IR 05000309/1998002
| ML20237E547 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 08/26/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20237E486 | List: |
| References | |
| 50-309-98-02, 50-309-98-2, NUDOCS 9809010034 | |
| Download: ML20237E547 (8) | |
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U. S. NUCLEAR REGULATORY COMMISSION
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REGION I
Docket No:
50-309 License No:
DPR-36 Report No:
50-309/98-02 Licensee:
Maine Yankee Atomic Power Company (MYAPC)
Facility:
Maine Yankee Atomic Power Station Location:
Bailey Point Wiscasset, Maine Dates:
' March 17,1998 to May 6,1998
!nspectors:
Richard Rasmussen, Senior Resident inspector, DNMS Mark Roberts, Senior Health Physicist, DNMS James Kottan, Senior Health Physicist, DNMS Approved by:
. Mark C. Roberts, Chief Decommissioning and Laboratory Branch Division of Nuclear Materials Safety
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9809010034 980826
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PDR ADOCK 05000309 G
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EXECUTIVE SUMMARY t
i Maine Yankee Atomic Power Company l
NRC Inspection Report 50-309/98-02
This inspection report presents % results of radiological sample analyses performed on water samples obtained from and in t's vicinity of the Wiscasset, Maine landfill. Samples were collected by the State of Mainr at five locations. The samples were split between the licensee (Maine Yankee), the Sate of Maine, and NRC Region 1. The samples were analyzed for gross alpha and gross beta activitias, tritium concentration, and concentrations of gamma-emitting radionuclides (gamma spectrometry). The gamma spesumstry results did not indicate detectable concentrations of any radionuclides that were derived from operations at the Maine Yankee plant. Naturally occurring radionuclides were identifed in some of the samples. The tritium, gross alpha, and gross beta measurements, which are primarily screening measurements, were all below the EPA drinking water requirements with one exception. The one sample with an elevated gross alpha concentration result was also high in naturally occurring radionuclides from the uranium decay chain. The State of Maine has regulatory authority for naturally occurring radionuclides and is aware of this sample result. Although not documented in this report, the NRC found that Maine Yankee and State of Maine analytical '
results were consistent with the NRC analytical results, in particular for potential plant derived radionuclides. These analysis were separately reported by the State of Maine and Maine Yankee at a meeting of the Maine Yankee Community Advisory Panel (CAP).
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REPORT DETAILS 1. Collection of Water Samples a.
Inspection Scope l
As a result of information indicating that radioactive materials from the Maine Yankee plant may have been disposed at the Wiscasset Landfill, the NRC, along with the State of Maine and Maine Yankee collected water samples from within and in the vicinity of the now closed landfill. The samples were analyzed in the NRC Region I Laboratory for various radiological parameters.
b.
Observations and Findinas Water samples from three on-site wells, an on-site leachate collection area, and an off-site well were collected by representatives from the State of Maine, Department of Environmental Protection (DEP). The DEP retained an aliquot of the water samples and also provided aliquots of the samples to Maine Yankee (MY).and the NRC. The DEP, MY, and the NRC each performed gamma spectrometry, tritium, gross beta, and gross alpha analyses on each of the five samples. The NRC results are reported in the accompanying tabes to this report (Tables 1 through 4). All results are reported in units of picoCuries/literi a one standard deviation uncertainty (1 o). Radionuclides concentrations that are not statistically present above the detection limit for the analysis are reported as being less than the minimum detectable concentration (MDC). The MDC is a numerical value, based on analysis parameters (such as sample size, counting time, etc.), that represents the statistical lower limit of detection for the analytical method.
1.
Gamma Spectrometry Results
An untreated aliquot of each sample was poured into a standard counting geometry (Marinelli beaker) for routine gamma spectrometry analysis. This analysis provides the most comprehensive data because the technique is capable of identifying a wide variety of gamma-emitting radionuclides and quantifying the concentration of each radionuclides in the sample. Although naturally-occurring and plant-derived radionuclides can be identified and quantified by this technique, of primary interest in these particular samples are plant-derived radionuclides. In Table 1, the concentrations of two plant-derived radionuclides, cobalt 60 (Co-60) and cesium 137 (Cs-137), are reported for these samples. All results were less than the detection limit for the analysis. Although the gamma spectrometry analysis is capable of identifying a variety of gamma-emitting radionuclides, only Co-60 and Cs-137 are reported because they represent two of the more common plant-derived radionuclides with half-lives sufficiently long that they could still be detected if they had been present in the landfill. The analysis also did not identify any other plant-derived radionuclides.
Naturally occurring radionuclides were identified in each of the samples; however, the results are not reported for these samples. The DEP has regulatory authority for naturally occurring radioactive material.
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2.
Tritium Results An untreated aliquot of each sample was distilled to remove chemical and radiological interferences. An aliquot of the sample was analyzed for the concentration of tritium (radioactive hydrogen) by a standard liquid scintillation counting technique. The results of the analyses are reported in Table 2. Tritium is naturally occurring, but also is produced by operating nuclear power plants.
The results in Table 2 are within the range of measurements in unaffected samples. The EPA drinking water limit for tritium is 20,000 picoCuries/ liter (pCl/l).
