ML20138K118
| ML20138K118 | |
| Person / Time | |
|---|---|
| Site: | 07000139 |
| Issue date: | 02/07/1997 |
| From: | ENGELHARD CORP. |
| To: | |
| Shared Package | |
| ML20138K115 | List: |
| References | |
| PROC-970204, NUDOCS 9702140212 | |
| Download: ML20138K118 (14) | |
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LETTER REPORT CONFIRMATORY SURVEY FOR SURVEY UNITS 1 AND 2 INTERIOR OF BUILDING 2 ENGELIIARD PLANT PLAINVILLE, MASSACIIUSETTS INTRODUCTION AND SITE HISTORY l
D.E. Makepeace, predecessor of the current Engelhard Corporation, manufactured nuclear fuel elements at its plant on Route 152 in Plainville, Massachusetts from 1957 until cessation of operations in 1962.
Manufacturing operations were performed under the Atomic Energy Commission (AEC), predecessor agency to U. S. Nuclear Regulatory Commission (NRC), Docket i
No. 070-139. The Building 2 interior and equipment used in the fuel fabrication operations were I
decontaminated and a final radiological survey was performed by Engelhard industries in 1963.
Based on the results of this survey, and a confinnatory survey of the Building 2 interior and equipment conducted by the AEC, the facility licentes were terminated (Engelhard 1996). The decontaminated equipment was removed from the plant and sold to the Italian government.
Subsequently, the area used for nuclear fabrication was converted to other non-nuclear metal-fabrication operations.
A radiation scoping survey of the plant was conducted in July 1988 as a part of a multi-phase site assessment initiated by Engelhard Corporatior, to identify potential areas of environmental concern.
This survey identified the radiological contaminants of concern as U-238, U-235, and U-234, with low enrichments of U-235.
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A more detailed characterization survey of Buildings 1 and 2 was conducted in March 1994, which resulted in delineating affected and unaffected areas based on current NRC regulatory guidelines.
An NRC-approved Decontamination Plan for releasing the Building 2 affected areas in accordance with current criteria was then implemented. The affected areas were decontaminated from June through October 1996. The building decommissioning activities consisted of the removal of l
remaining equipment from the affected area, collecting and removing loose material, scabbling contaminated surfaces (mainly floors and some walls) and collecting the removed material, and sawing and breaking concrete floors to remove piping and floorjoints. The piping was generally g g g g gggjg4 e w= mow 3 PDR ADOCK 07000139 C
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found to be physically intact and without perforation, with a few small pockets of contaminated soil under locations where the pipe had been cut-contaminated soil was removed. In eddition,
' expansion joints were cut out of the floor to remove any contamination that had collected in these i
locations and localized areas of contaminated material had been removed from overhead piping, o
i structural members, and electrical buss ducts. Remediation control surveys performed by Engelhard indicated that all surfaces were within NRC residual surface contamination criteria.
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l-Engelhard conducted a final radiological status survey of each of two survey units in Building 2 as l
the decontamination effort was completed. The results of the survey demonstrated that the radiation lebis in the building now satisfy NRC residual contamination guidelines, established for release of i
formerly licensed sites to unrestricted use. The final status survey report covers only Buildings 1 and 2; the decommissioning project for the exterior regions of the facility is scheduled to be undertaken later upon NRC approval of Engelhard Corporation's proposed approach to exterior decontamination.
At the request of the NRC's Division of Waste Management, the Environmental Survey and Site Assessment Program (ESSAP) of the Oak Ridge Institute for Science and Education (ORISE) performed an independent confirmatory survey of Building 2 at the Engelhard Corporation plant in 3
Plainville, Massachusetts.
SITE DESCRIPTION The Engelhard facility is located at 30 Taunton Street (also known as Massachusetts Highway Route 152) in Plainville, Norfolk County, Massachusetts. The facility housed areas used both for nuclear fuel fabrication and non-nuclear operations-fuel element fabrication operations were totally segregated from the non-nuclear manufacturing and other operations.
A significant portion of the concrete floor surfaces in Building 2 were scabbled. Many of the floor trenches, created during Engelhard's remediation efforts to remove contaminated drain lines and i
contamination identified between floor expansion joints, had been backfilled. The walls were
' generally ofpainted concrete block construction.
