**Brookhaven National Laboratory**

**Brookhaven Medical Research Reactor**

**Groundwater Contamination Investigation**

**Final Report**

# December 22, 1997

Prepared by:

Douglas E. Paquette

S&EP Division Hydrogeologist

**Table of Contents**

[Text]{.underline} [Page]{.underline}

Introduction 1

General Hydrogeology 1

Historical Groundwater Monitoring in the BMRR Area 2

Installation of New Monitoring Wells at the BMRR 3

Notifications to DOE and Regulators (June 18, 1997) 3

Characterization of the BMRR Tritium Plume 4

Sample Collection and Analysis 5

Possible Tritium Sources 5

Conclusions 8

Follow-up Actions 9

[Figures]{.underline}

Figure 1 Facility Location Map

Figure 2 Water Table Potentiometric Map - July 1997

Figure 3 Geoprobe Well Location Map

Figure 4 Historical Tritium Concentrations in Well 94-01

Figure 5 Operable Unit III Location of Phase I Temporary Wells

Figure 6 Sample Profile for Phase I Geoprobe Wells

Figure 7 Lines of Hydrogeologic Cross Section

Figure 8 Hydrogeological Cross Section A-A' - Tritium

Figure 9 Hydrogeological Cross Section A-A' - Gross Alpha

Figure 10 Hydrogeological Cross Section A-A' - Gross Beta

Figure 11 Sample Profile for Phase II Geoprobe Wells

Figure 12 Hydrogeological Cross Section B-B' - Tritium

Figure 13 Hydrogeological Cross Section B-B' - Gross Alpha

Figure 14 Hydrogeological Cross Section B-B' - Gross Beta

Figure 15 Tritium Distribution in the Shallow Upper Glacial Aquifer

Figure 16 Water Table Potentiometric Map - November 1994

Figure 17 BMRR Sump and Floor Drain Systems

Figure 18 Radiological Survey and Soil Sample Locations at Former
Haul-Away Tank Area

Figure 19 Sanitary Lines in the Vicinity of the BMRR

Figure 20 Proposed Locations of New Monitoring Wells

**Table of Contents (Continued)**

[Tables]{.underline}

Table 1 Historical Tritium Data for Process Well 104

Table 2 Historical Tritium Data for Process Well 105

Table 3 Groundwater Monitoring Program Tritium Results for CY 1997

Table 4 Geoprobe Well Sample Data - Tritium

Table 5 Geoprobe Well Sample Data - Gamma

Table 6 Geoprobe Well Sample Data - Gross Alpha

Table 7 Geoprobe Well Sample Data - Gross Beta

Table 8 Geoprobe Well Sample Data - Strontium-90

Table 9 Additional Samples for Sr-90 and Alpha Spectroscopy Analyses

Table 10 Chronology of Historical Spills and Discharges at the BMRR

Table 11 Primary Cooling Water - Gamma Analysis

Table 12 SU-2 Sump Sludge Analysis

Table 13 Soil Sample Analyses - Former Haul-Away Tank Area

**Introduction**

Low-level tritium (2,450 pCi/L) was detected in a groundwater sample
collected in January 1997 from a shallow Upper Glacial aquifer
monitoring well located 400 feet south of the BNL's Brookhaven Medical
Research Reactor (BMRR). Following the initial detection of tritium, BNL
installed two shallow monitoring wells directly downgradient of the
BMRR. Subsequent sampling of the new wells indicated tritium
concentrations of up to 11,400 pCi/L. Twenty-five temporary Geoprobe
wells were then installed to further characterize the source and extent
of the tritium contamination. The highest tritium levels were detected
in temporary wells installed within 50 feet of the BMRR, where a maximum
concentration of 11,800 pCi/L was detected. The tritium plume was traced
from the BMRR to approximately 400 feet south (downgradient), where a
maximum concentration of 3,800 pCi/L was detected. The BMRR is located
over 1 mile from the BNL site boundary (Figure 1).

Potential environmental vulnerabilities at the BMRR were initially
evaluated during the High Flux Beam Reactor (HFBR) Tritium Remediation
Project, and more recently as part of the BNL's Facility Review Project.
The BMRR is a 3 MW light water reactor. The primary cooling water system
consists of a recirculation piping system that contains 2,550 gallons of
water. The tritium concentration in the primary water is currently 465
μCi/L, for a total tritium content of 4.5 Ci. Unlike the High Flux Beam
Reactor, the BMRR does not have a spent fuel storage canal or
pressurized imbedded piping systems that contain radioactive liquids.
Any fuel elements that require storage are either stored within the
reactor vessel or are transferred to the HFBR spent fuel canal. The
primary system's piping is fully exposed within the containment
structure, and is accessible for routine visual inspections. Excess heat
is transferred by means of heat exchangers with once through (secondary)
cooling water which is obtained from a process supply well (Well 105) or
the BNL Chilled Water System. This secondary water is discharged to
recharge basin (Basin HP) located 800 feet to the south of the Medical
Department complex.

