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State of Wisconsin - 2008

Point Beach - Kewaunee

Environmental Radioactivity Survey

Wisconsin Department of Health Services
Division of Public Health
Bureau of Environmental and Occupational Health
Radiation Protection Section
P.O. Box 2659
Madison, Wisconsin 53701-2659

Table of Contents

Introduction
WI DHS LACBWR Environmental Monitoring Program
Program Modifications
Laboratory Services and Quality Assurance
Detection Limits
Reporting of Sample Analysis Results
Results and Discussion
List of Tables
References

Introduction

Wisconsin Public Health Statues 254.41 mandates the Department of Health Services to conduct environmental radiation monitoring around the nuclear power facilities that impact Wisconsin. This environmental monitoring report is for the Point Beach and Kewaunee nuclear generating plants for the calendar year January - December, 2008 and provides a description and results of this environmental monitoring program.

WI DHS Point Beach - Kewaunee Environmental Monitoring Sampling Program

The WI DHS environmental monitoring program consists of the collection of various types of samples from the air, water and terrestrial exposure pathways.  The sampling program included samples of air, precipitation, ambient gamma radiation (TLD), surface water, fish, shoreline sediment, soil, milk, well water and vegetation that are collected from selected locations at planned sampling intervals.

Table 1 provides a listing of types of samples collected, collection frequency, sites where samples are collected, the number of samples collected, number of samples that were missed or had sample or analysis deviations and a listing of the required analyses.  Table 2 is a listing of sampling sites and includes a description, direction and distance from the monitored power plants.  Table 3 provides an explanation of missing samples or non-routine sample analyses.  Figure 1 is a map showing the location of environmental sampling sites in relation to the Kewaunee plant and Figure 2 is a map showing the location of environmental sampling sites in relation to the Point Beach plant.

Program Modifications

There were no program modifications for 2008.

Laboratory Services and Quality Assurance

The analysis of the samples is performed under contract with the State Laboratory of Hygiene (SLH).  SLH maintains a quality assurance program.  Analytical procedures provide for routine replicate analyses to verify methods and instrument operation.  Traceable sources are used to regularly calibrate the counters and daily performance checks are made between calibrations.  In addition, quality control charts are maintained on the counters.

SLH participates in the Environmental Resource Associates’ Proficiency Testing program and has performed satisfactorily over the report period.   Proficiency testing results are available from the State Laboratory of Hygiene.

Detection Limits

Detection limits, required by WI DHS, will be expressed as a lower limit of detection (LLD).  The required WI DHS LLD as indicated in Table 4 under the heading “LLD” is an "a priori" estimate of the capability for detecting an activity concentration by a given measurement system, procedure, and type of sample.   Counting statistics of the appropriate instrument background are used to compute the LLD for each specific analysis.  Using 4.66 times the standard deviation (s_b) of the instrument background, the LLD for each specific analysis is defined at the 95% Confidence Level.

The LLD for each radioisotope listed in Table 4 has been calculated from the following equation: 

Where:

Results for specific analyses will be reported as either a “less than” (<) value or an actual activity value. The reporting of results in Table 4 under the heading “Range” and in Tables 5-15 are “a posteriori” calculations based on the actual analysis performed using the actual sample values for E, V, Y and dt. Typically the reported “less than” (<) results are lower than the required WI DHS LLD indicating that the required WI DHS LLD has been met.

An actual activity value will be accompanied by an uncertainty term for that analysis.  The uncertainty term is a plus or minus counting uncertainty term at the 2 sigma (95%) confidence interval and is printed as (+- or ±).  Examples and explanations of data reporting are:

Example

Activity reported

1

¹³⁷Cs

< 10 pCi/liter

2

¹³⁷Cs

Results And Discussion

Air Particulate

A summary of reported activities by WI DHS for air particulate samples is included in Table 4.  Results from the individual sample analyses are listed in Tables 5-6.