Engelhard Corporation (678)- February 4,1997 2
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' Buildings 1 and 2 were the only buildings existing at the time of nuclear fuel fabrication. Neither l
l Building 1 or 2 is currently being used for any Engelhard operations, and there is no Engelhard worker population in these buildings. The affected areas in Building 2 were well delineated, based on the results of the characterization survey and knowledge of the plant operating history. The affected area was entirely within Building 2 and consisted of:-
Rooms where localized average surface contamination levels on the floor and in cracks and crevices exceed applicable residual surface contamination criteria. These rooms included the tunnel ramp, the former precious metal storage room (2L), the fonner scrap melt room (2M), the corridor and part of the floor in the room north of 1
the scrap melt room (2N), part of the floor in the former melt room (2H), and the room on the left of the entrance corridor in Building 2 (2B).
1 Rooms where localized average floor surface contamination levels were less than the.
residual surface contamination release criteria, but were elevated above background j
levels (greater than 2-3 times background). These rooms were decontaminated based on ALARA considerations. The rooms were designated as 2A,2C,2D,2F, room to the north of 2I (subsequently designated 2P), and 2K.
i Subfloor piping originating in the affected area where elevated radiation levels were measured in the drain inlet openings and outlets.
The remainder of Building 2, and all of Building 1, was classified as unaffected. During decontamination activities, rooms 2E and 2G were added to the affected area.
OBJECTIVE i
i The objective of the confirmatory survey was to obtain sufficient radiological data for use by the j
l NRC in evaluating the radiological condition, relative to current guidelines, ofinterior areas of i
i Buildings 2 of the Engelhard facility.
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'e DOCUMENT REVIEW i
ESSAP has reviewed Engelhard's final survey report for the Engelhard facility (Engelhard 1996) and correspondence between the NRC and Engelhard conceming NRC's comments on the final report.
Procedures and methods used by Engelhard were reviewed for adequacy and appropriateness. The
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data were reviewed for accuracy, completeness, and comphance with guidelines.
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PROCEDURES i
I During the period January 7 through 9,1997, ESSAP performed independent confirmatory survey I
activities at the Engelhard facility in Plainville, Massachusetts. The survey was in accordance with a plan dated December 30,19% (ORISE 1996a) submitted to and approved by the NRC's Division i
of Waste Management. Furvey procedures were performed in accordance with the ORISE/ESSAP Survey Procedures and Quality Assurance Manuals (ORISE 1995a and b). This report summarizes I
the procedures and results of the survey.
i SURVEY PROCEDURES
' i The rooms within Building 2 that were surveyed included the tunnel ramp, the former precious metal storage room (2L), the former scrap melt room (2M), the scrap melt room (2N), the former melt room (2H), and rooms 2A,2B,2C,2D,2E,2F,2G 2K,2P and the Entry corridor.
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t Reference. Grid ESSAP referenced measurement and sampling data to both Engelhard's grid system and to prominent building features, and recorded the survey information on appropriate drawings.
Surface Scans Surface scans for alpha, beta, and gamma radiation were performed on approximately 100% of the accessible floor surfaces, and on approximately 5 to 10% of wall surfaces, in the surveyed rooms.
Surface scans were also performed on overhead areas in rooms 2M and 2L where contaminated r m.nsco,por.iio <67:3. r.bru.ry 4. i,97 4
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material may have accumulated. Scans were performed using gas proportional, GM, and/or Nal scintillation detectors coupled to ratemeters or ratemeter-scalers with audible indicators. Locations -
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l of elevated direct radiation identified by surface scans were marked for funher investigation.
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SurfaceActivity_ Measurements j
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Construction material specific backgrounds for scabbled concrete, metal, ceramic brick, and dry wall were determined 'within Building 1, in areas of similar construction but without a history of radioactive material use.
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' A total of 177 direct measurements for total uranium surface activity levels were performed on i
interior building surfaces. Two direct measurements were also performed on the building roof.
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Five, five-point measurements were performed to determine the average surface activity level over 1 m' areas. Direct measurements were performed using gas proportional or GM detectors coupled to ratemeter-scalers. Areas of residual activity, in excess of the guidelines, were brought to the 6
immediate attention of Engelhard and the NRC. In one instance, additional remediation was j
performed by Engelhard in room 2G and ESSAP performed follow-up measurements.
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A smear sample for determining the removable gross alpha and gross beta activity was collected at _
l cach direct measurement location.
Exposure _ Rate. Measurements I
Background exposure rate measurements were performed at five locations of similar construction within Building 1, but without a history of radioactive material use. Exposure rates were measured at ten locations within Building 2. Exposure rates were measured at 1 meter above the surface using a microrem meter.
SoilSampling I
r Eleven soil samples were collected from trenches, excavations and subfloor areas within the Building 2 areas.
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. Engelhard Corporation (678)-February 4,1997 5
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. Background soil samples were collected during a previous site survey in the vicinity of the l
Engelhard site (ORISE 1985).
