is discharged below the ground (Tigure 1).
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The discharge will occur at any time there is flow into the lagoon. I unless the system is shut down. A valving system is used to shut off I the systen for sowing and to divert the discharge to a separate areas l
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21 discharge born serves to divert storavater from above, away from the irrigation area. The following design parameters are established for this type of system:
Operation average 10 hrs. per day Irrigation volume 12.456 GFD Cated pipe hear 4.6 feet aintaum (2.0 PSI)
Race of application 100 GFD per 650 sq. ft.
Length of pipe 540 feet length of slope 150' ainimus Non-application times harvtst time Holes in pipe 1/8" at 6.94' intervals Slope of pipe 0.2 percent nis system would be manually operated including:
- 1) Start up by opening valves for continuous operation.
- 2) Shut down for moving.
- 3) Observation of flows to retain vastewater on the site.
Figure 2 is a copy of the site plan locating the lagoon sits and outlining the A3C Laboratory property. The plan sheet (scale 1"=100')
provides 2 foot contours of the proposed application area. The plan sheet locates the well se rving the laboratory facilities. A site inspection did not reveal any exposed bedrock or any evidence of sink-holes or solution openings such as mines. There is one shallow hand-dug well (20'-4" deep) which will be lett open f or monitoring purposes.
This is performed at the suggestion of t.s e Missouri DNR. This well '
indicates that the high groundwater levela at that site is approziantely )
4 feet belov the surface during vet v.aather (February, 1934) ne site required minor grading to spread the flov evenly over the width of the slope. The penseability of 1.2 inches per hour of this soil provides more than adequata capacity for the vaste to percolate into the soil, except for extremely heavy rain events. Because of the lov applicatien ra;e and the soil thickness in that area, groundwater monitcring is not required.
The proposed systen should eliminate any nuisance aspects of the ;
land application systema by providing over 60 days recention for patho- '
gen reduction and 0.25 inches per day overland flow to eliminate aero-sols, he discharge on the slope during high precipitation events will i be highly dilor.ed. For example, in a 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, one inch rain, the vaste discharge u ine slope would be 0.05 inches. nis would dilute the '
waste by a factor of 20 parts rain to 1 part vaste. J ne ir. goon and application area vill be fenced and appropriate {
varnings will be posted. '
l Tie sewer has been designed to serve the maximum of developable '
area currently owned. !
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8tM% water and water from the fish culture tanks (untreated bulk i fish). In AE's aquatic division is channeled into an existing poud.
This lacers the overs 11 flow to the lagoon.
To give se idea of I'C levels discharged into MC's sewage system, four sediment pDs samples were taken from A5Qs former lagoon system on September 8 1983. At that time low level C waste had been flowing intothasystemforapproxingfy6 l years. The s:. moles were composited. {
extracted and analyzed for C activity. The c posite results were I determined to be 31 DPN/g (dry basis) or 1.4 31$ ~p'wC1/& .me^tu ' '
We also surveyed the ac.w lagoon for C on August 5. 1987. Samples were taken from the application area, water from the overflows and in i the lagoon. All sample displayed no counts (DFM) above background levels.
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