ML20248K195
| ML20248K195 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 12/31/1996 |
| From: | NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML20248K150 | List: |
| References | |
| NUDOCS 9806100026 | |
| Download: ML20248K195 (9) | |
Text
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I Praire Island Nuclear RADIATION ENVIRONMENTAL Rev.I
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Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT 4
Appendix D
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i APPENDIX D Special Ground and Well Water Samples i
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j Praire Island Nuclear RADIATION ENVIRONMENTAL Rev.1 l
Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT l
Appendix D
1.0 INTRODUCTION
This revision corrects the tritium numbers from October 1994 through 1996 that were reported in Tritium Units instead of pCi/L.- One (1) Tritium Unit equals 3.2 pCi/L. All previously reported tritium numbers from October 1994 through 1996 have been multiplied by 3.2.
This appendix to the Radiation Environmental Monitoring Program Annual Report to the United States Regulatory Commission summarizes and interprets results of the special well and seepage water samples taken at the Prairie Island Nuclear Generating Plant, Red Wing, Minnesota, during the period January - December,1996. This supplemental special sampling program was established in December of 1989 when higher than expected levels of tritium were detected in a nearby residence well sample.
Tabulation's of the special sampling program individual analyses made during the year are
< included in this appendix. A summary table of tritium analyses is also included in this appendix.
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Praire Island Nuclear RADIATION ENVIRONMENTAL Rev.1 Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT Appendix D l
2.0
SUMMARY
This special sampling program was established following the detection of tritium in a residence well water sample south of the PINGP during 1989. This program is described and the results for 1996 are summarized and discussed.
Program findings for 1996 detect low levels of tritium in nearby residence wells and some ground water scepage samples at or near the expected natural background levels. The 1996 sample results ranged from <l9 pCi/L to 490 pCi/L. All tritium results are far below the Environmental Protection Agency's drinking water standard of 20,000 pCi/L and present no harm to any members of the public.
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Praire Island Nuclear RADIATION ENVIRONMENT!
Rev.1 Generating Plant MONITORING PROGRAM 1996 ANNUA!. REPORT Appendix D 3.0 Snecial Tritium Samnling Program 3.1 Program Design and Data Intemretation The purpose of this sampling program is to assess the impact of any tritium leaching into the environment (ground water system) from the PINGP discharge canal. For this purpose, special water samples are collected and analyzed for radioactive content.
3.2 Program Description The sampling and analysis schedule foi the special water sampling program is summarized in Table 4.1 and briefly reviewed below. Table 4.2 defines the additional sample locations and codes for the special water sampling program.
Special well and ground water samples were collected semi-annually at nine locations:
one sample from the PINGP Environmental Laboratory (P-30); one from the nearest residence deep well (P-24d, Suter residence); two ground water seepages from near Birch Lake (P-31 and P-32); well water from the Prairie Island Training Center (P-26); well water from the Prairie Island Indian Community (P-8); and three other nearby residences (P-27, Nauer residence; P-28, Allyn (Perkins) residence; P-29, Childs residence). The Rohl farm well (part of the quarterly REMP sampling) is used as a control location for these special samples.
In order to detect low levels of tritium at or below natural background levels, analyses of the samples have been contracted to a laboratory (University of Waterloo Laboratories) capable of detecting tritium concentrations down to 19 pCi/L.
l 3.3 Program Execution The special water sampling was executed as described in the preceding section.
3.4 Program Modifications The sampling of water from the Prairie Island Indian Community well system was added to this program in 1996.
3.5 Results and Disc.usSIDD D-4
Praire Island Nuclear RADIATION ENVIRONMENTAL Rev.1 Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT Appendix D Results obtained show tritium in well water and ground water samples at or near expected natural background levels. Table 4.4 provides the complete data table of results for each period and sampling location.
The tritium level annual averages have shown a downward trend since the special sampling begun in 1989. Annual averages for the nearest resident south of the plant were: 1430 pCi/L in 1989,1360 pCi/L in 1990,960 pCi/L in 1991,835 pCi/L in 1992,516 pCi/L in 1993,370 pCi/L in 1994,170 pCi/L in 1995 and 64 pCi/L in 1996.
The 1996 levels are near or within the range of expected background tritium levels in shallow ground water and surface water due to tritium concentrations measured in precipitation. Sampling points in North America have shown tritium concentrations in precipitation ranging from 5 pCi/L to 157 pCi/L (Environmental Isotope Data No.10; World Survey ofIsotope Concentration in Precipitation (1988-1991)).