Review of systems and operations within the BMRR facility has identified
two potential sources for the tritium detected in the groundwater: 1) a
former above ground storage tank that was used to temporally store
radioactive liquids; and 2) a floor drain system and associated sump
which had received primary cooling water on a number of occasions.

**General Hydrogeology**

The BMRR is underlain by weakly stratified coarse-grained sands of the
Upper Glacial aquifer. The Upper Glacial aquifer in this part of the BNL
site is approximately 150 feet thick. Depth to groundwater from land
surface immediately south of the reactor is approximately 57 feet. Depth
to groundwater from the basement floor of the BMRR is approximately 42
feet. During the investigation, the direction of groundwater flow in the
area of the Medical Research Facility was generally to the south (Figure
2), and had a flow rate of approximately 0.75 feet per day. However,
throughout the operational history of the BMRR, groundwater flow
directions and rates are likely to have varied significantly as the
result of the extraction of groundwater from nearby BMRR cooling water
supply wells, and the recharge of this water at Basin HP.

Former BMRR supply well 104, which has been permanently decommissioned,
was located approximately 350 feet northeast of the BMRR. Supply well
105 is located approximately 700 feet northwest of the BMRR. No BNL
drinking water supply wells are located near the BMRR. When active,
these cooling water supply wells, especially well 104 pumping at nearly
1,200 gpm, may have had effective capture zones that extended well into
the BMRR area. When active, supply well 105 provides cooling water to
the BMRR at a rate of nearly 1,000 gpm. Since June 1997, Basin HP has
also been receiving water discharged from the Operable Unit III
groundwater remediation system located adjacent to the basin. With the
combined pumpage of supply well 105 and the six Operable Unit III
groundwater remediation wells located at BNL's southern boundary,
approximately one million gallons of water per day is discharged to
Basin HP. By July 1997, this combined discharge resulted in the
formation of a significant groundwater mound beneath Basin HP (Figure
2). With time, the groundwater mound will become larger, and will likely
cause significant changes in groundwater flow directions over a large
area, possibly as far north as the BMRR area. Preliminary modeling
suggests that groundwater flow directions in the BMRR area are likely to
change from a southern to a more westerly direction.

**Historical Groundwater Monitoring in the BMRR Area**

[Process Supply Wells]{.underline}: As a result of 1,1,1-trichloroethane
(TCA) contamination, supply wells 105 and 104 were shut down in February
and April 1990, respectively. In 1990, TCA was detected in supply well
105 at a concentration of 31 μg/L, which was above the NYS Drinking
Water Standard of 5 μg/L. TCA was detected in well 104 at a
concentration of 13 μg/L. The TCA detected in these wells is likely to
have originated from identified TCA source areas located upgradient of
the Medical Research Facility such as spill sites located in the
Alternating Gradient Synchrotron (AGS) research and support areas and
former Building T-111 (see BNL 1995 Site Environmental Report).
Following the shut down of these wells, the cooling water requirements
for the BMRR were met by the BNL Chilled Water System. Well 105 has been
back in service since February 1996, following the installation of
organic carbon filters to remove the TCA. A review of available
analytical data from 1971 through 1989 indicates tritium concentrations
in wells 104 and 105 were usually \<700 pCi/L (Table 1 and Table 2).
However, tritium was detected in well 104 at concentrations of 1,900
pCi/L in 1976 and 1,480 pCi/L in 1989. It is unclear whether the tritium
detected in well 104 originated from the BMRR or from upgradient sources
such as the Waste Concentration Facility areas where tritium has been
detected in the range of 1,000 to 5,000 pCi/L.

[Groundwater Surveillance Wells]{.underline}: Prior to May 1997, routine
groundwater surveillance monitoring near the BMRR was limited to one
shallow Upper Glacial aquifer monitoring well located approximately 400
feet downgradient (south) of the facility (Figure 3). Well 94-01, along
with a similarly screened well (94-02) located several feet away, are
located near Building 494, the Medical Department's former Large Animal
Facility. The wells were installed in the early 1980s at the request of
the NYS Department of Transportation to assess potential impacts of an
underground fuel oil tank that had failed tightness testing. The wells
are screened from 60 to 70 feet below land surface. Apparently, these
wells were checked for floating product following installation, then
left un-used until they were incorporated into BNL's Routine
Environmental Monitoring Program in the summer of 1991. The wells are
used to evaluate groundwater flow patterns and groundwater quality
downgradient of the Medical Research complex, which includes the BMRR.
The S&EP Division started to collect water level measurements from these
wells in October 1991, and began using well 94-01 in April 1994 for the
collection of groundwater samples for chemical and radionuclide
analyses.

