ML15132A084
| ML15132A084 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 04/28/2015 |
| From: | Radiation Safety & Control Services |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML15132A076 | List: |
| References | |
| BYR 2015-018 | |
| Download: ML15132A084 (27) | |
Text
YANKEE NUCLEAR POWER STATION INDEPENDENT SPENT FUEL STORAGE INSTALLATION License Nos. DPR-3 and SFGL-13 ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT January - December 2014 RSCS R~awrt~. Safety &CmW SormJ April 2015 Prepared by:
Radiation Safety & Control Services 91 Portsmouth Avenue Stratham, NH 03885-2468
EXECUTIVE
SUMMARY
Yankee Nuclear Power Station was permanently shutdown in 1991. All fuel has been transferred into dry storage casks and placed at the Independent Spent Fuel Storage Installation. The Radiological Environmental Monitoring Program (REMP) for the Yankee Nuclear Power Station (YNPS) Independent Spent Fuel Storage Installation (ISFSI) located in Rowe, MA was continued for the period January through December 2014 in compliance with the YNPS Offsite Dose Calculation Manual (ODCM).
By design, there are no liquid or gaseous effluents associated with the operation of the ISFSI. Therefore, the ODCM only requires monitoring of direct exposure from the facility. TLDs were used to measure direct gamma exposure at six locations in the vicinity of the ISFSI and one control location 7.6 kilometers away. The results of these measurements showed no significant change in exposure rates and potential doses to members of the public during the monitoring period. The results of the monitoring performed in 2014 also show that operating the YNPS ISFSI results in only a small fraction of the 40 CFR Part 190 and 10 CFR Part 72.104 direct radiation dose limit of 25 mrem/year to members of the public.
YNPS 2014 Annual REO Report Page 2 of 27
TABLE OF CONTENTS Section Title Page
1.0 INTRODUCTION
........................................................................................ 6 2.0 GENERAL ISFSI AND SITE INFORMATION ............................................ 7 3.0 PROGRAM DESIGN .................................................................................. 7 3.1 MONITORING ZONES .......................................................................................... 8 3.2 PATHWAYS MONITORED .................................................................................... 8
3.3 DESCRIPTION
OF MONITORING PROGRAM ........................................................ 8 4.0 RADIOLOGICAL DATA
SUMMARY
TABLES ......................................... 15 5.0 ANALYSIS OF ENVIRONMENTAL RESULTS ........................................ 26 5.1 SAMPLING PROGRAM DEVIATIONS ................................................................... 26 5.2 DIRECT RADIATION PATHWAY ........................................................................ 26
6.0 REFERENCES
........................................................................................ 27 YNPS 2014 Annual REO Report Page 3 of 27
LIST OF TABLES Table Title Pace 3.1 Radiological Environmental Monitoring Program ................................ 9 3.2 Radiological Environmental Monitoring Locations ............................ 10 4.1 TLD Measurements by Half-Year ......................................................... 16 4.2 TLD Data Sum m ary ................................................................................ 17 4.3 Direct Dose from ISFSI Operations ...................................................... 18 YNPS 2014 Annual REO Report Page 4 of 27
LIST OF FIGURES Figure Title Paqe 3.1 All Radiation Monitoring Locations ....................................................... 11 3.2 Onsite Direct Radiation Monitoring Locations .................................... 12 3.3 Direct Radiation Monitoring Locations (Within I mile) ...................... 13 3.4 Offsite Control Location ...................................................................... 14 4.1 Annual Dose Trend at GM-02 ............................................................... 20 4.2 Annual Dose Trend at GM-06 ............................................................... 21 4.3 Annual Dose Trend at GM-15 ................................................................ 22 4.4 Annual Dose Trend at GM-16 ................................................................ 23 4.5 Annual Dose Trend at GM-17 ............................................................... 24 4.6 Annual Dose Trend at GM-21 ............................................................... 25 YNPS 2014 Annual REO Report Page 5 of 27
1.0 INTRODUCTION
This report summarizes the findings of the Radiological Environmental Monitoring Program (REMP) conducted by Yankee in the vicinity of the Independent Spent Fuel Storage Installation in Rowe, Massachusetts during the calendar year. It is submitted annually in compliance with the Offsite Dose Calculation Manual (ODCM). The remainder of this report is organized as follows:
Section 2: Provides a brief description of the Yankee site and its environs.
