SUBJECT: FINAL REPORT—HAZARD ASSESSMENT REPORT FOR .../67531/metadc... · Rapaport Building,...

$: SUBJECT: FINAL REPORT—HAZARD ASSESSMENT REPORT FOR .../67531/metadc... · Rapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd$
May 8, 2000

Mr. Dennis WaskiewiczU.S. Army Corps of EngineersNew England District696 Virginia RoadConcord, MA 01742-2751

SUBJECT: FINAL REPORT—HAZARD ASSESSMENT REPORT FOR RESIDUALURANIUM CONCENTRATIONS IN STORM DRAINS, RAPAPORTBUILDING, WINDSOR, CONNECTICUT

Dear Mr. Waskiewicz:

Enclosed are 10 copies of the subject report which describes the dose calculations that theEnvironmental Survey and Site Assessment Program (ESSAP) of the Oak Ridge Institute for Scienceand Education (ORISE) performed for the subject facility.

ESSAP appreciates the opportunity to have worked with the USACE on this project. Please contactme at (865) 576-5073 or Eric Abelquist at (865) 576-3740 should you have any further questions.

Sincerely,

(Original Signature on File)

Timothy J. VitkusSurvey Projects ManagerEnvironmental Survey and Site Assessment Program

TJV:klp

Enclosure

cc: W. Beck, ORISE/ESSAPE. Abelquist, ORISE/ESSAPFile/405

Rapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd

HAZARD ASSESSMENT REPORT FORRESIDUAL URANIUM CONCENTRATIONS IN STORM DRAINS

RAPAPORT BUILDINGWINDSOR, CONNECTICUT

Prepared by

Timothy J. Vitkus

Environmental Survey and Site Assessment ProgramRadiological Safety, Assessments and TrainingOak Ridge Institute for Science and Education

Oak Ridge, Tennessee 37831-0117

Prepared for the

U.S. Army Corps of EngineersNew England District

FINAL REPORT

APRIL 2000

This report is based on work performed under a contract with the U.S. Department of Energy.

ORISE 00-0575



RAPAPORT BUILDING WINDSOR, CONNECTICUT

Prepared by: Timothy J. Vitkus (Original Signature on File) Date: 4/19/00 T. J. Vitkus, Survey Projects ManagerEnvironmental Survey and Site Assessment Program

Reviewed by: R. Dale Condra (Original Signature on File) Date: 4/24/00 R. D. Condra, Laboratory ManagerEnvironmental Survey and Site Assessment Program

Reviewed by: Ann T. Payne (Original Signature on File) Date: 4/25/00 A. T. Payne, Quality Manager Environmental Survey and Site Assessment Program

Reviewed by: Eric W. Abelquist (Original Signature on File) Date: 4/30/00 E. W. Abelquist, Assistant Program Director Environmental Survey and Site Assessment Program

Reviewed by: W. L. Beck (Original Signature on File) Date: 5/3/00 W. L. Beck, Program DirectorEnvironmental Survey and Site Assessment Program


ACKNOWLEDGMENTS

The author would like to acknowledge the significant contributions of the following staffmembers:

FIELD STAFF

J. R. MortonT. D. Herrera

LABORATORY STAFF

R. D. CondraJ. S. CoxW. P. Ivey

CLERICAL STAFF

K. G. DavisD. K. Herrera

K. L. Pond

ILLUSTRATOR

T. D. Herrera

iRapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd

TABLE OF CONTENTS

PAGE

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Site History and Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Assumptions for Dose Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Dose Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

iiRapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd

LIST OF FIGURES

PAGE

FIGURE 1: Location of the Rapaport Building Warehouse Site—Windsor, Connecticut . . . . 9

FIGURE 2: Plot Plan of the Rapaport Building Warehouse (circa 1930), Windsor, Connecticut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

FIGURE 3: Building C, Storm Drains—Sampling Locations . . . . . . . . . . . . . . . . . . . . . . . . 11

iiiRapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd

LIST OF TABLES

TABLE 1: Uranium Concentrations in Sediment Samples . . . . . . . . . . . . . . . . . . . . . . . . . . 13

ivRapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd

ABBREVIATIONS AND ACRONYMS

µCi/cm3 microcuries per cubic centimeterµR/h microroentgens per hourµg/day micrograms per dayµg/m3 micrograms per cubic meterAEC Atomic Energy CommissionANL Argonne National LaboratoryCE Combustion Engineering, Inc.cm centimetercm3 cubic centimeterDOE U.S. Department of EnergyECC Environmental Chemical CorporationESSAP Environmental Survey and Site Assessment Programg/cm3 grams per cubic centimeterg/day grams per dayGEI Grove Engineering, Inc.g/m grams per meterg/µg grams per microgramkg kilogramsm meterm3 cubic metersmg/day milligrams per daymR milliroentgenmrem milliremmrem/y millirem per yearmR/h milliroentgens per hourmrem/day millirems per daymrem/pCi millirem per picocurieNRC U.S. Nuclear Regulatory CommissionORISE Oak Ridge Institute for Science and EducationpCi/g picocuries per grampCi/m3 picocuries per cubic meterUSACE U.S. Army Corps of Engineers