From 1994 through 1996, well 94-01 was sampled six times. During this
period, tritium was detected slightly above the MDL on two occasions;
354 pC/L (MDL = 275 pCi/L) in March 1995, and 522 pCi/L (MDL = 323
pCi/L) in December 1995. The federal drinking water standard for tritium
is 20,000 pCi/L. Results for the remaining four collection periods were
below detection levels (Figure 4). Low level tritium was also detected
in one Operable Unit III Remedial Investigation temporary vertical well
installed by the Office of Environmental Restoration (OER) along
Princeton Avenue, approximately 1,400 feet downgradient of Medical
Research Department complex. Tritium was detected at 602 pCi/L in well
TW-34 in a screen interval 70 feet below land surface (Figure 5).
Tritium was not detected in OU III temporary vertical profile wells
installed south of the BMRR, along BNL's southern boundary (see BNL Site
Environmental Report for CY 1995).

On January 23, 1997, additional groundwater samples were collected from
monitoring well 94-01 as part of the Routine Groundwater Monitoring
Program. Analysis of this sample was not completed until April 17 due to
the large number of HFBR groundwater investigation samples being
analyzed by the S&EP Analytical Services Laboratory during this time
period. Analysis of the January 23 sample indicated a tritium
concentration of 2,450 pCi/L (Table 3). On April 28, the S&EP Division
re-sampled Well 94-01. Later that day, the S&EP Analytical Services
Laboratory analyzed this sample and re-analyzed an archived sample from
January 23. The tritium results for the re-analyzed sample of January 23
was 2,540 pC/L, which confirmed the earlier results. However, the
tritium result for the April 28 sample was non-detect (\<401 pCi/L).

**Installation of New Monitoring Wells at the BMRR**

In May 1997, BNL installed two groundwater monitoring wells directly
south (downgradient) of the BMRR (Figure 3). The new wells, 84-12 and
84-13, are screened across the water table from approximately 55 feet to
70 feet below land surface. Wells 84-12 and 84-13 were sampled for the
first time on May 22 and May 29, respectively, and tritium analyses were
completed by June 12 (Table 3). Whereas slightly detectable levels of
tritium were found in Well 84-12 (at 686 pCi/L), tritium concentration
in the sample from Well 84-13 was 4,310 pCi/L. Upon receipt of these
results, BNL immediately re-sampled the wells. The results of the June
12, 1997 sampling were similar to earlier findings, with 501 pCi/L
detected in Well 84-12 and 4,800 pCi/L detected in Well 84-13.
Additional analyses of the well samples indicated no reactor-related
gamma-emitting radionuclides. However, samples from Well 84-12 did show
gross beta level of 23 pCi/L.

On June 18, 1997, wells 84-12 and 84-13 were re-sampled. During this
sampling event, discrete samples were collected from the uppermost two
to three feet of the aquifer. The results from these samples indicate
tritium concentrations of 3,030 pCi/L in well 84-12 and 11,400 pCi/L in
well 84-13. Additional analyses of the well samples indicated no
reactor-related gamma-emitting radionuclides, and gross alpha and gross
beta analyses indicated trace to non-detectable levels.

**Notifications to DOE and Regulators**

On June 18, 1997, BNL notified the DOE's Brookhaven Area Group of the
elevated tritium concentrations detected in monitoring wells 84-12 and
84-13. (Note: These wells were formerly referred to as 94-09 and 94-10.)
Following a meeting between BNL and DOE that same day, the elevated
tritium levels were categorized as an Off Normal Occurrence (Report
CH-BH-BNL-BNL-1997-0020), and entered into the Occurrence Reporting
Processing System (ORPS) at 1647 HRS (EST). The DOE-BHG notified the US
Environmental Protection Agency (USEPA), the New York State Department
of Environmental Conservation (NYSDEC), and the Suffolk County
Department of Health Services (SCDHS) the following day.

**Characterization of the BMRR Tritium Plume**

[Phase I Geoprobe Investigation]{.underline}: As a result of the
detection of tritium in monitoring wells 84-12 and 84-13, ten temporary
(Geoprobe) wells were installed to evaluate the extent of tritium in
groundwater near the BMRR. The wells were installed from June 19 through
July 2, 1997. Three wells (GP-1, GP-2 and GP-10) were installed
immediately upgradient of the reactor building, and seven (GP-3 through
9) were installed approximately 50 feet downgradient of the reactor
building (Figure 3). The Geoprobe wells were installed to a maximum
depth of 78 feet (Figure 6). At each well, samples for tritium, gross
alpha, gross beta, gamma, Sr-90 and volatile organic compound (VOC)
analyses were collected at four depths, for a total of 40 separate
sample intervals.