From the gross beta activities listed in Table 5, it may be noted that there are no significant differences due to distance from either the Kewaunee or the Point Beach facility.  With no significant differences due to distance, an increase in gross beta activity attributable to the Kewaunee or the Point Beach facilities is not evident.

The gamma isotopic analysis of the quarterly air particulate filter composites detected only small amounts of the radioisotopes listed in Table 4.  All other radioisotopes were below their respective LLD.  Beryllium-7 (⁷Be), detected in all composites, is a naturally occurring radioisotope that is constantly produced through nuclear reactions between cosmic rays and nuclei in the atmosphere and is detected in air composites from other areas of the state.

Influence by the Kewaunee or the Point Beach nuclear facility on air quality is not evident from air particulate analysis.

Air Iodine

A summary of reported activities by WI DHS for air iodine samples is included in Table 4.  Results from the individual sample analyses are listed in Table 5.

Air iodine measurements were all below the LLD of 0.07 pCi/m³. 

Ambient Gamma Radiation (TLD)

A summary of reported activities by WI DHS for direct radiation is included in Table 4.  Results from the individual sample analyses are listed in Table 7. 

Significant differences in exposure were not noticed at different distances from either the Kewaunee or the Point Beach nuclear facilities for sites PBK-T9 through PBK-T31.  Excluding the sites around the perimeter of the Point Beach ISFSI (T1 – T8), the average quarterly exposure from the remaining 23 sites was 14.1 ± 1.6 milliroentgens.  The average quarterly exposure for 2008 is at background levels and is comparable to other areas within Wisconsin.

Precipitation

A summary of reported activities by WI DHS for precipitation samples is included in Table 4.  Results from the individual sample analyses are listed in Table 8. 

The gross beta activity in precipitation was within the normal range of activity when compared to previous year’s data.

Fish

A summary of reported activities by WI DHS for fish samples is included in Table 4.  Results from the individual sample analyses are listed in Table 9.

Shoreline Sediment

A summary of reported activities by WI DHS for shoreline sediment samples is included in Table 4.  Results from the individual sample analyses are listed in Table 10.

Analysis of the shoreline samples showed no unusual activities.  Naturally occurring potassium-40 (⁴⁰K) was detected in all samples.  The reported activities for cesium-137 (¹³⁷Cs) were also detected in previous years and are probably attributable to residual fallout from previous atmospheric nuclear weapons testing.  Naturally occurring radioisotopes such as radium-226 (²²⁶Ra), bismuth-214 (²¹⁴Bi), lead-214 (²¹⁴Pb), actinium-228 (²²⁸Ac), bismuth-212 (²¹²Bi), lead-212 (²¹²Pb) from the naturally occurring uranium-238 (²³⁸U) and thorium-232 (²³²Th) decay series are commonly detected but have not been quantified or reported.

Surface Water

A summary of reported activities by WI DHS for surface water samples is included in Table 4.  Results from the individual sample analyses are listed in Table 11. 

From the gamma isotopic analysis all radioisotopes were below their respective LLD.  All reported activities for gross beta; gross alpha and tritium (³H) are at background levels and are comparable to data from previous years.  One quarterly composite for tritium (³H) from site PBK-12a, Kewaunee discharge channel, had a reported activity of 3250 ± 160 probably due to the release of an effluent tank at the time of collection. The surface water samples uniformly show activities well below state or federal standards.

Well Water

A summary of reported activities by WI DHS for well water samples is included in Table 4.  Results from the individual sample analyses are listed in Table 12.

The well water samples showed no unusual gross alpha and gross beta activities and all activities for tritium (³H) were less than its LLD.  The measured activities are all below state and federal standards.

Milk

A summary of reported activities by WI DHS for milk samples is included in Table 4.   Results from the individual sample analyses are listed in Table 13.

The analysis of milk samples detected no unusual activities.  Naturally occurring potassium-40 (⁴⁰K) was detected in all samples.  The detected activities for strontium-90 (⁹⁰Sr), attributable to residual fallout from previous atmospheric nuclear weapons testing, were also detected in previous years at similar activity levels.

