ML20058G151
| ML20058G151 | |
| Person / Time | |
|---|---|
| Issue date: | 11/22/1993 |
| From: | Kinneman J, Roberts M, Duane White NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20058G141 | List: |
| References | |
| REF-QA-99990001-931124 99990001-93-16, NUDOCS 9312090112 | |
| Download: ML20058G151 (9) | |
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U.S. NUCLEAR REGULATORY COMMISSION REGION I t
Repon No.
99990001/93-016 j
Docket No.
070-00903 i
License No.
SNM-871 (Terminated)
Former Licensee:
Gulf United Nuclear Fuels Comoration Pawline. New York i
Present Owner:
U.S. Denanment of the Interior National Park Service Facility Name:
Nuclear 12ke f
Inspection at:
Nuclear Lake Site West Pawling. New York j
Inspection Conducted: October 19.1993 tN
//[/P/13 Inspectors:
u tc m Duncan White, Health Physicist dite i
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Mark C. Roberts, Senior Health Physicist date i
Approved:
sifh9 7 J uiD. Ifinne/ nan, Chief
' da'te ite mmissioning Section Instection Summary: Inspection on October 19,1993 (Inspection Report No. 99990001/93-016) i i
Amas Insoccted: Announced inWon limited to a survey of portions of the Nuclear I.ake site for rrsidual contamination and a review of the contractor's procedures for release of debris from the site for unrestricted use. Eight samples of soil and rock were taken and assayed by gamma spectroscopy. The site was surveyed to identify residual radioactive contamination in soil and building materials and for surface radioactive contamination.
Results No violations were identified. The contractor's procedures were adequate.
i 9312090112 931124 REC 1 GA999 EUSDOI 99990001 PDR i
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DETAILS 1.
Persons Contacted
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- William Needrith - Site Project Manager, NES Corporation l
John Aldana - Tecimician, NES Corpontion l
Jim Robson - Site Caretaker, National Park Service Frances Austin - Equipment Operator, Stamford Wrecking Company
- Timothy Johnson - Project Manager, NRC, NMSS, Decommissioning and Regulatory i
Issues Branch (by telephone) l
- denotes those present at the exit interview 2.
B;ickground The Gulf United Nuclear Fuels Corporation facility adjacent to Nuclear Lake in West f
Pawling, New York operated from 1961 to 1972 under contract to the United States Atomic Energy Commission (USAEC). From 1965 to 1972 the facility used
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plutonium and umnium for fuel development under a USAEC license. The facilhj t
also included a gamma laboratory (hot cell facilities) for studying irradiated fuel j
material. Following an explosion in a glove box in the plutonium laboratory building, j
operations at the site were tenninated in 1972. In April 1974, after decontamination i
of the facility by the licensee, the USAEC conducted a closeout sunrey and inspection I
of the site. USAEC then terminated the license on July 14,1974. In 1979 the site was sold to the US Department of the Interior for use by the National Park Service (NPS).
In February 1984 Nuclear Energy Services (NES), a contractor, conducted a l
radiological survey for the NPS. The survey identified an area on the concrete floor in the waste storage building with fixed beta-gamma radiation levels in excess of I'
current NRC guidelines for release of facilities for unrestricted use. The NRC conducted a verification survey of the building on May 22,1984. Most of the contamination was removed on February 25 and 26,1985.
Oak Ridge Associated Universities (ORAU) conducted a site-wide radiological survey for the NPS during September 1986 and issued a report in July 1988. The survey l
i identified limited areas of residual contamination in the plutonium laboratory and the multiple failure building. In addition to the cesium-137 (Cs-137) and plutonium contamination in these buildings, the ORAU survey identified areas of contaminated soil and contamination in the septic tank of the plutonium laboratory and in lake sediments near the discharge point for the waste storage building. The plutonium used at the facility was primarily plutonium 439 (Pu-239): however, smaller fractions of Pu-238, Pu-240, Pu-241, and Pu-242 we.e also present.
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In March 1993 the NPS and Chevron Corporation, the successor to the licensee, agreed to the remediation of the facility including demolition of the buildings. The remediation was to include the removal of all hazardous material (radioactive materials and asbestos) and bulk wastes fmm building demolition (concrete and stmetural materials). During July and August 1993, NES performed the remediation of the contaminated areas identified in the ORAU survey. In a letter dated August 31,1993, NES submitted a final project report to the NRC documenting the remediation activities conducted during the previous months. In September 1993 the Oak Ridge Institute for Science and Education (ORISE), formerly ORAU, conducted a confirmatory survey of the site for the NRC. At the time of this inspection, the ORISE draft report of the confinnatory survey was under review by the NRC.
3.
Instmments Used in Survey Ambient gamma radiation measurements were made with a Ludlum Model 19 micro-R meter (NRC Serial No. 019634) calibrated to read in microroentgens per hour
( R/hr) for Cs-137 radiation. This instmment was last calibrated on October 1,1993.
The background gamma radiation level measured in the vicinity of the site was 8 to 11 pR/hr.