RAPAPORT BUILDING WINDSOR, CONNECTICUT

INTRODUCTION

This report presents the results of the hazard assessment activities conducted for the exterior storm

drains located in the parking area of the Rapaport Building in Windsor, Connecticut. This report

addresses residual uranium concentration levels that were identified in storm drain sediments during

the designation survey of the facility (ORISE 1998).

Previous and current regulatory guidance provides for the release of property without radiological

restrictions, provided that the residual contamination does not pose a potential present or future

exposure risk in excess of the specified dose limit. For comparison of the dose calculations provided

in this report, the U.S. Nuclear Regulatory Commission codified a dose limit of 25 mrem/y (NRC

1997). This assessment is based on site-specific data and plausible use scenarios.

SITE HISTORY AND DESCRIPTION

Combustion Engineering, Inc., (CE) has operated a facility in Windsor, Connecticut as a contractor

for the U.S. Department of Energy (DOE) and its predecessor, the Atomic Energy Commission

(AEC), for nuclear reactor and fuel projects since 1955. It was during 1955 that CE leased the

Rapaport Warehouse (specifically the C Building) for use as a temporary fuel manufacturing facility

for the Navy's nuclear program until completion of the current CE facility at 2000 Day Hill Road

(Figure 1). Although activities at the C Building only occurred for approximately one year, CE

served as a direct contractor to the DOE for over a decade and a subcontractor to other firms for a

number of projects involving the use of varying enrichments of uranium.

The Rapaport Warehouse was initially constructed in 1920 for tobacco storage by P. Lorillard

Company, Inc. and consists of three attached buildings identified as A, B, and C (Figure 2). Building

C was used from May 16, 1956 into early 1957 for the manufacturing of two prototype fuel

2Rapaport Building, Windsor, Connecticut (0405) - April 19, 2000 essap\projects\0405_CE Rappaport\hazardassessmentfinalrpt.wpd

assemblies—one from natural uranium and one from fully enriched uranium—to validate the

manufacturing process before moving the activities to Building 3 at the current CE Windsor site

(ABB 1998). The first floor accommodated the fuel manufacturing processes, which included

melting metallic uranium, vapor blasting, acid cleaning, forming, welding, and machining, while the

third floor housed the health physics laboratory. Local exhausts were directed to both the inside and

outside of the building. During the period of fuel manufacturing, a number of accidents were

reported, including a uranium fire which occurred while attempting to drill an ingot without

sufficient cooling liquid (CE 1956). This fire was quickly extinguished and the resulting floor

contamination was removed. It is believed that the majority of material was moved in and out of the

facility at the loading platform on the building’s south side, although smaller items were also carried

through the door on the north side. Building C was later used for storage of contaminated equipment

from reactor critical experiments and Navy fuel manufacturing equipment at the Windsor site.

The Environmental Survey and Site Assessment Program (ESSAP) of the Oak Ridge Institute for

Science and Education (ORISE) performed a radiological scoping survey of the Rapaport Building

site in March 1998 on behalf of the U.S. Army Corps of Engineers (USACE). This survey identified

low levels of enriched uranium within a storm drain’s sediments. This storm drain, referred to as

the south storm drain, is located beneath the parking area on the south side of Building C. Residual

uranium concentrations within the sample were 36.00 pCi/g for U-234, 1.29 pCi/g for U-235, and

0.8 pCi/g for U-238, based on alpha spectrometry analysis (Table 1). These values equate to a total

uranium concentration of 38 pCi/g and a U-235 enrichment of approximately 20%.

As a result of this, ESSAP was subsequently requested to confirm the uranium concentration within

the storm drain. Therefore, an ESSAP representative returned to the site on November 18, 1998 and

resampled the south storm drain and two additional drains (Figure 3).

The south storm drain is located east of the loading dock and measures approximately 0.5 meters (m)

× 0.5 m and is approximately 1.8 m in depth. The depth of the sediment contained at the bottom of

the drain was estimated as 0.15 to 0.30 m. Total sediment volume was estimated at 0.08 cubic

meters (m3). Both inlet and outlet pipes into the drain were noted and appear to run west to east.