Results from the downgradient Phase I wells indicated a shallow tritium
plume with a concentration up to 5,270 pCi/L (Table 4, Figures 7 and 8).
Tritium was also detected at concentrations up to 3,210 pCi/L in
upgradient well GP-01, which is located approximately 10 feet from the
reactor building. Most gamma spectroscopy analyses indicate no
reactor-related gamma-emitting radionuclides (Table 5). However, a trace
amount (0.2 pCi/L) of Cs-137 was detected in one sample from
downgradient well GP-9. Additionally, several samples showed gross alpha
levels up to 17.7 pCi/L and gross beta levels up to 21.7 pCi/L (Tables 6
and 7; Figures 9 and 10). In most cases, however, there was poor
correlation between samples with elevated gross alpha and beta and those
with elevated tritium. In order to determine whether the elevated gross
beta results were due to strontium-90, three representative Phase I
samples that had gross beta results ranging between 9.3 and 19.4 pCi/L
were selected for detailed analysis (Table 8). Sr-90 was not detected in
the three samples. Trace amounts of VOCs were detected in two Phase I
samples. In GP-09 (76\'-78\' level), a trace amount of
1,1,1-Trichloroethane (TCA) was detected (0.8J μg/L; J=estimated
quantity), and in GP-4 (60\'-62\' level) 1,1-Dichloroethene (0.8J μg/L),
Chloroform (1.5J μg/L), TCA (1.1J μg/L), Tetrachloroethylene (0.8J μg/L)
and benzene (1.1J μg/L) were detected. These sample intervals did not,
however, correlate to intervals with detectable levels of tritium.

[Phase II Geoprobe Investigation]{.underline}: On August 1, 1997, a
second phase of plume characterization began with the installation of
nine Geoprobe wells (Figure 2). Two wells (GP-11 and GP-12) were
installed east of GP-09 to define the eastern edge of the plume in that
area. Seven other wells (GP-13 through GP-19) were installed
approximately 400 feet south of the BMRR, directly south of the former
Large Animal Facility (Building 494) and close to existing monitoring
well 94-01. Downgradient Geoprobe wells GP-13 through GP-19 were
installed to determine the downgradient extent of the plume, and
determine whether the tritium detected in well 94-01 in January 1997 was
related to the BMRR. The wells were installed to a maximum depth of 98
feet (Figure 8), and samples for tritium, gross alpha, gross beta,
gamma, and Sr-90 analyses were collected at four to six depths, for a
total of 47 separate sample intervals.

Phase II wells GP-11 and GP-12 were not able to define the eastern edge
of the tritium plume directly downgradient of the BMRR. Tritium was
detected at maximum concentrations of 1,530 in GP-11 and 11,800 pCi/L in
GP-12 (Table 4, Figure 8). Phase II wells were able to trace the tritium
plume to the area south of Building 494, with concentrations ranging
from 1,060 to 3,820 pCi/L in wells GP-16, GP-17 and GP-18 (Table 4,
Figure 10). At these locations, tritium was usually detected in the
64-66 and 72-74 feet below land surface (bls) sample collection
intervals. The occurrence of tritium at these intervals suggests that
the tritium detected previously in well 94-01 (which is screened from
59-69 feet bls) is related to the BMRR plume. Tritium was also detected
at a concentration of 433 pCi/L in GP-19 at the 64-66 feet bls level.
Therefore, well 94-01 is likely to be just to the east of the \>1,000
pCi/L portion of the plume (Figure 11). Gamma spectroscopy data for the
Phase II samples indicate no reactor-related gamma-emitting
radionuclides (Table 5). Samples from four Geoprobe wells (GP-12, GP13,
GP-14 and GP-17) showed gross alpha levels above the drinking water
standard of 15 pCi/L, with concentrations ranging between 16 pCi/L and
47.4 pCi/L (Table 6; Figure 13). Gross beta levels \>20 pCi/L were
detected in five Geoprobe wells (GP-11, GP-12, GP-13, GP-13 and GP-17),
with concentrations ranging between 20.8 pCi/L and 60 pCi/L (Tables 7;
Figure 14). In order to determine whether the elevated gross beta
results were due to strontium-90, two Phase II samples that had elevated
gross beta and tritium concentrations were selected for detailed
analysis. Trace amounts of Strontium-90 (≤0.46 pCi/L) were detected in
two samples from GP-12 (Table 8). The drinking water standard for Sr-90
is 8 pCi/L. Additional Sr-90 analyses will be performed on samples
showing elevated gross beta, and alpha spectroscopy analyses will be
performed on samples with gross alpha concentrations of \>15 pCi/L (see
Follow-up Actions and Table 9).

[Phase III Geoprobe Investigation]{.underline}: Based upon the 11,800
pCi/L tritium detected in GP-12, three additional Geoprobe wells (GP-20,
21, and 22) were installed east of GP-12 to define the eastern margin of
the plume, and three additional wells were installed upgradient of the
BMRR's "Receiving Room" (Figure 3). The wells were installed to a
maximum depth of 70 feet. Two of the upgradient wells (GP-23 and 24)
were installed to determine whether any sources are located within the
Medical Departments research facility area, and one well (GP-25) was
installed to characterize groundwater quality near the sanitary line
that runs directly north of the Receiving Room. The six wells were
installed during August 18 through August 25. At each well, samples for
tritium, gross alpha, gross beta, gamma, and Sr-90 analyses were
collected at three depths, for a total of 18 separate sample intervals
(Figure 8).