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SAMPLE ANALYSIS AND DATA INTERPRETATION j
i Samples and suivey data were retumed to ORISE's ESSAP laboratory in Oak Ridge, Tennessee for j
l analysis and interpretation. Soil samples were analyzed by solid-state gamma spectrometry, and
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based on sample results, three samples were analyzed by alpha spectrometry. Sample analyses were 1
l performed in accordance with the ORISE/ESSAP Laboratory Procedures Manual (ORISE 1995c).
j Enriched uranium was the radioactive material of concern; spectra were reviewed for U-238 and U-235, and any other identifiable photopeaks. Soil sample rcsults were reported in units of picocuries per gram (pCi/g). Smears were analyzed for gross alpha and gross beta activity using a l
low-background proportional counter. Direct measurement data were convened to units of l
disintegrations per minute per 100 square centimeters (dpm/100 cm'). Specifically, the residual j
uranium surface activity was calculated by:
I surface activity = 2.9 *
(eficiency) (probe areal 100)
This equation is specific to measurements of 4% enriched uranium using gas pmponional detectors i
(3.8 mg/cm window) calibrated to SrY-90; the technical basis is documented in the site logbook.
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The conversion factor (2.9) accounts for the detector's response to 4% enriched uranium alpha and l
l beta radiations (12% efficiency) relative to the detector efficiency for SrY-90. Smear data were convened to units ofdpm/100 cm'. Exposure rates were reported in microroentgens per hour (pR/h).
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l FINDINGS AND RESULTS DOCUMENT REVIEW t
ESSAP reviewed Engelhard's final survey repod, inchiding the final status survey data and comment g
letters, documenting these reviews, were submitted to the NRC (ORISE 1996b). Engelhard's documentation provides an adequate description of the radiological status of the surveyed areas, w pmim
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SURFACE SCANS Surface scans identified several locations exhibiting elevated direct radiation. In room 2F, a small amount of significantly elevated contamination (approximately 36,000 dpm/100 cm ) was identified 2
between a floor expansionjoint. Another location was identified on the concrete floor in room 2G.
Two locations were identified on overhead surfaces in room 2M. Engelhard performed remediation activities at each of these locations-small amount of contaminated material was removed from room 2F, concrete floor was scabbled in room 2G, overhead light fixture was removed in room 2M, and a window ledge was vacuumed in room 2M. Other locations identified by surface scans were either resolved through averaging surface activity levels in 1 m' areas or by noting that surface activity was less than guideline.
SURFACE ACTIVITY LEVELS i
Uranium surface activity levels are shown in Table 1. Prior to additional remediation by Engelhard, i
uranium surface activity levels range from -1,400 to 36,000 dpm/100 cm for single-point
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measurements. Following remediation, the surface activity levels ranged from -1,400 to 12,000
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dpm/100 cm'. The average uranium surface activity within the five 1 m' areas investigated ranged l
from 1,400 to 7,600 dpm/100 cm'.
1 Two direct measurements performed on the building roofindicated background levels of surface activity.
All removable activity was less than the minimum detectable concentration of the procedure, which was 9 dpm/100 cm' for alpha and 15 dpm/100 cm for beta.
2 EXPOSURE RATES i
Background exposure rates (Table 2) performed in Building I ranged from 7 to 9 R/h. Site exposure rates for Building 2 surveyed areas ranged from 8 to 12 pR/h and are summarized in Table 2.
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Enselhard cerrannon (678) February 4,1997 7
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RADIONUCLIDE CONCENTRATIONS IN Soit Total uranium concentrations for samples were calculated by multiplying the measured U-235 concentration by 21 to account for the U-234 (based on Engelhard's isotopic uranium results) and adding to that value the measured U-235 and U-238 concentrations.
l Total uranium concentrations (based on natural isotopic abundances) in background samples, previously determined at a nearby site, ranged from 1.0 to 2.4 pCi/g (ORISE 1985).
Concentrations of U-235, U-238, and total uranium in soil samples ranged from <0.1 to 190.1 pCi/g, 0.7 to 656 pCi/g, and <3.5 to 4,260 pCi/g, respectively. Results are summarized in Table 3.
Alpha spectrometry was performed on 3 samples to verify the U-235 enrichment levels reponed by j
Engelhard. Preliminary results indicate that the U-234 to U-235 isotopic ratios are consistent with the ratios reponed by Engelhard.