Surface gamma radiation measurements were taken with an Eberline Model SPA-3 sodium iodide (Nal) detector (NRC Serial No. 021936) coupled to an Eberline Model ESP-2 scaler /ratemeter (NRC Serial No. 021940). The NaI detector is a 5 centimeter by centimeter (5 cm by 5 cm) crystal. This instrument was last calibrated on March 4,1993 to Cs-137 radiation. The readout for this instmment is in counts per minute (cpm). The background gamma radiation level measured with this instmment in the vicinity of the site was 7,000 to 8,000 cpm.
Beta-gamma radiation measurements for surface contamination were made with an i
Eberline Model HP-260 GM pancake detector (NRC Serial No. 021942) coupled to the same Eberline Model ESP-2 ratemeter/ scaler. The background beta-gamma l
radiation level for this instmment was 25 to 50 cpm. The minimum detectable activity (MDA) for Cs-137 with this instmment is approximately 3,000 disintegrations per minute per 100 square centimeters.
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Soil samples were counted for 10,000 seconds in 500-milliliter Marinelli beakers on a Princeton Gamma-Tech high purity germanium detector coupled to a Nuclear Data Accu-Spec multichannel analyzer at the Region I offices. The relative efficiency of this detector is '28%. The MDA for Cs-137 is 0.05 picoeuries per gram (pCi/g) for these samples. Plutonium (in this case, the sum of the five plutonium isotopes).
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contamination in the soil samples was evaluated using the photon emissions from americium-241 (Am-241), a decay product of plutonium-241 (Pu-241). Since i
plutonium will typically contain a small fraction of Pu-241, Am-241 can be used to l
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l infer the total amount of plutonium present in the soil. The ratio of plutonium /Am-i 241 varies depending on the source of the material and will change over time.
Typical ratios range from 5 to 14; however, due to the age of this material, the ratio is most likely to be appoximately 7. The MDA for Am-241 in these samples is approximately 0.1 pCi/g; therefore, the inferred MDA for total plutonium is approximately 0.7 pCi/g.
4.
Site Tour l
The water level in the lake adjacent to the site (Nuclear Lake) was approximateiy 2.1 meters (7 feet) lower than normal due to the reconstmetion of the dam earlier in the year. The lower level of the water exposed the lake bottom close to the shore. In the vicinity of the plutonium laboratory and the waste storage building, the water line had receded approximately 10 metere from its pmvious location, exposing the area where the discharge pipe from the waste storage building entered Nuclear Lake.
NES and their contractor, Stamford Wrecking, had received approval to demolish a' number of stmetures on the site. The debris was to be disposed off-site by recycling certain materials or through disposal in a landfill. At the time of the inspection, the critical facility, the lodge, the engineering building and the shield mock-up building had been completely or partially demolished. The debris from these stmetures was still present on-site.
5.
Survey for Surface Contamination The inspectors made surface contamination measurements for a small sampling of select portions of building material, concrete shields, and duct work from the following areas: the waste storage building, the engineering building, the shield mock-up building, the multiple failure building, the sodium tent and the critical facility. No measurements exceeded background levels.
No safety concerns were identified.
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Survey for Gamma Radiation Gamma mdiation levels at ground level were evaluated with the ESP-2 with the 5 cm I
by 5 cm Nal detector by the continuous scanning of the ground or other surfaces.
Locations surveyed included inside all structures and in the areas immediately adjacent to the stmetures, the liquid discharge area in the exposed bottom of Nuclear Lake, and the trails and roads connecting the structures. In addition, a sampling of concrete shields near the multiple failure and shield mock-up structures were also scanned. At locations where ground level gamma radiation levels were greater than two times background, gamma exposure rate measurements were taken with the l
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t micro-R meter at one meter above the surface. One meter exposum rates were also taken at other areas. The locations where the gamma radiation surveys was performed are found in Figure 1 The results of the gamma radiation survey are summarized in Table 1.
Eleuted radiation levels measured near the multiple failure building, the lake f
discharge area and in the dam area were determined to be the result of naturally
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occurring uranium and thorium present in the mck native to the area. The inspectors took a sample of the rock exhibiting elevated radiation levels in the discharge ama for gamma spectmscopy analysis. The analysis identified the presence of uranium and thorium decay products. The inspectors discussed the presence of elevated radiation i
levels in the dam area with NES and NPS personnel. These elevated radiation levels wem previously identified during the reconstmetion of the dam. Analysis determined
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that the radiation levels were a result of naturally occurring mdioisotopes present in the rock.
The slightly elevated gmund level gamma radiation levels identified in the waste disposal building and near the shield mock-up building were at locations where Cs-137 was measured in the soil. The concentration of residual contamination in soil at these locations is discussed in Section 7.
The highest gamma radiation exposure rate measured at one meter in areas where Cs-137 was measured in the soil was 8 R/hr. These measurements are within the range of local backgmund.
i No safety concerns were identified.
j 7.