Influence by the Kewaunee or Point Beach facilities is not evident in milk samples.

Vegetation

A summary of reported activities by WI DHS for vegetation samples is included in Table 4.  Results from the individual sample analyses are listed in Table 14.

Analysis of the vegetation samples showed no unusual activities.  The gamma isotopic analysis detected only small amounts of naturally occurring potassium-40 (⁴⁰K) and beryllium-7 (⁷Be) listed in Table 4. 

Influence by the Kewaunee or Point Beach facilities in vegetation samples is not evident.

Soil

A summary of reported activities by WI DHS for soil samples is included in Table 4.  Results from the individual sample analyses are listed in Table 15.

Analysis of the soil samples showed no unusual activities.  Naturally occurring potassium-40 (⁴⁰K) was detected in all samples.  The reported activities for cesium-137 (¹³⁷Cs) were also detected in previous years and are probably attributable to residual fallout from previous atmospheric nuclear weapons testing.  Naturally occurring radioisotopes such as radium-226 (²²⁶Ra), bismuth-214 (²¹⁴Bi), lead-214 (²¹⁴Pb), actinium-228 (²²⁸Ac), bismuth-212 (²¹²Bi), lead-212 (²¹²Pb) from the naturally occurring uranium-238 (²³⁸U) and thorium-232 (²³²Th) decay series are commonly detected but have not been quantified or reported.  

Point Beach ISFSI

A summary of reported activities by WI DHS for ambient gamma radiation monitored in the vicinity of the Point Beach Independent Spent Fuel Storage Installation (ISFSI) is included in Table 7.

Ambient gamma exposure levels greater than background, as measured by thermoluminecent dosimeters (TLDs), are apparent at all sites (T1 – T8) that are on the Point Beach ISFSI perimeter fence closest to the ventilated storage casks.  An increase in ambient gamma exposure levels at sites T9 - T14 (0.8 – 1.9 miles from the Point Beach ISFSI) or at sites T15 – T31 (greater than 2 miles from the Point Beach ISFSI was not evident and the ambient gamma exposure levels are consistent with previous years data.  The average standard quarterly ambient gamma exposure for 2008 for sites.

T9 – T31 was 14.1 ± 1.6 milliroentgens and for sites T1 – T8 varied from 19.5 – 71.9 milliroentgens per standard quarter depending on the distance from the storage casks.

Dose to an Average Individual

Federal regulations 10 CFR 20, 10 CFR 50 Appendix I and 40 CFR 190 restrict the annual exposure of the population from all parts of the nuclear fuel cycle, including nuclear power plants. Doses resulting from gaseous and liquid effluent releases from the Point Beach or Kewaunee nuclear generating facilities are less than the limits as stated in these Federal regulations.

The WI DHS limits for permissible levels of radiation exposure from external sources in unrestricted areas is defined in the Wis. Adm. Code section DHS 157.23.  Doses resulting from gaseous and liquid effluent releases from the Point Beach or Kewaunee nuclear generating facilities are less than the limits as stated in Wis. Adm. Code section DHS 157.23.

References

State of Wisconsin, Wisconsin Administrative Code, DHS 157.23

State of Wisconsin, “FINAL ENVIRONMENTAL IMPACT STATEMENT, Point Beach Nuclear Power Plant Plant Projects Proposed by Wisconsin Electric Power Company, Temporary Storage of Spent Nuclear Fuel in Dry Casks, PSC Docket 6630-CE-197, Unit 2 Steam Generator Replacement, PSC Docket 6630-CE-209, AUGUST 1994”.

U.S. Environmental Protection Agency, Environmental Radiation Requirements for Normal Operations of Activities in the Uranium Fuel Cycle, EPA 520/4-76-016, 40 CFR Part 190, November 1976.

U.S. Nuclear Regulatory Commission, Title 10, Part 20.

U.S. Nuclear Regulatory Commission, Title 10, Part 50, Appendix I.