COMPARISON OF RESULTS WITII GUIDELINES The primary contaminant of concern for this site is enriched uranium (approximately 4%). The applicable surface activity guidelines for uranium are as follows (NRC 1987h TotalActivity 2
5,000 a dpm/100 cm, averaged over a 1 m' area 2
15,000 a dpm/100 cm, maximum in a 100 cm' area RemovableActivity 2
1,000 a dpm/100 cm As previously discussed, surface scans identified several locations of elevated direct radiation at the site that were marked for further investigation. Direct measurements were performed at each of these locations which resulted in four of the locations exceeding surface activity guidelines that were t,,m.e c,muo. gasp nun ry4.i m 8
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remediated by Engelhard. Following the additional remediation, with the exception of surface activity levels in the tunnel, all surface activity levels satisfied the guidelines. Surface activity levels on the floor at the east end of the tunnel exhibited 1 m' averages of 1,900 and 7,600 dpm/100 cm,
2 All removable activity levels satisfied the guideline.
The exposure rate guideline is 10 R/h above background at one meter above soil surfaces and 5 R/h above background at one meter above building surfaces (NRC 1991). All exposure rates i
satisfied the guideline levels.
i The generic NRC guidelines for residual concentrations of uranium in soil are provided in the NRC Branch Technical Position on " Disposal or Onsite Storage of Thorium and Uranium Wastes from Past Operations" (NRC 1981). Specifically, the Option 1 average soil guideline for enriched uranium is 30 pCi/g. Total uranium concentration within the tunnel soil areas and two locations within the excavation in room 2M exceeded the soil guideline for enriched uranium. All other soil samples satisfied the guideline.
SUMMARY
During the period of January 7 through 9,1997, the Environmental Survey and Site Assessment Program of ORISE performed a confirmatory survey of Building 2 at the Engelhard facility in Plainville, Massachusetts. Survey activities included document reviews, surface scans, surface activity measurements, exposure rate measurements, and soil sampling.
The confirmatory survey identified several locations of elevated direct radiation in Building 2 that required funher remediation. The confirmatory survey surface activity results, following additional remediation, are consistent with those of Engelhard and support the licensee's conclusion that residual surface activity levels, excluding the east end of the tunnel, satisfy the guidelines for release for unrestricted use.
I Engelhard Corporation (678) February 4.1997 9
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While elevated soil concentrations were anticipated in the tunnel oil areas, two soil samples from within the excavation in room 2M exceeded the enriched uranium soil guideline. Results of the remaining soil sample analyses support the final survey performed by Engelhard, and in ESSAP's j
l-opinion, indicate that the radiological conditions of the surveyed areas satisfy the NRC guidelines for release for unrestricted use.
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Engelhard Carporatun (678). F,bnery 4,1997 10 m:s,. psi,,,,,,sio,,ii.co3 r
i TABLE 1 l
SUMMARY
OF SURFACE ACTIVITV LEVELS BUILDING 2 ENGELHARD CORPORATION PLAINVILLE, MASSACHUSETTS Total Uranium Surface Number of Activity Range Removable Measurement (dpm/100 cm )
Activity Range 2
Location Locations (dpm/100 cm')
Single Grid Block Single-Grid Measurement Average Point Blocks Alpha Beta Room 2A/ Floor and Lower Walls 10 NA'
-150 to 3,100 NA
<9
<l5 Room 2B/ Floor and Lower Walls 10 NA
-340 to 770 NA
<9
<l5 Room 2C/ Floor and Lower Walls 17 2
-590 to 6,700 1,800 to 2,100
<9
<l5 Room 2D/ Floor and Lower Walls 10 NA
-220 to 3,200 NA
<9
<l5 Room 2E/ Floor and Lower Walls 5
NA 39 to 2,700 NA
<9
<l5 6
Room 2F/ Floor and Lower Walls 12 NA
-200 to 3,100 NA
<9
<l5 6
Room 2G/ Floor and Lower Walls 12 NA
-280 to 2,800 NA
<9
<l5 Room 2H/ Floor and Lower Walls 10 NA
-1,400 to 20 NA
<9
<l5 Room 2K/ Floor and Lower Walls 10 NA
-660 to 610 NA
<9
<l5 Room 2UFloor and Lower Walls 14 1
-20 to 6,000 1,400
<9
<l5 Room 2UOverheads 2
NA
-350 to 39 NA
<9
<l5 9
Room 2M/ Floor and Lower Walls 14 NA 140 to 4,000 NA
<9
<l5 6
Room 2M/ Overheads 5
NA
-370 to 640 NA
<9
<l5 Room 2N/ Floor and Lower Walls 1I NA
-l80 to 4,000 NA
<9
<l5 Room 2P/ Floor and Lower Walls 5
NA
-550 to 53 NA
<9
<l5 Entry / Floor and Lower Walls 10 NA
-13 to 2,100 NA
<9
<l5 Tunnel / Floor and Lower Walls 20 2
-370 to 12,000 1,900 to 7,600
<9
<15 j
'Not applicable.