Soil Sampling During the inspection, the inspectors took seven soil samples and one sample of rock.
l The soil samples were collected from the top 15 centimeters of soil (except samples taken near the Multiple Failure building; see Table 2), placed into plastic bags and l
marked with identifying information. The samples were transferred to 500-milliliter Marinelli beakers at the Region I ofGce for analysis. The rock sample was taken in I
the vicinity of the waste storage building discharge pipe to the lake. The sample of rock was part of an approximately 25 kilogram larger rock that had indicated a count j
rate on the survey meter significantly above background. Transportable samples of l
the rock were taken by breaking the larger rock into smaller pieces with a sledge i
hammer. The locations of the soil and rock samples are indicated on Figure 1.
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The concentration of radionuclides in the samples of soil and rock are found in Table
- 2. The concentration for the uranium series is based on the concentration of bismuth-l 214 (Bi-214). The concentration of the thodum series is based on the concentration of actinium-228 (Ac-2.28). The level of uncertainty is reponed at one standard deviation.
l No safety concerns were identified.
8.
Transfer of Matedal The inspectors observed the loading of concrete debris by Stamford Wrecking during the inspection. According to NES, all debris that is released from the site must first be surveyed to determine that the residual contamination levels meet the_NRC's j
" Guidelines for Decontamination of Facilities and Equipment Prior to Release for i
Unrestricted Use or Termination of Licenses for Byproduct, Source or Special Nuclear Material". Survey results for release of debris from the site were located at NES's offices in Danbury, Connecticut and were not available for review at the time of the inspection. The inspectors noted that NES had appropriate survey equipment available on-site to determine if contamination levels on the debris would meet the Guidelines.
i The inspectors noted that the contractor had two 55-gallon dmms of radioactive waste
-i stored in the plutonium laboratory. NES representatives stated that these drums would be shipped directly to a commercial radioactive waste disposal site in Barnwell, South Camlina after the demolition of the plutonium laboratory.
No safety concerns were identified.
j 9.
Exit Interview j
The results of this survey were discussed with the individuals indicated in Section 1 of j
this repon.
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FIGURE 1: LOCATION OF GAMMA RADIATION SURVEY AND SOIL SAMPLES L
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- Gamma Radiadon Survey
@ Soil Samples
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TABLE 1:
SUMMARY
OF GAMMA RADIATION MEASUREMENTS Surface Gamma Exposure Rate at i
Radiation Level One meter location (cpm)
(uR/hr)
Iedge 7,000 to 8,000 (background) 8 (foundation and debris)
Waste Disposal Building 18,000 (maximum) 8 7,000 to 8,000 (average)
Plutonium Laboratory 10,000 (maximum) 8 7,000 to 8,000 (average)
Engineering building 7,000 to 8,000 (background)
(debris)
Shield Mock-up Building 10,000 (maximum) 8 (debris) 7,000 to 8,000 (avenge) i Multiple Failure Building 160,000 (maximum) 12 7,000 to 8,000 (average)
Sodium Tent 7,000 to 8,000 (background)
Critical Facility 7,000 to 8,000 (background)
(debris)
Concrete Shields 7,000 to 8,000 (backgmund)
Lake Discharge Area 220,000 (maximum) 12 5,000 to 8,000 (average) i Tmils and Roads 10,000 (maximum) 8 7,000 to 8,000 (average)
Dam Area 15,000 (maximum) 8 7,000 to 10,000 (avenge) s e
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TABLE 2: CONCENTRATION OF RADIONUCLIDES IN SOIL AND ROCK r
Sample No.
Iecation Radionuclide Concentration (pCilg) 1 Waste Storage Cs-137 1.14 i 0.03 Building Outfall Bi-214 2.86 i 0.07 Ama (soil next Ac-228 0.60 0.07 i
to rock)
< MDA j
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e Sample No. I Uranium Series Qualitative analysis only -
l occk sample)
Thorium Series concentration not determined j
3 Floor in Waste Cs-137 4.16 + 0.04
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Storage Building Bi-214 0.36 i 0.03 Ac-228 0.78 i 0.06 Am-241
< MDA l
4 Engineering Cs-137
< MDA Building Bi-214 0.43 0.07 I
Ac-228 0.82 i 0.06 Am-241
< MDA i
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Shield Mock-Up Cs-137 10.79 + 0.07 i
Building Bi-214 0.35 0.03 l
Ac-228 0.5610.05 Am-241
< MDA i
6 Multiple Failum Cs-137 0.104 1 0.011 Building (0-10 cm) Bi-214 0.35 i 0.03 j
Ac-228 0.6610.06 Am-241
< MDA t
7 Multiple Failure Cs-137
< MDA i
Building (10-15 cm) Bi-214 0.41 i 0.03 i
Ac-228 0.78 i 0.06
.l Am-241
< MDA l
8 Critical Facility Cs-137
<MDA (south end of Bi-214 0.3410.02 shield wall)
Ac-228 0.57 i 0.04 Am-241
<MDA j
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