Section 3: Provides a description of the overall REMP design. Included is a summary of the ODCM requirements for REMP sampling, tables listing TLD monitoring locations with compass sectors and distances from the ISFSI, and maps showing the location of each of the TLD monitoring locations.
Section 4: Provides a complete set of TLD data showing measured results (mR) and calculated doses (mrem per year). This section also provides the summarized TLD data in the format specified by the NRC Branch Technical Position on Environmental Monitoring (Reference 1).
Section 5: Provides the results of the calendar year monitoring program. The performance of the program in meeting ODCM requirements is discussed, and the data acquired during the year is analyzed.
Section 6: References YNPS 2014 Annual REO Report Page 6 of 27
2.0 GENERAL ISFSI AND SITE INFORMATION The Yankee Nuclear Power Station site is located on over 1800 acres in a predominantly rural area of northwestern Massachusetts, three-quarters of a mile south of the Vermont border. The site resides in the town of Rowe, Massachusetts, approximately 9 air miles east-northeast of North Adams, Massachusetts. The surrounding area is heavily forested and lightly populated.
Hills bounding the river valley rise 500 to 1000 feet above the site, reaching elevations of 2100 feet.
The Deerfield River is used extensively for hydroelectric power generation both upstream and downstream of YNPS. The Sherman Dam, immediately adjacent to the site, operates as a hydroelectric generating station. Sherman Pond, the impoundment behind this dam, had been used as a source of cooling water for the former power plant.
The former nuclear power plant was voluntarily shut down on October 1, 1991 after 31 years of operation. The site was involved in the process of decommissioning over the years which involved the disassembly and removal of the plant components and structures and was completed in 2006. This process took place in strict conformance with USNRC regulations. Oversight of the site closure process also took place from the U.S. Environmental Protection Agency, the Massachusetts Department of Environmental Protection, and Massachusetts Department of Public Health.
3.0 PROGRAM DESIGN The Radiological Environmental Monitoring Program (REMP) for the Yankee Nuclear Power Station ISFSI was designed to provide assurance to regulatory agencies and the public that the station's environmental impact is known and within anticipated limits. The direct dose limit for members of the public from operation of the ISFSI is 25 mrem per year (References 3 and 4).
The detailed sampling requirements of the REMP are given in the ODCM. The sampling requirements specified in the ODCM are summarized in Table 3.1 of this report. Details of the monitored locations are shown in Table 3.2, as well as Figures 3.1 through 3.4 of this report.
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3.1 Monitoring Zones The REMP is designed to allow comparison of levels of radioactivity in samples from the area possibly influenced by the ISFSI to levels found in areas not influenced by the ISFSI. The first area is called "indicator stations". The second area is called "control stations". The distinction between the two is based on relative direction from the facility and distance. Analysis of survey data from the two zones aids in determining if there is a significant difference between the two areas. It can also help in differentiating between radioactivity or radiation due to releases and that due to other fluctuations in the environment, such as seasonal variations in the natural background.
3.2 Pathways Monitored Based on the design of the ISFSI, only the direct radiation exposure pathway is monitored by the REMP. This pathway is monitored by the collection of thermoluminescent dosimeters (TLDs) which are described in more detail below.
3.3 Description of Monitoring Program 3.3.1 Direct Radiation Direct gamma radiation exposure was continuously monitored during 2014 with the use of thermoluminescent dosimeters (TLDs). At each monitoring location, these TLDs are sealed in plastic bags and attached to an object such as a tree, fence or utility pole. The TLDs are posted and retrieved on a semi-annual basis.
All TLDs are provided and processed by a National Voluntary Laboratory Accreditation Program (NVLAP) certified vendor. The TLDs are placed at various locations around the Independent Spent Fuel Storage Installation (ISFSI). Table 3.2 lists the Station ID Codes, distances and direction of the TLDs from the ISFSI.
3.3.2 Special Monitoring Special samples can be taken that are not required in the ODCM. The sample locations do not appear in Table 3.1 or 3.2 of this report. For this monitoring period, no special samples were collected as part of the YNPS ISFSI Radiological Environmental Monitoring Program.