Phase III samples were able to define the eastern edge of the tritium
plume with a maximum of 1,090 pCi/L detected in GP-20 (Table 4, Figure
8). Tritium was detected at very low concentrations in all three
upgradient wells with a maximum observed concentration of 606 pCi/L in
the shallow sample from GP-25, which was installed between the BMRR's
Receiving Room and the sanitary line and manhole (Table 4). Gamma
spectroscopy analyses performed on Phase III groundwater samples
indicate no reactor-related gamma-emitting radionuclides (Table 5). A
sample from GP-22 showed elevated gross beta levels up to 47.2 pCi/L
(Tables 6 and 7).

[Summary of Plume Characteristics]{.underline}: The BMRR tritium plume
has been traced from the BMRR to an area approximately 400 feet south
(downgradient) near the former Large Animal Facility. The highest levels
of tritium were detected in wells installed within 50 feet of the BMRR,
where tritium was detected at concentrations up to 11,800 pCi/L. Near
the reactor, the plume is situated within the uppermost 10 feet of the
Upper Glacial aquifer and is approximately 120 feet wide (Figure 8).
South of the Large Animal Facility, the tritium plume drops to a
concentration of less than 3,800 pCi/L. In the former Large Animal
Facility area, the plume is situated approximately 10 to 15 feet below
the water table, and is approximately 240 feet wide by 15 feet thick
(Figure 12). Since tritium migrates through the aquifer at a rate equal
to water, the groundwater travel time for tritium from the BMRR to the
former Large Animal Facility is approximately 1.5 years. The ability to
trace the plume south of the Large Animal Facility would be difficult
due to the presence of Recharge Basin HP, where the recharge of
approximately one million gallons of water per day will significantly
change groundwater flow pathways and cause further dilution of the
tritium plume (see Figure 2). From April 1991 through 1996, the BMRR
supply wells were not operational, and water was not being recharged at
Basin HP. During this period, the BMRR tritium plume would have been
able to able to migrate approximately 1,400 feet (to the East Princeton
Avenue area), unimpeded by groundwater withdrawal and recharge effects
(compare groundwater flow patterns in Figure 2 with those in Figure 16).
In 1995, tritium was detected in one OU III RI temporary vertical
profile well (TW-34) installed downgradient of the BMRR along Princeton
Avenue (Figure 5). The tritium was detected at a concentration of 602
pCi/L, and at a depth of 70 feet below land surface (approximately 20
feet below the water table). It is likely that the tritium detected in
TW-34 is related to the BMRR tritium plume.

A number of groundwater samples collected during the investigation had
elevated gross alpha and gross beta concentrations (Tables 6 and 7).
Gamma spectroscopy results could not, by themselves, account for these
gross counts. Potassium-40, a naturally occurring radionuclide, was
detected in most samples with concentrations up to 17.8 pCi/L. A trace
amount of Cs-137, a reactor-related fission product, was detected in one
sample from well GP-09 located near the BMRR. Based upon initial gross
beta results, six samples were chosen for Sr-90 analysis. These samples
were chosen based upon the presence of elevated gross beta and their
proximity to the defined position of the tritium plume. The analytical
results indicated only trace amounts of Sr-90 in one sample (Table 8).
To ensure that elevated gross alpha and beta readings detected in other
samples are not related to laboratory operations, it will be necessary
to perform additional Sr-90 analyses on six groundwater samples with
gross beta results of \>20 pCi/L, and alpha spectroscopy on six
groundwater samples with gross alpha results of \>15 pCi/L (Table 9).
Although most of these samples were collected from outside of the
presently defined BMRR tritium plume, the position of the plume may
shifted periodically due to variations in groundwater flow patterns (see
Figures 9, 10, 13, and 14). Furthermore, the distribution of
contaminants may also be complicated by differences in contaminant
migration characteristics (i.e., retardation factors).

**Sample Collection and Analysis**

Permanent groundwater monitoring wells were sampled by the S&EP Division
using S&EP Division Standard Operating Procedure EM-SOP-25. Temporary
Geoprobe wells were installed and sampled by the OER using procedures
approved for the Operable Unit III and Operable Unit V Remedial
Investigations. All Geoprobe groundwater samples, except those analyzed
for VOCs, were filtered in the field using an in-line 0.45 μm filter.
All VOC (EPA Method 624), gross alpha and beta (Method 900), gamma
spectroscopy (Method 901.1), and tritium (Method 906) analyses were
performed by the S&EP Division's Analytical Services Laboratory (ASL).
Strontium-90 analyses were performed (using Method 905) by American
Environmental Network (AEN) Laboratory, Cary, North Carolina.

The ASL is certified by the New York State Department of Health Services
for each of the analyses performed. The ASL also participates in the DOE
Environmental Measurements Laboratory (EML) QA Program and the EPA
National Exposure Research Laboratory Performance Evaluation Study. AEN
is also a NYSDOH certified laboratory for Sr-90 analysis. The BNL ASL
and AEN Labs have established standard operating procedures to calibrate
instruments, analyze samples, and check quality control. Depending upon
the analytical method, quality control checks include the analysis of
blanks or background concentrations, use of Amersham or National
Institute for Standards and Technology (NIST) traceable standards, and
analysis of reference standards, spiked samples, and duplicate samples.
All analytical results were reviewed by BNL ASL supervisors for
completeness and accuracy.