6 Surface activity level following additional remediation.
i Engelhard Cor}eration (678). February 4,1997 1$
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TABLE 2 EXPOSURE RATES ENGELHARD CORPORATION PLAINVILLE, MASSACIlUSETTS l
Number of Exposure Rate Exposure Rate Range
,0 cation Measurements at 1 m (pR/h)
Room 2B 1
11 Room 2C 1
12 Room 2H 1
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Room 2K 1
9 Room 2L 1
9 Room 2M 2
9 to 10 I
Room 2N 1
8 i
Tunnel 2
10 to 11
Background
j Building 1 5
7 to 9 l
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TABLE 3 URANIUM CONCENTRATIONS IN SOIL BUILDING 2 ENGELHARD CORPORATION PLAINVILLE, MASSACIIUSETTS Uranium Concentration (pCilg)
Location U-238 U-235 l Total Uranismi" Room 2A 4.9 0.8' O.8 0.2 22.5 Room 2K 1.6
- 0.6 0.2 0.1 C.0 Room 2L 1.3
- 0.6
<0.1
<3.5 Room 2M/ Pit North Wall 29.4
- 2.1 18.5 0.8 436 Room 2M/ Pit East Wall 0.7 0.5
<0.2
<5.1 Room 2M/ Pit Bottom 8.1 1.0 3.3
- 0.3 81 Room 2N 1.0
- 0.7 0.3
- 0.2 7.6 Tunnelffrench 76.1 6.2 57.2
- 2.5 1,330 Tunnelffrench 656
- 34 101.4
- 4.4 2,890 Tunne1ffrench Wall 77.7
- 7.2 190.1 7.4 4,260 Tunnel / Pipe Chase Area 1.2 + 0.9
<0.2
<5.6
' Uncertainties represent the 95% confidence level, based only on counting statistics.
6Total uranium calculated based on a U-234 to U-235 ratio of 21:1; background levels have not been subtracted.
Engelhard Corporation (678)- February 4. Im 13 n w apener,w n w u J
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I REFERENCES I
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. Engelhard Corporation.' Final Status Survey Report, Survey Units 1 and 2 in Interior of Plainville, i
Massachusetts Plant of Engelhard Corporation. Plainville, Massachusetts; November 1996.
i Oak Ridge Institute for Science and Education (ORISE). Radiological Survey of the Texas Instruments Site, Attleboro, Massachusetts. Oak Ridge, Tennessee; January 1985.
j Oak Ridge Institute for Science and Education.
Survey Procedures Manual for the.
Energy / Environment Systems Division, Environmental Survey and Site Assessment Program, Revision 9. Oak Ridge, Tennessee; April 30,1995a.
l Oak Ridge Institute for Science and Education.
Quality Assurance Manual for the.
Energy / Environment Systems Division, Environmental Survey and Site Assessment Program, 6
Revision 9. Oak Ridge, Tennessee; January 31,1995b.
Oak Ridge Institute for Science and Education.
Laboratory Procedures Manual for the Energy / Environment Systems Division, Environmental Survey and Site Assessment Program, l
Revision 9. Oak Ridge, Tennessee; January 31,1995c.
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Oak Ridge Institute for Science and Education. Confirmatory Survey Plan for Survey Units 1 and 2 in Interior of Building 2, Engelhard Plant, Plainville, Massachusetts (Docket No. 070-139; RFTA No. 97-7). Oak Ridge, Tennessee; December 30,1996a.
Oak Ridge Institute for Science and Education. Document Review-Final Status Survey Report, i
No. 070-139; RFTA No. 97-7). Oak Ridge, Tennessee; December 6,1996b.
Survey Units 1 and 2 in Interior ofPlainville, Massachusetts Plant of Engelhard Corporation (Docket
' U.S. Nuclear Regulatory Commission (NRC). Disposal or Onsite Storage of Thorium and Uranium '
l Wastes from Past Operations. Washington, DC: Federal Register 46 (205): 52061-52063; October 23,1981.
U.S. Nuclear Regulatory Commission (NRC). Guidelines for Decontamination of Facilities and Equipment Prior to Release for Unrestricted Use or Termination of License for Byproduct, Source, or Special Nuclear Material. Washington, DC; August 1987.
U.S. Nuclear Regulatory Commission. Office of Nuclear Safety and Safeguards, Review Plan:
l Evaluating Decommissioning Plans for Licensees Under 10 CFR Parts 30,40, and 70, Washington, L
DC; 1991.
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W Engelhard G sporauon (676). February 4.1997 I4 hNssap\\lettersiturtiL003
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