The higher level results at Suter and Birch Lake in 1989 were possibly due to seepage from the PINGP discharge canal water into the ground water. This is thought to occur due to the elevation difference between the Vermillion River and the discharge canal. The Suter residence is located between the discharge canal and Birch Lake, which connects to the Vermillion River. The PINGP discharge canal piping was lengthened during 1991, so that liquid discharges from the plant are released near the end of the discharge canal, diffused and discharged to the Mississippi River. In 1992, the underground liquid discharge pipe from the plant to the discharge canal piping was replaced with a double walled leak l
detectable piping system. It is expected that these modifications will eliminate the suspected radioactive effluent flow into the local ground water. The 1996 sample results supports this expectation.
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f Praire Island Nuclear RADI ATION ENVIRONMENTAL Rev.1 Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT i
Appendix D l
l Table D-4.1 Sample collection and analysis program for special well and seepage water samples,
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Prairie Island Nuclear Generating Plant,1996.
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Location codes Collection :ype Analysis typec ar.d type and frequencyb l
a Well water 8
P-24d, P-25 (C),
G/SA H-3 semi-annual P-26, P-27, P-28, j
P-29, P-30, P-8
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Ground water 2
P-31, P-32 G/SA H-3 a Location codes are defined in table D-4.2. Control Station are indicated by (C). All other stations are indicators.
b Collection type is codes as follows: C/ = continuous; G/ = grab. Collection frequency is coded as follows: W = weekly; M = monthly; Q = quarterly; SA = semi-annually; A =
annually; X = no specified frequency or one time.
c Analysis type is coded as follows: GB = gross beta; GS = gamma spectroscopy; H-3 =
i tritium; I-131 = iodine 131.
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Praire Island Nuclear RADIATION ENVIRONMENTAL Rev.I Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT Appendix D Table D-4.2.
Sampling locations for special well and seepage water samples, Prairie Island Nuclear Generating Plant,1996.
Code typea Collection site Type of sampleb Distancc and l
direction from reactor P-24d Suter residence, deep well WW 0.6 mi. @ 158 /SSE P-25 C
Rohl farm WW 12.9 mi @ 352 /N P-26 PITC WW 0.4 mi. @ 258 /WSW P-27 Nauer residence WW 0.9 mi. @ 154 /SSE P-28 Allyn (Perkins)
WW l.0 mi. @ 152 /SSE residence P-29 Childs residence WW l.2 mi. @ 149 /SSE P-30 PINGP Environmental Laboratory WW 0.2 mi. @ 32 /NNE P-31 Birch Lake Seepage #1 GW 0.7 mi. @ 179 /S P-32 Birch Lake Seepage #2 GW 0.8 mi. @ 169 /SSE P-8 Prairie Island Indian Community Well WW l.0 mi. @ 321 /Whv l
a "C" denotes control location. All other locations are indicators.
b Sample codes: WW = Well water; GW = Ground Water.
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M Praire Island Nuclear RADIATION ENVIRONMENTAL Rev.1
' Generating Plant MONITORING PROGRAM 1996 ANNUAL REPORT Appendix D Table D-4.3 Radiation Environmental Monitoring Program Summary: Special well and seepage water samples.
Name of Facility Prairic Island Nuclear Power Station Docket No.
50-282.50-3 %
1.ocation of Facility Goodhue, Mmnesota Reporting Period Eary. December 1996 (County, State)
Indicator Location with liighest Control Number Sample Type and Locations Semi-Annual Mean locations Non-Type.
Number of LLD Mean (F)c Mean (F)c -
Mean (F)e Routine b
(Units)
Analyses Range Range Range Results' e
Locationd a
e Well Water 11-3 16 19 80 (11/14)
P-29, 106 (2/2) 64 (2/2) 0 (pCi/L)
(32-138)
Child well, (96-112)
(58 70) 1.2 mi. @ 149 /SSE 4
Ground Water 11-3 6
19 362 (4/4)
P-32, Dirch Lake 483 (2/2) 64 (2/2) 0 (pCi/L)
(112 368)
Seepage #2, (477-490)
(58-70) 0 0.8 mi. @ 169 /SSE a 11-3 = tritium b
LLD = Nominal lower limit of detection based on 4.66 sigma error for background sample. Value shown is lowest for the period.
e Mean and range are based on detectable measurements only. Fraction of detectable measurements at specified locations is indicated in parentheses (F).
d locations are specified: (1) by name, and code (Table 2) and (2) by distance, direction and sector relative to reactor site.
- Non-routine results are those which exceed ten times the control station value.
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1996 ANNUAL REPORT I
Appendix D Table D-4.4 Radiological Environmental M; emg Program, Complete Data Table,1996.
SAMPLE DATES MAY 1996 OCT.1996 SAMPLE LOCATIONS pCi/L pCi/L Suter residence 45 83 Rohl Farm (Control) 70 58 PITC 67 138 Nauer residence 67 67 Allyn (Perkin) residence 74 93 Child residence 96 112 Environmental Lab 32
<19 Birch Lake Seepage #1 112 368 Birch Lake Seepage #2 477 490 Prairie Island Indian
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<19 Community Well l
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