ML101390116

Entergy Vermont Yankee, Area of Tritium Impacts in Shallow Groundwater, Figure 4

ML101390116
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	04/15/2010
From:	GZA GeoEnvironmental
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2010-0209
Download: ML101390116 (1)

Text

LEGEND 7O0 WELLO VERMONT YANKEE BEDROCK OL W DRINKING WATER WELL

/ - OFF-LINE FOR 0 I GZ-IO PRECAUTIONARY REASONS MONITORING WELL INSTALLED 2 JANUARY-MARCH 2010 GROUNDWATER ELEVATION IN FEET (FEBRUARY 26,2010)

GZ-l+GPI MONITORING WELL INSTALLED NOVEMBER 2007 320O+ OTHER VERMONT YANKEE

'7 MONITORING WELL 225----- INFERRED GROUNDWATER CONTOUR IN FEET (FEBRUARY 26,2010)

- INFERRED AREA OF TRITIUM ACTIVITY IN SHALLOW GROUNDWATER (>MDA)

INFF=RRFnltf=hlTFRI INIFtflF TRITIUM IMPACT IN SHALLOW GROUNDWATER 0100 20W SCALE IN FEET NOTES:

1. AREA OF TRITIUM ACTIVITY IN SHALLOW GROUNDWATER INFERRED FROM DATAFROM WIDELY SPACED MONITORING WELLS. ACTUALCONDITIONS MAYVARY. RECENTLY, A TRACE LEVEL OF TRITIUM ACTIVITY HAS BEEN INCONSISTENTLY DETECTED AT GZ-1 1.

2. GROUNDWATER CONTOURS AND FLOW DIRECTIONS INFERRED FROM GROUNDWATER ELEVATION MEASUREMENTS COLLECTED FROM WIDELY SPREAD MONITORING WELLS ON FEBRUARY 26,2610. ACTUAL CONDITIONS MAY VARY.

3. IT SHOULD BE NOTED THAT WHILE THE COB WELLAND GZ-14D ARE LOCATED WITHIN THE SHADED AREA SHOWN, BOTH WELLS ARE SCREENED BELOW THE SHALLOW GROUNDWATER ZONE AND NOT WITHIN IT. GZ-14D IS A DEEP OVERBURDEN WELL AND HAS GENERALLY SHOWN NO DETECTABLE LEVELS OF TRITIUM. THE COB WELL IS A DEEP BEDROCK WELL THAT WAS FORMERLY USED FOR WATER SUPPLY, AND HAS SHOWN NO DETECTABLE LEVELS OF TRITIUM. LOW LEVELS OF TRITIUM HAVE RECENTLY BEEN DETECTED AT THE DEEP OVERBURDEN WELL, GZ-13D, ALONG THE NORTH FLANK OF THE AREA OF TRITIUM ACTIVITY.

4. FLUCTUATIONS IN LOCAL GROUNDWATER ELEVATIONS MAY OCCUR OVER TIME DUE TO RAINFALL,SEASONAL CHANGES IN THE RATE OF EVAPOTRANSPIRATION, RELEASE RATES FROM THE LOCAL DAM, AND OTHER VARIOUS FACTORS.

5. THE LOCATIONS AND REFERENCE ELEVATIONS OF MONITORING WELLS AND DRINKING WATER WELLS WERE SURVEYED BY SOUTHERN VERMONT ENGINEERING OF BRATTLEBORO VERMONT (EXCEPT GZ-20 AND GZ-21, WHICH WERE ESTIMATED FENDING FORMAL SURVEY).

6. BASE PLAN, INCLUDING SITE TOPOGRAPHY, PROVIDED TO GZA IN ELECTRONIC FORMAT BYVERMONT YANKEE.

ENTERGY VERMONT YANKEE VERNON, VERMONT AREA OF TRITIUM IMPACTS IN SHALLOW GROUNDWATER

• l ENTERGY VERMONT YANKEE

-, VERNON, VERMONT 4