YNPS 2014 Annual REO Report Page 8 of 27
Table 3.1 Radiological Environmental Monitoring Program Exposure Collection Analysis Pathway and/or Number of Routine Collection Analysis Analysis Sample Sample Sampling Frequency Type Frequency Media Locations Mode Direct Total Locations: 7 Continuous Semi- Gamma Semi-Radiation (6 around annual dose annual (TLD) perimeter of the site and 1 offsite control location)
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Table 3.2 Radiological Environmental Monitoring Locations Distance Direction Station Code Station Description Zone* From ISFSI FromeSFSi (km)
GM-15 Onsite Perimeter (I)** 1 0.24 NW GM-16 Onsite Perimeter (I)** 1 0.22 NNW GM-17 Onsite Perimeter (I)** 1 0.13 NNE GM-21 Onsite Perimeter (I)** 1 0.17 WSW GM-02 Observation Stand (O)** 1 0.50 NW GM-06 Tunnel Road Readsboro 1 1.30 N Town Line (O)**
GM-27 Number Nine Road (O)* 2 7.60 ENE
Figure 3.1 All Radiation Monitoring Locations I~
F ~ ~ - -
______s~I~1~
YNPS 2014 Annual REO Report Page 11 of 27
Figure 3.2 Onsite Direct Radiation Monitoring Locations MWFS 3NC M~ SWG&hZam COLkwwsdAa'ea C OvmnurCoi~edAau Prepared1Dae: BRP 0512813 Checked~ate: MGV 08128113 ai I TILD Locatlous I
YNPS 2014 Annual REO Report Page 12 of 27
Figure 3.3 Direct Radiation Monitoring Locations (Within 1 mile)
YNPS 2014 Annual REO Report Page 13 of 27
Figure 3.4 Offsite Control Location YNPS 2014 Annual REO Report Page 14 of 27
4.0 RADIOLOGICAL DATA
SUMMARY
TABLES This section summarizes the analytical results of the environmental samples, which were collected during the monitoring period.
Data from direct radiation measurements made by TLDs are presented in Table 4.1.
The summarized TLD measurements, shown in Table 4.2, are presented in a format similar to that prescribed in the NRC's Radiological Assessment Branch Technical Position on Environmental Monitoring (Reference 1).
Table 4.3 presents the estimated direct dose from ISFSI operations as determined by TLD data shown in Table 4.1.
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Table 4.1 TLD Measurements by Half-Year (mR)
Station ID Location Ist Half-Year 2nd Half-Year GM-02 Observation Stand 48 37 GM-06 Tunnel Road Readsboro 49 42 Town Line GM-15 On-site perimeter 58 51 GM-16 On-site perimeter 51 46 GM-1 7 On-site perimeter 45 43 GM-21 On-site perimeter 45 43 GM-27 Control 36 38 GM-27a Control Backup 45 37 Note: the TLD at location GM-16 was not present for retrieval at the end of the year. The value listed is the average of the year 2013 measurements.
YNPS 2014 Annual REO Report Page 16 of 27
Table 4.2 TLD Data Summary (mR)
Indicator TLDs Control TLDs Station With Highest Mean Mean Mean Station # Mean (Range) (Range) (Range)
(No. Measurements)* (No. Measurements)* (No. Measurements)*
46 39 GM-15 55 (37- 58) (36 -45) (51 - 58)
(11) (4) (2)
Note: the TLD at location GM-1 6 was not present for retrieval at the end of the year. The values listed in the Indicator TLDs column include the 2013 average GM-1 6 value substituted for the missing measurement.
- Each "measurement" is based on semi-annual readings YNPS 2014 Annual REO Report Page 17 of 27
Table 4.3 Direct Dose from ISFSI Operations (mrem) 1 st Half-Year 2 nd Half-Year Net TLD Calculated Net TLD Calculated Annual Station ID Result Dose Result Dose Dose GM-02 7.50 0.43 0.00 0.00 0.43 GM-06 8.50 0.48 4.50 0.26 0.74 GM-15 17.50 1.00 13.50 0.77 1.77 GM-16 10.50 0.60 8.00* 0.46 1.06 GM-17 4.50 0.26 5.50 0.31 0.57 GM-21 4.50 0.26 5.50 0.31 0.57 Max Dose => 1.77 Note: the TLD at location GM-1 6 was not present for retrieval at the end of the year. The value shown in the Net TLD result column in the 2 nd Half-Year was based upon the average of the year 2013 measurements.