**Possible Tritium Sources**

Four potential sources for the tritium detected in groundwater were
evaluated during this investigation. Initially, a possible source within
the Medical Department (Building 490) was thought to be an isotope
storage and preparation lab located directly north (upgradient) of the
BMRR. Although significant quantities of tritium were stored and used in
the isotopes lab, all piping systems from this and all other research
labs are exposed in the basement of the building, and there is no record
of significant leakage from the piping. More likely sources for the
tritium are located within the BMRR. These potential sources include a
floor drain system and associated unlined 150 gallon capacity sump
located in the basement of the BMRR, a sanitary line that runs from the
BMRR which received discharges from the sump, and a former above ground
storage tank used to store radioactive liquids which was located
directly south of the BMRR (immediately south of the new monitoring well
84-13). The floor drain system and sump are known to have received
radioactive water containing tritium from the primary cooling system,
and available records indicate three historical spills associated with
the transfer of radioactive liquids to the above ground storage tank.

[SU-2 Sump and Associated Floor Drains]{.underline}: All drains on the
basement floor of the BMRR are connected to a steam ejector sump SU-2
with the exception of one drain in the immediate vicinity of the primary
coolant water polishing system which discharges directly to the
radioactive waste sump SU-1 (discussed below). SU-2 is a rectangular
concrete sump about four feet deep and has a capacity of approximately
150 gallons (Figure 17). Piping from the floor drain system enters the
sump approximately two feet from the top. Little design and construction
information has been found for this drain system and sump. A recent
video inspection indicates that the drain system is constructed of
common cast iron drain piping. The survey could not determine the type
of gasket material used at the connection joints or their condition.
Recently, the Reactor Division conducted qualitative leak-rate test of
the combined SU-2 sump and floor drain system. During this test, the
SU-2 sump was completely filled to floor level, allowing the water to
flood the floor drain piping - a situation that has occurred on a number
of occasions in the past with primary water discharges. The test
indicated a leak rate of approximately 2 gallons over a 24-hour period.

Review of available records indicates that from 1962 to 1987, primary
water was either spilled or discharged to the floor drains and SU-2 sump
during maintenance and repair of the primary coolant system. Records
indicate a total of 16 spills or discharges totaling nearly 800 gallons
of primary water to the floor drains and/or SU-2 sump (Table 10). Water
from the primary system that entered SU-2 was sampled and analyzed to
determine proper disposal methods (i.e., discharge to the sanitary
system or treatment) - a process that may have lasted a week or more. A
recent gamma spectroscopy analysis of the BMRR primary cooling water is
presented in Table 11. The presence of Cs-137 in the primary water
suggests that another fission related products, such as Sr-90, may also
be present. The tritium concentration in the primary water is currently
465 μCi/L. The leak rate test noted above suggests that some amount of
primary water released to this system is likely to have leaked into the
underlying soils. Other liquids that have entered the SU-2 sump and
floor drain system include air conditioning condensate (with tritium
concentration typically \<MDL), air compressor condensate (with up to
15,000 pCi/L tritium), water from a wash-up sink (used for hand washing
and floor mop cleaning), and secondary (non-radioactive) cooling water.
The last documented discharge of primary coolant water to the floor
drains and sump occurred on January 28, 1987. At that time,
approximately 70 gallons was discharged to SU-2 and the floor drain
system. From 1987 to 1996, primary water that had been removed from the
system during maintenance was containerized in the SU-1 sump, and later
disposed of as radioactive waste. For the past year, however, drained
water has typically been returned to the primary system for re-use.

During most of its operational history, the lower foot of the SU-2 sump
was continuously wet. In February 1997, the Reactor Division extended
the steam ejector suction line to the base of the sump and removed a one
foot layer of sludge that contained low levels of Na-22, Co-60, Cs-137,
Eu-152 and Pb-212 (Table 12). The sump is currently kept dry, and a
liquid sensor has been installed. Furthermore, large portions of the
floor drain piping network may have been continuously wet, especially
when the sump was filled to a level above the piping inlets. How much of
the piping system flooded during these operations has not been
determined. Since the beginning of reactor operations, the SU-2 sump has
been routinely used to collect secondary (non-radioactive) coolant water
during maintenance operations on the secondary system. A detailed record
of secondary system discharges to the SU-2 sump has not been maintained.
Low level tritium (1,757 pCi/L) was detected in a recent water sample
from the SU-2 sump, which indicates that residual contamination is
present in the sump and/or floor drain lines.