The pipe was assumed to intersect the sanitary sewer line that is located on the east end of the


property running perpendicular to the storm drain in a north-south orientation. A definitive

determination could not be made at the time of this investigation as to whether the storm drain

discharged to the sanitary line or to the flood plain area located directly east of the Rapaport

Building. This second sampling effort confirmed the presence of enriched uranium in the sediment

of the south storm drain (Table 1, Sample ID #7). The second storm drain sampled is associated

with the PI valve pit (a pit containing the water main connection and main valve to the building)

located immediately west of the loading dock. This structure measured approximately 1 m × 1 m

and was approximately 2.5 m deep. Sediment contained in the bottom of the structure was

approximately 0.15 m in depth. Enriched uranium was also identified within the PI valve pit

sediments although at lower levels than what was identified in the south storm drain. The third drain

sampled was the southwest storm drain and was constructed identically to the south storm drain. The

sampling did not identify uranium levels distinguishable from expected background within the

southwest storm drain. The uranium results for these samples are also shown in Table 1.

As a result of this investigation, the USACE contracted Environmental Chemical Corporation (ECC)

to remove the sediments from the south storm drain and to perform a dye tracing study to determine

the storm drain line outlet. The results of the dye study showed that the storm drain line discharged

to the sanitary sewer line (ECC 2000).

OBJECTIVES

The objectives of the hazard assessment were to evaluate the possible dose that could result to a

maximally exposed individual under plausible use scenarios.

ASSUMPTIONS FOR DOSE CALCULATIONS

Two scenarios were initially considered as plausible, the intruder scenario and the hypothetical

worker removing the drain line. Because the drains themselves are not occupiable, the intruder

scenario was not considered as plausible. Therefore, only the hypothetical construction worker

removing the drain line was evaluated as this scenario was considered to be both the most

conservative and the most likely.


Conservative dose estimation techniques were used to calculate the per day dose to the hypothetical

construction worker who would excavate the sediment (which has since been removed) from the

storm drain pit, excavate the pipe, manually section and remove the pipe from the ground, tamp each

section of pipe to dislodge sediment, and loiter in the area of the dislodged sediment pile.

The source term was derived from the following assumptions:

` 7.6 centimeter diameter pipe (3 inch), 40 meters (4000 centimeters) in length

Pipe volume = _ × r2 × h = (3.14) × (3.8 cm)2 × (4000 cm) = 1.8E5 cm3

` Pipe is half-full of sediment (sediment density assumed to be 1.8 g/cm3); the volume of

sediment calculated to be in the pipe was:

` Storm drain measures 50 cm × 50 cm with 30 cm of sediment which equates to 7.5E4 cm3

of sediment for a total sediment volume = 1.66E5 cm3

Note: This material was removed during the ECC site investigations (ECC 2000)

` 8-hour work day

` Mass loading factor of 600 µg/m3 (ANL 1993a)

` Ingestion rate of 100 mg/day (ANL 1993a)

` Breathing rate of 20 m3/8-hour work day

` External exposure at a point 30 cm above the ground 70 cm distance from the sediment pile

` Uranium concentrations were 36.00 pCi/g for U-234, 1.29 pCi/g for U-235, and 0.80 pCi/g

for U-238

` Inhalation dose conversion factors (all values used are for Y inhalation class) of 0.13

mrem/pCi for U-234 and 0.12 mrem/pCi for both U-235 + progeny and U-238 + progeny

(ANL 1993b)

` Ingestion dose conversion factors of 2.6E-4 mrem/pCi for U-234 and 2.5E-4 mrem/pCi for

both U-235 + progeny and U-238 + progeny (ANL 1993b)


DOSE CALCULATIONS

The total effective dose equivalent was calculated by summing the daily dose that would result from

inhalation, ingestion, and direct exposure for each uranium isotope. Calculations for each parameter

are provided below:

INHALATION

The following calculations provide the airborne concentration levels and inhalation dose:

Airborne Concentrations

U-234: (36.00 pCi/g) × (600 µg/m3) × (1E-6 g/µg) = 2.16E-2 pCi/m3



Inhalation Dose Rate

U-234: (2.16E-2 pCi/m3) × (20 m3/8-hour) × (8-hours/work day) × (0.13 mrem/pCi) =

5.6E-2 mrem/day


1.86E-3 mrem/day


1.15E-3 mrem/day

_______________

_ = 5.9E-2 mrem/day total dose from inhalation during storm drain and pipe excavation activities.


INGESTION

The following calculations provide the dose that would result from ingestion of the sediment:

Ingestion Dose Rate

U-234: (36.00 pCi/g) × (0.10 g/day) × (2.6E-4 mrem/pCi) = 9.36E-4 mrem/day



__________________

_ = 9.9E-4 mrem/day total dose from ingestion during storm drain and pipe excavation activities.