Note: Doses based on a 250 hour0.00289 days <br />0.0694 hours <br />4.133598e-4 weeks <br />9.5125e-5 months <br /> occupancy in both of the first and second half-years.
YNPS 2014 Annual REO Report Page 18 of 27
Radiological Environmental Monitoring Program Trending A series of graphs of REMP TLD data have been developed and are provided for trending purposes. The trending is developed for each of the indicator locations based on the annual historical doses. The trending is provided for the "real members of the public" based on the guidance provided in the ODCM. The analysis of the trends and associated data shows very small annual doses with minor fluctuations in the data. The analysis and trending of the REMP TLD data in this report has changed from the previous years. Previously, the net TLD results were converted to exposure rates, summarized and then plotted for trending purposes. Starting with this report, only the uncorrected TLD results will be summarized and the annual doses, calculated for "real members of the public" based upon guidance in the ODCM, will be plotted for trending.
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Figure 4.1 Annual Dose Trend at GM-02 GM-02 30.00 25.00 20.00 E 15.00 GM-02 E 10.00 5.00 0.44 0.63 0.17 0.00 0.43 0.11 0.37 0.43 0.00 2007 2008 2009 2010 2011 2012 2013 2014 Year Annual Doses (mrem/yr)
Location 1 2007 2008 2009 2010 1 2011 2012 1 2013 2014 I GM-02 1 0.44 0.63 0.17 1 0.00 1 0.43 1 0.11 1 0.37 1 0.43 YNPS 2014 Annual REO Report Page 20 of 27
Figure 4.2 Annual Dose Trend at GM-06 GM-06 30.00 25.00 m
, 20.00 15.00 -- *GM-06 10.00 -U i 5.00 0.63 0.29 0.71 0.88 .97 0.74 0.00 6 -dt- - --
2007 2008 2009 2010 2011 2012 2013 2014 Year Annual Doses (mrem/yr)
Location 2007 2008 2009 2010 2011 2012 2013 2014 GM-06 0.92 0.63 0.29 0.71 0.88 0.97 0.54 0.74 YNPS 2014 Annual REO Report Page 21 of 27
Figure 4.3 Annual Dose Trend at GM-15 GM-15 30.001 25.00 IF*
20.00 i 15.00
-- *-'GM-15 10.00
-- W-limit 5.00 1 1.88 1.4 1.34 1.14 1.51 1.77 0.00 2007 2008 2009 2010 2011 2012 2013 2014 Year Annual Doses (mrem/yr)
Location 2007 2008 2009 2010 2011 2012 2013 2014 GM-15 1.79 1.31 1.88 1.34 1.74 1.14 1.51 1.77 YNPS 2014 Annual REO Report Page 22 of 27
Figure 4.4 Annual Dose Trend at GM-16 GM-16 30.00 25.00 20.00 E 15.00 El GM-16 E 10.00 U--limit 5.00 -. 41t 0.29 0.71 U.66 L.UO 0.00 _I 2007 2008 2009 2010 2011 2012 2013 2014 Year Annual Doses (mrem/yr)
I Location 1 2007 1 2008 2009 2010 2011 1 2012 1 2013 20147 I GM-16 1 1.13 1 1.20 0.29 1 0.71 1 1.68 1 1.37 1 0.88 1 1.06 1 YNPS 2014 Annual REO Report Page 23 of 27
Figure 4.5 Annual Dose Trend at GM-17 GM-17 30.00 25.00 20.00 E 15.00
-- $--GM-17 10.00
-U-limit 5.00 1.14 1.54 0.86 1.54 1.57 L.uo 1.34 0.57 0.00 2007 2008 2009 2010 2011 2012 2013 2014 Year Annual Doses (mrem/yr)
Location 2007 2008 2009 2010 2011 2012 2013 2014 GM-17 1.14 1.54 0.86 1.34 1.57 1.08 1.34 0.57 YNPS 2014 Annual REO Report Page 24 of 27
Figure 4.6 Annual Dose Trend at GM-21 GM-21 30.00 25.00 1 --
m - m n n n -_
20.00 15.00 i --- GM-21 10.00
-- limit 5.00 7 1.20 0.74 0.97 0.94 1.00 0.91 1.40 0.57 0.00 2007 2008 2009 2010 2011 2012 2013 2014 year Annual Doses (mrem/yr)
Location 2007 2008 2009 2010 2011 2012 2013 2014 GM-21 1.20 0.74 0.97 0.94 1.00 0.91 1.40 0.57 YNPS 2014 Annual REO Report Page 25 of 27
5.0 ANALYSIS OF ENVIRONMENTAL RESULTS 5.1 Sampling Program Deviations A sampling program deviation is defined as samples that are unobtainable due to hazardous conditions or to malfunction of sampling equipment. Such deviations do not compromise the program's effectiveness and in fact are considered insignificant with respect to what is normally anticipated for this Radiological Environmental Monitoring Program.