[Above Ground Storage Tank]{.underline}: An outdoor above ground
haul-away tank located near the south side of the reactor building was
used to temporarily store liquid radioactive waste produced from
regeneration and back washing of the BMRR's ion exchange column which is
used to polish the primary water. The ion exchange column removes much
of any fission product contamination and keeps the water properly
conditioned to minimize corrosion. Waste water from the ion exchange
column is likely to have had high tritium concentrations, that were
equivalent to concentrations within the primary system during those
periods. The ion exchange column is located in south side of the
basement of the BMRR, and the regeneration water would be drained to the
SU-1 sump then pumped to the above ground tank by means of a partially
buried underground line (Figure 17). The haul-away tank was used by the
S&EP Waste Management Section to transport this radioactive liquid waste
to Building 801 for processing. The SU-1 sump was recently qualitatively
leak-rate tested by the Reactor Division. No losses greater than those
associated with evaporation were observed. Initial review of historical
records indicate that line leakage or inadvertent overfilling of the
haul-away tank occurred on at least three occasions while transferring
liquids (Table 10). During these events, the water apparently dripped
onto to an underlying asphalt pad. In at least one instance, records
indicate that the asphalt pad and surrounding area were flushed with
water following a spill event. The haul-away tank was decommissioned in
June 1988. Since that time, the resin from the ion exchange column has
been partially dewatered and then disposed of as radioactive waste. A
recent walk-over radiological survey of the former tank area has
identified residual contamination and remnants of the asphalt pad
(Figure 18). Analysis of soil samples from this area indicate Sr-90 up
to 12.5 pCi/g and Cs-137 up to 65 pCi/g (Table 13).

[Sanitary Line]{.underline}: A sanitary line exits the northeast section
of the basement of the BMRR (Figure 19). As the sanitary line exits the
BMRR, it extends underground, eastward toward sanitary manhole M-101D. A
separate sanitary line from the Medical Research Facility also ties into
manhole M-101D.

In the past, water that entered SU-2 sump was first sampled and
analyzed, then if the water met the appropriate discharge criteria, it
was discharged to the sanitary line by means of a steam ejector. The
present condition of the sanitary line is unknown. If small cracks are
present in the sanitary line, leakage of some radioactive water may have
occurred. To characterize groundwater quality near the sanitary line and
manhole, one Phase III Geoprobe well (GP-25) was installed adjacent to
manhole M-101D (Figure 3). Results from GP-25 indicate the presence of
low level tritium (612 pCi/L) at the water table. It is unclear,
however, whether this tritium originated from sewer line leakage or
leakage from the floor drain system located in the basement of the
BMRR's Receiving Room (see Figure 17).

All discharges of radioactive liquids to the sanitary system are
controlled and documented by the S&EP Division (S&EP Division Standard
Operating Procedure RP-SOP-3). Current discharges of radioactive liquids
from the BMRR consists of small volumes (10-15 gallons per month) of air
conditioning condensate, which typically contains tritium at \<15,000
pCi/L. Tritium was not detected in recent water samples collected from
manhole M-101D.

[Medical Research Facility]{.underline}: In the past, significant
amounts of tritium were used within the Medical Research Department
(Building 490) for several experiments. Presently, the Medical
Department uses only small quantities of tritium in its research
programs. During this investigation, a potential source for the tritium
was thought to be an isotope storage and preparation lab (also known as
the Dilution Room) located directly north (upgradient) of the BMRR.
Although significant quantities of tritium were stored and used in the
isotopes lab, all piping systems from this lab are exposed in the
basement of the building. Review of historical records indicate only one
documented leak from the Dilution Room's piping system. In February
1964, blockage of a radioactive waste line resulted in the leakage to
the basement floor of cooling water from a condenser running in an
experiment hood located in the Dilution Room. A radiological survey
found the water to be "10 times background," however, records which
would indicate whether a detailed isotopic analysis of the water was
conducted are not available. Furthermore, the amount of water spilled,
whether the water leaked into a basement floor drain, and details of
cleanup efforts were not documented.

The Medical Department also manages three 500 gallon-capacity
radioactive waste tanks located in the basement of Building 490. The
tanks, which were installed above the basement floor, were used to store
low-level radioactive liquid waste. Standard disposal procedures
included sampling of the water, and release to the sanitary system
following S&EP Division's approval. There are no records indicating that
these tanks have leaked, and there have been no discharges to the
sanitary system for the past three years. The tanks are of no future
use, and are presently schedule to be abandoned by the Plant Engineering
Division.

Although tritium was detected at 3,210 pCi/L in one (GP-1) of six
Geoprobe wells installed between the Medical department and the BMRR,
the tritium is likely to be the result of lateral spreading of tritiated
water as it migrates through the vadose (or unsaturated) zone below the
BMRR, rather than a separate source within the Medical Research
Facility. Well GP-1 is located within ten feet of the northwest side of
the reactor building, within 15 feet of one of the BMRR floor drains,
and 20 feet from the SU-2 sump (Figure 17).