3.
Gross Alpha and Gross Beta Results Gross alpha and gross beta analyses are typically used as screening analyses to determine if additional measurements on a sample are warranted. The analyses are not specific to uniquely identify plant-derived radionuclides. Samples may be filtered prior to analysis in order to evaluate only the radionuclides dissolved in the sample and eliminate suspended material in the sample. Sample aliquot sizes may be increased to improve the detection limit of the analysis. Samples are prepared by evaporating an aliquot of the sample to dryness on a standard counting planchet. The prepared sample is then counted for gross alpha and gross beta activity in a gas flow proportional counter. A correction factor must be applied to the analytical result to account for the residual dry material on the planchet. The correction factor accounts for any alpha or beta particles that are not detected because of interactions with the residual sample.
Initially, a 10 milliliter (mt), unfiltered sample aliquot was used for the analyses.
The samples were re-analyzed with a 100 mi sample aliquot to provide additional sensitivity. Due to a relatively large amount of residual material on the counting planchet, three of the samples were further re-analyzed using a filtered sample to reduce the large correction factor associated with the residual dried material on the planchet.
The results for all the analyses performed on these samples appear in Tables 3 and 4. The results using the larger sample size are considered to better represent the measured activity in the sample. None of the results for the larger sample sizes exceed the EPA criteria for treated drinking water. These criteria are 15 pCi/t and 50 pCl/t for gross alpha and gross beta, respectively. The initial gross beta analysis using the smaller sample may be elevated due to a non-representative sample. The two analyses with the larger sample size were both less than the EPA criterion.
c.
Conclusions Water samples from and in the vicinity of the Wiscasset landfill were analyzed for a variety of radiological parameters. The gamma spectrometry results for these samples, which can specifically identify gamma-emitting radioactive isotopes, did not measure any Cs-137 or Co-60 above the detection level of the analysis. These two radionuclides are
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two of the more common radionuclides derived from plant operations. Tritium, gross alpha, and gross beta screening analysis were not remarkable in identifying elevated i
cored,.uons to consider additional analyses.
II. ManagementMeetings On April 7,1998, NRC staff made a presentabon to residents living near the closed l
Wiscasset landfill. The preseritation was limited to a discussion of the results obtained l
from the analysis of the water samples from the vicinity of the landfill. Repr=d.t;=
from MY and the DEP also made similar data presentations. The date presented by the NRC, MY, and the DEP were in general agreement.
Also on April 7,1998, NRC staff made a similar presentation to the April moeiing of the Maine Yankee Community Advisory Panel (CAP). This meeting was open for public L
observation and participation.
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lli. Exit Meeting Summary l
The inspectors presented the inspection results to represen$tives of the licensee on f-May 6,1998. The licensee acknowledged the findings presented.
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TABLE 1 Gamma Spectrometry Analysis Co-60 Concentration Cs-137 Concentration l
Sample Location (pCi/ti10)
(pCl/t i10)
MW 202
< 5.4
< 5.1 MW 102 '
< 5.7
<5.1 Leachate
<4.6
< 5.0 j
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MW 101
< 5.7
< 5.6 i
Residence
< 5.5
< 5.3
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TABLE 2 TriHum Analysis H-3 Concentration
- Sample Location (pCi/t * io)
MW 202 240*80
MW 102 -
340 * 80 i
Leachate 230*80 MW 101 200 * 80 i
Residence 220*80
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- TABLE 3 Gross Alpha Analysis Gross Alpha Concentrations (pCi/t i 10)
Sample Location 10 mt unfiltered 100 me unfiltered 100 me filtered MW 202 -
'3*6 0.2 * 1.1 1.3 * 1.0 MW 102 9*7 12 * 4 6*4 Leachate 8*7 3*3 1*3
MW 101 6*6 1.2 i 0.7 Residence '
22 7 4.9 * 0.9
- No filtered sample was analyzed. See text for discussion.
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TABLE 4 Gross Beta Analysis
Gross Beta Concentrations (pCi/t i io)
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Sample Location 10 me unfiltered 100 mt unfiltered 100 mifiltered MW 202 7 *10 5.7*1.1 9.9 * 1.1 MW 102 39*10 30.2 * 1.2 28.6 * 1.2 Leachate 53 * 10 37.6 i 1.3 32.3 i 1.2 MW 101 15 i 10 3.7 * 1.0
Residence 38*10 3.4 * 1.0
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- No filtered sample was analyzed. See text for discussion.
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PARTIAL LIST OF PERSONS CONTACTED Licensee M. Meisner, President j
W. Odell, Directorof Operations
M. Ferri, Director of Decommissioning l
S. Dahlgren, Manager of Site Charactenzation
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'J. Sauger, Manager of Decommissioning l
J. Mallon, Manager of H.PJTechnical Services
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P. Dostie, Maine, Nuclear Safety inspector l
LIST OF ACRONYMS USED
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CAP Citizen's Advisory Panel DEP Department of Environmental Protection
MDC Minimum Detectable Concentration MY Maine Yankee -
pCl/f picoCuries perliter -
mi milliliters o
sigma (standard deviation)
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