There were two deviations in the sampling program in 2014.
- 1. The TLD at location GM-1 6 was not present for retrieval at the end of the year due to the tree it was mounted on was taken down by a beaver. The average of the year 2013 GM-1 6 readings were used as the value for the second half of 2014.
- 2. The incorrect TLD model was deployed at YNPS in 2014. At the time of the second quarter TLD change-out at the Connecticut Yankee and Maine Yankee ISFSI sites, it was discovered that the wrong type TLD (model BT36) was deployed instead of the requested TLD (model BT17). The model BT36 was'also deployed at YNPS in 2014. A condition report was initiated and parallel testing at those two sites was initiated for the remainder of 2014. The results of the parallel testing concluded that the variation between the BT17 and BT36 TLD readings is insignificant and consistent with the variations observed in the past BT1 7 TLD readings.
5.2 Direct Radiation Pathway 5.2.1 Annual Dose Trends Direct radiation is continuously measured at 6 indicator locations surrounding the YNPS ISFSI, along with 1 control location at Number Nine Road using thermoluminescent dosimeters (TLDs). These dosimeters are collected semi-annually for readout at the NVLAP certified dosimetry services vendor.
Review of Figures 4.1 through 4.6 shows no significant difference in annual doses over time at the indicator locations and their relation to the 25 mrem/yr limit.
YNPS 2014 Annual REO Report Page 26 of 27
5.2.2 Direct Doses from ISFSI Operations The ODCM specifies that a cumulative dose estimate from direct radiation is required to be determined semi-annually. This dose estimate is the potential dose to any real member of the public that could use portions of the site or be present adjacent to the site for recreational activities throughout the year. The ODCM states that direct exposure above background can be estimated by subtracting the average TLD value of the control station from the indicator location measurements. As in previous years, the 2014 dose estimate assumes a total of 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> occupancy for the dose calculation; of which 250 hours0.00289 days <br />0.0694 hours <br />4.133598e-4 weeks <br />9.5125e-5 months <br /> are used in both the first and second half-years. The most likely location for exposure to a member of the public from the ISFSI is in Sherman Reservoir for boating and fishing; however, the time estimates are conservatively applied to all monitoring locations.
Table 4.3 presents the results of the dose calculations. The highest calculated dose is at Station ID number GM-15. The maximum calculated annual dose at this location is 1.77 mrem. This value is only 7 percent of the 25 mrem per year limit. This represents a conservative dose estimate because a member of the public would normally be situated further away in the reservoir.
6.0 REFERENCES
- 1. USNRC Radiological Assessment Branch Technical Position, "An Acceptable Radiological Environmental Monitoring Program," Revision 1, November 1979.
- 2. Yankee Nuclear Power Station Offsite Dose Calculation Manual, Revision 22.
- 3. 40 CFR Part 190, "Environmental Radiation Protection Standards for Nuclear Power Operation".
- 4. 10 CFR Part 72.104, "Criteria for Radioactive Materials in Effluents and Direct Radiation from an ISFSI or MRS".
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