**Conclusions**

A low level tritium plume has been detected in shallow Upper Glacial
aquifer monitoring wells installed near the BMRR. The maximum tritium
concentration detected in wells within 50 feet of the BMRR was 11,800
pCi/L. The tritium plume has been traced approximately 400 feet south of
the BMRR near the former Large Animal Facility, where the maximum
observed concentration was 3,800 pCi/L. The groundwater travel time from
the BMRR to the former Large Animal Facility is approximately 1.5 years.
The most likely source for the tritium is the floor drain system and
associated unlined 150 gallon capacity SU-2 sump located in the basement
of the BMRR. The floor drain system and SU-2 sump are not leak tight,
and are known to have received radioactive water containing tritium from
the primary cooling system. Some small amount of the tritium detected in
groundwater may have also originated from spills from a former above
ground storage (haul-away) tank used to store radioactive liquids.

Records indicate a total of 16 spills or discharges totaling nearly 800
gallons of primary water to the floor drains or directly to the SU-2
sump. The last such discharge occurred in January 1987. Although most of
the primary water that was discharged was properly disposed of, recent
qualitative leak-rate testing indicates that the sump and/or floor drain
piping system is not entirely leak tight and some amount of radioactive
water may have leaked to the underlying soils. Furthermore, throughout
the history of the BMRR, secondary (non-radioactive) coolant water was
routinely discharged to the SU-2 sump and floor drain system. Leakage of
secondary water could have provided sufficient water volume to drive the
tritium through the unsaturated zone and into the groundwater below the
reactor building. Although tritium was detected up to 3,210 pCi/L in one
of the upgradient wells (GP-01), a possible source within the Medical
Research Facility is less likely. The upgradient well is located very
close to the BMRR structure and within 20 feet of the SU-2 sump. The
tritium detected in the upgradient well is probably the result of
leakage of the SU-2 sump and/or the floor drain system, and lateral
spreading as the tritiated water migrates through the unsaturated zone
and into the groundwater.

**Follow-up Actions**

1)  The S&EP Division will perform additional Sr-90 analyses on six
    groundwater samples with gross beta results of \>20 pCi/L, and alpha
    spectroscopy on six groundwater samples with gross alpha results of
    \>15 pCi/L. Although most of these samples were collected from
    outside of the presently defined BMRR tritium plume, the position of
    the plume may shifted periodically due to variations in groundwater
    flow patterns. Furthermore, the distribution of contaminants may
    also be complicated by differences in contaminant migration
    characteristics (i.e., retardation factors). The alpha spectroscopy
    analyses (U, Th, Pu, Am, and Ra series using a PERALS^©^
    spectrometer) and Sr-90 analyses (using DOE Method RP-500) will be
    performed by the S&EP Analytical Services Laboratory by early
    February 1998.

\*\*Post Publication Note: It was later determined that the elevated
gross alpha and beta results were the result of cross contamination of
analytical equipment. Therefore, these additional recommended analyses
were not performed. See explanation and reanalysis data in S. Scarpitta
to D. Paquette memorandum of April 13, 1998.

2\) Since the floor drain system is not leak tight and does not meet
Suffolk County Article 12 requirements for secondary containment, the
Reactor Division and Plant Engineering Division will abandon the floor
drains in a manner that is acceptable to the SCDHS. Although the last
documented discharge of primary water to the SU-2 sump and floor drain
system occurred in January 1987, continued use of the sump and floor
drain system is likely to leach any residual contamination from the
unsaturated zone and into the groundwater.

3\) The Reactor Division will seal the SU-2 sump with a SCDHS approved
material, and a plastic container will be placed in the sump pit. A
liquid sensor was recently installed in the sump, and will be used to
detect any liquids outside the plastic container. The plastic container
will be used to collect water that is discharged from secondary cooling
systems. Alternative approved storage containers will be used when
maintenance requires the draining of primary water systems.

4\) The Reactor Division will make appropriate changes to the BMRR work
procedures to ensure that radioactive water removed from the primary
system or water from air compressor condensate is placed in approved
storage containers. The primary water will be returned to the cooling
system, or disposed of through the S&EP Division's Waste Management
Section. The Reactor Division and S&EP Division will evaluate the option
of disposing of air compressor condensate water through the Waste
Management Section rather than discharging the water to the sanitary
system. This water is generated at a rate of approximately 15 gallons
per month, and contains tritium at concentrations of \<15,000 pCi/L.

5\) The S&EP Division will establish a long-term groundwater monitoring
program for the BMRR using existing and new wells. To evaluate the
effectiveness of the new engineering controls noted above, the
groundwater monitoring program will focus on groundwater quality
directly downgradient of the BMRR. Due to groundwater pumpage and
recharge effects, groundwater flow directions in the BMRR area will be
re-evaluated prior to the installation of the new wells. Preliminary
locations for the wells are: two monitoring wells to the west/northwest
of the BMRR; and one well immediately south of the BMRR's Receiving Room
(Figure 20). The wells will be installed in early 1998 as part of BNL's
Groundwater Monitoring Improvements Program.

6\) The Cs-137 concentrations (65 pCi/g) detected in soils at the former
haul-away tank area are above the OU I soil cleanup criteria of 23
pCi/g. Remediation of these soils will be conducted by the OER as part
of the OU I cleanup efforts of radiologically contaminated landscaping
soils located south of the Medical Research Facility.