EXTERNAL EXPOSURE

The external exposure dose calculations were determined by modeling using the computer software

program Microshield (GEI 1995).

Exposure Rate

The total sediment volume was assumed to be stockpiled and the modeling performed based on a

cylindrical geometry with the radionuclide inventory calculated from the concentration levels

provided in the assumptions. The original total sediment volume estimate of 1.66E5 cm3—this value

conservatively includes the sediment volume that was originally found in the storm drain pit—was

modeled as a cylinder measuring 60 cm high with a radius of 30 cm. The radionuclide inventory was

calculated as 6.48E-5 µCi/ cm3 for U-234, 2.32E-6 µCi/ cm3 for U-235, and 1.44E-6µCi/ cm3 for U-

238, based on sediment density and uranium concentrations.

The exposure rate at a point that is a distance of 70 cm from the pile and at 30 cm above the ground,

including buildup, is 1.5E-5 mR/h. For the assumed 8-hour work day the direct external exposure

was calculated as 1.2E-4 mR. Because the conversion from mR to mrem is essentially unity, the

direct exposure dose rate is estimated at 1.2E-4 mrem/day.


CONCLUSIONS

When the values calculated above are summed, the total estimated dose rate is 6.0E-2 mrem/day with

the predominate pathway, inhalation, accounting for 98% of the dose. Ingestion and direct exposure

account for less than 2% and less than 1% of the total dose, respectively. Therefore, the total

effective dose equivalent for the hypothetical construction worker, for an assumed project duration

of 30 days, to excavate and remove the storm drain and associated piping is conservatively estimated

at 1.9 mrem for the period. Extension of the exposure period to a standard work year of 2000 hours

(250 days) results in an annual dose of 16 mrem/y. However, this exposure duration is considered

to be unrealistic because of the minor scope of the assumed project.

For a member of the general public, with the assumption the pipe is left in place, the primary dose

pathway would be from direct exposure. Background exposure rates in the Windsor area average

10 µR/h (ORISE 1998). The conservative estimate for direct exposure for the hypothetical worker

from the sediment was 1.5E-5 mR/h (1.5E-2 µR/h). This level is a small fraction of background.

In addition, the shielding effects of the soil and asphalt over the pipe and greater distance from the

sediment in the storm drain (upwards of 250 cm versus the 70 cm distance that was modeled) would

further significantly reduce any potential direct gamma exposure.

The results of these conservative estimations show that the potential for present or future dose due

to the residual radioactive material within the storm drains is minimal and that leaving this material

in place does not pose a significant risk to either the hypothetical construction worker (assumed

maximally exposed individual) or to a member of the general public.


FIGURES


TABLE


TABLE 1

URANIUM CONCENTRATIONS IN SEDIMENT SAMPLESRAPAPORT BUILDING STORM DRAINS

WINDSOR, CONNECTICUT

Location/Sample IDaRadionuclide concentration (pCi/g)

U-234 U-235 U-238

South Storm Drain/2 36.00 ± 3.96b 1.29 ± 0.19 0.80 ± 0.13

South Storm Drain Resample/7 15.18 ± 1.76 0.46 ± 0.14 0.18 ± 0.10

PI Valve Pit/8 2.30 ± 0.28 0.12 ± 0.04 0.83 ± 0.12

Southwest Storm Drain/9 0.78 ± 0.12 0.04 ± 0.02 0.63 ± 0.10

aRefer to Figure 3.bUncertainties are total propagated uncertainties at the 95% confidence level.


REFERENCES

ABB Support Services (ABB). Letter to T. Vitkus (ORISE) from John F. Conant (ABB). Windsor,CT. January 22, 1998.

Argonne National Laboratory (ANL). Data Collection Handbook to Support Modeling the Impactsof Radioactive Material in Soil. Argonne, IL; April 1993a.

Argonne National Laboratory. Manual for Implementing Residual Radioactive Material GuidelinesUsing RESRAD, Version 5.0. Argonne, IL; September 1993b.

Combustion Engineering, Inc. (CE). Health Physics Startup Report. Windsor, CT; August 10, 1956.

Environmental Chemical Corporation (ECC). Final Project Completion Report, Project ActionRapaport Building, Windsor, Connecticut. Bloomfield, NJ; February 18, 2000.

Grove Engineering, Inc. (GEI). Microshield Version 4.2 User’s Manual. Rockville, MD; February1995.

Oak Ridge Institute for Science and Education (ORISE). Revision 0—Radiological Survey of theRapaport Building Warehouse, Combustion Engineering, Inc., Windsor, Connecticut. Oak Ridge,TN; July 1998.

U.S. Nuclear Regulatory Commission (NRC). Final Rule on Radiological Criteria for LicenseTermination. 62 Federal Register 39058. Washington, DC; July 21, 1997.

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